Pesticide residues have seriously damaged the natural environment and social security.Here,we prepared the efficient functional biochar(FB)for sulfonylurea herbicides from cotton straw cellulose(CSC)by hydrothermal ca...Pesticide residues have seriously damaged the natural environment and social security.Here,we prepared the efficient functional biochar(FB)for sulfonylurea herbicides from cotton straw cellulose(CSC)by hydrothermal carbonization with the methacrylic acid.The molecular simulation of FB indicated thatπ-πelectron-donor-acceptor(EDA)interaction and formation of charge-assisted H-bond were both the main factors for effective adsorption process.The adsorption process can match the pseudo-second-order kinetic equation and Freundlich model.The whole process is physical adsorption,spontaneous and rapid,and can quickly reach equilibrium.The FB with carbon-oxygen functional groups and aromatic conjugated structures can remove pesticides in water very quickly(within 30 s),with effective adsorption over 95%of Sulfonylurea herbicides(SUHs).Therefore,functional FB might be an effective way to get excellent absorbent for pesticide treatment.展开更多
Biochar is a widely known soil amendment.Here we synthesize the available information on influence of biochar application on different soil properties and crop productivity using meta-analysis.Global data on influence...Biochar is a widely known soil amendment.Here we synthesize the available information on influence of biochar application on different soil properties and crop productivity using meta-analysis.Global data on influence of biochar applications on different soil physical,chemical,microbial properties,and crop productivity were extracted from literature and statistically analyzed.Based on selection criteria,59 studies from the literature published between 2012 and 2021 were selected for the meta-analysis.Correlations were developed between effect size of biochar application on different soil properties and crop productivity.Application of biochar increased soil pH,cation exchange capacity,and organic carbon by 46%,20%,and 27%,respectively,with greater effects in coarse and fine-textured soils.Effects on chemical properties were variable among biochar prepared from different feedstocks.Among physical properties,biochar application reduced bulk densities by 29%and increased porosity by 59%.Biochar prepared at higher pyrolytic temperatures(>500℃)improved bulk density and porosity to greater extents(31%and 66%,respectively).Biochar prepared at lower pyrolytic temperatures(<500℃)had a greater effect on microbial diversity(both bacterial and fungal),with more diverse bacterial populations in medium and coarse textured soils,while fungal diversity increased in fine textured soils.Biochar applications increased crop productivity only in fine and coarse textured soil.The effect size of biochar application on crop productivity was correlated with responses to physical properties of soils.The meta-analysis highlighted the need to conduct long-term field experiments to provide better explanations for changes in biochar properties as it undergoes aging,its longer-term effects on soil properties,and timing of re-application of different biochars.展开更多
The application of Fe-Mn-modified biochar for the remediation of Cd-contaminated soil over long time periods has been little studied.In this paper,we describe the performance of coconut-shell-derived biochar modified ...The application of Fe-Mn-modified biochar for the remediation of Cd-contaminated soil over long time periods has been little studied.In this paper,we describe the performance of coconut-shell-derived biochar modified with ferromanganese in relation to soil Cd stabilization and rice Cd bioaccumulation during a 3-year laboratory study.Different application dosages(0.05-0.5 wt%)and different rice varieties(the early and late rice)are also considered.The results show that ferromanganese is mainly loaded in biochar pores as MnFe_(2)O_(4),and that it decreases the specific surface area(SSA)and total pore volume of biochar.Ferromanganese biochar(0.5 wt%)applied to paddy soil is more effective than the same dose of pristine biochar in decreasing the soil-exchangeable Cd fraction(27.42-41.92%vs 22.56-33.85%),predominantly by decreasing soil Eh and increasing root Fe plaques.Ferromanganese biochar application helps to reduce Cd bioaccumulation in rice,especially in the grain(up to 48.6%-61.0%),and grain Cd levels(0.2 mg/kg)are all within the acceptable limit for food security in China.It is shown that ferromanganese modification and application can maintain soil at low redox status,keep root Fe plaques at a high level,and may also increase the stability of pristine biochar.All of these effects contribute to maintaining its high remediation efficiency over a 3-year inoculation period.The results presented in this paper demonstrate the potential appli-cations of ferromanganese biochar in soil remediation and the improvement of food safety.展开更多
In recent years,numerous investigations have explored the use of biochar for the removal of organic and inorganic pollutants in single component systems.Biochar is a carbonaceous material produced from waste biomass,m...In recent years,numerous investigations have explored the use of biochar for the removal of organic and inorganic pollutants in single component systems.Biochar is a carbonaceous material produced from waste biomass,mainly by thermochemical conversion methods.This material was used as a biosorbent in various removal processes of pollutants,and its efficiency was strongly influenced by the characteristics of the biomass feedstock.This review integrates the recent works of literature to understand the biosorption behaviour of dyes onto biochar-based biosorbents.The factors influencing the biosorption process and the mechanisms describing the biosorption behaviours of the biochar have been broadly reviewed.Furthermore,the biosorption models can be used to comprehend the competence of the biochar as biosorbent for dye removal techniques.展开更多
Biochar pores in the micrometer range(1-100μm)derive from cellular structures of the plant biomass subjected to pyrolysis or can be the result of mechanical processing,such as pelleting.In this study,synchrotron X-ra...Biochar pores in the micrometer range(1-100μm)derive from cellular structures of the plant biomass subjected to pyrolysis or can be the result of mechanical processing,such as pelleting.In this study,synchrotron X-ray microtomography was used to investigate the internal pore structure of softwood pellet biochar produced by slow pyrolysis at 550 and 700°C.The microtomographic data sets consisted of 2025 images of 2560×2560 voxels with a voxel side length of 0.87μm.The three-dimensional reconstructions revealed that pelleting and pyrolysis significantly altered the pore structures of the wood feedstock,creating a network of connected pores between fragments that resembled the wood morphology.While higher pyrolysis temperature increased the specific surface area(as determined by BET nitrogen adsorption),it did not affect the total observed porosity.Multifractal analysis was applied to assess the characteristics of the frequency distribution of pores along each of the three dimensions of reconstructed images of five softwood pellet biochar samples.The resulting singular-ity and Rényi spectra(generalized dimensions)indicated that the distribution of porosity had monofractal scaling behavior,was homogeneous within the analyzed volumes and consistent between replicate samples.Moreover,the pore distributions were isotropic(direction-independent),which is in strong contrast with the anisotropic pore structure of wood.As pores at the scale analyzed in this study are relevant,for example,for the supply of plant accessible water and habitable space for microorganisms,our findings combined with the ability to reproduce biochar with such pore distribution offer substantial advantages in various biochar applications.展开更多
Removal of antimonite[Sb(Ⅲ)]from the aquatic environment and reducing its biotoxicity is urgently needed to safeguard environmental and human health.Herein,crawfish shell-derived biochars(CSB),pyrolyzed at 350,500,an...Removal of antimonite[Sb(Ⅲ)]from the aquatic environment and reducing its biotoxicity is urgently needed to safeguard environmental and human health.Herein,crawfish shell-derived biochars(CSB),pyrolyzed at 350,500,and 650℃,were used to remediate Sb(Ⅲ)in aqueous solutions.The adsorption data best fitted to the pseudo-second-order kinetic and Langmuir isotherm models.Biochar produced at 350℃(CSB350)showed the highest adsorption capacity(27.7 mg g^(−1)),and the maximum 78%oxidative conversion of Sb(Ⅲ)to Sb(V).The adsorption results complemented with infrared(FTIR),X-ray photoelectron(XPS),and near-edge X-ray absorption fine structure(NEXAFS)spectroscopy analyses indicated that the adsorption of Sb(Ⅲ)on CSB involved electrostatic interaction,surface complexation with oxygen-containing functional groups(C=O,O=C-O),π-πcoordination with aromatic C=C and C-H groups,and H-bonding with-OH group.Density functional theory calculations verified that surface complexation was the most dominant adsorption mechanism,whilstπ-πcoordination and H-bonding played a secondary role.Furthermore,electron spin resonance(ESR)and mediated electrochemical reduction/oxidation(MER/MEO)analyses confirmed that Sb(Ⅲ)oxidation at the biochar surface was governed by persistent free radicals(PFRs)(•O_(2)^(−)and•OH)and the electron donating/accepting capacity(EDC/EAC)of biochar.The abundance of preferable surface functional groups,high concentration of PFRs,and high EDC conferred CSB350 the property of an optimal adsorbent/oxidant for Sb(Ⅲ)removal from water.The encouraging results of this study call for future trials to apply suitable biochar for removing Sb(Ⅲ)from wastewater at pilot scale and optimize the process.展开更多
This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced ...This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced oxidation processes(AOP).Iron,copper,and two different cobalt-based catalysts were prepared and evaluated.The catalysts were supported on a biochar obtained from the pyrolysis of woody pruning wastes.They were characterized by C,H,and N elemental analysis,X-Ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM).The metal content in each catalyst was determined by means of atomic absorption spectroscopy(AAS).The degradation reac-tions of benzoic acid(BA),catechol(C),and cinnamic acid(CA)were carried out in a lab scale batch glass reactor and were followed by UV-Visible spectroscopy(UV-Vis).A colorimetric technique was employed to verify the presence of oxidant during the reaction progress.The catalyst/oxidant optimal ratio was determined for the cobalt catalysts.The mineralization degree of the pollutants after the degradations was verified by means of total organic carbon(TOC)content in the residual liquids.After 4 h of reaction,the maximum mineralization was reached when C was treated with a cobalt-based catalyst(>80%),and its stability was evaluated through successive cycles of use.展开更多
Graphene-based composite aerogel doped with other low-cost materials can reduce the cost and promote the use in water treatment.This work prepared ball-milled biochar/reduced graphene oxide aerogel(BC/rGA)using GO and...Graphene-based composite aerogel doped with other low-cost materials can reduce the cost and promote the use in water treatment.This work prepared ball-milled biochar/reduced graphene oxide aerogel(BC/rGA)using GO and low-cost ball-milled biochar(BC)in a certain proportion with the freeze-thawing technique and sol-gel method,and applied BC/rGA on the Cr(Ⅵ)removal from aquatic environments.The characterization results showed that aerogel had a honeycomb briquette three-dimension(3D)and mesoporous structure with interconnected pores,and proved the preparation progress of aerogel in principle.Compared with GO,rGA and BC/rGA had better adsorption performance with 3D structure and well-developed pores,and BC/rGA with the mixture ratio of BC and GO of 1:4 was more appropriate.The adsorption kinetics data of rGA and BC/rGA_((1:4))were fitting well with the pseudo-second-order model(R^(2)>0.951),and the isotherm adsorption results were fitting the Langmuir model well(R^(2)>0.974).The results demonstrated that the adsorption process was monolayer and endothermic adsorption involving chemisorp-tion.Additionally,the adsorption capacities of rGA and BC/rGA_((1:4))at solution pH 2 were 3.71 and 3.89 times greater than those at solution pH 8,respectively.High background ion strength and low temperature slightly inhibited the adsorption of Cr(Ⅵ)by both rGA and BC/rGA_((1:4)).The adsorption mechanisms of Cr(Ⅵ)on rGA and BC/rGA_((1:4))were electrostatic interaction,reduction and ion exchange.The use of BC/rGA could reduce the cost and promote the green reuse of agricultural waste.Overall,BC/rGA could be used as a promising green adsorbent alternative for the feasible treatment of heavy metal contaminated water.展开更多
Biochar is the carbon-rich product obtained from the thermochemical conversion of biomass under oxygen-limited conditions.Biochar has attained extensive attention due to its agronomical and environmental benefits in a...Biochar is the carbon-rich product obtained from the thermochemical conversion of biomass under oxygen-limited conditions.Biochar has attained extensive attention due to its agronomical and environmental benefits in agro-ecosystems.This work adopts the scientometric analysis method to assess the development trends of biochar research based on the literature data retrieved from the Web of Science over the period of 1998-2018.By analysing the basic characteristics of 6934 publications,we found that the number of publications grew rapidly since 2010.Based on a keyword analysis,it is concluded that scholars have had a fundamental recognition of biochar and preliminarily found that biochar application had agronomic and environmental benefits during the period of 1998-2010.The clustering results of keywords in documents published during 2011-2015 showed that the main research hotspots were“biochar production”,“biochar and global climate change”,“soil quality and plant growth”,“organic pollutants removal”,and“heavy metals immobilization”.While in 2016-2018,beside these five main research hotspots,“biochar and composting”topic had also received greater attention,indicating that biochar utilization in organic solid waste composting is the current research hotspot.Moreover,updated reactors(e.g.,microwave reactor,fixed-bed reactor,screw-feeding reactor,bubbling fluidized bed reactor,etc.)or technologies(e.g.,solar pyrolysis,Thermo-Catalytic Reforming process,liquefaction technology,etc.)applied for efficient energy production and modified biochar for environmental remediation have been extensively studied recently.The findings may help the new researchers to seize the research frontier in the biochar field.展开更多
Biological nitrogen fixation(BNF)can help replenish available nitrogen(N)in cropland and reduce the use of chemical N fertilizers,with diazotrophs playing an important role.However,the response of diazotroph community...Biological nitrogen fixation(BNF)can help replenish available nitrogen(N)in cropland and reduce the use of chemical N fertilizers,with diazotrophs playing an important role.However,the response of diazotroph community and BNF activity in biochar amendment soil,especially in the deep soil horizon,are poorly understood.In this study,soil samples were collected from topsoil(0-20 cm)and subsoil(20-40 cm)in the field experiment(established in 2013)comprising treatments with no chemical fertilizer(CK),chemical fertilizer(NPK),biochar(BC),and biochar plus chemical fertilizers(BNPK).Here,we investigated the diazotroph community using real-time PCR and high-throughput sequencing of the nifH gene,and assessed the soil N_(2)fixation rate(R_(Nfix))using acetylene reduction assay(ARA).Results showed that in the topsoil,the treatments with biochar significantly increased nifH gene copies and R_(Nfix),which was consistent with the increased soil organic matter(SOM),total carbon-to-nitrogen ratio(C/N),dissolved organic carbon(DOC)and pH.In the subsoil,applying chemical fertilizers(NPK)strongly decreased R_(Nfix),but had no effect on diazotroph abundance;in contrast,biochar application(BC)had no effect on R_(Nfix),but suppressed the growth of bacteria and diazotrophs while increasing the abundance of Rhizobiales order.Diazotroph and bacterial gene copies were significantly and positively correlated in both top-and sub-soil,and they were mainly influenced by SOM and total nitrogen(TN).In addition,soil nitrate nitrogen(NO_(3)^(−)-N)was the major factor in shaping the vertical stratification of diazotroph community structure.Although nifH gene abundance was significantly cor-related with R_(Nfix)in the topsoil,the structure equation modeling(SEM)showed the highest correlation between diazotroph community structure and R_(Nfix).Hence,we suggested that soil carbon and nitrogen sources were the key factors correlated with changes in the vertical pattern of diazotroph abundance.Biochar induced the dominant diazotroph community succes-sion and increased soil carbon content and pH,which contributed to the BNF activity.Changes in the BNF activity were driven by the variation in diazotroph community structure.展开更多
Biochar amendment and substituting chemical fertilizers with organic manure(organic substitution)have been widely reported to increase crop production and decrease reactive nitrogen(Nr)loss including nitrous oxide(N_(...Biochar amendment and substituting chemical fertilizers with organic manure(organic substitution)have been widely reported to increase crop production and decrease reactive nitrogen(Nr)loss including nitrous oxide(N_(2)O),nitric oxide(NO),and ammonia(NH3)emissions,and N runoff and leaching.However,few comprehensive evalua-tions have been performed on the environmental and economic aspects of biochar amendment or organic sub-stitution.Here,we studied the comprehensive effects of biochar amendment,organic substitution,and biochar amendment combined with organic substitution on crop production,Nr loss,and net ecosystem economic benefit(NEEB)in intensive vegetable production by integrating life-cycle assessment for Nr footprints,empirical models for NH3 volatilization and N runoff and leaching derived from peer-reviewed publications and validated by the current measurements and direct field measurement for N_(2)O and NO emissions during 5 consecutive years of vegetable crop rotations.Five fertilization treatments were applied(SN:synthetic fertilizer application;SNB:SN plus 20 t ha^(−1)biochar amendment;SNM:substituting 50%of chemical N fertilizer with organic manure;SNMB:SNM plus 20 t ha^(−1)biochar amendment;and CK:no fertilizer or biochar addition).Compared with the SN,the SNB increased vegetable yield(28.4%,p<0.05;interannually varying from−10 to 74.9%)and nitrogen use efficiency(29.2%,interannually varying from−39.7 to 150.4%),and decreased field Nr loss(45.4%,p<0.01;interannually varying from−40.3 to 78.4%),and thus improved NEEB by 7.1%;meanwhile,the SNM increased vegetable yield(11.6%,interannually varying from−5.4 to 27.1%)and nitrogen use efficiency(45.7%,p<0.05;interannually varying from 2.3 to 154%),reduced field Nr loss(34.9%,p<0.01;interannually varying from 8.4-39.0%),and thus improved NEEB by 17.8%(p<0.05)compared to the SN,being 56.0×10^(3)Chinese Yuan(CNY)ha^(−1)crop^(−1).Due to the high foreground Nr loss during organic manure production and high input costs of biochar production,the SNMB decreased the NEEB by 8.0%as compared to the SN.Moreover,the SNB and SNM improved vegetable qualities by increasing protein,soluble sugar,and vitamin C contents while decreasing nitrate content(p<0.05).Therefore,single application of biochar amendment or organic substitution would achieve better NEEB and product quality in vegetable production.展开更多
Sewage sludge(SS)is a residual/semi-solid material produced from industrial and municipal wastewater treatment processes.SS contains a high content of lipids and earth alkaline metals that can be used as catalysts for...Sewage sludge(SS)is a residual/semi-solid material produced from industrial and municipal wastewater treatment processes.SS contains a high content of lipids and earth alkaline metals that can be used as catalysts for various chemical applications;however,its valorization has rarely been the focus of research.This study demonstrates that SS could be a promising raw material for biodiesel production and a biochar catalyst to promote the reaction kinetics of alkylation.Thermally induced transesterification of the SS extract(SSE)was performed in comparison with the conventional homogeneous reaction.SS biochar was fabricated via pyrolysis.The highest yield(33.5 wt.%per SSE)of biodiesel production was achieved in 1 min of reaction at 305℃via thermally induced transesterification in the presence of SS biochar,while the yield of biodiesel from(trans)esterification with 5 wt.%H_(2)SO_(4)was less than 1%even after 24 h.The reaction kinetics(<1 min)of thermally induced transesterification was extraordinarily faster than that of conventional transesterification(3-24 h).The porous structure and high content of alkaline species in the SS biochar expedited the reaction kinetics.Consequently,the integrated/hybridized process for thermally induced transesterification and pyrolysis of the solid residue of SS was experimentally proved for the valorization of SS in this study.Considering that SS is being disposed of as a waste material and generates toxic chemicals in the environment,its valorization into value-added biodiesel and a catalyst could be an environmentally benign and sustainable technique.展开更多
The effects of uncoated and Fe-coated biochars(BC)on the removal of bacteria,microspheres,and dissolved reactive phosphorus(DRP)in sand filters were compared.Filters were packed with 1.2 or 2.0-mm sand mixed with 30%(...The effects of uncoated and Fe-coated biochars(BC)on the removal of bacteria,microspheres,and dissolved reactive phosphorus(DRP)in sand filters were compared.Filters were packed with 1.2 or 2.0-mm sand mixed with 30%(vol/vol)uncoated BC,Fe-coated BC,or a control without BC.Removal of E.coli,Salmonella,and Enterococci increased from 23,42,and 25%in the unamended 1.2-mm sand to 48,80,and 75%in the uncoated BC treatment,though only the increase for Enterococci was significant(p<0.05).For the Fe-coated BC,removal efficiencies were 89,93,and 94%,respectively,which were all significantly(p<0.05)greater than the unamended sand but only the removal of E.coli was significantly greater than the uncoated BC sand filter.For the 2.0-mm sands,the only significant increase in removal following BC addition was observed for Salmonella.Trends in microsphere removal were generally consistent with bacteria.Removal of DRP in the unamended and uncoated BC filters was 33 and 13%(p>0.05),respectively,whereas removal in the Fe-coated BC filters was 98%(p<0.05).Results from batch sorption experiments indicate that both BCs similarly increased bacterial sorption to sand.In contrast,DRP sorption to the unamended and uncoated BC-amended sands were similar(p>0.05)with DRP sorption to the Fe-coated BC-amended sand being significantly greater(p<0.05).Results indicate that Fe-coated BC is more effective at retaining DRP than bacteria and microspheres in sand filters.展开更多
Hydrogen sulfide(H_(2)S)removal has been a significant concern in various industries.In this study,food waste diges-tate-derived biochar(DFW-BC),a by-product of food waste treatment with abundant minerals,was assessed...Hydrogen sulfide(H_(2)S)removal has been a significant concern in various industries.In this study,food waste diges-tate-derived biochar(DFW-BC),a by-product of food waste treatment with abundant minerals,was assessed for removing H_(2)S from different simulated biogas containing oxygen(O_(2))and carbon dioxide(CO_(2))and under differ-ent moisture(H_(2)O)contents(0%and 20%)of biochar.The influencing mechanisms of the gas conditions combined with the moisture contents were also investigated.The results showed an H_(2)S removal of 1.75 mg g^(−1)for dry bio-char under pure H_(2)S,4.29 mg g^(−1)for dry biochar under H_(2)S+O_(2),5.29 mg g^(−1)for humid biochar under H_(2)S,and 12.50 mg g^(−1)for humid biochar under H_(2)S+O_(2).For dry DFW-BC,the high Fe content was responsible for the O_(2)enhancement.In contrast,O_(2)+H_(2)O activated the catalytic H_(2)S oxidation of the less reactive minerals(mainly Ca).The inhibition of CO_(2)on H_(2)S adsorption was not obvious for dry DFW-BC;the specific pore structure may have provided a buffer against the physisorption competition of CO_(2).However,when H_(2)O was present on DFW-BC,the changes in critical biochar properties and sulfur speciation as opposed to that without H_(2)O implied an evident occurrence of CO_(2)chemisorption.This CO_(2)chemisorption partially hindered O_(2)+H_(2)O enhancement,decreasing the H_(2)S removal capacity from 12.50 to 8.88 mg g^(−1).The negative effect was ascribed to mineral carbonation of CO_(2),neutralizing the alkaline surface and immobilizing metal oxides,which thus reduced the acceleration in H_(2)S dissociation and activa-tion in catalytic H_(2)S oxidation by O_(2)+H_(2)O.展开更多
Cadmium(Cd)and lead(Pb)contaminated soils that are used for food production can lead to metal bioaccumulation in the food chain and eventually affect human health.In these agroecosystems,means by which Cd and Pb bioav...Cadmium(Cd)and lead(Pb)contaminated soils that are used for food production can lead to metal bioaccumulation in the food chain and eventually affect human health.In these agroecosystems,means by which Cd and Pb bioavailability can be reduced are desperately required,with biochar as a proxy for bioavailability reductions.Molecular Cd and Pb sorption mecha-nisms within short-(0-2 years)or long-term(8-10 years)time periods following biochar application to a contaminated rice paddy soil were investigated.A combination of Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,and soft X-ray imaging was utilized to discern potential metal sorption mechanisms.Following both short-and long-term biochar applications,soil Cd and Pb bioavailable fractions shifted partially towards metal(hydr)oxide and carbonate pre-cipitates,and partially towards biochar-organic function group associations;oxygen-containing groups,such as C=O and O-H,appeared to bind Cd and Pb.Soft X-ray imaging results suggested that heavy metals were primarily sorbed on biochar exterior surfaces,yet given time and particle disintegration,metals sorbed onto biochar interior pore walls.Findings sug-gest that biochar may play a pivotal role in reducing long-term bioavailable Cd and Pb in contaminated soils.Observations also support previous findings that suggest biochar use can lead to reduced heavy metal transfer to plants and potentially to reduced heavy metal consumption by humans.展开更多
In paddy fields, the opposing transformation of arsenic (As) and cadmium (Cd) poses many challenges for their simultaneous remediation.In our previous study,we reported that combined biochar and zero-valent iron(ZVI)a...In paddy fields, the opposing transformation of arsenic (As) and cadmium (Cd) poses many challenges for their simultaneous remediation.In our previous study,we reported that combined biochar and zero-valent iron(ZVI)amendment had great potential for the simultaneous alleviation of As and Cd bioavailability in contaminated acid paddy soil.In this study,an As-and Cd-contaminated alkaline paddy soil was further studied,and the same ZVI-biochar mixtures amendments were applied to evaluate the impact of the mixtures on As and Cd transformation and translocation in the soil-rice system by performing pot experiments with rice.In line with our previous study,the ZVI-biochar composites significantly reduced As and Cd accumulation in different rice tissues,leading to a 42%and 47%decrease in rice grain As and Cd levels,respectively,compared with the control values.The ZVI-biochar mixtures exhibited synergistic effects of biochar and ZVI by enhancing the transformation of bioavailable As and Cd fractions into less bioavailable fractions,and by increasing iron plaque formation to reduce As and Cd bioavailability.Although the bioaccumulation and translocation factors of As and Cd in alkaline paddy soil were generally lower than those in acid paddy soil,particularly in the presence of the ZVI-biochar mixtures,the grain As and Cd levels did not achieve the desired food safety standard levels,probably related to the high soil As content and the small changes in soil pH.Nevertheless,for treating lightly and moderately contaminated paddy soils,ZVI-biochar mixtures can still be a good choice in the future.展开更多
The transformation of mercury(Hg)into the more toxic and bioaccumulative form methylmercury(MeHg)in soils and sediments can lead to the biomagnification of MeHg through the food chain,which poses ecological and health...The transformation of mercury(Hg)into the more toxic and bioaccumulative form methylmercury(MeHg)in soils and sediments can lead to the biomagnification of MeHg through the food chain,which poses ecological and health risks.In the last decade,biochar application,an in situ remediation technique,has been shown to be effective in mitigating the risks from Hg in soils and sediments.However,uncertainties associated with biochar use and its underlying mechanisms remain.Here,we summarize recent studies on the effects and advantages of biochar amendment related to Hg biogeochemistry and its bioavailability in soils and sediments and systematically analyze the progress made in understanding the underlying mechanisms responsible for reductions in Hg bioaccumulation.The existing literature indicates(1)that biochar application decreases the mobility of inorganic Hg in soils and sediments and(2)that biochar can reduce the bioavailability of MeHg and its accumulation in crops but has a complex effect on net MeHg production.In this review,two main mechanisms,a direct mechanism(e.g.,Hg-biochar binding)and an indirect mechanism(e.g.,biochar-impacted sulfur cycling and thus Hg-soil binding),that explain the reduction in Hg bioavailability by biochar amendment based on the interactions among biochar,soil and Hg under redox conditions are highlighted.Furthermore,the existing problems with the use of biochar to treat Hg-contaminated soils and sediments,such as the appropriate dose and the long-term effectiveness of biochar,are discussed.Further research involving laboratory tests and field applications is necessary to obtain a mechanistic understanding of the role of biochar in reducing Hg bioavailability in diverse soil types under varying redox conditions and to develop completely green and sustainable biochar-based functional materials for mitigating Hg-related health risks.展开更多
Biochar is a promising carbon dioxide removal(CDR)technology for climate change mitigation.Current procedures for its determination are lengthy,labor-intensive,and difficult to conduct.Benzene polycarboxylic acids(BPC...Biochar is a promising carbon dioxide removal(CDR)technology for climate change mitigation.Current procedures for its determination are lengthy,labor-intensive,and difficult to conduct.Benzene polycarboxylic acids(BPCA)are the most promising molecular markers for identification and quantification of biochar and its quality as they specifically represent the stable polyaromatic backbone of biochar.Therefore,using the BPCA method,its stability and,thus,its C sequestration potential could be used for CDR accounting.The current BPCA method relies on a specific high-pressure digestion apparatus,which is not available around the world.Therefore,the aims of the present work were(i)to compare the conventional high-pressure nitric acid oxidation with a microwave-assisted digestion technique and optimize the oxidation conditions in such a way that previous results are comparable with future ones,and(ii)to significantly reduce the digestion time of soil samples of 8 h and to develop a suitable routine method that produces comparable and reproducible results.For this purpose,soil and control sample series were prepared for different temperature-time-program.Obtained results were compared with the values of the conventional method both for individual samples and for the whole dataset separately.To ensure the representative-ness of the results,in addition to various soil samples with different properties,we included two reference materials into our data set,one without biochar(wheat flour)and a biochar sample.Our results showed that conventional nitric acid oxidation in the BPCA determination at 170°C and 8 h can be substituted by digestion in a microwave reaction system(CEM Mars6)at 190°C and 1 h.Our results further showed that this condition needs to be strictly matched,because,otherwise,over-or underestimation of biochar quantity and/or quality will be the consequence.The goal of a less time-consuming BPCA extrac-tion from soil samples was achieved by reducing the extraction time from 8 to 1 h using the microwave-assisted method.However,one disadvantage of the new method is that five times more sample material and chemicals are needed for further BPCA analysis,compared to the original method.展开更多
Pennisetum purpureum is one of the most invasive perennial grasses of the Poaceae family,which are abundant in south-east Asia including Brunei Darussalam.The pyrolysis process at a slow heating rate proved to be high...Pennisetum purpureum is one of the most invasive perennial grasses of the Poaceae family,which are abundant in south-east Asia including Brunei Darussalam.The pyrolysis process at a slow heating rate proved to be highly promising for biochar production.The production and characterization of different Pennisetum purpureum biochars have been investigated at the pyrolysis temperatures of 400℃,500℃and 600℃with a heating and nitrogen flow rate of 5℃/min and 0.5 L/min,respec-tively.The observed higher heating values were 22.18 MJ/kg,23.02 MJ/kg,23.75 MJ/kg,and the alkaline pH were 9.10,9.86,10.17 for the biochar at 400℃,500℃,600℃temperatures,respectively.The water holding capacity was one hundred percent for all biochars and continued to increase for higher pyrolysis temperature.SEM images show that the porosity of the biochars has been enhanced with increased temperatures due to the rearrangement of crystallinity and aromaticity.On the other hand,the yields of biochar have been decreased from 35.13%to 23.02%for the increase of pyrolysis temperature from 400℃to 600℃.Energy dispersive X-ray analysis shows that the O/C atomic ratios were 0.15,0.08 and 0.06 for the biochar of 400,500 and 600℃which validates the improvement in heating values.FT-IR analysis revealed that the available functional groups in the biochars were C-O,C=C,and C-H.Thermogravimetric analysis(TGA)under pyrolysis condi-tion showed residue of 46.56%,51.13%and 55.67%from the biochar at 400,500,and 600℃,respectively.The derivative thermogravimetry(DTG)graph indicates that the degradation rate is higher for 400℃biochar than the 600℃biochar.展开更多
In this study,four biochars prepared from different crop residue waste i.e.sugarcane bagasse(SBB),coconut shell(CNB),paddy straw(PDB),and distilled waste of lemongrass(LGB)were evaluated for removal of Remazol Brillia...In this study,four biochars prepared from different crop residue waste i.e.sugarcane bagasse(SBB),coconut shell(CNB),paddy straw(PDB),and distilled waste of lemongrass(LGB)were evaluated for removal of Remazol Brilliant Blue R from the aqueous system.The RBBR adsorption capacities of biochar were 97-79%for SBB,99.9-99.47%for CNB,66.1-48%for PDB,and 78-68%for LGB,dominantly controlled by their aromaticity and mineral content.The Langmuir and Freundlich isotherms and pseudo-second-order kinetic models have described the chemisorption of RBBR on biochar surfaces.The thermodynamic data suggested that adsorption was spontaneous and endothermic.These biochars demonstrated excellent reusability(till four cycles with 50-61%regeneration).The purified water and biochar dye sludge demonstrated no phytotoxicity.The findings obtained in this study may provide supports for the potential of biochars for anionic dye removal from water and utilization of generated sludge for zero waste-producing technologies in the future.展开更多
基金This work was supported by the national key research and development program of China(2016YFD0201203)municipal innovative training program for college students of Beijing(2017Bj093)+2 种基金the special fund for agro-scientific research in the public interest(201203098)Beijing nova program interdisciplinary studies cooperative project(Z171100001117130)National Nature Science Foundation of China(21873115).
文摘Pesticide residues have seriously damaged the natural environment and social security.Here,we prepared the efficient functional biochar(FB)for sulfonylurea herbicides from cotton straw cellulose(CSC)by hydrothermal carbonization with the methacrylic acid.The molecular simulation of FB indicated thatπ-πelectron-donor-acceptor(EDA)interaction and formation of charge-assisted H-bond were both the main factors for effective adsorption process.The adsorption process can match the pseudo-second-order kinetic equation and Freundlich model.The whole process is physical adsorption,spontaneous and rapid,and can quickly reach equilibrium.The FB with carbon-oxygen functional groups and aromatic conjugated structures can remove pesticides in water very quickly(within 30 s),with effective adsorption over 95%of Sulfonylurea herbicides(SUHs).Therefore,functional FB might be an effective way to get excellent absorbent for pesticide treatment.
基金a National Institute of Food and Agriculture,United States Department of Agriculture research award(Number 2019-68012-29888)the Sustainable Intensification Innovation Lab funded by the United States Agency for International Development(Grant Number AID-OAA-L-14-00006)+1 种基金funds allocated to the USDA-ARS project 3070-21610-003-00Dthe sole responsibility of authors and do not reflect the views of funding agencies and representing organizations.Contribution No.21-310-J from the Kansas Agricultural Experiment Station.The US Department of Agriculture(USDA)is an equal opportunity employer and provider of services in all its programs and activities.
文摘Biochar is a widely known soil amendment.Here we synthesize the available information on influence of biochar application on different soil properties and crop productivity using meta-analysis.Global data on influence of biochar applications on different soil physical,chemical,microbial properties,and crop productivity were extracted from literature and statistically analyzed.Based on selection criteria,59 studies from the literature published between 2012 and 2021 were selected for the meta-analysis.Correlations were developed between effect size of biochar application on different soil properties and crop productivity.Application of biochar increased soil pH,cation exchange capacity,and organic carbon by 46%,20%,and 27%,respectively,with greater effects in coarse and fine-textured soils.Effects on chemical properties were variable among biochar prepared from different feedstocks.Among physical properties,biochar application reduced bulk densities by 29%and increased porosity by 59%.Biochar prepared at higher pyrolytic temperatures(>500℃)improved bulk density and porosity to greater extents(31%and 66%,respectively).Biochar prepared at lower pyrolytic temperatures(<500℃)had a greater effect on microbial diversity(both bacterial and fungal),with more diverse bacterial populations in medium and coarse textured soils,while fungal diversity increased in fine textured soils.Biochar applications increased crop productivity only in fine and coarse textured soil.The effect size of biochar application on crop productivity was correlated with responses to physical properties of soils.The meta-analysis highlighted the need to conduct long-term field experiments to provide better explanations for changes in biochar properties as it undergoes aging,its longer-term effects on soil properties,and timing of re-application of different biochars.
基金This work was financially supported by the National Key Research and Development Program of China(2017YFD0801505)National Natural Science Foundation of China(NSFC)(No.41907015)+1 种基金China Postdoctoral Science Foundation(2019M662782)Scientific Research Fund of Hunan Provincial Education Department,China(18B120).
文摘The application of Fe-Mn-modified biochar for the remediation of Cd-contaminated soil over long time periods has been little studied.In this paper,we describe the performance of coconut-shell-derived biochar modified with ferromanganese in relation to soil Cd stabilization and rice Cd bioaccumulation during a 3-year laboratory study.Different application dosages(0.05-0.5 wt%)and different rice varieties(the early and late rice)are also considered.The results show that ferromanganese is mainly loaded in biochar pores as MnFe_(2)O_(4),and that it decreases the specific surface area(SSA)and total pore volume of biochar.Ferromanganese biochar(0.5 wt%)applied to paddy soil is more effective than the same dose of pristine biochar in decreasing the soil-exchangeable Cd fraction(27.42-41.92%vs 22.56-33.85%),predominantly by decreasing soil Eh and increasing root Fe plaques.Ferromanganese biochar application helps to reduce Cd bioaccumulation in rice,especially in the grain(up to 48.6%-61.0%),and grain Cd levels(0.2 mg/kg)are all within the acceptable limit for food security in China.It is shown that ferromanganese modification and application can maintain soil at low redox status,keep root Fe plaques at a high level,and may also increase the stability of pristine biochar.All of these effects contribute to maintaining its high remediation efficiency over a 3-year inoculation period.The results presented in this paper demonstrate the potential appli-cations of ferromanganese biochar in soil remediation and the improvement of food safety.
文摘In recent years,numerous investigations have explored the use of biochar for the removal of organic and inorganic pollutants in single component systems.Biochar is a carbonaceous material produced from waste biomass,mainly by thermochemical conversion methods.This material was used as a biosorbent in various removal processes of pollutants,and its efficiency was strongly influenced by the characteristics of the biomass feedstock.This review integrates the recent works of literature to understand the biosorption behaviour of dyes onto biochar-based biosorbents.The factors influencing the biosorption process and the mechanisms describing the biosorption behaviours of the biochar have been broadly reviewed.Furthermore,the biosorption models can be used to comprehend the competence of the biochar as biosorbent for dye removal techniques.
基金The research leading to these results received funding from BiofuelNet Canada(funded by the Canadian Networks of Centers of Excellence)and the Leverhulme Trust.
文摘Biochar pores in the micrometer range(1-100μm)derive from cellular structures of the plant biomass subjected to pyrolysis or can be the result of mechanical processing,such as pelleting.In this study,synchrotron X-ray microtomography was used to investigate the internal pore structure of softwood pellet biochar produced by slow pyrolysis at 550 and 700°C.The microtomographic data sets consisted of 2025 images of 2560×2560 voxels with a voxel side length of 0.87μm.The three-dimensional reconstructions revealed that pelleting and pyrolysis significantly altered the pore structures of the wood feedstock,creating a network of connected pores between fragments that resembled the wood morphology.While higher pyrolysis temperature increased the specific surface area(as determined by BET nitrogen adsorption),it did not affect the total observed porosity.Multifractal analysis was applied to assess the characteristics of the frequency distribution of pores along each of the three dimensions of reconstructed images of five softwood pellet biochar samples.The resulting singular-ity and Rényi spectra(generalized dimensions)indicated that the distribution of porosity had monofractal scaling behavior,was homogeneous within the analyzed volumes and consistent between replicate samples.Moreover,the pore distributions were isotropic(direction-independent),which is in strong contrast with the anisotropic pore structure of wood.As pores at the scale analyzed in this study are relevant,for example,for the supply of plant accessible water and habitable space for microorganisms,our findings combined with the ability to reproduce biochar with such pore distribution offer substantial advantages in various biochar applications.
基金the National Key Research and Development Program of China(2020YFC1807704)the National Natural Science Foundation of China(21876027)the Science and Technology Innovation Project of Foshan,China(1920001000083).
文摘Removal of antimonite[Sb(Ⅲ)]from the aquatic environment and reducing its biotoxicity is urgently needed to safeguard environmental and human health.Herein,crawfish shell-derived biochars(CSB),pyrolyzed at 350,500,and 650℃,were used to remediate Sb(Ⅲ)in aqueous solutions.The adsorption data best fitted to the pseudo-second-order kinetic and Langmuir isotherm models.Biochar produced at 350℃(CSB350)showed the highest adsorption capacity(27.7 mg g^(−1)),and the maximum 78%oxidative conversion of Sb(Ⅲ)to Sb(V).The adsorption results complemented with infrared(FTIR),X-ray photoelectron(XPS),and near-edge X-ray absorption fine structure(NEXAFS)spectroscopy analyses indicated that the adsorption of Sb(Ⅲ)on CSB involved electrostatic interaction,surface complexation with oxygen-containing functional groups(C=O,O=C-O),π-πcoordination with aromatic C=C and C-H groups,and H-bonding with-OH group.Density functional theory calculations verified that surface complexation was the most dominant adsorption mechanism,whilstπ-πcoordination and H-bonding played a secondary role.Furthermore,electron spin resonance(ESR)and mediated electrochemical reduction/oxidation(MER/MEO)analyses confirmed that Sb(Ⅲ)oxidation at the biochar surface was governed by persistent free radicals(PFRs)(•O_(2)^(−)and•OH)and the electron donating/accepting capacity(EDC/EAC)of biochar.The abundance of preferable surface functional groups,high concentration of PFRs,and high EDC conferred CSB350 the property of an optimal adsorbent/oxidant for Sb(Ⅲ)removal from water.The encouraging results of this study call for future trials to apply suitable biochar for removing Sb(Ⅲ)from wastewater at pilot scale and optimize the process.
基金funded by SGCyT-UNS M24/Q075,PICTO COVIAR 2017-0112Agregando Valor VT42-UNS11738 research Grants.
文摘This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced oxidation processes(AOP).Iron,copper,and two different cobalt-based catalysts were prepared and evaluated.The catalysts were supported on a biochar obtained from the pyrolysis of woody pruning wastes.They were characterized by C,H,and N elemental analysis,X-Ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM).The metal content in each catalyst was determined by means of atomic absorption spectroscopy(AAS).The degradation reac-tions of benzoic acid(BA),catechol(C),and cinnamic acid(CA)were carried out in a lab scale batch glass reactor and were followed by UV-Visible spectroscopy(UV-Vis).A colorimetric technique was employed to verify the presence of oxidant during the reaction progress.The catalyst/oxidant optimal ratio was determined for the cobalt catalysts.The mineralization degree of the pollutants after the degradations was verified by means of total organic carbon(TOC)content in the residual liquids.After 4 h of reaction,the maximum mineralization was reached when C was treated with a cobalt-based catalyst(>80%),and its stability was evaluated through successive cycles of use.
基金the National Natural Science Foundation of China(Grant No.21377074).
文摘Graphene-based composite aerogel doped with other low-cost materials can reduce the cost and promote the use in water treatment.This work prepared ball-milled biochar/reduced graphene oxide aerogel(BC/rGA)using GO and low-cost ball-milled biochar(BC)in a certain proportion with the freeze-thawing technique and sol-gel method,and applied BC/rGA on the Cr(Ⅵ)removal from aquatic environments.The characterization results showed that aerogel had a honeycomb briquette three-dimension(3D)and mesoporous structure with interconnected pores,and proved the preparation progress of aerogel in principle.Compared with GO,rGA and BC/rGA had better adsorption performance with 3D structure and well-developed pores,and BC/rGA with the mixture ratio of BC and GO of 1:4 was more appropriate.The adsorption kinetics data of rGA and BC/rGA_((1:4))were fitting well with the pseudo-second-order model(R^(2)>0.951),and the isotherm adsorption results were fitting the Langmuir model well(R^(2)>0.974).The results demonstrated that the adsorption process was monolayer and endothermic adsorption involving chemisorp-tion.Additionally,the adsorption capacities of rGA and BC/rGA_((1:4))at solution pH 2 were 3.71 and 3.89 times greater than those at solution pH 8,respectively.High background ion strength and low temperature slightly inhibited the adsorption of Cr(Ⅵ)by both rGA and BC/rGA_((1:4)).The adsorption mechanisms of Cr(Ⅵ)on rGA and BC/rGA_((1:4))were electrostatic interaction,reduction and ion exchange.The use of BC/rGA could reduce the cost and promote the green reuse of agricultural waste.Overall,BC/rGA could be used as a promising green adsorbent alternative for the feasible treatment of heavy metal contaminated water.
基金support by the National Natural Science Foundation of China(21537002,41422105,41671478)the Natural Science Foundation of Jiangsu Province,China(Project No.BK20130050).
文摘Biochar is the carbon-rich product obtained from the thermochemical conversion of biomass under oxygen-limited conditions.Biochar has attained extensive attention due to its agronomical and environmental benefits in agro-ecosystems.This work adopts the scientometric analysis method to assess the development trends of biochar research based on the literature data retrieved from the Web of Science over the period of 1998-2018.By analysing the basic characteristics of 6934 publications,we found that the number of publications grew rapidly since 2010.Based on a keyword analysis,it is concluded that scholars have had a fundamental recognition of biochar and preliminarily found that biochar application had agronomic and environmental benefits during the period of 1998-2010.The clustering results of keywords in documents published during 2011-2015 showed that the main research hotspots were“biochar production”,“biochar and global climate change”,“soil quality and plant growth”,“organic pollutants removal”,and“heavy metals immobilization”.While in 2016-2018,beside these five main research hotspots,“biochar and composting”topic had also received greater attention,indicating that biochar utilization in organic solid waste composting is the current research hotspot.Moreover,updated reactors(e.g.,microwave reactor,fixed-bed reactor,screw-feeding reactor,bubbling fluidized bed reactor,etc.)or technologies(e.g.,solar pyrolysis,Thermo-Catalytic Reforming process,liquefaction technology,etc.)applied for efficient energy production and modified biochar for environmental remediation have been extensively studied recently.The findings may help the new researchers to seize the research frontier in the biochar field.
基金the National Natural Science Foundation of China(Grant No.31972511)the National Key R&D Program of China(Grant No.2018YFD0201001)China Agriculture Research System of MOF and MARA(CARS-13).
文摘Biological nitrogen fixation(BNF)can help replenish available nitrogen(N)in cropland and reduce the use of chemical N fertilizers,with diazotrophs playing an important role.However,the response of diazotroph community and BNF activity in biochar amendment soil,especially in the deep soil horizon,are poorly understood.In this study,soil samples were collected from topsoil(0-20 cm)and subsoil(20-40 cm)in the field experiment(established in 2013)comprising treatments with no chemical fertilizer(CK),chemical fertilizer(NPK),biochar(BC),and biochar plus chemical fertilizers(BNPK).Here,we investigated the diazotroph community using real-time PCR and high-throughput sequencing of the nifH gene,and assessed the soil N_(2)fixation rate(R_(Nfix))using acetylene reduction assay(ARA).Results showed that in the topsoil,the treatments with biochar significantly increased nifH gene copies and R_(Nfix),which was consistent with the increased soil organic matter(SOM),total carbon-to-nitrogen ratio(C/N),dissolved organic carbon(DOC)and pH.In the subsoil,applying chemical fertilizers(NPK)strongly decreased R_(Nfix),but had no effect on diazotroph abundance;in contrast,biochar application(BC)had no effect on R_(Nfix),but suppressed the growth of bacteria and diazotrophs while increasing the abundance of Rhizobiales order.Diazotroph and bacterial gene copies were significantly and positively correlated in both top-and sub-soil,and they were mainly influenced by SOM and total nitrogen(TN).In addition,soil nitrate nitrogen(NO_(3)^(−)-N)was the major factor in shaping the vertical stratification of diazotroph community structure.Although nifH gene abundance was significantly cor-related with R_(Nfix)in the topsoil,the structure equation modeling(SEM)showed the highest correlation between diazotroph community structure and R_(Nfix).Hence,we suggested that soil carbon and nitrogen sources were the key factors correlated with changes in the vertical pattern of diazotroph abundance.Biochar induced the dominant diazotroph community succes-sion and increased soil carbon content and pH,which contributed to the BNF activity.Changes in the BNF activity were driven by the variation in diazotroph community structure.
基金the National Natural Science Foundation of China(41977078,32001213)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX21_0618,KYCX20_0591).
文摘Biochar amendment and substituting chemical fertilizers with organic manure(organic substitution)have been widely reported to increase crop production and decrease reactive nitrogen(Nr)loss including nitrous oxide(N_(2)O),nitric oxide(NO),and ammonia(NH3)emissions,and N runoff and leaching.However,few comprehensive evalua-tions have been performed on the environmental and economic aspects of biochar amendment or organic sub-stitution.Here,we studied the comprehensive effects of biochar amendment,organic substitution,and biochar amendment combined with organic substitution on crop production,Nr loss,and net ecosystem economic benefit(NEEB)in intensive vegetable production by integrating life-cycle assessment for Nr footprints,empirical models for NH3 volatilization and N runoff and leaching derived from peer-reviewed publications and validated by the current measurements and direct field measurement for N_(2)O and NO emissions during 5 consecutive years of vegetable crop rotations.Five fertilization treatments were applied(SN:synthetic fertilizer application;SNB:SN plus 20 t ha^(−1)biochar amendment;SNM:substituting 50%of chemical N fertilizer with organic manure;SNMB:SNM plus 20 t ha^(−1)biochar amendment;and CK:no fertilizer or biochar addition).Compared with the SN,the SNB increased vegetable yield(28.4%,p<0.05;interannually varying from−10 to 74.9%)and nitrogen use efficiency(29.2%,interannually varying from−39.7 to 150.4%),and decreased field Nr loss(45.4%,p<0.01;interannually varying from−40.3 to 78.4%),and thus improved NEEB by 7.1%;meanwhile,the SNM increased vegetable yield(11.6%,interannually varying from−5.4 to 27.1%)and nitrogen use efficiency(45.7%,p<0.05;interannually varying from 2.3 to 154%),reduced field Nr loss(34.9%,p<0.01;interannually varying from 8.4-39.0%),and thus improved NEEB by 17.8%(p<0.05)compared to the SN,being 56.0×10^(3)Chinese Yuan(CNY)ha^(−1)crop^(−1).Due to the high foreground Nr loss during organic manure production and high input costs of biochar production,the SNMB decreased the NEEB by 8.0%as compared to the SN.Moreover,the SNB and SNM improved vegetable qualities by increasing protein,soluble sugar,and vitamin C contents while decreasing nitrate content(p<0.05).Therefore,single application of biochar amendment or organic substitution would achieve better NEEB and product quality in vegetable production.
基金National Research Foundation of Korea(NRF)Grant funded by the Korean government(MSIT)(NRF-2020R1A2C1010748).
文摘Sewage sludge(SS)is a residual/semi-solid material produced from industrial and municipal wastewater treatment processes.SS contains a high content of lipids and earth alkaline metals that can be used as catalysts for various chemical applications;however,its valorization has rarely been the focus of research.This study demonstrates that SS could be a promising raw material for biodiesel production and a biochar catalyst to promote the reaction kinetics of alkylation.Thermally induced transesterification of the SS extract(SSE)was performed in comparison with the conventional homogeneous reaction.SS biochar was fabricated via pyrolysis.The highest yield(33.5 wt.%per SSE)of biodiesel production was achieved in 1 min of reaction at 305℃via thermally induced transesterification in the presence of SS biochar,while the yield of biodiesel from(trans)esterification with 5 wt.%H_(2)SO_(4)was less than 1%even after 24 h.The reaction kinetics(<1 min)of thermally induced transesterification was extraordinarily faster than that of conventional transesterification(3-24 h).The porous structure and high content of alkaline species in the SS biochar expedited the reaction kinetics.Consequently,the integrated/hybridized process for thermally induced transesterification and pyrolysis of the solid residue of SS was experimentally proved for the valorization of SS in this study.Considering that SS is being disposed of as a waste material and generates toxic chemicals in the environment,its valorization into value-added biodiesel and a catalyst could be an environmentally benign and sustainable technique.
基金This research was supported by the U.S.Department of Agriculture,Agricultural Research Service。
文摘The effects of uncoated and Fe-coated biochars(BC)on the removal of bacteria,microspheres,and dissolved reactive phosphorus(DRP)in sand filters were compared.Filters were packed with 1.2 or 2.0-mm sand mixed with 30%(vol/vol)uncoated BC,Fe-coated BC,or a control without BC.Removal of E.coli,Salmonella,and Enterococci increased from 23,42,and 25%in the unamended 1.2-mm sand to 48,80,and 75%in the uncoated BC treatment,though only the increase for Enterococci was significant(p<0.05).For the Fe-coated BC,removal efficiencies were 89,93,and 94%,respectively,which were all significantly(p<0.05)greater than the unamended sand but only the removal of E.coli was significantly greater than the uncoated BC sand filter.For the 2.0-mm sands,the only significant increase in removal following BC addition was observed for Salmonella.Trends in microsphere removal were generally consistent with bacteria.Removal of DRP in the unamended and uncoated BC filters was 33 and 13%(p>0.05),respectively,whereas removal in the Fe-coated BC filters was 98%(p<0.05).Results from batch sorption experiments indicate that both BCs similarly increased bacterial sorption to sand.In contrast,DRP sorption to the unamended and uncoated BC-amended sands were similar(p>0.05)with DRP sorption to the Fe-coated BC-amended sand being significantly greater(p<0.05).Results indicate that Fe-coated BC is more effective at retaining DRP than bacteria and microspheres in sand filters.
基金the National Key R&D Program of China(2018YFC1902903)National Natural Science Foundation of China(22176005)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Project no.22qntd2701).
文摘Hydrogen sulfide(H_(2)S)removal has been a significant concern in various industries.In this study,food waste diges-tate-derived biochar(DFW-BC),a by-product of food waste treatment with abundant minerals,was assessed for removing H_(2)S from different simulated biogas containing oxygen(O_(2))and carbon dioxide(CO_(2))and under differ-ent moisture(H_(2)O)contents(0%and 20%)of biochar.The influencing mechanisms of the gas conditions combined with the moisture contents were also investigated.The results showed an H_(2)S removal of 1.75 mg g^(−1)for dry bio-char under pure H_(2)S,4.29 mg g^(−1)for dry biochar under H_(2)S+O_(2),5.29 mg g^(−1)for humid biochar under H_(2)S,and 12.50 mg g^(−1)for humid biochar under H_(2)S+O_(2).For dry DFW-BC,the high Fe content was responsible for the O_(2)enhancement.In contrast,O_(2)+H_(2)O activated the catalytic H_(2)S oxidation of the less reactive minerals(mainly Ca).The inhibition of CO_(2)on H_(2)S adsorption was not obvious for dry DFW-BC;the specific pore structure may have provided a buffer against the physisorption competition of CO_(2).However,when H_(2)O was present on DFW-BC,the changes in critical biochar properties and sulfur speciation as opposed to that without H_(2)O implied an evident occurrence of CO_(2)chemisorption.This CO_(2)chemisorption partially hindered O_(2)+H_(2)O enhancement,decreasing the H_(2)S removal capacity from 12.50 to 8.88 mg g^(−1).The negative effect was ascribed to mineral carbonation of CO_(2),neutralizing the alkaline surface and immobilizing metal oxides,which thus reduced the acceleration in H_(2)S dissociation and activa-tion in catalytic H_(2)S oxidation by O_(2)+H_(2)O.
基金This study was partially supported by,the National Natural Science Foundation of China under a grant number of 41501339,21677119Jiangsu Province Science Foundation for Youths under a grant number of BK20140468sponsored by the QingLan Project.
文摘Cadmium(Cd)and lead(Pb)contaminated soils that are used for food production can lead to metal bioaccumulation in the food chain and eventually affect human health.In these agroecosystems,means by which Cd and Pb bioavailability can be reduced are desperately required,with biochar as a proxy for bioavailability reductions.Molecular Cd and Pb sorption mecha-nisms within short-(0-2 years)or long-term(8-10 years)time periods following biochar application to a contaminated rice paddy soil were investigated.A combination of Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,and soft X-ray imaging was utilized to discern potential metal sorption mechanisms.Following both short-and long-term biochar applications,soil Cd and Pb bioavailable fractions shifted partially towards metal(hydr)oxide and carbonate pre-cipitates,and partially towards biochar-organic function group associations;oxygen-containing groups,such as C=O and O-H,appeared to bind Cd and Pb.Soft X-ray imaging results suggested that heavy metals were primarily sorbed on biochar exterior surfaces,yet given time and particle disintegration,metals sorbed onto biochar interior pore walls.Findings sug-gest that biochar may play a pivotal role in reducing long-term bioavailable Cd and Pb in contaminated soils.Observations also support previous findings that suggest biochar use can lead to reduced heavy metal transfer to plants and potentially to reduced heavy metal consumption by humans.
基金the National Natural Science Foundation of China(41420104007 and 41671472)the Special Support Plan for High-level Talents of Guangdong,China(2016TQ03Z565)Guangdong Academy of Sciences’Projects(2019GDASYL-0103050,2018GDASCX-0501,and 2017GDASCX-0106).
文摘In paddy fields, the opposing transformation of arsenic (As) and cadmium (Cd) poses many challenges for their simultaneous remediation.In our previous study,we reported that combined biochar and zero-valent iron(ZVI)amendment had great potential for the simultaneous alleviation of As and Cd bioavailability in contaminated acid paddy soil.In this study,an As-and Cd-contaminated alkaline paddy soil was further studied,and the same ZVI-biochar mixtures amendments were applied to evaluate the impact of the mixtures on As and Cd transformation and translocation in the soil-rice system by performing pot experiments with rice.In line with our previous study,the ZVI-biochar composites significantly reduced As and Cd accumulation in different rice tissues,leading to a 42%and 47%decrease in rice grain As and Cd levels,respectively,compared with the control values.The ZVI-biochar mixtures exhibited synergistic effects of biochar and ZVI by enhancing the transformation of bioavailable As and Cd fractions into less bioavailable fractions,and by increasing iron plaque formation to reduce As and Cd bioavailability.Although the bioaccumulation and translocation factors of As and Cd in alkaline paddy soil were generally lower than those in acid paddy soil,particularly in the presence of the ZVI-biochar mixtures,the grain As and Cd levels did not achieve the desired food safety standard levels,probably related to the high soil As content and the small changes in soil pH.Nevertheless,for treating lightly and moderately contaminated paddy soils,ZVI-biochar mixtures can still be a good choice in the future.
基金Financial support was provided to Huan Zhong by the National Natural Science Foundation of China(41673075).
文摘The transformation of mercury(Hg)into the more toxic and bioaccumulative form methylmercury(MeHg)in soils and sediments can lead to the biomagnification of MeHg through the food chain,which poses ecological and health risks.In the last decade,biochar application,an in situ remediation technique,has been shown to be effective in mitigating the risks from Hg in soils and sediments.However,uncertainties associated with biochar use and its underlying mechanisms remain.Here,we summarize recent studies on the effects and advantages of biochar amendment related to Hg biogeochemistry and its bioavailability in soils and sediments and systematically analyze the progress made in understanding the underlying mechanisms responsible for reductions in Hg bioaccumulation.The existing literature indicates(1)that biochar application decreases the mobility of inorganic Hg in soils and sediments and(2)that biochar can reduce the bioavailability of MeHg and its accumulation in crops but has a complex effect on net MeHg production.In this review,two main mechanisms,a direct mechanism(e.g.,Hg-biochar binding)and an indirect mechanism(e.g.,biochar-impacted sulfur cycling and thus Hg-soil binding),that explain the reduction in Hg bioavailability by biochar amendment based on the interactions among biochar,soil and Hg under redox conditions are highlighted.Furthermore,the existing problems with the use of biochar to treat Hg-contaminated soils and sediments,such as the appropriate dose and the long-term effectiveness of biochar,are discussed.Further research involving laboratory tests and field applications is necessary to obtain a mechanistic understanding of the role of biochar in reducing Hg bioavailability in diverse soil types under varying redox conditions and to develop completely green and sustainable biochar-based functional materials for mitigating Hg-related health risks.
基金provided by Martin Luther University Halle-Wittenberg,Germany.
文摘Biochar is a promising carbon dioxide removal(CDR)technology for climate change mitigation.Current procedures for its determination are lengthy,labor-intensive,and difficult to conduct.Benzene polycarboxylic acids(BPCA)are the most promising molecular markers for identification and quantification of biochar and its quality as they specifically represent the stable polyaromatic backbone of biochar.Therefore,using the BPCA method,its stability and,thus,its C sequestration potential could be used for CDR accounting.The current BPCA method relies on a specific high-pressure digestion apparatus,which is not available around the world.Therefore,the aims of the present work were(i)to compare the conventional high-pressure nitric acid oxidation with a microwave-assisted digestion technique and optimize the oxidation conditions in such a way that previous results are comparable with future ones,and(ii)to significantly reduce the digestion time of soil samples of 8 h and to develop a suitable routine method that produces comparable and reproducible results.For this purpose,soil and control sample series were prepared for different temperature-time-program.Obtained results were compared with the values of the conventional method both for individual samples and for the whole dataset separately.To ensure the representative-ness of the results,in addition to various soil samples with different properties,we included two reference materials into our data set,one without biochar(wheat flour)and a biochar sample.Our results showed that conventional nitric acid oxidation in the BPCA determination at 170°C and 8 h can be substituted by digestion in a microwave reaction system(CEM Mars6)at 190°C and 1 h.Our results further showed that this condition needs to be strictly matched,because,otherwise,over-or underestimation of biochar quantity and/or quality will be the consequence.The goal of a less time-consuming BPCA extrac-tion from soil samples was achieved by reducing the extraction time from 8 to 1 h using the microwave-assisted method.However,one disadvantage of the new method is that five times more sample material and chemicals are needed for further BPCA analysis,compared to the original method.
基金Md Sumon Reza is highly acknowledged in the University Graduate Scholarship from UBD.The author is also grateful to Dr.Nikdalila Radenahmad for supporting this work.This project was funded by a UBD competitive research grant:UBD/OVACRI/CRGWG(006)/161201.
文摘Pennisetum purpureum is one of the most invasive perennial grasses of the Poaceae family,which are abundant in south-east Asia including Brunei Darussalam.The pyrolysis process at a slow heating rate proved to be highly promising for biochar production.The production and characterization of different Pennisetum purpureum biochars have been investigated at the pyrolysis temperatures of 400℃,500℃and 600℃with a heating and nitrogen flow rate of 5℃/min and 0.5 L/min,respec-tively.The observed higher heating values were 22.18 MJ/kg,23.02 MJ/kg,23.75 MJ/kg,and the alkaline pH were 9.10,9.86,10.17 for the biochar at 400℃,500℃,600℃temperatures,respectively.The water holding capacity was one hundred percent for all biochars and continued to increase for higher pyrolysis temperature.SEM images show that the porosity of the biochars has been enhanced with increased temperatures due to the rearrangement of crystallinity and aromaticity.On the other hand,the yields of biochar have been decreased from 35.13%to 23.02%for the increase of pyrolysis temperature from 400℃to 600℃.Energy dispersive X-ray analysis shows that the O/C atomic ratios were 0.15,0.08 and 0.06 for the biochar of 400,500 and 600℃which validates the improvement in heating values.FT-IR analysis revealed that the available functional groups in the biochars were C-O,C=C,and C-H.Thermogravimetric analysis(TGA)under pyrolysis condi-tion showed residue of 46.56%,51.13%and 55.67%from the biochar at 400,500,and 600℃,respectively.The derivative thermogravimetry(DTG)graph indicates that the degradation rate is higher for 400℃biochar than the 600℃biochar.
基金financial support by the Department of Biotechnology(DBT),New Delhi(BT/PR24706/NER/95/822/2017)under the twinning program.
文摘In this study,four biochars prepared from different crop residue waste i.e.sugarcane bagasse(SBB),coconut shell(CNB),paddy straw(PDB),and distilled waste of lemongrass(LGB)were evaluated for removal of Remazol Brilliant Blue R from the aqueous system.The RBBR adsorption capacities of biochar were 97-79%for SBB,99.9-99.47%for CNB,66.1-48%for PDB,and 78-68%for LGB,dominantly controlled by their aromaticity and mineral content.The Langmuir and Freundlich isotherms and pseudo-second-order kinetic models have described the chemisorption of RBBR on biochar surfaces.The thermodynamic data suggested that adsorption was spontaneous and endothermic.These biochars demonstrated excellent reusability(till four cycles with 50-61%regeneration).The purified water and biochar dye sludge demonstrated no phytotoxicity.The findings obtained in this study may provide supports for the potential of biochars for anionic dye removal from water and utilization of generated sludge for zero waste-producing technologies in the future.
