Dust particles emitted from smelters can be hazardous to ecosystems and humans,as they are often enriched in metallic compounds.Here,we combined multi-method mineralogical analysis with a sophisticated size sorting ap...Dust particles emitted from smelters can be hazardous to ecosystems and humans,as they are often enriched in metallic compounds.Here,we combined multi-method mineralogical analysis with a sophisticated size sorting approach for copper smelting dust to study the nanosize-effect on heavy metal distribution,which has hitherto been underestimated.Three types of dust were collected from a copper flash smelter and then size-sorted using a Dekati low-pressure impactor.Results showed that all three samples could easily sort out nanoscale dust particles(<1μm,grades 10–2)and even those smaller than 100 nm(grades 5–2).Especially for electrostatic precipitators dust,the mass fraction of nanoscale dust(<1μm)could reach 10.71%.The presence of heavy metals(Pb,Zn,Cu,and As)and their mineral species in dust was examined at various particle sizes.It was discovered that different heavy metals are enriched on nanoparticles in specific sizes.In micron-sized particles,heavy metals are generally found in discrete phases(e.g.,CuSO_(4),PbSO_(4),and As_(2)O_(3)).In nanoscale particles,the dominant phase is Fe_(3)O_(4),while heavy metals are mostly found in lattice substitution(e.g.,CuFe_(2)O_(4)and ZnFe_(2)O_(4)).Two distinct nano-dust morphologies were found:One with irregular mesh or chain structures consisting of particles of a few nanometers,and the other with polygonal crystals in larger sizes of hundreds of nanometers.The enrichment of heavy metals in the latter morphology is more pronounced,possibly because lattice substitution of heavy metals is more likely to occur when polycrystalline particles are formed.展开更多
Magnetic chitosan composites(Fe3O4@chitosan) were synthesized in one single-step, characterized and applied in Cr(VI) removal from water. With the increase of loading proportion of chitosan, Cr(Ⅵ) adsorption capacity...Magnetic chitosan composites(Fe3O4@chitosan) were synthesized in one single-step, characterized and applied in Cr(VI) removal from water. With the increase of loading proportion of chitosan, Cr(Ⅵ) adsorption capacity of Fe3O4@chitosan composites increased from 10.771 to 21.040 mg/g. The optimum adsorption capacities of Cr(VI) on Fe3O4@chitosan-3 were found in a pH range of 3.0-5.0. Kinetic study results show that the adsorption process follows pseudo-second-order model, indicating that the rate-limiting step in the adsorption of Cr(Ⅵ) involves chemisorptions. Moreover, FT-IR spectra analysis confirms that the amine and hydroxyl groups of chitosan are predominantly responsible for binding. Results from this work demonstrate that the prepared Fe3O4@chitosan composites possess great potential in Cr(Ⅵ) removal from contaminated water.展开更多
Hydrophobic treatment of the catalyst surfaces can suppress the competitive hydrogen evolution reaction(HER) during the nitrogen reduction reaction(NRR).In this work,the surface of Ti_(3)C_(2)Ti_(x) MXene is modified ...Hydrophobic treatment of the catalyst surfaces can suppress the competitive hydrogen evolution reaction(HER) during the nitrogen reduction reaction(NRR).In this work,the surface of Ti_(3)C_(2)Ti_(x) MXene is modified by cetyltrimethylammonium bromide(CTAB) and trimethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8-trideca fluorooctyl) silane(FOTS) to increase the hydrophobicity of MXenes.The ammonia(NH_(3)) production rate and faradaic efficiency(FE) are improved from 37.62 to 54.01 μg h^(-1)mg_(cat)^(-1).and 5.5% to 18.1% at-0.7 V vs.RHE,respectively after surface modification.^(15)N isotopic labeling experiment confirms that nitrogen in produced ammonia originates from N_(2) in the electrolyte.The excellent NRR activity of surface hydrophobic MXenes is mainly due to surfactant molecules,which inhibit the entry of water molecules and the competitive HER,which have been verified by in situ FT-IR,DFT and molecular dynamics calculations.This strategy provides an ingenious method to design more active NRR electrocatalysts.展开更多
Heavy metal(loid)s(HMs)have caused serious environmental pollution and health risks.Although the past few years have witnessed the achievements of studies on environmental behavior of HMs,the related toxicity mechanis...Heavy metal(loid)s(HMs)have caused serious environmental pollution and health risks.Although the past few years have witnessed the achievements of studies on environmental behavior of HMs,the related toxicity mechanisms,and pollution control,their relationship remains a mystery.Researchers generally focused on one topic independently without comprehensive considerations due to the knowledge gap between environmental science and human health.Indeed,the full life cycle control of HMs is crucial and should be reconsidered with the combination of the occurrence,transport,and fate of HMs in the environment.Therefore,we started by reviewing the environmental behaviors of HMs which are affected by a variety of natural factors as well as their physicochemical properties.Furthermore,the related toxicity mechanisms were discussed according to exposure route,toxicity mechanism,and adverse consequences.In addition,the current state-of-the-art of available technologies for pollution control of HMs wastewater and solid wastes were summarized.Finally,based on the research trend,we proposed that advanced in-operando characterizations will help us better understand the fundamental reaction mechanisms,and big data analysis approaches will aid in establishing the prediction model for risk management.展开更多
Lignin is a common soil organic matter that is present in soils,but its effect on the transformation of ferrihydrite(Fh)remains unclear.Organic matter is generally assumed to inhibit Fh transformation.However,lignin c...Lignin is a common soil organic matter that is present in soils,but its effect on the transformation of ferrihydrite(Fh)remains unclear.Organic matter is generally assumed to inhibit Fh transformation.However,lignin can reduce Fh to Fe(Ⅱ),in which Fe(Ⅱ)-catalyzed Fh transformation occurs.Herein,the effects of lignin on Fh transformation were investigated at 75℃ as a function of the lignin/Fh mass ratio(0-0.2),pH(4-8)and aging time(0-96 hr).The results of Fh-lignin samples(mass ratios=0.1)aged at different pH values showed that for Fh-lignin the time of Fh transformation into secondary crystalline minerals was significantly shortened at pH 6 when compared with pure Fh,and the Fe(Ⅱ)-accelerated transformation of Fh was strongly dependent on pH.Under pH 6,at low lignin/Fh mass ratios(0.05-0.1),the time of secondary mineral formation decreased with increasing lignin content.For high lignosulfonate-content material(lignin:Fh=0.2),Fh did not transform into secondary minerals,indicating that lignin content plays a major role in Fh transformation.In addition,lignin affected the pathway of Fh transformation by inhibiting goethite formation and facilitating hematite formation.The effect of coprecipitation of lignin on Fh transformation should be useful in understanding the complex iron and carbon cycles in a soil environment.展开更多
Air pollutant emissions represent a critical challenge in the green development of the non-ferrous metallurgy industry.This work studied the emission characteristics,formation mechanisms,phase transformation and separ...Air pollutant emissions represent a critical challenge in the green development of the non-ferrous metallurgy industry.This work studied the emission characteristics,formation mechanisms,phase transformation and separation of typical air pollutants,such as heavy metal particles,mercury,sulfur oxides and fluoride,during non-ferrous smelting.A series of purification technologies,including optimization of the furnace throat and hightemperature discharge,were developed to collaboratively control and recover fine particles from the flue gas of heavy metal smelting processes,including copper,lead and zinc.Significant improvements have been realized in wet scrubbing technology for removing mercury,fluoride and SO_(2)from flue gas.Gas-liquid sulfidation technology by applying H_(2)S was invented to recycle the acid scrubbing wastewater more efficiently and in an eco-friendly manner.Based on digital technology,a source reduction method was designed for sulfur and fluoride control during the whole aluminum electrolysis process.New desulfurization technologies were developed for catalytic reduction of the sulfur content in petroleum coke at low temperature and catalytic reduction of SO_(2)to elemental sulfur.This work has established the technology for coupling multi-pollutant control and resource recovery from the flue gas from non-ferrous metallurgy,which provides the scientific theoretical basis and application technology for the treatment of air pollutants in the non-ferrous metallurgy industry.展开更多
Cubic boron arsenide(BAs)has attracted great attention due to its high thermal conductivity,however,its controllable,stable,and ideal preparation remains challenging.Herein,we investigated the effect of iodine-contain...Cubic boron arsenide(BAs)has attracted great attention due to its high thermal conductivity,however,its controllable,stable,and ideal preparation remains challenging.Herein,we investigated the effect of iodine-containing transport agents I_(2) and boron triiodide(BI_(3))on BAs synthesized and grown through chemical vapor transport.Results show that similar to the commonly used I_(2),BI_(3) accelerates the synthesis and improves the mass fraction of BAs from ~12% to over 90% at 820℃ and 1.5 MPa,a value beyond the promoting effect of only increasing temperature and pressure.Both agents enhance the quality of BAs crystals by reducing the full width at half maximum by up to 10%-20%.I_(2) agglomerates the grown crystals with twin defects(~50 nm wide),and BI_(3) improves the crystal anisotropy and element uniformity of BAs crystals with narrow twins(~15 nm wide)and increases the stoichiometry ratio(~0.990)to almost 1.Owing to the boron interstitials from the excessive boron supply,the spacing of layers in {111} increases to 0.286 nm in the presence of I_(2).Owing to its coordinated effect,BI_(3) only slightly influences the layer spacing at 0.275 nm,which is close to the theoretical value of 0.276 nm.In the chemical vapor transport,the anisotropic crystals with flat surfaces exhibit single-crystal characteristics under the action of BI_(3).Different from that of I_(2),the coordinated effect of BI_(3) can promote the efficient preparation of high-quality BAs crystal seeds and facilitate the advanced application of BAs.展开更多
With over 30 years of development for lithium ion batteries(LIBs),LIBs have achieved great success in terms of their cathodes,anodes,electrolytes,and other necessary components[1].Their battery chemistry has also been...With over 30 years of development for lithium ion batteries(LIBs),LIBs have achieved great success in terms of their cathodes,anodes,electrolytes,and other necessary components[1].Their battery chemistry has also been extended to sodium,potassium,and other alkaline ion batteries,which have also made great achievements[2-4].展开更多
The hexavalent chromium(Cr(Ⅵ))would frequently impose inhibition to anaerobic ammonium oxidation(anammox)process,hindering the efficiency of nitrogen removal in wastewater treatment.Hydrazine(N2H4),which is an interm...The hexavalent chromium(Cr(Ⅵ))would frequently impose inhibition to anaerobic ammonium oxidation(anammox)process,hindering the efficiency of nitrogen removal in wastewater treatment.Hydrazine(N2H4),which is an intermediate product of anammox,participates in intracellular metabolism and extracellular Cr(Ⅵ)reduction.However,the roles of N_(2)H_(4)-induced intracellular metabolism and extracellular reduction in nitrogen removal under Cr(Ⅵ)stress remain unclear.The addition of 3.67 mg/L of N2H4 increased the anammox activity by 17%.As an intermediate,N2H4 enhanced anammox metabolism by increasing the heme c content and electron transfer system activity.As a reductant,N_(2)H_(4) accelerated the reduction of c-Cyts-mediated extracellular Cr(Ⅵ)to the less toxic Cr(Ⅲ).Extracellular Cr(Ⅲ)accounts for 74%of the total Cr in a Cr(Ⅵ)-stressed anammox consortia.These findings highlight that N_(2)H_(4)-induced extracellular Cr(Ⅵ)reduction is the dominant mechanism for the survival of anammox consortia.We also found that N_(2)H_(4) increased the production of extracellular polymeric substances to sequester excessive Cr(Ⅵ)and produced Cr(Ⅲ).Taken together,the study findings suggest a potential strategy for enhancing nitrogen removal from ammonium-rich wastewater contaminated with Cr(Ⅵ).展开更多
Antimony(Sb)in natural water has long-term effects on both the ecological environment and human health.Iron mineral phase transformation(IMPT)is a prominent process for removing Sb(V)from natural water.However,the imp...Antimony(Sb)in natural water has long-term effects on both the ecological environment and human health.Iron mineral phase transformation(IMPT)is a prominent process for removing Sb(V)from natural water.However,the importance of IMPT in eliminating Sb remains uncertain.This study examined the various Sb–Fe binding mechanisms found in different IMPT pathways in natural water,shedding light on the underlying mechanisms.The study revealed that the presence of goethite(Goe),hematite(Hem),and magnetite(Mag)significantly affected the concentration of Sb(V)in natural water.Elevated pH levels facilitated higher Fe content in iron solids but impeded the process of removing Sb(V).To further our understanding,polluted natural water samples were collected from various locations surrounding Sb smelter sites.Results confirmed that converting ferrihydrite(Fhy)to Goe significantly reduced Sb levels(<5μg/L)in natural water.The emergence of secondary iron phases resulted in greater electrostatic attraction and stabilized surface complexes,which was the most likely cause of the decline of Sb concentration in natural water.The comprehensive findings offer new insights into the factors governing IMPT as well as the Sb(V)behavior control.展开更多
This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and iden...This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and identified the factors limiting their degradation in synthetic human urine.A kinetic model was established to expose the radical production in various reaction conditions,and experiments were conducted to verify the modeling results.In the phosphate-containing mFe-PS system,the 120 min removal efficiency of CFA decreased from 95.1%to 76.6%as the phosphate concentration increased from 0.32 to 6.45 mmol/L,but recovered to 90.5%when phosphate concentration increased to 16.10 mmol/L.Meanwhile,the increased concentration of phosphate from 0.32 to 16.10mmol/L reduced the BZF degradation efficacy from 91.5%to 79.0%,whereas SMX removal improved from 37.3%to 62.9%.The m Fe-PS system containing(bi)carbonate,from 4.20 to166.70 mmol/L,reduced CFA and BZF removal efficiencies from 100%to 76.8%and 80.4%,respectively,and SMX from 83.5%to 56.7%within a 120-min reaction time.In addition,alkaline conditions(pH≥8.0)inhibited CFA and BZF degradations,while nonacidic pH(pH≥7.0)remarkably inhibited SMX degradation.Results of the kinetic model indicated the formation of phosphate(H_(2)PO_(4)^(·)/HPO_(4)^(·-))and/or carbonate radicals(CO_(3)^(·-))could limit pharmaceutical removal.The transformation products(TPs)of the pharmaceuticals revealed more incompletely oxidized TPs occurred in the phosphate-and(bi)carbonate-containing m Fe-PS systems,and indicated that H_(2)PO_(4)^(·)/HPO_(4)^(·-)mainly degraded pharmaceuticals via a benzene ring-opening reaction while CO_(3)^(·-)preferentially oxidized pharmaceuticals via a hydroxylation reaction.展开更多
Organo-chromium(III)complex is one of the chromium contaminant species,which would transform to high-toxic Cr(VI)during migrating in the environment.Such natural organo-chromium(III)(NOCr)is difficult to remove by tra...Organo-chromium(III)complex is one of the chromium contaminant species,which would transform to high-toxic Cr(VI)during migrating in the environment.Such natural organo-chromium(III)(NOCr)is difficult to remove by traditional degradation or precipitation methods,due to its high stability and solubility.Herein,we demonstrated a novel NOCr removing method by transforming it to certain structures similar to Cr-Fe minerals in nature,through a self-circulating decomplex and immobilization mechanism with nano zero-valent iron(nZVI).Taking chromium glycinate(Cr-Gly)as a probe,nZVI showed a high Cr removal efficiency of 99.4%under ambient conditions.The removal process included three stages of adsorption,decomplexation,and re-immobilization.Cr-Gly was first adsorbed on the surface of nZVI by chemisorption of the oxide shell.Then,the adsorbed Cr-Gly was decomplexed and oxidized to Cr(VI)by·OH and 1O_(2),which were generated from molecular oxygen activated by nZVI.Meanwhile,the released Cr(VI)could be in-situ adsorbed and re-reduced to Cr(III),which was further immobilized in form of Cr-O-Fe complex.As the Cr-O-Fe complexing structure was similar to that of Cr-Fe minerals(such as chromohercynite)in nature,this work explored a novel and efficient NOCr removing method that was potential to weaken chromium pollution in the environment.展开更多
UV/chlorine process,as an emerging advanced oxidation process(AOP),was effective for removing micro-pollutants via various reactive radicals,but it also led to the changes of natural organic matter(NOM)and formation o...UV/chlorine process,as an emerging advanced oxidation process(AOP),was effective for removing micro-pollutants via various reactive radicals,but it also led to the changes of natural organic matter(NOM)and formation of disinfection byproducts(DBPs).By using negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS),the transformation of Suwannee River NOM(SRNOM)and the formation of chlorinated DBPs(Cl-DBPs)in the UV/chlorine AOP and subsequent post-chlorination were tracked and compared with dark chlorination.In comparison to dark chlorination,the involvement of Cl O·,Cl·,and HO·in the UV/chlorine AOP promoted the transformation of NOM by removing the compounds owning higher aromaticity(AI mod)value and DBE(double-bond equivalence)/C ratio and causing the decrease in the proportion of aromatic compounds.Meanwhile,more compounds which contained only C,H,O,N atoms(CHON)were observed after the UV/chlorine AOP compared with dark chlorination via photolysis of organic chloramines or radical reactions.A total of 833 compounds contained C,H,O,Cl atoms(CHOCl)were observed after the UV/chlorine AOP,higher than 789 CHOCl compounds in dark chlorination,and one-chlorine-containing components were the dominant species.The different products from chlorine substitution reactions(SR)and addition reactions(AR)suggested that SR often occurred in the precursors owning higher H/C ratio and AR often occurred in the precursors owning higher aromaticity.Post-chlorination further caused the cleavages of NOM structures into small molecular weight compounds,removed CHON compounds and enhanced the formation of Cl-DBPs.The results provide information about NOM transformation and Cl-DBPs formation at molecular levels in the UV/chlorine AOP.展开更多
基金supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52121004)National Natural Science Foundation of China(Nos.22276218 and 52022111)+1 种基金Major program Natural Science Foundation of Hunan Province of China(No.2021JC0001)Science and Technology Innovation Program of Hunan Province(No.2021RC3013).
文摘Dust particles emitted from smelters can be hazardous to ecosystems and humans,as they are often enriched in metallic compounds.Here,we combined multi-method mineralogical analysis with a sophisticated size sorting approach for copper smelting dust to study the nanosize-effect on heavy metal distribution,which has hitherto been underestimated.Three types of dust were collected from a copper flash smelter and then size-sorted using a Dekati low-pressure impactor.Results showed that all three samples could easily sort out nanoscale dust particles(<1μm,grades 10–2)and even those smaller than 100 nm(grades 5–2).Especially for electrostatic precipitators dust,the mass fraction of nanoscale dust(<1μm)could reach 10.71%.The presence of heavy metals(Pb,Zn,Cu,and As)and their mineral species in dust was examined at various particle sizes.It was discovered that different heavy metals are enriched on nanoparticles in specific sizes.In micron-sized particles,heavy metals are generally found in discrete phases(e.g.,CuSO_(4),PbSO_(4),and As_(2)O_(3)).In nanoscale particles,the dominant phase is Fe_(3)O_(4),while heavy metals are mostly found in lattice substitution(e.g.,CuFe_(2)O_(4)and ZnFe_(2)O_(4)).Two distinct nano-dust morphologies were found:One with irregular mesh or chain structures consisting of particles of a few nanometers,and the other with polygonal crystals in larger sizes of hundreds of nanometers.The enrichment of heavy metals in the latter morphology is more pronounced,possibly because lattice substitution of heavy metals is more likely to occur when polycrystalline particles are formed.
基金Projects(51304252,51374237)supported by the National Natural Science Foundation of China
文摘Magnetic chitosan composites(Fe3O4@chitosan) were synthesized in one single-step, characterized and applied in Cr(VI) removal from water. With the increase of loading proportion of chitosan, Cr(Ⅵ) adsorption capacity of Fe3O4@chitosan composites increased from 10.771 to 21.040 mg/g. The optimum adsorption capacities of Cr(VI) on Fe3O4@chitosan-3 were found in a pH range of 3.0-5.0. Kinetic study results show that the adsorption process follows pseudo-second-order model, indicating that the rate-limiting step in the adsorption of Cr(Ⅵ) involves chemisorptions. Moreover, FT-IR spectra analysis confirms that the amine and hydroxyl groups of chitosan are predominantly responsible for binding. Results from this work demonstrate that the prepared Fe3O4@chitosan composites possess great potential in Cr(Ⅵ) removal from contaminated water.
基金fundings from the National Natural Science Foundation of China (No. 51872173)Taishan Scholar Foundation of Shandong Province (No. tsqn201812068)+3 种基金Natural Science Foundation of Shandong Province (No. ZR2022JQ21)Higher School Youth Innovation Team of Shandong Province (No. 2019KJA013)Hong Kong Scholars Program (No. XJ2019042)Innovation and Technology Commission of the Hong Kong Special Administrative Region (No. ITC-CNERC14EG03)。
文摘Hydrophobic treatment of the catalyst surfaces can suppress the competitive hydrogen evolution reaction(HER) during the nitrogen reduction reaction(NRR).In this work,the surface of Ti_(3)C_(2)Ti_(x) MXene is modified by cetyltrimethylammonium bromide(CTAB) and trimethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8-trideca fluorooctyl) silane(FOTS) to increase the hydrophobicity of MXenes.The ammonia(NH_(3)) production rate and faradaic efficiency(FE) are improved from 37.62 to 54.01 μg h^(-1)mg_(cat)^(-1).and 5.5% to 18.1% at-0.7 V vs.RHE,respectively after surface modification.^(15)N isotopic labeling experiment confirms that nitrogen in produced ammonia originates from N_(2) in the electrolyte.The excellent NRR activity of surface hydrophobic MXenes is mainly due to surfactant molecules,which inhibit the entry of water molecules and the competitive HER,which have been verified by in situ FT-IR,DFT and molecular dynamics calculations.This strategy provides an ingenious method to design more active NRR electrocatalysts.
基金supported by the National Key Research and Devel-opment Program of China(Grant No.2019YFA0210400)the National Natural Science Foundation of China(Grant Nos.21836002 and 52104315)+1 种基金the Foundation for Innovative Research Groups of the Na-tional Natural Science Foundation of China(Grant No.52121004)the Major program Natural Science Foundation of Hunan Province of China(No.2021JC0001).
文摘Heavy metal(loid)s(HMs)have caused serious environmental pollution and health risks.Although the past few years have witnessed the achievements of studies on environmental behavior of HMs,the related toxicity mechanisms,and pollution control,their relationship remains a mystery.Researchers generally focused on one topic independently without comprehensive considerations due to the knowledge gap between environmental science and human health.Indeed,the full life cycle control of HMs is crucial and should be reconsidered with the combination of the occurrence,transport,and fate of HMs in the environment.Therefore,we started by reviewing the environmental behaviors of HMs which are affected by a variety of natural factors as well as their physicochemical properties.Furthermore,the related toxicity mechanisms were discussed according to exposure route,toxicity mechanism,and adverse consequences.In addition,the current state-of-the-art of available technologies for pollution control of HMs wastewater and solid wastes were summarized.Finally,based on the research trend,we proposed that advanced in-operando characterizations will help us better understand the fundamental reaction mechanisms,and big data analysis approaches will aid in establishing the prediction model for risk management.
基金supported by the National Key Research and Development Program of China(No.2020YFC1808002)the National Natural Science Foundation of China(Nos.52104406,and U20A20267)the Natural Science Foundation of Hunan Province(Nos.2022JJ20074,and 2020JJ4740)。
文摘Lignin is a common soil organic matter that is present in soils,but its effect on the transformation of ferrihydrite(Fh)remains unclear.Organic matter is generally assumed to inhibit Fh transformation.However,lignin can reduce Fh to Fe(Ⅱ),in which Fe(Ⅱ)-catalyzed Fh transformation occurs.Herein,the effects of lignin on Fh transformation were investigated at 75℃ as a function of the lignin/Fh mass ratio(0-0.2),pH(4-8)and aging time(0-96 hr).The results of Fh-lignin samples(mass ratios=0.1)aged at different pH values showed that for Fh-lignin the time of Fh transformation into secondary crystalline minerals was significantly shortened at pH 6 when compared with pure Fh,and the Fe(Ⅱ)-accelerated transformation of Fh was strongly dependent on pH.Under pH 6,at low lignin/Fh mass ratios(0.05-0.1),the time of secondary mineral formation decreased with increasing lignin content.For high lignosulfonate-content material(lignin:Fh=0.2),Fh did not transform into secondary minerals,indicating that lignin content plays a major role in Fh transformation.In addition,lignin affected the pathway of Fh transformation by inhibiting goethite formation and facilitating hematite formation.The effect of coprecipitation of lignin on Fh transformation should be useful in understanding the complex iron and carbon cycles in a soil environment.
基金Project(2021M703651)supported by the Postdoctoral Science Foundation of ChinaProject(52121004)supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China+1 种基金Project(51825403)supported by the National Natural Science Fundation for Distinguished Young Scholars of ChinaProject(2021RC2010)supported by the Science and Technology Innovation Program of Hunan Province,China。
基金supported by the National Natural Science Foundation of China(No.52234011)the National Key R&D Program of China(No.2017YFC0210400)。
文摘Air pollutant emissions represent a critical challenge in the green development of the non-ferrous metallurgy industry.This work studied the emission characteristics,formation mechanisms,phase transformation and separation of typical air pollutants,such as heavy metal particles,mercury,sulfur oxides and fluoride,during non-ferrous smelting.A series of purification technologies,including optimization of the furnace throat and hightemperature discharge,were developed to collaboratively control and recover fine particles from the flue gas of heavy metal smelting processes,including copper,lead and zinc.Significant improvements have been realized in wet scrubbing technology for removing mercury,fluoride and SO_(2)from flue gas.Gas-liquid sulfidation technology by applying H_(2)S was invented to recycle the acid scrubbing wastewater more efficiently and in an eco-friendly manner.Based on digital technology,a source reduction method was designed for sulfur and fluoride control during the whole aluminum electrolysis process.New desulfurization technologies were developed for catalytic reduction of the sulfur content in petroleum coke at low temperature and catalytic reduction of SO_(2)to elemental sulfur.This work has established the technology for coupling multi-pollutant control and resource recovery from the flue gas from non-ferrous metallurgy,which provides the scientific theoretical basis and application technology for the treatment of air pollutants in the non-ferrous metallurgy industry.
基金financially supported by the National Key R&D Program of China(Nos.2018YFC1900302 and 2020YFC1909201)the National Science Fund for Distinguished Young Scholars(No.51825403)。
文摘Cubic boron arsenide(BAs)has attracted great attention due to its high thermal conductivity,however,its controllable,stable,and ideal preparation remains challenging.Herein,we investigated the effect of iodine-containing transport agents I_(2) and boron triiodide(BI_(3))on BAs synthesized and grown through chemical vapor transport.Results show that similar to the commonly used I_(2),BI_(3) accelerates the synthesis and improves the mass fraction of BAs from ~12% to over 90% at 820℃ and 1.5 MPa,a value beyond the promoting effect of only increasing temperature and pressure.Both agents enhance the quality of BAs crystals by reducing the full width at half maximum by up to 10%-20%.I_(2) agglomerates the grown crystals with twin defects(~50 nm wide),and BI_(3) improves the crystal anisotropy and element uniformity of BAs crystals with narrow twins(~15 nm wide)and increases the stoichiometry ratio(~0.990)to almost 1.Owing to the boron interstitials from the excessive boron supply,the spacing of layers in {111} increases to 0.286 nm in the presence of I_(2).Owing to its coordinated effect,BI_(3) only slightly influences the layer spacing at 0.275 nm,which is close to the theoretical value of 0.276 nm.In the chemical vapor transport,the anisotropic crystals with flat surfaces exhibit single-crystal characteristics under the action of BI_(3).Different from that of I_(2),the coordinated effect of BI_(3) can promote the efficient preparation of high-quality BAs crystal seeds and facilitate the advanced application of BAs.
文摘With over 30 years of development for lithium ion batteries(LIBs),LIBs have achieved great success in terms of their cathodes,anodes,electrolytes,and other necessary components[1].Their battery chemistry has also been extended to sodium,potassium,and other alkaline ion batteries,which have also made great achievements[2-4].
基金supported by the National Natural Science Foundations of China(No.52000182,U21A20294,51878662)the Natural Science Foundation of Hunan Province(No.2020JJ4725)the Technological Innovation Guidance Program of Jiangxi Province(No.20203BDH80W017).
文摘The hexavalent chromium(Cr(Ⅵ))would frequently impose inhibition to anaerobic ammonium oxidation(anammox)process,hindering the efficiency of nitrogen removal in wastewater treatment.Hydrazine(N2H4),which is an intermediate product of anammox,participates in intracellular metabolism and extracellular Cr(Ⅵ)reduction.However,the roles of N_(2)H_(4)-induced intracellular metabolism and extracellular reduction in nitrogen removal under Cr(Ⅵ)stress remain unclear.The addition of 3.67 mg/L of N2H4 increased the anammox activity by 17%.As an intermediate,N2H4 enhanced anammox metabolism by increasing the heme c content and electron transfer system activity.As a reductant,N_(2)H_(4) accelerated the reduction of c-Cyts-mediated extracellular Cr(Ⅵ)to the less toxic Cr(Ⅲ).Extracellular Cr(Ⅲ)accounts for 74%of the total Cr in a Cr(Ⅵ)-stressed anammox consortia.These findings highlight that N_(2)H_(4)-induced extracellular Cr(Ⅵ)reduction is the dominant mechanism for the survival of anammox consortia.We also found that N_(2)H_(4) increased the production of extracellular polymeric substances to sequester excessive Cr(Ⅵ)and produced Cr(Ⅲ).Taken together,the study findings suggest a potential strategy for enhancing nitrogen removal from ammonium-rich wastewater contaminated with Cr(Ⅵ).
基金financially supported by the National Key R&D Program of China(No.2022YFC3900200)Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52121004)+3 种基金Major program Natural Science Foundation of Hunan Province of China(No.2021JC0001)National Natural Science Foundation of China(No.22276218)key projects of Science and Technology of Hunan Province(No.2020SK2006)Science and Technology Innovation Program of Hunan Province(No.2021RC3013).
文摘Antimony(Sb)in natural water has long-term effects on both the ecological environment and human health.Iron mineral phase transformation(IMPT)is a prominent process for removing Sb(V)from natural water.However,the importance of IMPT in eliminating Sb remains uncertain.This study examined the various Sb–Fe binding mechanisms found in different IMPT pathways in natural water,shedding light on the underlying mechanisms.The study revealed that the presence of goethite(Goe),hematite(Hem),and magnetite(Mag)significantly affected the concentration of Sb(V)in natural water.Elevated pH levels facilitated higher Fe content in iron solids but impeded the process of removing Sb(V).To further our understanding,polluted natural water samples were collected from various locations surrounding Sb smelter sites.Results confirmed that converting ferrihydrite(Fhy)to Goe significantly reduced Sb levels(<5μg/L)in natural water.The emergence of secondary iron phases resulted in greater electrostatic attraction and stabilized surface complexes,which was the most likely cause of the decline of Sb concentration in natural water.The comprehensive findings offer new insights into the factors governing IMPT as well as the Sb(V)behavior control.
基金supported by the Hong Kong Innovation and Technology Commission (No.ITC-CNERC14EG03)the Research Grants Council of the Hong Kong SAR (No.T21-604/19R)。
文摘This study investigated the degradation of clofibric acid(CFA),bezafibrate(BZF),and sulfamethoxazole(SMX)in synthetic human urine using a novel mesoporous iron powderactivated persulfate system(mFe-PS system),and identified the factors limiting their degradation in synthetic human urine.A kinetic model was established to expose the radical production in various reaction conditions,and experiments were conducted to verify the modeling results.In the phosphate-containing mFe-PS system,the 120 min removal efficiency of CFA decreased from 95.1%to 76.6%as the phosphate concentration increased from 0.32 to 6.45 mmol/L,but recovered to 90.5%when phosphate concentration increased to 16.10 mmol/L.Meanwhile,the increased concentration of phosphate from 0.32 to 16.10mmol/L reduced the BZF degradation efficacy from 91.5%to 79.0%,whereas SMX removal improved from 37.3%to 62.9%.The m Fe-PS system containing(bi)carbonate,from 4.20 to166.70 mmol/L,reduced CFA and BZF removal efficiencies from 100%to 76.8%and 80.4%,respectively,and SMX from 83.5%to 56.7%within a 120-min reaction time.In addition,alkaline conditions(pH≥8.0)inhibited CFA and BZF degradations,while nonacidic pH(pH≥7.0)remarkably inhibited SMX degradation.Results of the kinetic model indicated the formation of phosphate(H_(2)PO_(4)^(·)/HPO_(4)^(·-))and/or carbonate radicals(CO_(3)^(·-))could limit pharmaceutical removal.The transformation products(TPs)of the pharmaceuticals revealed more incompletely oxidized TPs occurred in the phosphate-and(bi)carbonate-containing m Fe-PS systems,and indicated that H_(2)PO_(4)^(·)/HPO_(4)^(·-)mainly degraded pharmaceuticals via a benzene ring-opening reaction while CO_(3)^(·-)preferentially oxidized pharmaceuticals via a hydroxylation reaction.
基金supported by the National Natural Science Foundation of China(No.22222612)Major program Natural Science Foundation of Hunan Province of China(No.2021JC0001)the National Key Research and Development Program of China(No.2019YFA0210400).
文摘Organo-chromium(III)complex is one of the chromium contaminant species,which would transform to high-toxic Cr(VI)during migrating in the environment.Such natural organo-chromium(III)(NOCr)is difficult to remove by traditional degradation or precipitation methods,due to its high stability and solubility.Herein,we demonstrated a novel NOCr removing method by transforming it to certain structures similar to Cr-Fe minerals in nature,through a self-circulating decomplex and immobilization mechanism with nano zero-valent iron(nZVI).Taking chromium glycinate(Cr-Gly)as a probe,nZVI showed a high Cr removal efficiency of 99.4%under ambient conditions.The removal process included three stages of adsorption,decomplexation,and re-immobilization.Cr-Gly was first adsorbed on the surface of nZVI by chemisorption of the oxide shell.Then,the adsorbed Cr-Gly was decomplexed and oxidized to Cr(VI)by·OH and 1O_(2),which were generated from molecular oxygen activated by nZVI.Meanwhile,the released Cr(VI)could be in-situ adsorbed and re-reduced to Cr(III),which was further immobilized in form of Cr-O-Fe complex.As the Cr-O-Fe complexing structure was similar to that of Cr-Fe minerals(such as chromohercynite)in nature,this work explored a novel and efficient NOCr removing method that was potential to weaken chromium pollution in the environment.
基金supported by the National Key Research and Development Program of China(No.2017YFE0133200)the National Natural Science Foundation of China(Nos.21876210 and 21806173)+1 种基金the Guangdong Provincial Science and Technology Planning Projects(No.2019A050503006)Hong Kong RGC(Nos.16206416 and T21-604/19-R)。
文摘UV/chlorine process,as an emerging advanced oxidation process(AOP),was effective for removing micro-pollutants via various reactive radicals,but it also led to the changes of natural organic matter(NOM)and formation of disinfection byproducts(DBPs).By using negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS),the transformation of Suwannee River NOM(SRNOM)and the formation of chlorinated DBPs(Cl-DBPs)in the UV/chlorine AOP and subsequent post-chlorination were tracked and compared with dark chlorination.In comparison to dark chlorination,the involvement of Cl O·,Cl·,and HO·in the UV/chlorine AOP promoted the transformation of NOM by removing the compounds owning higher aromaticity(AI mod)value and DBE(double-bond equivalence)/C ratio and causing the decrease in the proportion of aromatic compounds.Meanwhile,more compounds which contained only C,H,O,N atoms(CHON)were observed after the UV/chlorine AOP compared with dark chlorination via photolysis of organic chloramines or radical reactions.A total of 833 compounds contained C,H,O,Cl atoms(CHOCl)were observed after the UV/chlorine AOP,higher than 789 CHOCl compounds in dark chlorination,and one-chlorine-containing components were the dominant species.The different products from chlorine substitution reactions(SR)and addition reactions(AR)suggested that SR often occurred in the precursors owning higher H/C ratio and AR often occurred in the precursors owning higher aromaticity.Post-chlorination further caused the cleavages of NOM structures into small molecular weight compounds,removed CHON compounds and enhanced the formation of Cl-DBPs.The results provide information about NOM transformation and Cl-DBPs formation at molecular levels in the UV/chlorine AOP.
基金Projects(2018YFC1801805,2018YFC1903301)supported by National Key R&D Program of ChinaProject(51825403)supported by National Science Fund for Distinguished Young Scholars,ChinaProject(2019SK2281)supported by Key R&D Program of Hunan Province,China。
基金Project(2018YFC1900300)supported by the National Key R&D Program of ChinaProject(51825403)supported by the National Science Fund for Distinguished Young Scholars,ChinaProject(2018SK2026)supported by the Key R&D Program of Hunan Province,China。
基金Project(2018YFC1900304)supported by the National Key R&D Program of ChinaProject(2018SK2026)supported by the Key R&D Program of Hunan Province,ChinaProject(2017SK2420)supported by the Science and Technology of Hunan Province,China。
基金Project(2021JJ30792) supported by the Natural Science Foundation of Hunan Province,ChinaProject(52170031) supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities,China。
