Excessive waste production has led to the concept of a circular bioeconomy to deliver valuable by-products and improve environmental sustainability.The annual worldwide rice production accounts for more than 750 milli...Excessive waste production has led to the concept of a circular bioeconomy to deliver valuable by-products and improve environmental sustainability.The annual worldwide rice production accounts for more than 750 million tons of grain and 150 million tons of husk.Rice husk(RH)contains valuable biomaterials with extensive applications in various fields.The proportions of each component depend primarily on rice genotype,soil chemistry,and climatic conditions.RH and its derivatives,including ash,biochar,hydrochar,and activated carbon have been placed foreground of applications in agriculture and other industries.While the investigation on RH’s compositions,microstructures,and by-products has been done copiously,owing to its unique features,it is still an open-ended area with enormous scope for innovation,research,and technology.Here,we reviewed the latest applications of RH and its derivatives,including fuel and other energy resources,construction materials,pharmacy,medicine,and nanobiotechnology to keep this versatile biomaterial in the spotlight.展开更多
Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented ...Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented RH and to evaluate their influence on the behavior of raw earth for application in plaster. The influences of two types of RH are evaluated: granular rice husk (RHg) and powdered RH (RHp). The clay mainly consists of clay (40%), silt (22%), and sand (38.4%), with a small proportion of gravel (0.24%). Its liquidity limit is 40% and the plasticity index is 26.5%. The mixtures were designed using earth and each of the two rice husks at the volumetric content of 10%, 15% and 20% of the total volume mixed with water 36.5%, 38.5% and 40.3% and fermented for three weeks. Each fermented mixture was added to the soil to form the paste, and 40 × 40 × 160 mm<sup>3</sup> test speciments were made for characterization. The results generally show an improvement in the physico-mechanical properties and water resistance of the mortars containing fermented RH, with an optimal content between 10% and 15%. The powdered RH improved the performance of the mortar better than granular RH.展开更多
Managing agricultural waste and expanded polystyrene (EPS) poses significant environmental and economic challenges. This study aims to create composites from millet husks, rice husks, and recycled EPS, using a manufac...Managing agricultural waste and expanded polystyrene (EPS) poses significant environmental and economic challenges. This study aims to create composites from millet husks, rice husks, and recycled EPS, using a manufacturing method that involves dissolving the polystyrene in a solvent followed by cold pressing. Various particle sizes and two binder dosages were investigated to assess their influence on the physico-mechanical properties of the composites. The mechanical properties obtained range from 2.54 to 4.47 MPa for the Modulus of Rupture (MOR) and from 686 to 1400 MPa for the Modulus of Elasticity in Bending (MOE). The results indicate that these composites have potential for applications in the construction sector, particularly for wood structures and interior decoration. Moreover, surface treatments could enhance their durability and mechanical properties. This research contributes to the valorization of agricultural and plastic waste as eco-friendly and economical construction materials.展开更多
Increasing the population and infrastructure in both emerging and developed countries requires a considerable amount of cement, which significantly affects the environment. The primary materials of concrete (‘cement...Increasing the population and infrastructure in both emerging and developed countries requires a considerable amount of cement, which significantly affects the environment. The primary materials of concrete (‘cement’) production emit a large quantity of CO<sub>2</sub> into the environment. Also, the cost of conventional building materials like cement gives motivation to find geopolymer waste materials for concrete. To reduce harmful effects on the environment and cost of traditional concrete substance, alternative waste materials like rice husk ash (RHA), ground granulated blast-furnace (GGBS), fly ash (FA), and metakaolin (MK) can be used due to their pozzolanic behavior. RHA waste material with a high silica concentration obtained from burning rice husks can possibly be used as a supplementary cementitious material (SCM) in the manufacturing of concrete, and its strong pozzolanic properties can contribute to the strength and impermeability of concrete. This review paper highlights a summary of the positive effect of using RHA as a partial substitute for cement in building construction, as well as its optimal inclusion of enhanced mechanical properties like compressive strength, flexural strength, and split tensile strength of mortar and concrete.展开更多
Rice production generates a significant amount of agricultural waste. This study aimed to give results related to the existence of antioxidant phenols in agricultural waste of selected Northern Thai rice varieties. Th...Rice production generates a significant amount of agricultural waste. This study aimed to give results related to the existence of antioxidant phenols in agricultural waste of selected Northern Thai rice varieties. The antioxidant activities, contents of total flavonoids and phenolic compounds in the ethanolic rice husk extract were evaluated. The highest antioxidant activities were found in the variety PES1CMU, with 2,2’-azinobis-3-ethyl-benzothiazoline-6-sulfonic acid and 2,2-diphenyl-1-picrylhydrazyl as 679.66 and 4.16 mmol/(L·g) trolox equivalent, respectively, ferric reducing antioxidant power as 0.87 mmol/(L·g) Fe2+, total phenolic content as 29.90 mmol/(L·g) gallic acid and total flavonoid content as 12.16 mg/g catechin equivalent. Polyphenol compounds were identified mainly by standard polyphenols using the liquid chromatography mass spectrometry, with the highest contents of phytic acid, o-coumaric acid, naringin and kaempferol. The non-glutenous and wetland ecotypes of rice husk samples were the richest in antioxidant activities and polyphenol contents characterized by using principal component analysis. The glutenous rice husk contained higher antioxidant activities than the rest. Interestingly, quercetin is a significant phenolic compound that positively correlated with the overall antioxidant activities of rice husk. This finding will be relevant for future application of rice husk antioxidant components in the production of functional ingredients as well as for the food and pharmaceutical industries.展开更多
Fiber-reinforced soils have been increasingly used in geotechnical engineering.Over the years,research has sought to understand and investigate the influences of fibers as reinforcement in soilefiber mixtures.This stu...Fiber-reinforced soils have been increasingly used in geotechnical engineering.Over the years,research has sought to understand and investigate the influences of fibers as reinforcement in soilefiber mixtures.This study assessed the behavior of clayey soil in the city of Curitiba(Paraná,Brazil),adding rice husk fiber(RHF),an industrial waste from Cooperativa Agroindustrial in Alegrete(Rio Grande do Sul,Brazil).To evaluate the effect of the presence of natural RHF on the mechanical behavior of compacted soil,aspects such as the influence of fiber content and the drained and undrained behaviors of the soil were evaluated through unconfined triaxial compression tests.The following tests were realized:soil granulometry,specific mass of solids and Atterberg limits.Specimens were produced in quadruplicate for the soil and mixtures using the RHF contents of 0.5%,0.75%,1%and 1.5%to determine the unconfined compressive strength(UCS).Triaxial tests were realized on a pure soil specimen and the specimens with 1%RHF under confining pressures of 50 kPa,100 kPa,200 kPa and 400 kPa.The interactions at the interface between husk surface and soil were analyzed using scanning electron microscopy(SEM).In UCS tests,specimens with RHF percentages of 1%and 1.5%presented the highest results,with an increment of 36%compared to the soil without RHF.The results of the consolidated drained triaxial compression tests show that in terms of effective stress,there was a small difference in the strength of the compacted pure soil and soil with the addition of RHF.For the undrained tests,the strength increased with the inclusion of husk,with a reduction of 50%in cohesion and an increment of 22%in friction angle for specimens containing RHF compared to the soil without RHF additions.展开更多
This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeabil...This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeability and water absorption capacity. Thus, in this study, the water-to-cement ratio was kept constant (0.45), the binder materials content for conventional mix was kept constant at (350 kg/m<sup>3</sup>) and the partial replacement of cement with RHASBA used was 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The maximum compressive strength was noted at a 5% replacement level of cement with RHASBA. The Results showed that the optimum replacement of cement with RHASBA in concrete was 5%, which was found to increase the compressive strength by 15%, flexural strength by 3.4%, lowered permeability by 50%, lowered sorptivity by 11.34% as compared with control concrete at 90 days of curing time. The micro-structural test results further established that RHA and SBA have a high content of SiO<sub>2</sub> which enables them to be more reactive in concrete and also revealed that the presence of RHASBA depletes Ca(OH)<sub>2</sub> crystals, converting it into CaH<sub>2</sub>O<sub>4</sub>Si (C-S-H gel) leading to the strengthening of bond within the concrete matrix.展开更多
This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeabil...This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeability and water absorption capacity. Thus, in this study, the water-to-cement ratio was kept constant (0.45), the binder materials content for conventional mix was kept constant at (350 kg/m<sup>3</sup>) and the partial replacement of cement with RHASBA used was 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The maximum compressive strength was noted at a 5% replacement level of cement with RHASBA. The Results showed that the optimum replacement of cement with RHASBA in concrete was 5%, which was found to increase the compressive strength by 15%, flexural strength by 3.4%, lowered permeability by 50%, lowered sorptivity by 11.34% as compared with control concrete at 90 days of curing time. The micro-structural test results further established that RHA and SBA have a high content of SiO<sub>2</sub> which enables them to be more reactive in concrete and also revealed that the presence of RHASBA depletes Ca(OH)<sub>2</sub> crystals, converting it into CaH<sub>2</sub>O<sub>4</sub>Si (C-S-H gel) leading to the strengthening of bond within the concrete matrix.展开更多
Experimental work was mounted using 5.7 mL of the Conplast SP430 admixture and rice husk ash(RHA)at replacement levels of 0 to 50%at 10%intervals by wt.%of cement.It is on the performance of Conplast SP 430 admixture ...Experimental work was mounted using 5.7 mL of the Conplast SP430 admixture and rice husk ash(RHA)at replacement levels of 0 to 50%at 10%intervals by wt.%of cement.It is on the performance of Conplast SP 430 admixture and its effects on concrete and concrete with rice husk ash.Concrete specimens were cast and cured for 3 to 90 days and subjected to slump and mechanical characteristics tests.Data generated from the experiments were analyzed and sensitivity analysis of the concrete mix was determined using the Minitab 18 Statistical Package.The results showed that CP with concrete improves the workability of the concrete and reduces water absorption.The reverse was the case when RHA was used with the admixture which may be an issue of compatibility.The statistical characteristics restrict good and within the specified limits.展开更多
Rice husk is an organic silicon source for amorphous nano⁃silica particles.This paper reports the experimental study on the industrial production of nano⁃silica by rice husk combustion in a specially⁃designed 0.7 MW d...Rice husk is an organic silicon source for amorphous nano⁃silica particles.This paper reports the experimental study on the industrial production of nano⁃silica by rice husk combustion in a specially⁃designed 0.7 MW double⁃circulating fluidized bed(DCFB)based on acid pretreatment process.The physicochemical properties of RHA were characterized by various testing instruments.Results showed that acid pretreatment removed a large amount of metal impurities in the rice husk and thus inhibited the formation of crystalline silica or the agglomeration during the fluidized bed combustion process.The combustion efficiencies were as high as 99.5%.The obtained RHA comprised white fine particles and exhibited an amorphous structure,but factors such as collection point and acid type had certain influences on the quality of RHA.The highest SiO2 purity was greater than 98.6 wt.%,the lowest content of unburned carbon was 0.2 wt.%,the specific surface area reached 178 m2/g,and the pore size reached 5 nm.The circulating fluidized bed combustion of rice husk based on acid pretreatment can prepare nano⁃silica while providing heat for industrial processes,which is a highly energy⁃rich process.展开更多
This paper critically reviewed the current knowledge and challenges of rice husk biochar(RHB)production and its effects on soil properties,plant growth,immobilization of heavy metals,reduction of nutrient leaching and...This paper critically reviewed the current knowledge and challenges of rice husk biochar(RHB)production and its effects on soil properties,plant growth,immobilization of heavy metals,reduction of nutrient leaching and mitigation of greenhouse gas emissions.The characteristics of RHBs produced at various pyrolysis temperatures were discussed and compared to biochars derived from other agro-industrial wastes.RHBs produced at higher pyrolysis temperatures show lower hydrogen/carbon ratio,which suggests the presence of higher aromatic carbon compounds.The increase of pyrolysis temperature also results in production of RHBs with higher ash content,lower yield and higher surface area.RHB usually has higher silicon and ash contents and lower carbon content compared to biochars derived from other feedstocks at the same pyrolysis conditions.Although it depends on soil type,RHB application can improve soil organic carbon content,cation exchange capacity,available K concentration,bulk density and microbial activity.The effect of RHB on soil aggregation mainly depends on soil texture.The growth of different crops is also enhanced by application of RHB.RHB addition to soil can immobilize heavy metals and herbicides and reduce their bioavailability.RHB application shows a significant capacity in reduction of nitrate leaching,although its magnitude depends on the biochar application rate and soil biogeochemical characteristics.Use of RHB,especially in paddy fields,shows a promising mitigation effect on greenhouse gas(CH4,CO2 and N2O)emissions.Although RHB characteristics are also related to other factors such as pyrolysis heating rate and residence time,its performance for specific applications(e.g.carbon sequestration,pH amendment)can be manipulated by adjusting the pyrolysis temperature.More research is needed on long-term field applications of RHB to fully understand the advantages and disadvantages of RHB as a soil amendment.展开更多
This study investigates how large-surface-area biocarbons with high phenolic adsorption capacities can be obtained from cheap and abundant rice husk(RH).The RH is directly mixed with potassium hydroxide(KOH)and activa...This study investigates how large-surface-area biocarbons with high phenolic adsorption capacities can be obtained from cheap and abundant rice husk(RH).The RH is directly mixed with potassium hydroxide(KOH)and activated in a flowing N_(2) atmosphere,and the effects of the pyrolysis temperature and KOH to RH ratio on the structure of the obtained activated carbon adsorbents and their adsorption of p-nitrophenol and phenol are studied.The results show that the optimum pyrolysis temperature of RH is 750℃,whereby the highest surface area of 2047 m^(2)/g and best adsorption performance are obtained with a KOH to RH ratio of 3:1.Moreover,the obtained biocarbons achieve a maximum adsorption capacity of 175 mg/g for phenol and 430 mg/g for p-nitrophenol,which are higher than most previously reported data.展开更多
A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere.The rice husk substrate consists of porous activated carbon and silica,where spinel fer...A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere.The rice husk substrate consists of porous activated carbon and silica,where spinel ferrite particles with average diameter of 59 nm are distributed.The surface area of the composite is greater than 170 m^2 g^(-1) and the bulk density is less than 0.6 g cm^(-3).Inert atmosphere is indispensable for the synthesis of pure ferrite composites,while different preparation temperatur...展开更多
Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability.We herein demonstrate a molten salt thermoelectrolysis of rice husks(RHs)mainl...Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability.We herein demonstrate a molten salt thermoelectrolysis of rice husks(RHs)mainly consisting of organic mass and biosilica to achieve high-efficiency and upgraded utilization of both Si and C in RHs.By coupling pyrolysis of organic mass with electrochemical reduction of silica in molten salts,the thermoelectrolysis of RHs in molten CaCl_(2)-NaCl at 800℃ refines the RHs and acidleached RHs to SiC nanowire/C(SiC-NW/C)and Si nanoparticle/C(Si-NP/C),respectively.The present study highlights the molten salt thermoelectrolysis for reclamation of biomass wastes in an affordable and controllable manner.展开更多
An industrial mineral wollastonite (CaSiO3) was produced under solid state conditions from rice husk silica and limestone. Reaction was carried out at 900’C to 1300’C for 1 h. The product batches were subjected to X...An industrial mineral wollastonite (CaSiO3) was produced under solid state conditions from rice husk silica and limestone. Reaction was carried out at 900’C to 1300’C for 1 h. The product batches were subjected to XRD and chemical analysis techniques specific for wollastonite. Mole fractions of different product batches were calculated on the basis of accumulated data to study the kinetics. Specific rate constants and reaction rate were also found out. Various probable models of mechanism for reaction were considered and testified with the laid down criterion for suggesting the suitable one. The resulting data were treated with Arrhenius equation as well and activation energy was calculated--therefrom. In addition to finding it’s value from the slope of Arrhenius curve, an alternate method was also applied for this purpose. Both of the values were observed to be comparable. The activation energy required for performed reaction was found to be almost one third of that reported for synthesizing CaSiO3 by using quartz. This referred to the economical preparation of wollastonite by using rice husk as a source of silica instead of quartz.展开更多
According to empirical evidence,high levels of energy and considerable amounts of natural resources are used in the production of concrete.Given the context,this study explores self-consolidating concrete(SCC)that inc...According to empirical evidence,high levels of energy and considerable amounts of natural resources are used in the production of concrete.Given the context,this study explores self-consolidating concrete(SCC)that includes rice husk ash(RHA)and metal furnace slag(MFS)as an alternative to cement and the natural aggregates in standard SCC mixes.In this study,mixture designs are investigated with 20 wt.%of RHA,10–30 wt.%of MFS and water-to-powder material ratios of 0.30 and 0.40.Based on the findings regarding the fresh-state,hardened-state,and durability properties of the resulting SCC mixes,it is evident that the use of RHA and MFS can significantly improve the properties of concrete.The highest compressive strength was achieved for SCC with 20 wt.%RHA and 10 wt.%MFS.This outcome should be used as a basis for further investigations into the production of concrete materials that are both high-performance and sustainable.展开更多
[Objective] The aim was to study the adsorption property of adsorbent Ni-TiO2-SiO2 synthesized by using rice husks as silicon source and template to gentian violet.[Method] The renewable dye adsorbent Ni-TiO2-SiO2 was...[Objective] The aim was to study the adsorption property of adsorbent Ni-TiO2-SiO2 synthesized by using rice husks as silicon source and template to gentian violet.[Method] The renewable dye adsorbent Ni-TiO2-SiO2 was synthesized by using rice husks as raw material,and the adsorption property of Ni-TiO2-SiO2 to gentian violet was studied.[Result] The adsorption rate of Ni-TiO2-SiO2 to gentian violet reached about 90% after 1 h.In 100 ml gentian violet solution with concentration of 25 mg/L and pH=8,Ni-TiO2-SiO2 with dosage of 0.07 g had the best adsorption effect.More importantly,Ni-TiO2-SiO2 as adsorbent could be used repeatedly,and couldn't lead to secondary pollution due to leaking.[Conclusion] The study could provide references for practical engineering application.展开更多
Biobased adsorbents are eco-friendly materials used for water and wastewater treatment and air cleaning.This research work explores the potential use of rice husk chars as a low-cost adsorbent for pollutants from wate...Biobased adsorbents are eco-friendly materials used for water and wastewater treatment and air cleaning.This research work explores the potential use of rice husk chars as a low-cost adsorbent for pollutants from water,such as methylene blue and ethinylestradiol.Rice husk chars are prepared by combustion of rice husks(RH-Char)or pre-treated rice husks(PT-Char).A third char(M-Char)supplied by a local company which uses rice husks as combustion material is also studied.The chars are characterized by field emission scanning electron microscopy(FE-SEM)in conjunction with energy dispersive X-ray spectroscopy(EDX),X-ray powder diffraction(XRD),and zeta-potential measurements.The three bio-chars are tested as adsorbent for the removal of two wastewater contaminants:methylene blue(MB)and ethinylestradiol(EE2).According to the results,RH-Char and PT-Char present zeta-potential values near−52 mV,whereas M-Char shows a zeta-potential value of−32 mV.Both RH-Char and PTChar are rich in amorphous SiO_(2) and M-Char has crystalline SiO_(2)(cristobalite).The bio-chars remove MB and EE2 efficiently showing the following results for the adsorption capacity of MB(inμmol g^(−1)):769.2(RH-Char),41.2(PT-Char),and 31.7(M-Char).The adsorption capacity values for EE2(inμmol g^(−1))are:33.1(RH-Char),19.1(PT-Char),and 16.9(M-Char).The information gathered in the present work evidences the potential of rice husks bio-chars for bio-remediation and may in future contribute to the conversion of a side-stream from the rice industry into value-added materials.展开更多
Rice husk (biomass fuel) samples have been dried in drying oven and a series of drying curve for illustrating moisture migration of rice husk have been obtained. It is first research for rice husk drying,and it can pr...Rice husk (biomass fuel) samples have been dried in drying oven and a series of drying curve for illustrating moisture migration of rice husk have been obtained. It is first research for rice husk drying,and it can provide reference of fuel processing for different boilers which require rice husk with various water contents. In this paper,we apply Page equation to reflect the drying process and obtain drying characteristic curve,then analyze the drying law. Kinetic analysis of the results of moisture migration test has been done,after which, effective moisture diffusion coefficient,activation energy and drying kinetic equation of rice husk samples are obtained in test temperature range (80 - 130 ℃) . And these results show specific influence law of temperature for effective moisture diffusion coefficient.展开更多
Nowadays an alternate source of filler from renewable and plant derivatives are being thought of in rubber industries due to their reliability,environmental and economic benefits.Rice Husk Ash(RHA)a byproduct of the r...Nowadays an alternate source of filler from renewable and plant derivatives are being thought of in rubber industries due to their reliability,environmental and economic benefits.Rice Husk Ash(RHA)a byproduct of the rice milling industry is obtained on partial and as well as full combustion of the rice husks.This ash is a good source of silica,silicates and needle shaped carbon and hence can be used as filler for cements.In the present study,a detailed investigation was carried out to understand the RHA as reinforcing material using mechanical properties and fractography using SEM.The rubbers studied were natural rubber(NR),poly chloroprene(CR)and ethylene propylene diene monomer(EPDM).Interestingly,the RHA added NR stock on open mill mixing generated considerable amount of static charges.The properties of NR were found to be as good as regular formulations.EPDM compounds behaved well during mixing.But the properties were found to be poor.CR-RHA compounds were found to result in higher viscosity and the properties were not as good.The SEM studies showed surprisingly cohesive failure as evidenced with the presence of flow lines and the fibrous filler(RHA)remains embedded in the matrix regardless of the chemistry of the repeating unit,NR,EPDM and the chlorine containing monomer inCR.展开更多
文摘Excessive waste production has led to the concept of a circular bioeconomy to deliver valuable by-products and improve environmental sustainability.The annual worldwide rice production accounts for more than 750 million tons of grain and 150 million tons of husk.Rice husk(RH)contains valuable biomaterials with extensive applications in various fields.The proportions of each component depend primarily on rice genotype,soil chemistry,and climatic conditions.RH and its derivatives,including ash,biochar,hydrochar,and activated carbon have been placed foreground of applications in agriculture and other industries.While the investigation on RH’s compositions,microstructures,and by-products has been done copiously,owing to its unique features,it is still an open-ended area with enormous scope for innovation,research,and technology.Here,we reviewed the latest applications of RH and its derivatives,including fuel and other energy resources,construction materials,pharmacy,medicine,and nanobiotechnology to keep this versatile biomaterial in the spotlight.
文摘Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented RH and to evaluate their influence on the behavior of raw earth for application in plaster. The influences of two types of RH are evaluated: granular rice husk (RHg) and powdered RH (RHp). The clay mainly consists of clay (40%), silt (22%), and sand (38.4%), with a small proportion of gravel (0.24%). Its liquidity limit is 40% and the plasticity index is 26.5%. The mixtures were designed using earth and each of the two rice husks at the volumetric content of 10%, 15% and 20% of the total volume mixed with water 36.5%, 38.5% and 40.3% and fermented for three weeks. Each fermented mixture was added to the soil to form the paste, and 40 × 40 × 160 mm<sup>3</sup> test speciments were made for characterization. The results generally show an improvement in the physico-mechanical properties and water resistance of the mortars containing fermented RH, with an optimal content between 10% and 15%. The powdered RH improved the performance of the mortar better than granular RH.
文摘Managing agricultural waste and expanded polystyrene (EPS) poses significant environmental and economic challenges. This study aims to create composites from millet husks, rice husks, and recycled EPS, using a manufacturing method that involves dissolving the polystyrene in a solvent followed by cold pressing. Various particle sizes and two binder dosages were investigated to assess their influence on the physico-mechanical properties of the composites. The mechanical properties obtained range from 2.54 to 4.47 MPa for the Modulus of Rupture (MOR) and from 686 to 1400 MPa for the Modulus of Elasticity in Bending (MOE). The results indicate that these composites have potential for applications in the construction sector, particularly for wood structures and interior decoration. Moreover, surface treatments could enhance their durability and mechanical properties. This research contributes to the valorization of agricultural and plastic waste as eco-friendly and economical construction materials.
文摘Increasing the population and infrastructure in both emerging and developed countries requires a considerable amount of cement, which significantly affects the environment. The primary materials of concrete (‘cement’) production emit a large quantity of CO<sub>2</sub> into the environment. Also, the cost of conventional building materials like cement gives motivation to find geopolymer waste materials for concrete. To reduce harmful effects on the environment and cost of traditional concrete substance, alternative waste materials like rice husk ash (RHA), ground granulated blast-furnace (GGBS), fly ash (FA), and metakaolin (MK) can be used due to their pozzolanic behavior. RHA waste material with a high silica concentration obtained from burning rice husks can possibly be used as a supplementary cementitious material (SCM) in the manufacturing of concrete, and its strong pozzolanic properties can contribute to the strength and impermeability of concrete. This review paper highlights a summary of the positive effect of using RHA as a partial substitute for cement in building construction, as well as its optimal inclusion of enhanced mechanical properties like compressive strength, flexural strength, and split tensile strength of mortar and concrete.
基金supported by Fundamental Fund 2022the Office of Research Administration,Chiang Mai University,Thailand。
文摘Rice production generates a significant amount of agricultural waste. This study aimed to give results related to the existence of antioxidant phenols in agricultural waste of selected Northern Thai rice varieties. The antioxidant activities, contents of total flavonoids and phenolic compounds in the ethanolic rice husk extract were evaluated. The highest antioxidant activities were found in the variety PES1CMU, with 2,2’-azinobis-3-ethyl-benzothiazoline-6-sulfonic acid and 2,2-diphenyl-1-picrylhydrazyl as 679.66 and 4.16 mmol/(L·g) trolox equivalent, respectively, ferric reducing antioxidant power as 0.87 mmol/(L·g) Fe2+, total phenolic content as 29.90 mmol/(L·g) gallic acid and total flavonoid content as 12.16 mg/g catechin equivalent. Polyphenol compounds were identified mainly by standard polyphenols using the liquid chromatography mass spectrometry, with the highest contents of phytic acid, o-coumaric acid, naringin and kaempferol. The non-glutenous and wetland ecotypes of rice husk samples were the richest in antioxidant activities and polyphenol contents characterized by using principal component analysis. The glutenous rice husk contained higher antioxidant activities than the rest. Interestingly, quercetin is a significant phenolic compound that positively correlated with the overall antioxidant activities of rice husk. This finding will be relevant for future application of rice husk antioxidant components in the production of functional ingredients as well as for the food and pharmaceutical industries.
文摘Fiber-reinforced soils have been increasingly used in geotechnical engineering.Over the years,research has sought to understand and investigate the influences of fibers as reinforcement in soilefiber mixtures.This study assessed the behavior of clayey soil in the city of Curitiba(Paraná,Brazil),adding rice husk fiber(RHF),an industrial waste from Cooperativa Agroindustrial in Alegrete(Rio Grande do Sul,Brazil).To evaluate the effect of the presence of natural RHF on the mechanical behavior of compacted soil,aspects such as the influence of fiber content and the drained and undrained behaviors of the soil were evaluated through unconfined triaxial compression tests.The following tests were realized:soil granulometry,specific mass of solids and Atterberg limits.Specimens were produced in quadruplicate for the soil and mixtures using the RHF contents of 0.5%,0.75%,1%and 1.5%to determine the unconfined compressive strength(UCS).Triaxial tests were realized on a pure soil specimen and the specimens with 1%RHF under confining pressures of 50 kPa,100 kPa,200 kPa and 400 kPa.The interactions at the interface between husk surface and soil were analyzed using scanning electron microscopy(SEM).In UCS tests,specimens with RHF percentages of 1%and 1.5%presented the highest results,with an increment of 36%compared to the soil without RHF.The results of the consolidated drained triaxial compression tests show that in terms of effective stress,there was a small difference in the strength of the compacted pure soil and soil with the addition of RHF.For the undrained tests,the strength increased with the inclusion of husk,with a reduction of 50%in cohesion and an increment of 22%in friction angle for specimens containing RHF compared to the soil without RHF additions.
文摘This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeability and water absorption capacity. Thus, in this study, the water-to-cement ratio was kept constant (0.45), the binder materials content for conventional mix was kept constant at (350 kg/m<sup>3</sup>) and the partial replacement of cement with RHASBA used was 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The maximum compressive strength was noted at a 5% replacement level of cement with RHASBA. The Results showed that the optimum replacement of cement with RHASBA in concrete was 5%, which was found to increase the compressive strength by 15%, flexural strength by 3.4%, lowered permeability by 50%, lowered sorptivity by 11.34% as compared with control concrete at 90 days of curing time. The micro-structural test results further established that RHA and SBA have a high content of SiO<sub>2</sub> which enables them to be more reactive in concrete and also revealed that the presence of RHASBA depletes Ca(OH)<sub>2</sub> crystals, converting it into CaH<sub>2</sub>O<sub>4</sub>Si (C-S-H gel) leading to the strengthening of bond within the concrete matrix.
文摘This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeability and water absorption capacity. Thus, in this study, the water-to-cement ratio was kept constant (0.45), the binder materials content for conventional mix was kept constant at (350 kg/m<sup>3</sup>) and the partial replacement of cement with RHASBA used was 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The maximum compressive strength was noted at a 5% replacement level of cement with RHASBA. The Results showed that the optimum replacement of cement with RHASBA in concrete was 5%, which was found to increase the compressive strength by 15%, flexural strength by 3.4%, lowered permeability by 50%, lowered sorptivity by 11.34% as compared with control concrete at 90 days of curing time. The micro-structural test results further established that RHA and SBA have a high content of SiO<sub>2</sub> which enables them to be more reactive in concrete and also revealed that the presence of RHASBA depletes Ca(OH)<sub>2</sub> crystals, converting it into CaH<sub>2</sub>O<sub>4</sub>Si (C-S-H gel) leading to the strengthening of bond within the concrete matrix.
文摘Experimental work was mounted using 5.7 mL of the Conplast SP430 admixture and rice husk ash(RHA)at replacement levels of 0 to 50%at 10%intervals by wt.%of cement.It is on the performance of Conplast SP 430 admixture and its effects on concrete and concrete with rice husk ash.Concrete specimens were cast and cured for 3 to 90 days and subjected to slump and mechanical characteristics tests.Data generated from the experiments were analyzed and sensitivity analysis of the concrete mix was determined using the Minitab 18 Statistical Package.The results showed that CP with concrete improves the workability of the concrete and reduces water absorption.The reverse was the case when RHA was used with the admixture which may be an issue of compatibility.The statistical characteristics restrict good and within the specified limits.
文摘Rice husk is an organic silicon source for amorphous nano⁃silica particles.This paper reports the experimental study on the industrial production of nano⁃silica by rice husk combustion in a specially⁃designed 0.7 MW double⁃circulating fluidized bed(DCFB)based on acid pretreatment process.The physicochemical properties of RHA were characterized by various testing instruments.Results showed that acid pretreatment removed a large amount of metal impurities in the rice husk and thus inhibited the formation of crystalline silica or the agglomeration during the fluidized bed combustion process.The combustion efficiencies were as high as 99.5%.The obtained RHA comprised white fine particles and exhibited an amorphous structure,but factors such as collection point and acid type had certain influences on the quality of RHA.The highest SiO2 purity was greater than 98.6 wt.%,the lowest content of unburned carbon was 0.2 wt.%,the specific surface area reached 178 m2/g,and the pore size reached 5 nm.The circulating fluidized bed combustion of rice husk based on acid pretreatment can prepare nano⁃silica while providing heat for industrial processes,which is a highly energy⁃rich process.
文摘This paper critically reviewed the current knowledge and challenges of rice husk biochar(RHB)production and its effects on soil properties,plant growth,immobilization of heavy metals,reduction of nutrient leaching and mitigation of greenhouse gas emissions.The characteristics of RHBs produced at various pyrolysis temperatures were discussed and compared to biochars derived from other agro-industrial wastes.RHBs produced at higher pyrolysis temperatures show lower hydrogen/carbon ratio,which suggests the presence of higher aromatic carbon compounds.The increase of pyrolysis temperature also results in production of RHBs with higher ash content,lower yield and higher surface area.RHB usually has higher silicon and ash contents and lower carbon content compared to biochars derived from other feedstocks at the same pyrolysis conditions.Although it depends on soil type,RHB application can improve soil organic carbon content,cation exchange capacity,available K concentration,bulk density and microbial activity.The effect of RHB on soil aggregation mainly depends on soil texture.The growth of different crops is also enhanced by application of RHB.RHB addition to soil can immobilize heavy metals and herbicides and reduce their bioavailability.RHB application shows a significant capacity in reduction of nitrate leaching,although its magnitude depends on the biochar application rate and soil biogeochemical characteristics.Use of RHB,especially in paddy fields,shows a promising mitigation effect on greenhouse gas(CH4,CO2 and N2O)emissions.Although RHB characteristics are also related to other factors such as pyrolysis heating rate and residence time,its performance for specific applications(e.g.carbon sequestration,pH amendment)can be manipulated by adjusting the pyrolysis temperature.More research is needed on long-term field applications of RHB to fully understand the advantages and disadvantages of RHB as a soil amendment.
文摘This study investigates how large-surface-area biocarbons with high phenolic adsorption capacities can be obtained from cheap and abundant rice husk(RH).The RH is directly mixed with potassium hydroxide(KOH)and activated in a flowing N_(2) atmosphere,and the effects of the pyrolysis temperature and KOH to RH ratio on the structure of the obtained activated carbon adsorbents and their adsorption of p-nitrophenol and phenol are studied.The results show that the optimum pyrolysis temperature of RH is 750℃,whereby the highest surface area of 2047 m^(2)/g and best adsorption performance are obtained with a KOH to RH ratio of 3:1.Moreover,the obtained biocarbons achieve a maximum adsorption capacity of 175 mg/g for phenol and 430 mg/g for p-nitrophenol,which are higher than most previously reported data.
基金supported by National High Technology Research and Development(863) Program of China(No.2007AA06Z128).
文摘A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere.The rice husk substrate consists of porous activated carbon and silica,where spinel ferrite particles with average diameter of 59 nm are distributed.The surface area of the composite is greater than 170 m^2 g^(-1) and the bulk density is less than 0.6 g cm^(-3).Inert atmosphere is indispensable for the synthesis of pure ferrite composites,while different preparation temperatur...
基金the funding support from the National Natural Science Foundation of China(51722404,51674177,51804221 and 91845113)the National Key R&D Program of China(2018YFE0201703)+2 种基金the China Postdoctoral Science Foundation(2018M642906 and 2019T120684)the Fundamental Research Funds for the Central Universities(2042017kf0200)the Hubei Provincial Natural Science Foundation of China(2019CFA065)。
文摘Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability.We herein demonstrate a molten salt thermoelectrolysis of rice husks(RHs)mainly consisting of organic mass and biosilica to achieve high-efficiency and upgraded utilization of both Si and C in RHs.By coupling pyrolysis of organic mass with electrochemical reduction of silica in molten salts,the thermoelectrolysis of RHs in molten CaCl_(2)-NaCl at 800℃ refines the RHs and acidleached RHs to SiC nanowire/C(SiC-NW/C)and Si nanoparticle/C(Si-NP/C),respectively.The present study highlights the molten salt thermoelectrolysis for reclamation of biomass wastes in an affordable and controllable manner.
文摘An industrial mineral wollastonite (CaSiO3) was produced under solid state conditions from rice husk silica and limestone. Reaction was carried out at 900’C to 1300’C for 1 h. The product batches were subjected to XRD and chemical analysis techniques specific for wollastonite. Mole fractions of different product batches were calculated on the basis of accumulated data to study the kinetics. Specific rate constants and reaction rate were also found out. Various probable models of mechanism for reaction were considered and testified with the laid down criterion for suggesting the suitable one. The resulting data were treated with Arrhenius equation as well and activation energy was calculated--therefrom. In addition to finding it’s value from the slope of Arrhenius curve, an alternate method was also applied for this purpose. Both of the values were observed to be comparable. The activation energy required for performed reaction was found to be almost one third of that reported for synthesizing CaSiO3 by using quartz. This referred to the economical preparation of wollastonite by using rice husk as a source of silica instead of quartz.
基金funded by Faculty of Engineering,King Mongkut’s University of Technology North Bangkok,Contact No.ENG-62-48funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No.777823.
文摘According to empirical evidence,high levels of energy and considerable amounts of natural resources are used in the production of concrete.Given the context,this study explores self-consolidating concrete(SCC)that includes rice husk ash(RHA)and metal furnace slag(MFS)as an alternative to cement and the natural aggregates in standard SCC mixes.In this study,mixture designs are investigated with 20 wt.%of RHA,10–30 wt.%of MFS and water-to-powder material ratios of 0.30 and 0.40.Based on the findings regarding the fresh-state,hardened-state,and durability properties of the resulting SCC mixes,it is evident that the use of RHA and MFS can significantly improve the properties of concrete.The highest compressive strength was achieved for SCC with 20 wt.%RHA and 10 wt.%MFS.This outcome should be used as a basis for further investigations into the production of concrete materials that are both high-performance and sustainable.
基金Supported by Research Funds of Educational Commission of Yunnan Province(09Y0392)Scientific Research Funds of Qujing Normal University(2009QN032)+1 种基金Teaching Reform Project of Qujing Normal University about " Key Course of Analytical Chemistry" and " Excellent Course of Instrumental Analysis"Scientific Funds of Baoshan University(11B004K)
文摘[Objective] The aim was to study the adsorption property of adsorbent Ni-TiO2-SiO2 synthesized by using rice husks as silicon source and template to gentian violet.[Method] The renewable dye adsorbent Ni-TiO2-SiO2 was synthesized by using rice husks as raw material,and the adsorption property of Ni-TiO2-SiO2 to gentian violet was studied.[Result] The adsorption rate of Ni-TiO2-SiO2 to gentian violet reached about 90% after 1 h.In 100 ml gentian violet solution with concentration of 25 mg/L and pH=8,Ni-TiO2-SiO2 with dosage of 0.07 g had the best adsorption effect.More importantly,Ni-TiO2-SiO2 as adsorbent could be used repeatedly,and couldn't lead to secondary pollution due to leaking.[Conclusion] The study could provide references for practical engineering application.
基金financed in part by FinCEAL+Program,which provided a grant to participate in a research visit atÅbo Akademi University.
文摘Biobased adsorbents are eco-friendly materials used for water and wastewater treatment and air cleaning.This research work explores the potential use of rice husk chars as a low-cost adsorbent for pollutants from water,such as methylene blue and ethinylestradiol.Rice husk chars are prepared by combustion of rice husks(RH-Char)or pre-treated rice husks(PT-Char).A third char(M-Char)supplied by a local company which uses rice husks as combustion material is also studied.The chars are characterized by field emission scanning electron microscopy(FE-SEM)in conjunction with energy dispersive X-ray spectroscopy(EDX),X-ray powder diffraction(XRD),and zeta-potential measurements.The three bio-chars are tested as adsorbent for the removal of two wastewater contaminants:methylene blue(MB)and ethinylestradiol(EE2).According to the results,RH-Char and PT-Char present zeta-potential values near−52 mV,whereas M-Char shows a zeta-potential value of−32 mV.Both RH-Char and PTChar are rich in amorphous SiO_(2) and M-Char has crystalline SiO_(2)(cristobalite).The bio-chars remove MB and EE2 efficiently showing the following results for the adsorption capacity of MB(inμmol g^(−1)):769.2(RH-Char),41.2(PT-Char),and 31.7(M-Char).The adsorption capacity values for EE2(inμmol g^(−1))are:33.1(RH-Char),19.1(PT-Char),and 16.9(M-Char).The information gathered in the present work evidences the potential of rice husks bio-chars for bio-remediation and may in future contribute to the conversion of a side-stream from the rice industry into value-added materials.
文摘Rice husk (biomass fuel) samples have been dried in drying oven and a series of drying curve for illustrating moisture migration of rice husk have been obtained. It is first research for rice husk drying,and it can provide reference of fuel processing for different boilers which require rice husk with various water contents. In this paper,we apply Page equation to reflect the drying process and obtain drying characteristic curve,then analyze the drying law. Kinetic analysis of the results of moisture migration test has been done,after which, effective moisture diffusion coefficient,activation energy and drying kinetic equation of rice husk samples are obtained in test temperature range (80 - 130 ℃) . And these results show specific influence law of temperature for effective moisture diffusion coefficient.
文摘Nowadays an alternate source of filler from renewable and plant derivatives are being thought of in rubber industries due to their reliability,environmental and economic benefits.Rice Husk Ash(RHA)a byproduct of the rice milling industry is obtained on partial and as well as full combustion of the rice husks.This ash is a good source of silica,silicates and needle shaped carbon and hence can be used as filler for cements.In the present study,a detailed investigation was carried out to understand the RHA as reinforcing material using mechanical properties and fractography using SEM.The rubbers studied were natural rubber(NR),poly chloroprene(CR)and ethylene propylene diene monomer(EPDM).Interestingly,the RHA added NR stock on open mill mixing generated considerable amount of static charges.The properties of NR were found to be as good as regular formulations.EPDM compounds behaved well during mixing.But the properties were found to be poor.CR-RHA compounds were found to result in higher viscosity and the properties were not as good.The SEM studies showed surprisingly cohesive failure as evidenced with the presence of flow lines and the fibrous filler(RHA)remains embedded in the matrix regardless of the chemistry of the repeating unit,NR,EPDM and the chlorine containing monomer inCR.
