Two major problems facing agriculture at present are soil pollution and the disposal of solid wastes generated during plant growth. The method of preparing biochar from solid wastes produced by plants is a means of ma...Two major problems facing agriculture at present are soil pollution and the disposal of solid wastes generated during plant growth. The method of preparing biochar from solid wastes produced by plants is a means of maximizing the use of resources to combat the problem of soil pollution. In this study, we did not choose straw in the traditional sense but the waste branches from grape pruning, which has higher lignin cellulose, as the raw material. The biochar derived from grape branches pyrolyzed at 300˚C for two hours was utilized as a raw material to prepare modified biochar with varying concentrations of phosphoric acid. The adsorption performance and mechanism of Cd<sup>2 </sup> were explored through experiments involving different concentrations, addition amounts, reaction times, kinetic analyses, and isothermal adsorption tests. The findings indicated that the optimal adsorption of Cd<sup>2 </sup> occurred with a 20% phosphoric acid concentration, achieving the highest adsorption rate of 84.62%. At a dosage of 10 g/L, the maximum adsorption capacity reached 7.02 mg/g. The adsorption kinetics and isothermal adsorption of Cd<sup>2 </sup> on biochar modified with 0.2% phosphoric acid (0.2 PB) closely followed the pseudo-first-order kinetics model (R<sup>2</sup> > 0.98) and the Freundlich model (R<sup>2</sup> > 0.97), respectively. This suggests that the adsorption process involves both physical and chemical mechanisms. SEM and FTIR analyses revealed that phosphoric acid modification primarily increased the biochar’s specific surface area and enhanced certain original functional groups. The adsorption process predominantly involved rapid ion diffusion and chemical adsorption, as confirmed by kinetic analysis and isothermal adsorption model analysis. In summary, the adsorption efficiency of 0.2 PB significantly improved, showing potential and feasibility for heavy metal remediation in soil. This supports the environmentally friendly concept of “treating waste with waste”.展开更多
Nitrate(NO3-)is a widespread pollutant in high-salt wastewater and causes serious harm to human health.Although electrochemical removal of nitrate has been demonstrated to be a promising treatment method,the developme...Nitrate(NO3-)is a widespread pollutant in high-salt wastewater and causes serious harm to human health.Although electrochemical removal of nitrate has been demonstrated to be a promising treatment method,the development of low-cost electro-catalysts is still challenging.In this work,a phosphate modified iron(P-Fe)cathode was prepared for electrochemical removal of nitrate in high-salt wastewater.The phosphate modification greatly improved the activity of iron,and the removal rate of nitrate on P-Fe was three times higher than that on Fe electrode.Further experiments and density functional theory(DFT)calculations demonstrated that the modification of phosphoric acid improved the stability and the activity of the zero-valent iron electrode effectively for NO_(3)^(-) removal.The nitrate was firstly electrochemically reduced to ammonium,and then reacted with the anodic generated hypochlorite to N_(2).In this study,a strategy was developed to improve the activity and stability of metal electrode for NO_(3)^(-)removal,which opened up a new field for the efficient reduction of NO3-removal by metal electrode materials.展开更多
文摘Two major problems facing agriculture at present are soil pollution and the disposal of solid wastes generated during plant growth. The method of preparing biochar from solid wastes produced by plants is a means of maximizing the use of resources to combat the problem of soil pollution. In this study, we did not choose straw in the traditional sense but the waste branches from grape pruning, which has higher lignin cellulose, as the raw material. The biochar derived from grape branches pyrolyzed at 300˚C for two hours was utilized as a raw material to prepare modified biochar with varying concentrations of phosphoric acid. The adsorption performance and mechanism of Cd<sup>2 </sup> were explored through experiments involving different concentrations, addition amounts, reaction times, kinetic analyses, and isothermal adsorption tests. The findings indicated that the optimal adsorption of Cd<sup>2 </sup> occurred with a 20% phosphoric acid concentration, achieving the highest adsorption rate of 84.62%. At a dosage of 10 g/L, the maximum adsorption capacity reached 7.02 mg/g. The adsorption kinetics and isothermal adsorption of Cd<sup>2 </sup> on biochar modified with 0.2% phosphoric acid (0.2 PB) closely followed the pseudo-first-order kinetics model (R<sup>2</sup> > 0.98) and the Freundlich model (R<sup>2</sup> > 0.97), respectively. This suggests that the adsorption process involves both physical and chemical mechanisms. SEM and FTIR analyses revealed that phosphoric acid modification primarily increased the biochar’s specific surface area and enhanced certain original functional groups. The adsorption process predominantly involved rapid ion diffusion and chemical adsorption, as confirmed by kinetic analysis and isothermal adsorption model analysis. In summary, the adsorption efficiency of 0.2 PB significantly improved, showing potential and feasibility for heavy metal remediation in soil. This supports the environmentally friendly concept of “treating waste with waste”.
基金supported by the National Natural Science Foundation of China (No.22176068)the Research and Innovation Initiatives of WHPU (No.2022J03),the Hubei Provincial Natural Science Foundation (No.2023AFB938)the Scientific research project of Education Department of Hubei Province (No.D20221610).
文摘Nitrate(NO3-)is a widespread pollutant in high-salt wastewater and causes serious harm to human health.Although electrochemical removal of nitrate has been demonstrated to be a promising treatment method,the development of low-cost electro-catalysts is still challenging.In this work,a phosphate modified iron(P-Fe)cathode was prepared for electrochemical removal of nitrate in high-salt wastewater.The phosphate modification greatly improved the activity of iron,and the removal rate of nitrate on P-Fe was three times higher than that on Fe electrode.Further experiments and density functional theory(DFT)calculations demonstrated that the modification of phosphoric acid improved the stability and the activity of the zero-valent iron electrode effectively for NO_(3)^(-) removal.The nitrate was firstly electrochemically reduced to ammonium,and then reacted with the anodic generated hypochlorite to N_(2).In this study,a strategy was developed to improve the activity and stability of metal electrode for NO_(3)^(-)removal,which opened up a new field for the efficient reduction of NO3-removal by metal electrode materials.
