生物质炭及其纳米零价铁改性对不同氧化还原条件下土壤中重金属形态转化的影响机理

Redox potential is one of the most important factors affecting the transformation and bioavailability of heavy metals in soil. More research is needed for better understanding of the effect of soil redox potential on the interaction between biochars and heavy metals, and the associated mechanisms. The proposed study aims to investigate the effect of pristine and nano zerovalent iron-modified biochars (nZVI-BC) on the environmental behaviors of As, Cd and Cr in soil under various redox conditions. In the proposed study, biochars derived from woody green waste and straw materials will be used to prepare for the nano zerovalent iron-modified biochars. The effect of biochar type, aging process, dosage and other environmental factors on adsorption and immobilization of heavy metals on biochars will be elucidated, and the underlying mechanisms will be explored. Pot experiments will be conducted to evaluate the impact of different biochars on soil properties, plant growth and the distribution and bioavailability of heavy metals in soil with different redox potentials. The transformation and mobilization of heavy metals in soil-plant system will also be explored. An automated biogeochemical microcosm will be used to evaluate the effect of the biochars on the release kinetics, speciation and ecotoxicity of heavy metals in soil under systematic change of redox conditions. The proposed study will provide fundamental information for effective remediation of soils contaminated with heavy metals thereby enhancing environmental quality and promoting safe food production in China.

氧化还原电位是影响土壤中重金属形态和生物有效性的重要因素之一。目前，氧化还原条件对生物质炭稳定化土壤中重金属作用机理的影响尚需进一步研究。本项目旨在探讨生物质炭及纳米零价铁改性生物质炭对不同氧化还原条件下土壤中As、Cd和Cr环境行为的影响。项目拟利用园林废弃物和秸秆制备生物质炭，并合成供试纳米零价铁改性生物质炭；通过吸附试验，明确生物质炭类型、老化过程、添加量和其它环境因子对不同生物质炭吸附固定土壤中重金属的影响及机理；通过盆栽试验研究不同生物质炭对土壤理化性质、作物生长及土壤中重金属生物有效性和形态分布的影响，并探讨重金属在土壤-植物界面的转化和迁移特征；通过生物地球化学微环境模拟试验，揭示生物质炭对不同氧化还原条件下土壤中重金属结合形态、化学价态和生态毒性的影响。本项目的实施将为重金属复合污染土壤的修复提供科学依据和理论支撑，为提高我国生态环境质量和食品安全提供保障。

氧化还原电位是影响土壤中重金属形态和生物有效性的重要因素之一。目前，氧化还原条件对生物质炭稳定化土壤中重金属作用机理的影响尚需进一步研究。本项目探讨了功能生物质炭在不同氧化还原条件下对复合污染土壤中重金属环境行为的影响。通过吸附试验，明确了生物质炭类型、老化过程、添加量和其它环境因子对不同生物质炭吸附固定土壤中重金属的影响及机理；通过盆栽试验研究了功能生物质炭对土壤理化性质、作物生长及土壤中重金属生物有效性和形态分布的影响，并探讨了重金属在土壤-植物界面的转化和迁移特征；通过生物地球化学微环境模拟试验，揭示了生物质炭对不同氧化还原条件下土壤中重金属结合形态、化学价态和生态毒性的影响。本项目的顺利实施有助于可为提高修复重金属复合污染土壤的效率提供新途径，对提高我国生态环境质量和保障农产品质量安全具有重要的现实指导意义。