生物炭对土壤有效态重金属的作用机制进展

为了深入探究生物炭对土壤有效态重金属变化的影响，研究重点从生物炭的直接和间接作用两个方面对重金属有效态的影响机制进行了归纳概述。直接作用是指生物炭利用自身较大比表面积、疏松孔隙、丰富官能团和矿物质来吸附固定重金属，进而影响重金属形态转化的过程，包括物理吸附、静电吸引、官能团络合、离子交换、阳离子-π、化学沉淀等多种机理；间接作用是指生物炭通过改变土壤理化性质或者微生物群落多样性来影响有效态重金属含量变化的过程，以化学和微生物机制为主。最后提出结论与展望，以期为土壤重金属污染生物炭修复技术的潜在应用提供理论基础。

PROGRESS IN INFLUENTIAL MECHANISMS OF BIOCHAR ON AVAILABLE HEAVY METALS IN SOIL

In order to further explore the impact of biochar on the change of available heavy metals in soil, this study mainly summarized the mechanism of biochar influencing available heavy metals from the two aspects of direct and indirect effects. The biochar affected the speciation of heavy metal in soil, because of its large specific surface area, abundant functional-groups and minerals, during which physical adsorption, electrostatic attraction, complexation, ion exchange, and cation-π coordination, and chemical precipitation were involved in the binding of heavy metal. This is referred to direct effect, while the other was named as indirect effect. The biochar affected the speciation of heavy metal in soil by changing the physical and chemical properties of soil as well as the diversity of microbial communities, in which the chemical and microbial mechanisms played an important role in the immobilization of heavy metal. Finally, the conclusion and prospect were put forward in order to provide theoretical basis for the potential application of biochar remediation technology for soil heavy metal pollution.