秸秆生物炭的特性及其在重金属污染农田中的应用

Characteristics of Straw Biochar and Its Application in Heavy Metal-Contaminated Farmland

工农业的发展导致土壤重金属污染问题日渐突出,秸秆生物炭作为新型改良剂,可以有效缓解或修复重金属污染农田。本文综述了秸秆生物炭制备的条件、方法和技术等对其元素组成、孔隙结构、比表面积、pH、含氧基团、zeta电位等特性的影响,并探讨其对土壤重金属的影响机制,发现:(1)不同秸秆源生物炭、慢速热解及热解温度对生物炭的综合特性影响显著,直接或间接影响其对重金属污染土壤的修复效果;(2)生物炭中表面官能团的络合和无机盐的沉淀对土壤重金属的吸附固定起主要作用,可通过改性措施提高其修复效果。结合秸秆生物炭制备和应用中存在的问题,提出展望,以期为秸秆生物炭在重金属污染农田土壤修复中的实际应用提供参考。

The development of industry and agriculture brings the problem of heavy metal pollution into prominence. As a new amendment, the straw biochar can effectively alleviate or remediate the heavy metal pollution in farmland. In this study, the preparation conditions, methods and techniques of straw biochar which could affect the characteristics of straw biochar were investigated. These properties mainly included the elemental composition, pore structure, specific surface area, pH, oxygenic groups and zeta potential. Also, the influencing mechanism of these factors on soil heavy metals remediated by straw biochar was discussed. The conclusions are as follows.(1) Different straw sources, slow pyrolysis and pyrolysis temperature have significant effects on the comprehensive characteristics of biochar obtained, which directly or indirectly determined its remediation effect on the heavy metal-contaminated soil.(2) The complexation of surface functional groups on biochar and the precipitation of inorganic salts by biochar play major roles in the adsorption and fixation of heavy metals in soil, and the remediation effect can be improved by modification measures. According to the existing problems in the preparation and application of straw biochar, prospects have been put forward to provide reference for the practical application of straw biochar in the remediation of heavy metal-contaminated farmland.