铁改性生物炭的制备及其在重金属污染土壤修复技术中的应用进展

Preparation of iron-modified biochar and its application in heavy metal contaminated soils

生物炭已被广泛应用于修复重金属污染土壤,但粒径大、力学性能差、吸附点位较少等缺点限制了其应用。由铁基化合物和生物炭制备的铁改性生物炭,可优化生物炭的性能,弥补生物炭修复能力的不足,表现出良好的重金属钝化效果。综述了铁改性生物炭的制备方法,以及该材料对重金属污染土壤修复的研究进展:介绍了铁改性生物炭的制备方法和常用表征手段;总结了制备及修复过程中的主要影响因素(原材料、温度、投加量、修复时间等);从静电作用、离子交换、络合、氧化还原、共沉淀作用等方面阐明了铁改性生物炭对重金属的固定化机制;分析了施用铁改性生物炭对土壤微生态的影响;最后指出了铁改性生物炭材料在应用中可能存在的问题。以期为铁改性生物炭在重金属污染土壤修复中的应用提供理论依据。

At present, biochar has been widely used in the remediation of heavy metal contaminated soil, but its practical application is limited due to the shortcomings of large particle size, poor mechanical properties, and less adsorption sites. It was found that iron-modified biochar prepared by iron-based compounds and biochar could optimize the performance of biochar, make up for the lack of biochar repair ability, and show excellent heavy metal passivation effect. In this paper, the preparation and remediation of iron-modified biochar for heavy metal contaminated soil were reviewed. Firstly, the preparation and characterization methods of iron-modified biochar were introduced, and the main influencing factors(raw materials, temperature, dosage, time, etc.) in the process of preparation and remediation were summarized. Then, the immobilization mechanism of iron-modified biochar for heavy metals was elucidated from the aspects of electrostatic interaction, ion exchange,complexation, oxidation-reduction, and coprecipitation. The effects of iron-modified biochar on soil microecology were analyzed. Finally, the possible problems in the application of iron-modified biochar materials were pointed out, in order to provide theoretical basis for the application of iron-modified biochar in remediation of heavy metal contaminated soil.