State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China.
State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China.
J Hazard Mater. 2024 May 5;469:133938. doi: 10.1016/j.jhazmat.2024.133938. Epub 2024 Mar 2.
To reveal the respective evolution of soil and biochar on competitive heavy metal adsorption mechanisms after natural ageing, three soils and two biochars were tested in this study. The soil-biochar interlayer samples were buried in the field for 0.5, 1, and 2 years, for which competitive adsorption characteristics and mechanisms of soils and biochars in four systems (Cd, Cd+Ni, Cd+Cu, and Cd+Ni+Cu) were investigated. Results showed that physicochemical properties, adsorption capacity and mechanisms of soils and biochars all changed the most in the first 0.5 years. The properties and adsorption capacity of biochars gradually weakened with the ageing time, meanwhile, those of soils gradually enhanced. After co-ageing with acidic soil for 0.5 years, the Cd(II) adsorption capacity of modified biochar decreased by 86.59% in the ternary system; meanwhile, that of acidic soil increased by 65.52%. The contributions of mineral mechanisms decreased significantly, while non-mineral mechanisms were slightly affected by ageing. This study highlighted that when using biochar to remediate heavy metal-contaminated soils, biochar should be applied at least half a year in advance before planting crops so that biochar can fully contact and react with the soil.
为了揭示自然老化后土壤和生物炭对重金属竞争吸附机制的各自演变，本研究测试了三种土壤和两种生物炭。将土壤-生物炭夹层样品埋在野外 0.5、1 和 2 年，研究了四个系统（Cd、Cd+Ni、Cd+Cu 和 Cd+Ni+Cu）中土壤和生物炭的竞争吸附特性和机制。结果表明，土壤和生物炭的物理化学性质、吸附能力和机制在前 0.5 年变化最大。生物炭的性质和吸附能力随着老化时间的延长逐渐减弱，而土壤的性质和吸附能力则逐渐增强。经过 0.5 年与酸性土壤共老化后，改性生物炭在三元体系中对 Cd（II）的吸附能力下降了 86.59%；与此同时，酸性土壤的吸附能力增加了 65.52%。矿物机制的贡献显著降低，而非矿物机制受老化的影响较小。本研究强调，在使用生物炭修复重金属污染土壤时，应至少在种植作物前半年施用生物炭，以使生物炭能充分与土壤接触和反应。
