Meng Zhuowen, Wu Jingwei, Huang Shuang, Xin Lei, Zhao Qin
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.
Sci Total Environ. 2024 Feb 25;913:169524. doi: 10.1016/j.scitotenv.2023.169524. Epub 2023 Dec 21.
In this study, the effects of coexistence with microplastics and co-ageing with the soil on adsorption behaviors and mechanisms of biochar for heavy metals were investigated. Adsorption experiments of Cd, Ni, and Cu by microplastics, biochar, and their combination were conducted in single, binary, and ternary systems. The results indicated that the heavy metal adsorption by microplastics was ranked as Ni > Cd > Cu, which increased with decreasing particle size, and the adsorption capacity of microplastics was enhanced after dry-wet and freeze-thaw ageing. Biochar preferentially adsorbed Cd in the single system, while the maximum adsorption of Cu was observed in the binary and ternary systems due to the minimizing impact of competition on the Cu adsorption by biochar. The heavy metal adsorption by the combination of microplastics and biochar was less than that by single biochar, and the smaller the particle size of microplastics, the greater the negative effects on heavy metal adsorption. Coexistence with microplastics reduced Cd adsorption of biochar by 0.72 %-50.35 %, Ni adsorption by 1.17 %-30.43 %, and Cu adsorption by 5.78 %-47.88 %, respectively. Moreover, coexistence with microplastics exacerbated the adverse impacts of competition on biochar adsorption for heavy metals. The contribution percentages of biochar mineral mechanisms for heavy metal adsorption were ranked as Cu > Cd > Ni. When coexisting with microplastics or after ageing, the mineral mechanisms of heavy metal adsorption by biochar significantly decreased. This study investigated the competitive adsorption behaviors and mechanisms of heavy metals by biochar when coexisting with microplastics, which highlighted that the application of biochar for the remediation of heavy metal pollution should be concerned with the impacts of microplastics.
本研究考察了微塑料共存及与土壤共老化对生物炭吸附重金属行为及机制的影响。在单体系、双体系和三体系中开展了微塑料、生物炭及其组合对镉、镍和铜的吸附实验。结果表明，微塑料对重金属的吸附顺序为镍>镉>铜，且随粒径减小而增加，干湿老化和冻融老化后微塑料的吸附能力增强。在单体系中生物炭优先吸附镉，而在双体系和三体系中观察到对铜的吸附量最大，这是因为竞争对生物炭吸附铜的影响最小。微塑料与生物炭组合对重金属的吸附小于单一生物炭，且微塑料粒径越小，对重金属吸附的负面影响越大。微塑料共存分别使生物炭对镉的吸附降低了0.72% - 50.35%，对镍的吸附降低了1.17% - 30.43%，对铜的吸附降低了5.78% - 47.88%。此外，微塑料共存加剧了竞争对生物炭吸附重金属的不利影响。生物炭矿物机制对重金属吸附的贡献百分比顺序为铜>镉>镍。当与微塑料共存或老化后，生物炭对重金属吸附的矿物机制显著降低。本研究考察了生物炭与微塑料共存时对重金属的竞争吸附行为及机制，强调生物炭在修复重金属污染中的应用应关注微塑料的影响。
