Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
J Environ Manage. 2022 Nov 15;322:116113. doi: 10.1016/j.jenvman.2022.116113. Epub 2022 Aug 30.
The complicated contamination of microplastics (MPs) and heavy metals in sludge has garnered substantial attention in recent years; however, research on the behavior of MPs loading of heavy metals in sludge after sludge treatment methods is limited. Four representative sludge treatment methods were selected herein: anaerobic digestion, thermal drying, thermal hydrolysis (TH), and aerobic composting. Before and after sludge treatment, the chemical bonding of MPs, cadmium (Cd) adsorption properties, and metabolic changes in the microbial community succession was analyzed, and the factors influencing differences in Cd sorption by sludge MPs were explored. The results revealed that Cd adsorption by MPs occurs as multilayer physical adsorption that can be well fitted by Freundlich isotherms. Compared with the other three treatments, TH led to the most significant effect on the chemical bonding properties of the MPs, with a more than two-fold increase in C-O single bonds and CO double bonds, as well as adsorption of the highest amount of Cd at 767 μg/g. In addition, sludge conductivity and water content also affected Cd sorption capacity, with correlation coefficients of 0.405 and -0.384. Pedobacter, Flavobacterium, Lysobacter, and Sphingobacterium in the sludge presented a high degree of coupling with adsorption capacity, it was inferred that the above dominant species of bacteria may affect the adsorption of Cd by microplastics through the production of extracellular enzyme forms.
近年来，污泥中微塑料（MPs）和重金属的复杂污染受到了广泛关注；然而，关于污泥处理方法后 MPs 负载重金属行为的研究还很有限。本文选择了四种代表性的污泥处理方法：厌氧消化、热干燥、热水解（TH）和好氧堆肥。在污泥处理前后，分析了 MPs 的化学结合、镉（Cd）吸附特性以及微生物群落演替的代谢变化，并探讨了影响污泥 MPs 对 Cd 吸附差异的因素。结果表明，MPs 对 Cd 的吸附是多层物理吸附，可以很好地用 Freundlich 等温线拟合。与其他三种处理方法相比，TH 对 MPs 的化学结合性质影响最大，C-O 单键和 CO 双键增加了一倍以上，对 Cd 的吸附量最高，达到 767μg/g。此外，污泥电导率和含水量也影响 Cd 的吸附能力，相关系数分别为 0.405 和 -0.384。污泥中的 Pedobacter、Flavobacterium、Lysobacter 和 Sphingobacterium 与吸附能力具有高度的耦合性，可以推断上述优势细菌可能通过产生细胞外酶的形式影响微塑料对 Cd 的吸附。
