用 N，N-双（羧甲基）谷氨酸和柠檬酸的混合螯合剂从污水污泥中去除重金属。
Heavy metals removal from sewage sludge with mixed chelators of N, N-bis(carboxymethyl) glutamic acid and citric acid.
机构信息
School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan, People's Republic of China.
出版信息
Environ Technol. 2022 Jan;43(2):255-263. doi: 10.1080/09593330.2020.1783373. Epub 2020 Jun 24.
The mixed chelators (MC) of N, N-bis(carboxymethyl) glutamic acid (GLDA) and citric acid (CA), which were biodegradable chelating ligand, were employed to remove heavy metals from sewage sludge. The extraction of Cd, Cu, Zn, Mn, and Cr from sludge was studied under different experimental conditions. Results showed that the removal efficiencies of heavy metals from both sludges were the highest with MC of GLDA and CA at the molar ratio of 1:5. For the sludge of plant A, the extraction efficiencies increased with increasing contact time, but only slowly increase was observed after 24 h. However, for the sludge of plant B, the removal efficiencies were significantly decreased after 16 h, and sharply decreased after 24 h. The removal efficiencies of heavy metals decreased with the increase of the solution pH, while they increased with the increase of the solution concentration. For the sludge of plant A, single washing with 200 mmol·L MC might be favourable to remove heavy metals. However, for the sludge of plant B, duplicate washing with 100 mmol·L MC could remove much more heavy metals. The concentration of Cu in sludge of plant B decreased from 695.79-139.16 mg·kg, which was conformed to the standard (GB 4284-2018). These results suggested that MC may be useful and environmentally friendly chelators in the removal of heavy metals from sewage sludge.
混合螯合剂（MC）由 N，N-双（羧甲基）谷氨酸（GLDA）和柠檬酸（CA）组成，是一种可生物降解的螯合剂，用于从污水污泥中去除重金属。研究了不同实验条件下从污泥中提取 Cd、Cu、Zn、Mn 和 Cr 的情况。结果表明，在 GLDA 和 CA 的摩尔比为 1:5 时，两种污泥中重金属的去除效率最高。对于植物 A 的污泥，提取效率随接触时间的增加而增加，但在 24 h 后仅缓慢增加。然而，对于植物 B 的污泥，在 16 h 后去除效率显著降低，在 24 h 后急剧降低。重金属的去除效率随溶液 pH 值的增加而降低，随溶液浓度的增加而增加。对于植物 A 的污泥，用 200 mmol·L 的 MC 进行单次洗涤可能有利于去除重金属。然而，对于植物 B 的污泥，用 100 mmol·L 的 MC 进行两次洗涤可以去除更多的重金属。植物 B 污泥中的 Cu 浓度从 695.79-139.16 mg·kg 降低，符合标准（GB 4284-2018）。这些结果表明，MC 可能是一种有用且环保的螯合剂，可用于从污水污泥中去除重金属。
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