College of Environmental Sciences, Sichuan Agricultural University, Wenjiang, 611130, PR China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang, 611130, PR China.
College of Environmental Sciences, Sichuan Agricultural University, Wenjiang, 611130, PR China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang, 611130, PR China.
Ecotoxicol Environ Saf. 2020 Jan 15;187:109829. doi: 10.1016/j.ecoenv.2019.109829. Epub 2019 Oct 22.
Screening appropriate washing agents to remediate soils contaminated with heavy metals is crucial for decreasing metal hazards posing to environment and human health. In this study, two plant washing agents-water-extracted from Fagopyrum esculentum and Fordiophyton faberi, were applied to remove soil Pb, Zn, and Cd by washing. Results indicated that metal removals augmented with increase of washing solution concentrations, decreased with increasing pH values of the solution and followed the pseudo-second-order model depending on contact duration. At concentration of 50 g/L, pH 3 and contact duration of 120 min, F. esculentum had higher removals of Pb (5.98-6.83%), Zn (21.82-27.94%), and Cd (39.90-40.74%) than those of F. faberi. And metal ions could be removed by binding with carboxyl, hydroxyl, amide, amine and aromatic groups in washing solutions. The potential risks of residual metals declined by 51.35-52.12% for mine soil and 48.51-49.96% for farmland soil with exchangeable and carbonate-bound fractions obviously extracted after a single washing (P < 0.05). And soil organic carbon and nutrients increased to some extent except for total phosphorus and available potassium. Moreover, soil phytotoxicity lowered except that some adverse effects on seed germination existed. Therefore, the water extract from F. esculentum is a promising washing agent for heavy metal removal.
筛选合适的洗涤剂来修复重金属污染的土壤对于降低金属对环境和人类健康的危害至关重要。本研究采用水提取苦荞麦和尾穗苋两种植物洗涤剂来去除土壤中的 Pb、Zn 和 Cd。结果表明，金属去除率随洗涤溶液浓度的增加而增加，随溶液 pH 值的升高而降低，且随接触时间的延长而符合准二级动力学模型。在 50 g/L 浓度、pH 3 和 120 min 的接触时间下，苦荞麦对 Pb（5.98-6.83%）、Zn（21.82-27.94%）和 Cd（39.90-40.74%）的去除率均高于尾穗苋。金属离子可通过与洗涤液中的羧基、羟基、酰胺、胺和芳基结合而被去除。单次洗涤后，矿区土壤中可交换态和碳酸盐结合态的金属残留风险分别降低了 51.35-52.12%，农田土壤分别降低了 48.51-49.96%（P < 0.05）。除总磷和有效钾外，土壤有机碳和养分均有一定程度的增加。此外，土壤的生物毒性降低，仅存在对种子萌发的一些不利影响。因此，苦荞麦水提取物是一种很有前途的重金属去除洗涤剂。
