柱淋滤-巯基改性坡缕石钝化组合对弱碱性土壤镉铅污染控制效应  

Control effects of column leaching combined with mercapto-modified palygorskite immobilization on weakly alkaline Cd and Pb-contaminated soils

作　　者：王雅乐 徐应明 彭云英 赵立杰 秦旭 黄青青 WANG Ya-le;XU Ying-ming;PENG Yun-ying;ZHAO Li-jie;QIN Xu;HUANG Qing-qing(Agro-environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China;Key Laboratory of Original Agro-Environmental Pollution Prevention and Control,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China)

机构地区：[1]农业农村部环境保护科研监测所,天津300191 [2]农业农村部产地环境污染防控重点实验室,天津300191

出　　处：《农业环境科学学报》2020年第1期78-86,共9页Journal of Agro-Environment Science

基　　金：中国农业科学院创新工程项目(CAASCXGC-xym-2018);国家现代农业产业技术体系项目(CARS-03-25)~~

摘　　要：为研究弱碱性土壤镉(Cd)、铅(Pb)污染的控制技术,本文开展室内柱淋滤和巯基改性坡缕石钝化试验,探究柱淋滤-钝化组合对弱碱性土壤Cd和Pb污染控制效应。结果表明,乙二胺四乙酸(EDTA)和乙二胺二琥珀酸(EDDS)对弱碱性土壤Cd和Pb的淋滤效果优于谷氨酸二乙酸(GLDA),适宜淋滤浓度为3 mmol·L^-1。其中,EDTA、EDDS对土壤中Cd和Pb的总淋出率分别为58.60%和30.60%、44.78%和24.33%。随淋滤液体积的增加,淋出液pH值均逐渐增加,在淋出液体积为400 mL后逐渐趋于稳定。与原土相比,采用H2O、EDTA、GLDA和EDDS淋滤后,土壤中DTPA提取态Cd和Pb含量分别降低32.09%和16.08%、67.16%和33.64%、33.58%和18.93%、75.37%和51.15%。淋滤后土壤经0.3%巯基改性坡缕石(MPAL)钝化后DTPA提取态Cd和Pb浓度显著降低,与H2O+MPAL组合处理相比,EDTA+MPAL、GLDA+MPAL和EDDS+MPAL组合处理后土壤中DTPA提取Cd和Pb含量降低率分别为98.26%和48.01%、97.88%和45.80%、98.26%和55.59%。巯基改性坡缕石钝化可将土壤中可交换态和碳酸盐结合态Cd和Pb转变为稳定的铁锰氧化态Cd和Pb。研究表明:EDDS+MPAL组合效果较好,可显著降低土壤Cd和Pb总量和可交换态Cd和Pb含量,实现对弱碱性中重度Cd和Pb污染土壤重金属总量减少和有效态含量降低的减总降效双重控制作用。In order to study the control technology for Cd and Pb-contaminated soils, column leaching and immobilization experiments with mercapto-modified palygorskite(MPAL)were conducted to investigate the remediation effects of combined technologies on weakly alkaline contaminated soils. The results showed that ethylenediaminetetraacetic acid(EDTA)and ethylenediamine disuccinic acid(EDDS)were better than L-glutamic acid N,N-diacetic acid(GLDA)in extracting Cd and Pb, and the suitable extraction concentration was 3 mmol·L^-1. The leaching efficiencies of Cd and Pb in EDTA were 58.60% and 30.60% and those in EDDS were 44.78% and 24.33%, respectively. With the increase in the leachate volume, the pH of the leachate increased slowly and gradually stabilized after 400 mL. Compared with the original soil, DTPA-Cd and DTPA-Pb in the soil after H2 O, EDTA, GLDA, and EDDS-assisted leaching declined by32.09% and 16.08%, 67.16% and 33.64%, 33.58% and 18.93%, and 75.37% and 51.15%, respectively. Then, the soil after column leaching was remediated by MPAL with a dosage of 0.3%. In comparison with H2 O+MPAL, DTPA-Cd, and DTPA-Pb in EDTA+MPAL, GLDA+MPAL and EDDS+MPAL declined by 98.26% and 48.01%, 97.88% and 45.80%, 98.26% and 55.59%, respectively. MPAL could convert exchangeable and carbonate-bound Cd and Pb into Fe/Mn oxide-bound fractions in the soil. The results revealed that EDDS+MPAL could significantly decrease the total amounts and exchangeable concentrations of Cd and Pb in the soil. The combined methods could complete the goal of reducing the total amount of heavy metals and further decreasing the bioavailability of residual heavy metals in Cd and Pb-contaminated alkaline soils.

关 键 词：弱碱性土壤 镉铅污染 柱淋滤 螯合剂 巯基改性坡缕石 钝化 

分 类 号：X53[环境科学与工程—环境工程]