我国典型土壤Cr(Ⅵ)固-液分配系数K_(d)值及其在推导保护地下水的土壤环境基准中的应用研究  

Solid-Liquid Partition Coefficient(K_(d))of Cr(Ⅵ)in Typical Soils of China and Its Application in the Development of Groundwater Protection-Based Soil Environmental Criteria

作　　者：王天董 薛维纳[1] 罗飞 唐伟 余海波[2] 晏井春[2] 宋静[2,4] WANG Tiandong;XUE Weina;LUO Fei;TANG Wei;YU Haibo;YAN Jingchun;SONG Jing(School of Municipal and Environmental Engineering,Shandong Jianzhu University,Jinan 250101,China;Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;Shenzhen Academy of Environmental Sciences,Shenzhen 518001,China;University of Chinese Academy of Sciences,Nanjing 211135,China)

机构地区：[1]山东建筑大学市政与环境工程学院,山东济南250101 [2]中国科学院南京土壤研究所,江苏南京210008 [3]深圳市环境科学研究院,广东深圳518001 [4]中国科学院大学南京学院,江苏南京211135

出　　处：《环境科学研究》2024年第6期1326-1335,共10页Research of Environmental Sciences

基　　金：国家重点研发计划项目(No.2023YFC3708700)。

摘　　要：Cr(Ⅵ)是铬盐、电镀、皮革等行业的特征污染物,极易因土-水迁移造成地下水污染。对于迁移性较强的污染物〔如Cr(Ⅵ)〕,有必要制定保护地下水的土壤环境基准。Cr(Ⅵ)在不同土壤上的吸附和解吸特征参数不同,为获取我国典型土壤Cr(Ⅵ)吸附及解吸过程的固-液分配系数(K_(d)),本研究采用我国黑龙江海伦黑土、河南封丘潮土、海南儋州砖红壤等12种典型土壤,开展了吸附动力学及吸附-解吸平衡实验。动力学研究结果表明,12种土壤均在48 h内达到吸附平衡,与拟一级动力学模型和Elovich动力学模型相比,拟二级动力学模型对Cr(Ⅵ)的土壤吸附动力学过程有更好的拟合效果。吸附平衡实验表明,相较Langmuir等温吸附模型,Freundlich等温吸附模型能够更好地拟合Cr(Ⅵ)在我国典型土壤上的吸附特征。Cr(Ⅵ)土壤吸附过程的固-液分配系数(K_(d)x)非固定值,随着平衡液Cr(Ⅵ)浓度的增大,K_(d)x逐渐减小。解吸平衡实验表明,Cr(Ⅵ)土壤解吸过程的固-液分配系数(K_(d)j)高于吸附过程的对应值。基于三相平衡估算土壤平衡液Cr(Ⅵ)浓度时应采用K_(d)j,且其取值因平衡液Cr(Ⅵ)浓度而异。基于污染土壤与地下水直接接触且不存在地下水稀释的保守假设条件,本研究初步提出了保护地下水的不同土壤的Cr(Ⅵ)环境基准值,研究结果丰富了我国典型土壤Cr(Ⅵ)基础参数数据库,为我国分区制定保护地下水的土壤Cr(Ⅵ)环境基准积累了科学数据。Cr(Ⅵ)is a characteristic pollutant in chromium industries such as chromium salt production,electroplating and leather tanning.Since highly mobile contaminants such as Cr(Ⅵ)are highly sensitive to groundwater contamination and soil-water transport,it is necessary to develop soil environmental criteria based on groundwater protection.Different soil has different adsorption and desorption characteristic parameters for Cr(Ⅵ).In order to obtain the solid-liquid partition coefficient(K_(d))of the adsorption and desorption processes of Cr(Ⅵ)on Chinese soils,adsorption kinetics and adsorption-desorption equilibrium studies were conducted on 12 typical soils in China.The kinetic studies showed that all 12 soil samples reached adsorption equilibrium within 48 hours.Compared with the pseudo-first-order model and the Elovich model,the pseudo-second-order model better fits the soil adsorption kinetics of Cr(Ⅵ)in soil.The adsorption equilibrium experiments showed that the Freundlich adsorption model was more suitable than the Langmuir adsorption model for the adsorption of Cr(Ⅵ)in typical soils in China.The adsorption K_(d)x of Cr(Ⅵ)by soil was not a constant.As the concentration of Cr(Ⅵ)in the equilibrium solution increased,the K_(d)x gradually decreased.The desorption equilibrium experiments showed that the solid-liquid partition coefficient K_(d)j of Cr(Ⅵ)desorbed from soil was higher than the corresponding value of the adsorption process.To estimate the Cr(Ⅵ)concentration in equilibrium solution based on the three-phase equilibrium model,K_(d)j should be used.K_(d)j depends on the Cr(Ⅵ)concentration of the equilibrium solution.Based on the conservative assumption that soil leachate is in direct contact with groundwater and there is no groundwater dilution,Cr(Ⅵ)soil environmental criteria for different soils based on groundwater protection are proposed.This study enriches the database of basic soil Cr(Ⅵ)parameters in China and accumulates scientific data for the development of groundwater protectio

关 键 词：Cr(Ⅵ) 吸附-解吸 土-水迁移 固-液分配系数 保护地下水的土壤基准 

分 类 号：X53[环境科学与工程—环境工程]