基于双点位模型与多表面形态络合反应模型研究Cd^(2+)在负载黄原酸盐多孔介质中的迁移规律  

Investigating the migration of Cd~(2+) in xanthate-loaded porous media with two-site model and multisurface speciation model

作　　者：罗博闻 陈扣平 吴吉春[1] 李平[2] 郑贤武 陈华丽 LUO Bowen;CHEN Kouping;WU Jichun;LI ping;ZHENG Xianwu;CHEN Huali(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023;State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081;School of Environmental Science and Engineering,Zhejiang Gongshang University,Hangzhou 310012)

机构地区：[1]南京大学,地球科学与工程学院,南京210023 [2]中国科学院地球化学研究所,环境地球化学国家重点实验室,贵阳550081 [3]浙江工商大学,环境科学与工程学院,杭州310012

出　　处：《环境科学学报》2024年第7期449-461,共13页Acta Scientiae Circumstantiae

基　　金：国家重点研发项目(No.2020YFC1807601)。

摘　　要：选矿作业中使用的选冶有机物与矿区采选过程中遗留的重金属发生络合反应,导致重金属迁移复杂化.因此需要建立适用于实际多孔介质条件,考虑重金属-选冶有机物复合污染影响的高精度迁移模型.研究以重金属(Cd^(2+))与乙基黄原酸盐(EX)为例,根据室内土柱实验和FTIR结果,结合双点位模型和MSM模型分析Cd^(2+)在负载不同浓度EX的实际多孔介质中的迁移过程,定量刻画Cd^(2+)在多孔介质中各组分的固相分配规律;使用e FAST法进行全局敏感性分析,识别两种模型的关键参数.研究结果表明:两种模型均展现良好拟合效果(R^(2)≥0.96),多孔介质EX负载浓度的提高(0~2.5 mmol·L^(-1))会增加多孔介质表明黄原酸根吸附点位的浓度(Xa:0~41.12 mmol·kg^(-1)),增强介质整体吸附能力(K_(d):1.261~2.723 cm^(3)·g^(-1)),最终抑制Cd^(2+)的迁移能力.在没有EX负载的偏酸性水化学条件下,土壤黏土矿物和有机质是吸附Cd^(2+)的最重要组分,吸附占比分别为53.34%和41.89%;随着EX负载浓度的增加(0~2.5 mmol·L^(-1)),黄原酸盐成为最主要吸附组分(77.84%~95.84%)并与其余组分形成竞争吸附关系.FTIR结果亦证明铁氧化物、有机质、黏土矿物均会与Cd^(2+)发生吸附反应,且EX负载后黄原酸根在多孔介质上形成新的吸附点位.敏感性分析结果表明α_(L)和铁氧化物吸附点位浓度(Surfa OH、Surfb OH)分别为两种模型最敏感的参数,需重点关注其获取的准确性.The organic compounds used in mineral processing can chelate with heavy metals in contaminated mining sites,resulting in the complexity of heavy metal migration.Therefore,it is necessary to establish a high-precision migration model applicable to practical porous media,considering the combined pollution of heavy metals and organic compounds.In this study,taking heavy metal Cd^(2+)and ethyl xanthate (EX) as examples,combining the two-site model and MSM model,the migration process of Cd^(2+)in practical porous media loaded with different concentrations of EX was analyzed based on soil column experiments and FTIR results,and Cd^(2+)distribution in solid-phase was quantitatively characterized.Global sensitivity analysis method (e FAST) was performed to identify key parameters of the two models.The results showed that both models exhibited good fitting effects (R~2≥0.96).With increasement of concentration of EX loaded in porous media (0~2.5 mmol·L^(-1)),there was a corresponding increase in the concentration of xanthate adsorption sites on porous media (Xa:0~41.12 mmol·kg^(-1)) which led to an enhancement in the overall adsorption capacity of the media (K_d:1.261~2.723 cm^(3)·g^(-1)) and ultimately the inhibition of Cd^(2+)migration ability.Without EX loading,soil clay minerals and organic matter were the most important components for Cd^(2+)adsorption,accounting for 53.34%and 41.89%of the total adsorbed concentration,respectively.With the increasing concentration of EX (0~2.5 mmol·L^(-1)),xanthate became the main adsorption component (77.84%~95.84%) and competed with other components for adsorption.FTIR results also demonstrated that iron oxides,organic matter,and clay minerals participated in the adsorption reactions with Cd^(2+),and xanthate form new adsorption sites on porous media after EX loading.Sensitivity analysis results showed that α_(L) and the concentrations of iron oxide adsorption sites (Surfa OH,Surfb OH) were the most sensitive parameters for both models.Therefore,the accuracy in obtaining abov

关 键 词：黄原酸盐 镉 双点位模型 MSM模型 竞争吸附 

分 类 号：X53[环境科学与工程—环境工程]