S^(2-)对河砂吸附砷的影响及其作用机理  

Effects of S^(2-)on arsenic adsorption to river sand and its mechanisms

作　　者：杜海玲 单慧媚 陈辉[1,2] 彭三曦 黄健[1,2] Du Hailing;Shan Huimei;Chen Hui;Peng Sanxi;Huang Jian(Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology,Guilin University of Technology,Guilin Guangxi 541004,China;Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area,Guilin University of Technology,Guilin Guangxi 541004,China;College of Earth Science,Guilin University of Technology,Guilin Guangxi 541004,China)

机构地区：[1]桂林理工大学广西环境污染控制理论与技术重点实验室,广西桂林541004 [2]桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心,广西桂林541004 [3]桂林理工大学地球科学学院,广西桂林541004

出　　处：《地质科技通报》2022年第4期241-248,265,共9页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(41877194;41502232);广西自然科学基金项目(2017GXNSFAA198096;2018AD19142)。

摘　　要：水体中S^(2-)与砷(As)的迁移富集密切相关,但不同含水介质中其作用机理尚不明确。为了查明潜流带中常见含水介质河砂在S^(2-)作用下对As的吸附特征,设计并开展了As在河砂上的吸附动力学实验,以及S^(2-)作用下河砂对As的吸附实验,结合PHREEQC模拟计算,XRD、SEM-EDS、XPS和FTIR等表征测试技术,进一步识别其作用机理。结果表明:固液比为25 g/L情况下,河砂对As的吸附在200 h左右达到吸附平衡,且对As(Ⅴ)的吸附量明显高于As(Ⅲ);随着S^(2-)浓度的增加,河砂对As吸附能力逐渐减弱;模拟及表征测试结果显示,少量As被吸附在河砂表面,主要与其表面的Fe、Al结合,其中As(Ⅲ)的吸附可能还与Si-O键断裂后与S^(2-)结合形成的SiS_(2)有关。S^(2-)对河砂吸附As的主要影响机理为:①S^(2-)的加入使得溶液pH值升高、Eh值降低,从而抑制了As的吸附;②添加S^(2-)条件下河砂表面的Fe、Al等能与S和As形成AlAs、AlAsO_(4)、FeS_(2)及Fe_(4)As_(2)O_(11)等化合物,减少了河砂表面吸附As的活性位点。研究结果有助于丰富As-S作用机理,以及As在地下水环境中迁移过程的认识。Sulfur(S^(2-)) is closely related to the migration and enrichment of arsenic(As)in the water environment,but its mechanism of action in different aqueous medium is still unclear.To determine the adsorption characteristics of As by river sand,a common aqueous medium in the hyporheic zone,under the action of S^(2-),the adsorption kinetics experiment of As on river sand and the adsorption experiment of As by river sand under the action of S^(2-) are designed and carried out.Combined with simulation calculation by PHREEQC and characterization tests based on XRD,SEM-EDS,XPS and FTIR,the mechanism of action is further identified.The results show that the adsorption of As by river sand reaches adsorption equilibrium at approximately 200 h and the adsorption capacity of As(Ⅴ)is significantly higher than that of As(Ⅲ)at the solid-to-liquid ratio of 25 g/L;with increasing S^(2-) concentration,the adsorption capacity of river sand to As decreases gradually.The simulation and characterization test results show that a small amount of As is adsorbed on the surface of river sandandis mainly combined with Fe and Al on its surface.The adsorption of As(Ⅲ)may also be related to SiS_(2) that is formed after the fracture of the Si-O bondwith S^(2-).The main influence mechanism of S^(2-)on the adsorption of As by river sand is as follows:①the addition of S^(2-)increases the pH of the solution and decreases Eh,thus inhibiting the adsorption of As;②under the condition of adding S^(2-),Fe and Al on the surface of river sand can form compounds such as AlAs,AlAsO_(4),FeS_(2) and Fe_(4)As_(2)O_(11) with S and As,which reduces the active sites of As adsorption on the surface of river sand.

关 键 词：硫 河砂 表征 影响机理 

分 类 号：X141[环境科学与工程—环境科学]