摘要
河岸带作为一种常见的地下水和地表水相互作用带,砷在其主要含水层介质中的行为特征及其影响因素较少有研究报道.基于此,采集河岸带河砂开展室内实验,查明砷在河砂上的吸附动力学和等温吸附特征,重点探究不同pH、氧化还原条件和共存离子对砷与河砂相互作用的影响.结果发现:As(III)和As(V)在河砂上的吸附过程符合准二级动力学模型,均能很好地用Langmuir和Freundlich模型拟合(R^(2)>0.99);随着pH值(3~11)的增大,河砂对As(III)和As(V)的平衡吸附量(q_(e))逐渐减小;相对于有氧环境,缺氧环境下q_e较低且随着初始S^(2-)含量的增加而逐渐减小;整体上,共存阴离子对河砂吸附砷存在抑制作用,顺序为:PO_(4)^(3-)>SiO_(3)^(2-)>S^(2-)>HCO^(-)_(3)>SO_(4)^(2-)>NO^(-)_(3),共存阳离子对河砂吸附砷具有促进作用,顺序为:Fe^(3+)>Fe^(2+).
A riparian zone is an interface between land and a river where groundwater and surface water always exchange strongly,but the behavior of arsenic adsorption and its influencing factors in this zone are less reported.In this study,batch experiments are carried out to investigate the adsorption kinetics and isothermal adsorption characteristics of arsenic on river sand collected from the riparian area,and the effects of different pH,redox conditions,and coexisting ions on arsenic adsorption.Results show that:As(III)and As(V)adsorptions on river sand are well fitted by the pseudo-second-order kinetic model,as well as Langmuir and Freundlich models(R^(2)>0.99).With the increase of pH from 3 to11,the equilibrium adsorption capacities(qe)of As(III)and As(V)on river sand decrease gradually.Compared with the aerobic environment,qe is lower in an anoxic environment where qe decreases with the increase of S2-concentration.Addition of anions has inhibitory effects on arsenic adsorption as the order of PO_(4)^(3-)>SiO_(3)^(2-)>S^(2-)>HCO^(-)_(3)>SO_(4)^(2-)>NO^(-)_(3),and the addition of cations can promote arsenic adsorption following the order of Fe3+>Fe^(2+) .
作者
陈辉
单慧媚
彭三曦
黄健
廖丹雪
闫志为
CHEN Hui;SHAN Huimei;PENG Sanxi;HUANG Jian;LIAO Danxue;YAN Zhiwei(Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology,Guilin 541004;College of Environmental Science and Engineering,Guilin University of Technology,Guilin 541004;College of Earth Science,Guilin University of Technology,Guilin 541004)
出处
《环境科学学报》
CAS
CSCD
北大核心
2021年第7期2727-2739,共13页
Acta Scientiae Circumstantiae
基金
国家自然科学基金项目(No.41877194,41502232)
广西自然科学基金项目(No.2017GXNSFAA198096,2018AD19142)。
关键词
砷
河砂
吸附
水化学因素
arsenic
river sand
adsorption
hydrochemical factors
