摘要
水环境条件的改变会影响沉积物对砷(As)的吸附解吸行为,进而影响砷在水环境中的迁移和转化.本实验以西藏昌都昂曲表层沉积物为研究对象,通过正交试验,考察pH、转速、溶解氧(DO)、Fe/Mn含量、沉积物/水比例、温度、粒径及As含量对沉积物吸附解吸As的影响.研究结果表明:①沉积物对砷的吸附量随着初始As含量、Fe/Mn含量和pH值的升高而增大,随着颗粒物浓度的升高而减小;不同粒径的沉积物对砷的吸附主要与沉积物中的有机质含量有关,粒径为63~250μm的沉积物有机质含量最高(3.13 g·kg-1),平均吸附量最大(517.28 mg·kg-1).②不同粒径沉积物的解吸量与其砷含量和有机质含量有关,砷含量越高,有机质含量越少,砷的解吸量越大.砷的解吸量与转速和温度呈正相关,与pH、DO和颗粒物浓度呈负相关.③Langmuir模型对吸附等温线的拟合效果好于Freundlich模型,沉积物对砷的吸附存在明显的固体浓度效应.
The change of water environment conditions will affect the adsorption and desorption behavior of arsenic in sediment,and further influence its transportation and transformation in waters.This study used the surface sediments of Angqu River in Changdu,Tibet,to conduct simulated adsorption and desorption experiments.Through orthogonal experiments,the effect of pH,rotation speed,dissolved oxygen(DO),Fe/Mn content,sediment concentration,temperature,particle size,and As content on adsorption/desorption were studied.The results showed that the arsenic adsorption capacity of sediment increased with the increase of initial As content,Fe/Mn content and pH,and decreased with the increase of particle concentration.The arsenic adsorption capacity of sediment with different particle size was mainly related to the organic matter content in the sediment.The organic matter content was the highest(3.13 g·kg-1)in the particles with the size range from 63 to 250μm and the corresponding average adsorption capacity was the highest(517.28 mg·kg-1).The desorption capacity of sediment with different particle size was related to arsenic content and organic matter content.Particles with higher arsenic content and less organic matter content had greater arsenic desorption capacity.The desorption of arsenic was positively correlated with rotation speed and temperature,and negatively correlated with pH,DO and particle concentration.The Langmuir equation fits the adsorption isotherm better than the Freundlich equation,and there was obvious particle concentration effect on adsorption of arsenic on sediment.
作者
薛弘涛
边睿
齐维晓
刘会娟
XUE Hongtao;BIAN Rui;QI Weixiao;LIU Huijuan(School of Environmental Science and Engineering,Guilin University of Technology,Guilin 541004;School of Environment,Northeast Normal University,Changchun 130117;School of Environment,Tsinghua University,Beijing 100084)
出处
《环境科学学报》
CAS
CSCD
北大核心
2020年第9期3269-3276,共8页
Acta Scientiae Circumstantiae
关键词
砷
河流沉积物
吸附解吸
西藏
arsenic
river sediment
adsorption and desorption
Tibet
