Arsenic Adsorption and Desorption in Various Aqueous Media in the Nearshore Zone and Influencing Factors

Abstract

A profound understanding of the adsorption and desorption characteristics of arsenic on various media in aqueous solutions is helpful for evaluating the behavior of arsenic in groundwater. In this study, the characteristics of arsenic adsorption and desorption on aqueous media including silty clay, fine sand, medium sand, and coarse sand with gravel from Shenyang Huangjia water source, China were investigated by batch experiments. The results showed that the aqueous media in the study area had a strong fixation ability for arsenic, and both physical and chemical adsorption of arsenic occurred. Among them, silty clay had the strongest adsorption capacity and the largest buffer capacity for arsenic. As the specific surface area (SSA) of the medium decreased, the adsorption capacity decreased, and the desorption capacity increased. There was an obvious positive correlation between the desorption capacity and adsorption capacity of arsenic, and the force of the adsorption process was larger than that of the desorption process. The pH, temperature, carbonate, and ionic strength all affected the arsenic adsorption and desorption, and adsorption of arsenic occurred mainly by obligate adsorption in the study area.