Abstract:

High As concentrations have widely been found in potable groundwater in China, which can cause acute and chronic health effects on humans. It is nessesary to develop economic, efficient and eco-friendly technologies for As removal from As-contaminated groundwater. Chemical characteristics of high As groundwater in arid-semiarid inland basins in Northern China (including the Datong basin, the Hubao basin, the Hetao basin and the Yinchuan basin) were thoroughly reviewed and summarized. High As groundwater was typically characterized by high pH, high concentration of coexisting anions (such as(HCO^-3, SO^2-₄, and Cl^-), and high concentrations of dissolved organic carbon. Furthermore, effects of solution pH, co-existing anions and cations, dissolved organic matter on As adsorption onto activated natural siderite were investigated according to the chemical characteristics of the typical high As groundwater. Results showed that the activated natural siderite had high capacity for buffering solution pH. Arsenic removal was independent on solution pH, coexisting anions, Ca²⁺ and Mg²⁺, and humic acid. It indicated that activated natural siderite had good adsorption selectivity for As under any conditions. In addition, the removal efficiency of activated natural siderite for As(Ⅲ) was slightly higher than that for As(V). Therefore, the activated natural siderite, as an economic, efficient and eco-friendly reaction material, appears to be a promising adsorbent for remediation of As(Ⅲ)-dominated high arsenic groundwater.

Key words: high arsenic groundwater, hydrochemical characteristic, arsenic removal, activated natural siderite, adsorption