Removal of Arsenic from Landfill Leachate by Selected Low-Cost Sorbents: An Experimental Study at the Zixiaguan Landfill of Wuhan City, Central China

Abstract

The leachate from the Zixiaguan landfill of Wuhan City contains a lot of undesirable or toxic chemicals, among which arsenic may have the most serious threat to environment and human health. Lowering the arsenic concentration in the leachate is therefore of extreme importance. In this study, natural sediments obtained from Wuhan City, including clay, silty soil and silty sand, were used as low-cost sorbents to remove arsenic from solution. The results of the batch sorption experiments indicate that the sorption processes of clay and silty sand match well with linear isothermal sorption model, while that of silty soil is in good accordance with Langmuir isothermal sorption model. Among the three sorbents, clay has the best ability for arsenic removal from solution. Further experiments were carried out to determine the optimum sorption conditions for clay sorbent, the results showing that as the ratio of sorbent dosage to solution volume is 25.0 g/L, the reaction time is 120 min, and the pH of solution equals 7.0, the removal rate of arsenic from the leachate by clay sorbent reaches the highest value of 99.3 %.