Immobilization of arsenic in aqueous solution by waterworks alum sludge: prospects in China

In this study, groups of batch experiments were designed to identify the characteristics of alum sludge for arsenic (As) adsorption. Air-dried alum sludge (moisture content 13.9%) collected from a water treatment works in Xi’an, China, was subjected to artificial As-rich wastewater adsorption tests using As2O3 as a model As source. Adsorption behaviours were investigated and the results have shown that the Langmuir adsorption isotherm well fits the experimental data (R2 = 0.94957–0.99365). The maximum adsorption capacities range from 0.61 to 0.96 mg-As/g when the pH of the As solution was varied from 9.0 to 4.0. The prospects in China for the outcome of this study are discussed. This promising low-cost technique can eradicate As contamination in China.