Abstract : The adsorption of As(III), As(V), Se(IV) and Se(VI) by seawater neutralized red mud and alum water treatment sludge was investigated and compared using the batch adsorption technique. For water treatment sludge, adsorption of As(V), Se(IV) and Se(VI), at equimolar concentrations of added metalloid, declined with increasing pH. The decline was rapid above pH 4.0 for Se(VI), above pH 5…