AWWA ACE59867

The effect of potential competing anions (phosphate, sulfate, nitrate, fluoride, bicarbonate, silicate, chloride and natural organic matter) on arsenic removal was evaluated on activated alumina, Granular Ferric Hydroxide, and goethite. The presence of anions decreased arsenic adsorption on all three adsorbents tested; the volume of water treated per unit mass of adsorbent to exhaustion of the material decreased by 13 to 41%. Silicate, sulfate, and high concentrations of fluoride were the most influential at pH 6, each anion explaining 15 to 35% of the variation in arsenic adsorption. The influence of varying ionic strength and anion concentration differences was also assessed and was found to affect anion adsorption and thus competition with arsenic. Includes 27 references, table, figures.