Key parameters controlling an adsorption process for the selective removal of arsenic from drinking water

Arsenic can be selectively removed from water through adsorption on a natural manganese oxide. This paper presents some of the key parameters controlling such a process. Both production and regeneration steps were studied and the influence of three main controlling parameters was put to light. The water pH greatly influenced the adsorption capacity. Low water pH highly improved the treatment. The adsorption being under mass transfer limitation, flow rate influence was measured and optimization solutions were proposed. Finally, the impact of the regeneration procedure was evaluated on the adsorbent stability. It gave good arsenic elution results but the caustic elution step generated fine particles that could not be avoided. The following neutralization could however be adjusted in order to minimize further adsorbent dissolution.