Among inorganic contaminants, the metalloid arsenic has been widely studied due to its potential adverse to human health . Arsenic in natural waters occur in both organic and inorganic forms while its inorganic forms are more toxic to human health and commonly occur as arsenate (As(V)) and arsenite (As(III)). pH and redox potential are the most important parameters in domination of As(V) and As(III) in environment (Pokhrel and Viraraghavan, ).
The presence of high levels of arsenic in natural water resources is considered as a global problem while countries of Bangladesh, India, USA, China, Chile, Taiwan, Mexico, Argentine, Poland, Canada, Hungary, New Zealand, Japan and Iran have reported its high amounts in water resources [3–5]. Because of the high toxicity and carcinogenic effect of arsenic to human, the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA) have recommended a Maximum Contaminant Level (MCL) of 10 μg/L for arsenic in drinking water .
Until now the numerous and effective technologies has been developed in order to remove arsenic from water. The major techniques for arsenic removal are: oxidation, coagulation, sorption, precipitation/coprecipitation, ion exchange and reverse osmosis  as adsorption methods are much important because of their relatively low cost and easy operation (Do, [4, 8]).
The use of natural geomaterials as adsorbents like sand, olivine and quartz as support media which are amended with coating materials to enhance their adsorptive capacity for arsenic removal have been widely considered in recent years (; Kundu and Gupta, [10–12]). Therefore, in this study granular particles of pumice igneous stone were applied based on their capability to remove heavy metals [13–15] after being coated with iron and manganese as possible adsorbents for removal of As(V) from aqueous solutions. In fact, the main scope of this study was to examine various parameters such as adsorbent dosage, pH, initial concentration of As(V), contact time, sorption kinetics and equilibrium isotherm during removal procedure.