Removal of arsenic(III) from aqueous solution by activated carbons prepared from solvent extracted olive pulp and olive stones

The removal of As(III) from aquatic solutions at different concentrations and pH by using four types of activated carbons obtained from solvent extracted olive pulp and olive stone waste materials was studied. The adsorbents are obtained by chemical (K2CO3 and HNO3) activation and physical (water vapor) activation. The results show that carbons produced by chemical and physical activation of solvent extracted olive pulp and olive stones are efficient adsorbents for arsenic removal. Arsenic adsorption follows a Langmuir isotherm. The best results were obtained with the adsorbent, obtained from extracted olive pulp by pyrolysis in the presence of water vapor. The maximum removal was found to be 18.60 mu mol/g. The adsorption capacity for adsorbents, obtained from extracted olive pulp and olive stones, is 11.42 and 9.85 mu mol/g, respectively. The test showed that alkaline aqueous medium favored the removal of As(III). Some experiments were carried out to study the oxidation of arsenite to arsenate in the presence of activated carbons.