arsenic removal from synthetic water using activated carbon derived from walnut shell

increasing of fresh water consumption and consecutively drought periods caused reduction of renewable freshwater resources in recent years. one of the basic strategies to conquer this problem is using non-conventional water resources particularly reuse of polluted water. in this study, activated carbon derived from walnut shell was used as tertiary treatment. activated carbon powder was used in laboratory-scale experiments and was used for arsenic removal from synthetic samples. different parameters such as contact time, ph, concentration of adsorbate and adsorbent dose were investigated. the optimum equilibrium contact time, ph, concentration of adsorbate and adsorbent dose were achieved 3 minutes, 6.5, 120 g/l and 0.4 g/l, respectively. the results indicate that the freundlich isotherm (with r2=0.977) is more consistent with experimental data than langmuir isotherm. comparison of this study with other research studies indicates that low cost activated carbon derived from walnut has a high surface area and arsenic is well adsorbed up to 100 percent from aqueous solution.