Response surface methodology and optimization of arsenic continuous sorption process from contaminated water using chitosan

•Chitosan can be used in continuous treatment of water contaminated with arsenic.•As(V) continuous removal was 76.8% at optimal conditions: 4.6 cm bed height and 6.5 mL min−1 volumetric flow.•A critical bed depth, Z0, was determined to be 1.5 cm.•More than 75% of arsenic was recovery from columns after two regeneration cycles.