Asenic removal from groundwater using granular chitosan-titanium adsorbent

Arsenic (As) contamination poses an urgent environmental risk,and its removal from groundwater remains a challenge due to the lack of efficient adsorbents.Herein,a novel granular chitosan-titanium (CS-Ti) adsorbent was fabricated by the sol-gel method.Batch experiments show that As(Ⅴ) adsorption on CS-Ti followed the pseudo-second-order kinetic model,and the adsorption isotherm conformed to the Freundlich model with the correla-tion coefficient of 0.99.In situ FTIR spectra revealed that the CS-Ti adsorbent was composed of amorphous TiOx and chitosan by forming C-O-Ti and N-Ti bonds,and the amorphous TiOx was responsible for As(Ⅴ) adsorption.Rapid small-scale column tests show that 165.6μg/L of As in groundwater were effectively removed in approximately 126-bed volumes,and the spent adsorbents were regenerated with 0.01 mol/L NaOH and maintained the adsorp-tion efficiency after four cycles.This study provides a simple and practical route to fabricate adsorbents for water treatment.