Chitosan- and Iron-Chitosan-Coated Sand Filters: A Cost-Effective Approach for Enhanced Arsenic Removal

This paper describes the potential of chitosan-coated sand (CCS) and iron-chitosan-coated sand (ICCS) toward the removal of both As(V) and As(III) from aqueous systems. Various parameters including pH, equilibration time, initial arsenic concentration, and adsorbent dosage have been optimized for maximum adsorption. The adsorption data fitted well in both Langmuir and Freundlich adsorption models. The Langmuir monolayer adsorption capacity was found to be 17 and 23 mg/g for CCS and 26 and 56 mg/g for ICCS at pH 7 for As(III) and As(V), respectively. The reaction followed a pseudo-first-order model. Column studies revealed higher breakthrough capacity for As(V) using both CCS and ICCS. Adsorption plots were fitted with BDST model. The adsorbent was also successfully applied for the removal of total inorganic arsenic down to <10 mu g L-1 from real life arsenic-contaminated groundwater samples.