Arsenic Removal by Coagulation Using Ferric Chloride and Chitosan From Water Publisher



Hesami F¹ ; Bina B¹ ; Ebrahimi A¹ ; Amin MM¹ Show Affiliations
Source: International Journal of Environmental Health Engineering Published:2012

Abstract

Aims: In this study, the effect of arsenite and arsenate removal in synthetic water by coagulation using ferric chloride (FeCl3) as coagulant and chitosan as coagulant aid were investigated. Materials and Methods: A conventional jar test apparatus was used to evaluate the coagulation process. The effects of different conditions of pH (5.5‑9), coagulant doses of FeCl3 0–60 mg/l), Arsenic speciation (As (V) and As (III)), Chitosan as coagulant aid, and initial arsenic concentrations (0.2–2 mg/l) to Arsenic removal was investigated by considering the residual arsenic and iron after coagulation. Results: The finding showed that the optimum pH for FeCl3 as a coagulant to As (V) and As (III) removal was 7. As (V) removal efficiency of 90% or higher by FeCl3 alone were achieved for initial As (V) concentration 0.2–2 mg/l at optimum dosages (15‑30 mg/l). In contrast with As (V) removal, about 60% of the As (III) were removed in comparable conditions. The optimal dosage of chitosan was determined to be 0.5 mg/l. When chitosan (0.5 mg/l) was used as coagulant aid with FeCl3, the efficiency removal was enhanced almost to 100% and 80% for As (V) and As (III) removal, respectively. The optimum dosage of FeCl3 was reduced, especially at low initial concentration of arsenic. Conclusions: Chitosan as natural coagulant aid improved arsenic removal efficiency by coagulation process using FeCl3. This method can be used for regions with drinking water contaminated with initial arsenic concentration less than 1 000 μg/l. © 2012 Hesami F.