Comparative study on the effectiveness of natural coagulant aids and commercial coagulant: removal of arsenic from water

A novel cellulose and chitosan-based natural biopolymer or coagulant aids with a commercial coagulant (ferric chloride FeCl3) have been used for the removal of arsenite As(III) from synthetic tap water at 2 mg/L of initial arsenic concentration by coagulation-flocculation method. The maximum As(III) removal efficiency of 69.25% was obtained without coagulant aids at 40 mg/L concentration of FeCl3. The addition of cellulose and chitosan with FeCl3 enhanced the removal efficiency of As(III). The percentage of As(III) removal reached 84.62 and 74.87% at the concentration of 1 and 1.5 mg/L for cellulose and chitosan, respectively, with 25 mg/L of fixed FeCl3 concentration. Comparable As(III) removal efficiencies were obtained using cellulose, chitosan, and FeCl3. Moreover, As(III) removal efficiency of cellulose was significantly found greater (p < 0.01) than chitosan and comparable to that of FeCl3 (p < 0.01). In addition, the maximum percentage of As(III) removal was found at the pH range of 6-8.