Abstract

Aims: Drinking water pollution with trivalent arsenic As (III) is one of the most important health concerns in several countries. This research investigated the electrocoagulation process (EC) performance for As (III) elimination from water. Methods: This process was performed using a monopolar arrange of Al-Steel electrodes in which the effects of reaction time (5, 10, 15 min), initial pH (5, 7, 9), current intensity (0.2, 0.4, 0.8 A) and initial concentration of As(III) (0.25, 0.5, 1, 5, 10 mg/l) were studied. Results: The results revealed that elevation of pH from 5 to 7 and 9 led to decreasing the residual concentration of As (III) from 0.195 to 0.145 and 0.115 mg/l, respectively. Increasing of current intensity from 0.2 to 0.4 and 0.8 A led to decreasing of residual concentration of As (III) from 0.148 to 0.147 and 0.044 mg/l, respectively. The optimum operation status was determined as: pH=7, current density= 0.8 A and contact time 10 min, thus energy consumption was determined as 0.9423 Kwh/m3 of treated water. One-Way Analysis variance implied that initial concentration has significant effect on residual concentration of As (III) (p<0.05). So, in optimum status and initial concentrations of 0.25 and 0.5 mg/l of As (III) the process can meet the Iranian and WHO drinking water guidelines values. Conclusion: The EC process without oxidation can eliminate As (III) from water, up to the Iranian recommended guidelines.