EFFICIENT REMOVAL OF ARSENIC FROM WATER BY DIELECTROPHORESIS-ASSISTED ADSORPTION

Adsorption (ADS) and dielectrophoresis (DEP) technique were combined (ADS/DEP) to efficiently remove As (V) in aqueous solution. Fly ash, activated carbon, corncob and plant ash were tested to determine the best adsorbent by their adsorption capacity. Plant ash showed the highest adsorption capacity compared with the others. Different parameters such as solution pH, adsorbent dose were explored. The maximum arsenic removal efficiency was 91.4% when the pH was 9.0 and adsorbent dose 5 g/L with 7.5 mg/L initial concentration. With the ADS/DEP technique, the plant ash particles with adsorbed arsenic ions were trapped to the electrodes in a DEP device. The ADS/DEP process can increase the removal efficiency of As (V) to 94.7% at 14 V even when the initial concentration of As (V) was 15 mg/L. And the residual concentration of As (V) decreased to 0.34 mg/L after two series of ADS/DEP process. The adsorbents before and after DEP were examined by a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. After DEP process, the weight percentage of As (V) on the adsorbents surface increased to 0.96% from 0.5%. The ADS/DEP process could be a new efficient way to remove the arsenic pollutant in water matrices at high concentrations.