Study On Arsenate Removal From Water By Zero-valent Iron/activated Carbon Galvanic Couples

Ground water with high concentration arsenate is wide distribution in the world, and zero-valent iron is perceived as the most potential material for arsenate removal because of its easiness to obtain, low price, high efficiency, and environmental safety. But its efficiency and effectiveness have yet to enhance.In this paper, zero-valent iron single is replaced by zero-valent iron/activated carbon galvanic couples to remove arsenic from aqueous. Batch tests were performed to investigate the removing efficiency of arsenic by iron with different sorts of carbon and different proportion of iron to carbon. The results shows that the zero-valent iron/activated carbon has the best efficiency of removal As(V) comparied with other sorts of carbon material. When the proportion of iron to activated carbon being one to one, the removal rate is improved noticeably by comparison of the two kind of material individually. The corrosion irror was tested to explain the mechanism of the promoting.Product analyses proved that the system is safe. Fe ion and As(III) were not detected after the reaction. The transmission electron microscope(TEM) analyses, scanning electronic microscope(SEM) analyses and X-ray diffraction(XRD) analyses were performed to study the product of reaction between arsenate and iron-activated carbon, and the reacted solution was used for the arsenic species analysis.Any more, the effects of the initial arsenate concentration, NaCl concentration, pH value, and some conmon anion were examined.The study showed that zero-valent iron/activated carbon galvanic couples could be used in the field of As(V) removal, not only for its high efficiency, but also for the security to environment.