Effect of dissolved organic matter on arsenic removal by nanofiltration

Abstract

Arsenic is known as a carcinogen that causes skin cancer and various internal cancers. The arsenic contamination in water forced the water and health authorities to introduce stringent standards for arsenic control level in drinking water. Nanofiltration presents a promising method to remove arsenic, by the effect of both size exclusion and electric repulse, which is reliable, easy to produce, obtain, operate, and maintain. In this work, the influences of dissolved organic matter (DOM) on arsenic removal by nanofiltration process were investigated through a series of laboratory bench-level experiments. The existing of humic acid (HA), which was used as substitute of DOM, increased the arsenic removal due to the formation of humic/arsenic complexes. With the presence of high concentration of HA (10 mg total organic carbon [TOC]/L), the removal efficiency of arsenic was almost 100%, which was higher compared with the result (80%) obtained at low concentration of HA (2 mg TOC/L). The membrane flux for the membrane separation of the various concentration of DOM decreased to 80% of the initial flux after 400 min with the same cross-flow velocity (3.5 cm/s). The mechanism of arsenic removal by nanofiltration was further presented article.

Keywords:

• Arsenic
• DOM
• Nanofiltration
• Membrane fouling

Acknowledgments

This work was kindly supported by the following: the National Natural Science Foundation of China (Project 51178322), the International Science & Technology Cooperation Program of China (2010DFA92090), the National Major Project of Science & Technology Ministry of China (2012ZX07408-001), and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.