Factors Influencing the Removal of As(V) from Groundwater by NF/RO

Abstract:

The effect of coexisting sulfate [(SO4)2-], pH, and conversion rate on arsenic (As) removal from groundwater through nanofiltration, reverse osmosis (RO) membrane, and membrane fouling was studied. The results show that As concentration in permeate water was less than 10 μg/L when the feed As concentration was less than 135 μg/L, whereas As concentration after RO was less than 10 μg/L in all cases even if feed As concentration was more than 199 μg/L; these values in permeate water nearly meet the arsenic content level prescribed by China’s drinking water standards. The As rejection rate decreased with the increase in feed As and coexisting ion concentration, whereas the opposite occurred with regard to pH and conversion ratio. The decreasing percentage of the As rejection rate remained the same when arsenic concentration increased by 1 μmol or when (SO4)2- increased by 0.5 mol. The As rejection rate did not change significantly when the feed As concentration exceeded 200 μg/L. The As rejection rate increased when pH increased, and an ideal rejection rate was achieved at pH 6.5. Transmission electron microscopy and X-ray diffraction analysis showed that the main fouling component was CaCO3 which was deposited in the membrane pores and decreased the As rejection rate.

• Periodical: Advanced Materials Research (Volumes 690-693)
• Pages: 1074-1080
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.690-693.1074
• Online since: May 2013
• Authors: Wei Fang Ma, Wen Jun Liu, Pan Yue Zhang, Hao Guo
• Keywords: Coexisting Ions, Drinking Water, Membrane Fouling, Nanofiltration Membrane, Reverse Osmosis

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