Title: Effect of solution chemistry on organic fouling of reverse osmosis membranes in seawater desalination
Journal: Journal of Membrane Science
Authors: Youngbeom Yu, Sangyoup Lee, Seungkwan Hong
Corresponding author: Seungkwan Hong
Department of Civil, Environmental & Architectural Engineering, Korea University, 1?5 ga, Anam-dong, Sungbuk-gu, Seoul, 136-713, Republic of Korea
The original and creativity of paper: Researchers have been study the effect of pH and calcium concentration on organic fouling during seawater reverse osmosis process. They found that pH and calcium concentration of seawater have no effect to the intensity of organic fouling.
Feed solution chemistry (i.e., pH and calcium concentration) was assumed to affect fouling behavior. RO membrane process was run under different level of ionic strength conditions. The observations clearly showed that rapidly flux decline was observed when the system operated with low pH and high concentration of calcium. However, high ionic strength can inhibit this effect since the results of flux decline were almost identical at 600 mM of ionic strength (representative of seawater). That means under seawater RO process, pH and calcium concentration have less effect to organic fouling due to the significant masking of electrostatic interactions such as the charge neutralization of organic functional groups as well as organic calcium complexation. Also, at this high ionic strength showed greater deposited foulants on membrane surface. Researcher analyzed deposited foulants on membrane surface under this high ionic strength; found that hydrophobic fractions are the dominant constituents. Moreover, FEEM analyses used to confirm the above result. According to SUVA and FEEM results, it indicated that the effect of organic fouling during seawater desalination is mainly controlled by the enhanced hydrophobic interactions between organic matters and membrane as well as interactions between the organic matters. Therefore, pH adjustment and/or hardness control before SWRO process might not be an effective way to control organic fouling.
Contribution to ESEL: The results are very meaningful for understanding the effect of feed water chemistry on SWRO process. We can use this paper as reference.
Reviewed by Monruedee Moonkhum