Ultrafiltration of dissolved organic matter in surface water by a polyvinylchloride hollow fiber membrane

Fouling of ultrafiltration membranes by dissolved organic matter in surface water is not well understood due to the complexity of the DOM mixture. In this study, fulvic acid, tannin, aniline, citric acid, polysucrose and oligopeptide were selected to represent fractions of DOM with different hydrophobicity and acid/base properties. The impact of each model compound as well as their mixture on the fouling and cleaning behavior of a modified polyvinyl chloride UF membrane was investigated. The results show that the interplay of molecular size/structure, charge, hydrophobicity, and functionality determines the membrane rejection and fouling potential of individual DOM compounds, although rejection is not directly related to the fouling potential. Furthermore, the overall fouling and cleaning behavior of DOM mixtures, e.g., natural water, cannot be simply predicted from fouling behavior of individual DOM compounds. Significant synergy exists presumably due to interactions between DOM compounds, leading to significantly greater fouling rate compared to the additive sum of contributions from individual DOM compounds.