A Mechanistic Study of the Physical, Chemical, and Mechanical Properties of Natural Organic Matter on Photocatalytic Membranes to Understand Fouling Mitigation. Membrane fouling caused by natural organic matter (NOM) has a significant impact on the performance of membrane filtration, and hence increases the operational cost and maintenance for water and wastewater treatment. Photocatalysts can produce a series of reactive oxygen species under light irradiation, and previous studies have indicated that they hold great promise to couple with the membrane’s filtration capability for mitigating NOM fouling. However, the mechanisms of fouling control on photocatalytic membranes are largely unknown. The objective of our study is to understand the mechanisms of NOM fouling and its mitigation on photocatalytic membranes by the evaluation of physical, chemical, and mechanical properties of a probe NOM, namely humic acid (HA). Two photocatalysts, TiO2 and graphitic carbon nitride (g-C3N4), are selected for the oxidation of HA, and polyvinylidene fluoride (PVDF) is used as the probe membrane material for the fouling study. The untreated HA and oxidized HA will be characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), excitation emission matrix fluorescence, combined with parallel factor analysis (EEM-PARAFAC), and size-exclusion chromatography for the determination of the functional groups and molecular size of HA. The morphology of membrane fouling will be characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Atomic force microscopy (AFM) will be used to analyze the roughness of HA foulant layer, mechanical properties of HA (i.e., cohesiveness, stiffness and viscous dissipative properties), and the interactions of HA-HA and HA-PVDF membrane (i.e., adhesive forces and energies). A membrane filtration test will be also performed, and the flux will be monitored to evaluate the fouling potential of the untreated and oxidized HA. This research will help systematically understand fouling mechanisms on photocatalytic membranes, and provide insights on the design of novel membrane materials and treatment processes with improved performance for water purification. Ruochen Zhu1, Alfredo Diaz2, Santiago Solares2, Danmeng Shuai1

Mechanistic study of the physical, chemical, and mechanical properties of natural organic matter on photocatalytic membranes to understand fouling mitigation

251st National Meeting (2016)

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