Fouling mitigation in ultrafiltration for wastewater treatment using zinc oxide nanoparticles
Natural organic matter (NOM) is a common organic material present in natural water. NOM fouling is a main concern in membrane processes. This could be attributed to the gel layer formation on membrane surface and pore blocking. NOM is hard to be removed by chemical cleaning or backwashing and tend to cause irreversible fouling (Yamamura et al., 2014). Recent development of nanomaterial has shown a great potential of advanced treatment technology in wastewater treatment. Hybrid adsorption-membrane process has been introduced to be a reliable process in membrane fouling mitigation in wastewater treatment. Potential of zinc oxide (ZnO) nanoparticle as nano-absorbent in hybrid adsorption-membrane process has been studied in this work. ZnO has advantages over conventional absorbent such as powdered activated carbon due to their regenerable properties (Liqiang et al., 2004). ZnO nanoparticle (0.5 g/l) is well-mixed with the targeted natural organic pollutant surrogate - flower soil (FS) extract (1:500 dilution) - and was used as feed solution. Three ultrafiltration (UF) membranes with different nominal molecular weight cut-off (MWCO) (4 kDa, 5 kDa and 10 kDa) were used in a low pressure cross-flow ultrafiltration membrane system. The main objective in this work is to assess the membrane performance and fouling propensity when dealing with organic pollutant with or without the adsorption by ZnO. Further, this work also acts as a preliminary study prior to the fouling mitigation under UV irradiation.