Prevention of PVDF ultrafiltration membrane fouling by coating MnO2 nanoparticles with ozonation

Abstract

Pre-treatment is normally required to reduce or control the fouling of ultrafiltration (UF) membranes in drinking water treatment process. Current pre-treatment methods, such as coagulation, are only partially effective to prevent long-term fouling. Since biological activities are a major contributor to accumulated fouling, the application of an oxidation/disinfection step can be an effective complement to coagulation. In this study, a novel pre-treatment method has been evaluated at laboratory scale consisting of the addition of low dose ozone into the UF membrane tank after coagulation and the use of a hollow-fibre membrane coated with/without MnO2 nanoparticles over a test period of 70 days. The results showed that there was minimal fouling of the MnO2 coated membrane (0.5 kPa for 70 days), while the uncoated membrane experienced both reversible and irreversible fouling. The difference was attributed to the greatly reduced presence of bacteria and organic matter because of the catalytic decomposition of ozone to hydroxyl radicals and increase of the hydrophilicity of the membrane surface. In particular, the MnO2 coated membrane had a much thinner cake layer, with significantly less polysaccharides and proteins, and much less accumulated organic matter within the membrane pores.

A sustainable multi-function biomorphic material for pollution remediation or UV absorption: Aerosol assisted preparation of highly porous ZnO-based materials from cork templates

“…Although the FTIR technique is not quantitative, it is reasonable to assume that smaller quantities of residual carbon could be present in the material. All spectra show a very intense drift for  < 580 cm -1 , which is due to the presence of ZnO [31]. Residual graphitic carbon was also confirmed through Raman spectroscopy -as can be seen in Figure S4, the spectrum of the pyrolysed cork shows the characteristic peaks at about 1355 and 1580 cm -1 (D and G peaks respectively) [32].…”

Catalytic Ozonation and Membrane Contactors—A Review Concerning Fouling Occurrence and Pollutant Removal

“…In most cases ceramic membranes have been used in catalytic ozonation systems, because the substrate material is simpler to be coated. However, Yu et al [29] coated a PVDF (polymeric) membrane with MnO 2 nanoparticles. They observed that there was not any detectable additional pressure loss by the presence of coating at the beginning of process operation and the presence of MnO 2 surface layer was found to lower the fouling rate.…”

Catalytic Membrane Ozonation

“…In most relevant ozonation cases the ceramic membranes have been commonly applied in the catalytic ozonation systems, because they are fully ozone resistant and the substrate material is simpler to be used as coating substrate. However, Yu et al [23] who have coated a PVDF membrane with MnO 2 nanoparticles; they reported that the presence of these oxide particles lowered the fouling rate and the presence of ozone has limited the bio-accumulation of several components onto the membranes' surface, hence restricting the fouling problem. Furthermore, Sun et al [24] have doped a similar membrane with TiO 2 nanoparticles to examine the removal of nitrobenzene.…”