Investigation on the conditions mitigating membrane fouling caused by TiO₂ deposition in a membrane photocatalytic reactor (MPR) used for dye wastewater treatment

• Published in: Journal of hazardous materials 2012-02, Vol.203, p.348-356
• Main Authors: Damodar, Rahul-Ashok, You, Sheng-Jie, Chiou, Guan-Wei
• Format: Article
• Language: English
• Subjects: Catalysis; Color; Coloring Agents - isolation & purification; Filtration; Flux; Fouling; Hydrogen-Ion Concentration; hydrophilicity; hydrophobicity; Membranes; Membranes, Artificial; Microscopy, Electron, Scanning; Photochemistry; Tanks; Titanium - chemistry; Titanium dioxide; Turbidity; wastewater treatment; Water Pollutants, Chemical - isolation & purification; zeta potential
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2011.12.027

In this study, the effects of MPR's operating conditions such as permeate flux, solution pH, and membrane hydrophobicity on separation characteristics and membrane fouling caused by TiO₂ deposition were investigated. The extent of fouling was measured in terms of TMP and tank turbidity variation. The results showed that, at mildly acidic conditions (pH∼5), the turbidity within the tank decreased and the extent of turbidity drop increased with increasing flux for all the membranes. On the other hand, at pH≥7, the turbidity remained constant at all flux and for all membranes tested. The fouling variation at different pH was closely linked with the surface charge (zeta potential) and hydrophilicity of both membrane and particles. It was observed that the charge differences between the particles and membranes accelerate the intensity of fouling and binding of TiO₂ particles on the membrane surface under different pH conditions. The presence of a very thin layer of TiO₂ can alter the hydrophilicity of the membranes and can slightly decrease the TMP (filtration resistance) of the fouled membranes. Besides, the resistance offered by the dense TiO₂ cake layer would dominate this hydrophilic effect of TiO₂ particles, and it may not alter the filtration resistance of the fouled membranes.