Cleaning ceramic membranes used in treating desizing wastewater with a complex-surfactant SDBS-assisted method

Ceramic ultrafiltration membranes were used to treat desizing wastewater for recycling. Both the fouling mechanisms and the regeneration of fouled membranes obtained from an industrial park were studied. The fouling was mainly caused by polymethyl acrylate (PMA) deposition on membrane surface and blockage in membrane pores. A cleaning strategy and solution composed of NaOH and sodium dodecyl benzene sulfonate (SDBS) were developed based on analysis of fouling resistance and interaction between cleaning agents and foulants, respectively. The hydrolysis of NaOH and solubilization of SDBS micelles, which decreased the adhesion between foulants and membrane surface, played an important role during the cleaning. The flux of the membrane could be well recovered with the cleaning solution. The cleaning efficiency was sensitive to the concentration of SDBS (C_SDBS) and temperature (T), and was also affected by transmembrane pressure (TMP), crossflow velocity (CFV) and operation time of the permeate line (OTPL). The optimized cleaning condition was C_SDBS=0.30wt.%, TMP=0.10MPa, CFV=3m/s, T=60°C, and OTPL=80min. The dynamic and chemical interaction between chemical agents, foulants and the membrane was also studied in this research. The methods were successfully applied to the industry.