Treatment of laundry wastewater using polyethersulfone/polyvinylpyrollidone ultrafiltration membranes.

In this study, laundry wastewater filtration was studied using hydrophilic polyvinylpyrollidone (PVP) modified polyethersulfone (PES) ultrafiltration membranes. The performances of PES/PVP membranes were assessed using commercial PES membrane with 10kDa in ultrafiltration. Operating parameters The influence of transmembrane pressure (TMP) and stirring speed on laundry wastewater flux was investigated. A higher permeate flux of 55.2L/m(2)h was obtained for modified PES membrane with high concentration of PVP at TMP of 500kPa and 750rpm of stirring speed. The separation efficiencies of membranes were also studied with respect to chemical oxygen demand (COD), total dissolved solids (TDS), turbidity and conductivity. Results showed that PES membrane with 10% of PVP had higher permeate flux, flux recovery and less fouling when compared with other membranes. Higher COD and TDS rejection of 88% and 82% were also observed for modified membranes due to the improved surface property of membranes. This indicated that modified PES membranes are suitable for the treatment of surfactant, detergent and oil from laundry wastewater.

Modeling of the separation of inhibitory components from pretreated rice straw hydrolysate by nanofiltration membranes.

The main objective of this work was to remove inhibitors and concentrate sugars in hydrolysates obtained from dilute acid-treated rice straw. The Donnan steric pore flow model (DSPM) was applied for membrane characterization and it captured the membrane transport adequately. The polyamide and polyethylene sulfate nanofiltration membranes of 150 Da molecular weight cut-off showed a separation factor of 3 for acetic acid over glucose and xylose and 7 over cellobiose for a simulated mixture at the optimum pH of 3. A separation factor of 3 was also found for the inhibitors hydroxymethyl furfural, ferulic and vanilic acids over sugars. The concentration of rice straw acid hydrolysate by a volume concentration ratio of 4 increased the concentrations of xylose, glucose, arabinose, cellobiose and inhibitor by 100%, 104%, 93%, 151% and 3%, respectively which indicates the membrane can be used for separating the inhibitors from acid-pretreated rice straw hydrolysate while simultaneously concentrating sugars.