Nano-particles enhanced hydrophobic membranes: High-performance study for dye wastewater treatment using membrane distillation

Abstract

The most common problem with hydrophobic membrane distillation membrane is the deposition of foreign particles on the surface. This study aimed to fabricate nano-particles enhanced high-performance membranes using the phase-inversion method and tested for dye wastewater treatment using direct contact membrane distillation. The PVDF-PEG200 (M1) & PVDF-PEG200-TiO2 (M2) membranes are prepared, and Taguchi L9 orthogonal array is developed and examined at three different operating parameters at three levels, namely, feed temperature (45 °C, 55 °C, 65 °C), feed concentration (75 ppm, 100 ppm, 125 ppm) and flowrate (0.6 LPM, 0.7 LPM, 0.8 LPM). Using the Taguchi approach, optimum conditions (feed temperature: 65 °C, feed concentration: 75 ppm, flowrate: 0.8 LPM) are found, and optimum permeate flux is calculated at these conditions with both the membranes. A regression equation is developed for estimating the variation of operating parameters to obtain permeate flux. The effect of TiO2 on the membrane performance is examined, and it showed that modified membrane (flux: 6.22 ± 0.12 kg/m2h) exhibited 21.96% more permeate flux than unmodified membrane (flux: 5.10 ± 0.10 kg/m2h). Both the membranes, M1 and M2, showed 100% color rejection. The effect of operating parameters (feed temperature, feed concentration, & flow rate) on permeate flux has also been investigated. Different membrane characterization analysis methods like SEM, FTIR, and XRD are performed to identify the fouling resistance of both membranes. A long run test has also been examined to determine the performance of the M2 membrane. M2 membrane showed high stability in long run test, making it suitable for industrial-scale applications. Lastly, the self-cleaning ability of the membrane is also experimentally examined.