The effects of feed temperature and pH value on the removal of aqueous phenol wastewater by vacuum membrane distillation process are studied by experiments employing micro porous membranes of poly vinylidene fluoride ...The effects of feed temperature and pH value on the removal of aqueous phenol wastewater by vacuum membrane distillation process are studied by experiments employing micro porous membranes of poly vinylidene fluoride (PVDF) and ploy tetrafluoro ethylene (PTFE) with nominal average pore sizes 0.22 mm and 0.20 mm, respectively. It is found that the optimal feed temperature for PVDF membrane is 50 ℃; and for PTFE membrane, 60 ℃. The pH value of the feed has little influence on the membrane fluxes and ion rejection ratios, while it influenced considerably on the selectivity. Increase of pH value of the feed is conducive to the increase of selectivity. In the same experimental conditions, PTFE membrane shows better separation performance than PVDF membrane does.展开更多
Membrane distillation(MD) has not been widely studied in the concentrate of phenolic rich solution in comparison to osmotic distillation. In this work, the potential of MD to reduce solvent in the polyphenol rich prop...Membrane distillation(MD) has not been widely studied in the concentrate of phenolic rich solution in comparison to osmotic distillation. In this work, the potential of MD to reduce solvent in the polyphenol rich propolis extract was further investigated. Polyvinylidene fluoride(PVDF) membranes were engineered with the smaller pore size for the less hydrophobic surface in order to avoid wetting, allowing only the solvent vapor to be transferred from the warm feed into the cold permeate. All the membranes exhibited more than 95% rejection of phenolic and flavonoid compounds. Although the hydrophilic membranes exhibited less fouling, they displayed a lower flux than the hydrophobic membrane due to the hindrance in the wetted pores. The hydrophobic membrane was seriously fouled by the phenolic acid as shown in the Fourier transform infrared spectroscopy spectrum. Pore plugging occurred on these hydrophobic membranes as confirmed in the scanning electron microscope images.展开更多
文摘The effects of feed temperature and pH value on the removal of aqueous phenol wastewater by vacuum membrane distillation process are studied by experiments employing micro porous membranes of poly vinylidene fluoride (PVDF) and ploy tetrafluoro ethylene (PTFE) with nominal average pore sizes 0.22 mm and 0.20 mm, respectively. It is found that the optimal feed temperature for PVDF membrane is 50 ℃; and for PTFE membrane, 60 ℃. The pH value of the feed has little influence on the membrane fluxes and ion rejection ratios, while it influenced considerably on the selectivity. Increase of pH value of the feed is conducive to the increase of selectivity. In the same experimental conditions, PTFE membrane shows better separation performance than PVDF membrane does.
基金the Universiti Sains Malaysia for funding the research through Membrane Science and Technology Cluster
文摘Membrane distillation(MD) has not been widely studied in the concentrate of phenolic rich solution in comparison to osmotic distillation. In this work, the potential of MD to reduce solvent in the polyphenol rich propolis extract was further investigated. Polyvinylidene fluoride(PVDF) membranes were engineered with the smaller pore size for the less hydrophobic surface in order to avoid wetting, allowing only the solvent vapor to be transferred from the warm feed into the cold permeate. All the membranes exhibited more than 95% rejection of phenolic and flavonoid compounds. Although the hydrophilic membranes exhibited less fouling, they displayed a lower flux than the hydrophobic membrane due to the hindrance in the wetted pores. The hydrophobic membrane was seriously fouled by the phenolic acid as shown in the Fourier transform infrared spectroscopy spectrum. Pore plugging occurred on these hydrophobic membranes as confirmed in the scanning electron microscope images.
