| Membrane absorption method forflue gas desulfurization is a new effective way to control SO2.The hydrophobic membrane contactor can effectively solve the membrane wetting problem in the membrane absorption process,so that the membrane contactor can operate stably for a long time in the desulfurization process.Hydrophobic SiO2nanoparticles have the advantages for improving the hydrophobicity of the membrane due to their low surface energy and nanometer particle size.In this study,PVDF and PES were used as polymer based membranes,respectively.The superhydrophobic membrane with micro-nanoscale double-rough surface was constructed by the synergy between hydrophobic SiO2nanoparticles and polymer.The wettability and stability of the superhydrophobic membrane contactor based on flue gas desulfurization were studied.The main research work and conclusions are as following:1. The superhydrophobic PVDF/SiO2membrane was prepared by the combination of suspension coating and phase transformation method.The wettability and stability of superhydrophobic PVDF/SiO2membranes were studied under different polymer concentration and SiO2content in suspension solution.The results showed that the wettability and stability of superhydrophobic PVDF/SiO2membrane was better than PVDF original membrane,especially M??.The superhydrophobic PVDF/SiO2membrane has a high wettability,with a roughness of 0.961?m,LEPw of2.036 bar,the water contact angle of 158°.After long-term operation for 14 h,the absorption flux of SO2could be kept at 8.4×10-4?9.1×10-4mol·m-2·s-1.2. The PES micron-sized particles prepared by the cloud point method and SiO2 nanoparticles were introduced into the surface of the PES based membrane by suspension coating and phase inversion in succession to fabricate a superhydrophobic PES/SiO2membrane.The influence of polymer concentration and SiO2content on the wettability and stability of PES/SiO2membrane was investigated.The results showed that the wettability of PES/SiO2membrane was significantly improved,which the roughness,LEPw and water contact angle were up to 1.235 microns,1.359 bar and159°,respectively.After 12 h long-term operation,the absorption flux of SO2of superhydrophobic PES/SiO2membrane could be stabilized at 1.12×10-3?1.16×10-3mol·m-2·s-1,indicating that stability was also significantly improved.3. The superhydrophobic Elec-PVDF/SiO2membrane was prepared by electrospinning.The effects of different SiO2contents in spinning liquid on the wettability and stability of superhydrophobic-electrospinning PVDF/SiO2membranes were explored.The superhydrophobic Elec-PVDF/SiO2membrane had improved wettability,which possessed the roughness of 1.623?m,the LEPw of 1.69 bar,and the water contact angle of 155°.After 12 h desulfurization,the absorption flux of SO2was decreased by 15%,which was within the range of 8.9×10-4?9.5×10-4mol·m-2·s-1,indicating obviously better than the PVDF original membrane.Among them,M?showed the best SO2absorption flux and stability.4. The study on the wettability and stability of the superhydrophobic membrane contactor showed that the superhydrophobic PVDF/SiO2membrane prepared by suspension coating showed better wettability and stability than electrospinning,especially M??.Besides,compared with superhydrophobic PVDF/SiO2membrane,the superhydrophobic PES/SiO2membrane had better desulfurization stability,and its SO2absorption flux could be stable above 1.12×10-3mol·m-2·s-1. |
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