Preparation And Application Of FEP Hybrid Flat Film

With the increasing seriousness of water pollution, the separation membranes should have strong ability so that they can be long-term used in harsh environmental conditions. Because of the completely fluorinated molecular structure of Poly(tetrafluoroethylene-co-hexafluoropropylene)(FEP), it has excellent chemical stability and thermal stability. Besides, it has good melt performance. FEP hybrid flat-sheet membrane had been fabricated by hot pressing method with FEP as membrane forming polymer, Dioctyl Phthalate (DOP) as plasticizer and blending composite inorganic particles (including micro/nano scale SiO2, NaCl particles and interfacial treatment agent), powdered active carbon and Fe2O3 respectively. The particle sizes of composite inorganic particles, powdered active carbon and Fe2O3are 20-40 nm,10 μm,30-50 nm respectively.Firstly, FEP flat-sheet membrane had been fabricated by hot pressing method with FEP as membrane forming polymer, composite inorganic particles as pore forming agent and DOP as plasticizer. FEP hybrid flat-sheet membrane is a kind of homogeneous microporous membrane with interfacial pore structure. How the content of composite inorganic particles influence the structure and performance of FEP flat membrane is investigated in this article. Membranes’corresponding performances were characterized in terms of penetration, rejection rate, porosity and mechanical properties. The result showed that little inorganic particles distributed in the surface of FEP hybrid membrane and most of them were surrounded by matrix. Due to the low surface energy, FEP is easily separated with inorganic particles formatting pore structure. With the increase of inorganic particles, the number of pore increased, meanwhile the permeability and porosity increased, while the rejection ratio of carbonic ink decreased, and the mechanical properties of membranes first increased and then decreased.Secondly, FEP/active carbon/inorganic particles hybrid flat-sheet membrane had been fabricated by hot pressing method with the active carbon as adsorbent for further functionalization research on the basis of FEP hybrid flat-sheet membrane. How the experimental conditions:time, temperature, dye categories, ultrasonic vibrating, influence the adsorption of dyes was investigated in this article. The result showed that with the increase of experimental time and temperature, the FEP/active carbon/inorganic particles hybrid flat-sheet membrane’s absorbance of dye increased first and then reached saturation. Besides, ultrasonic vibrating obviously promoted the absorbance of dye.Finally, FEP/Fe2O3/inorganic particles hybrid flat-sheet membrane (FEP/Fe2O3-HFM) had been fabricated by hot pressing method with Fe2O3as catalyst on the basis of FEP hybrid flat-sheet membrane. The dye solution was oxidized by heterogeneous Fenton-like which consisted of H2O2 and FEP/Fe2O3-HFM. How the content of Fe2O3, H2O2, dye categories, dye concentration, reacting time and cycle use influence the absorbance of dye was investigated in this article. The result showed that the heterogeneous Fenton-like oxidation driven by FEP/Fe2O3-HFM achieved high removal of dyes. With the content of Fe2O3 and H2O2 increasing, the degradation efficiency increased and the highest of methylene blue dye (MB) was about 99.69% at the selected operating conditions (the content of Fe2O3 of 10%, PH of 3,25ml 40mg/l MB, [H2O2]:[FEP/Fe2O3-HFM] of 1.5(g/g)). The three cycles of the Fenton-like oxidation using the same membrane contributed to the relatively steady degradation of dye, which confirmed the pretty high stability of the FEP/Fe2O3-HFMs over the multity heterogeneous Fenton-like reaction.