Fabrication And Performance Of Oil-water Separation Membrane With Micro-nano Bionic Structure

The oil-water separation is kind of worldwide issue. However the complicated composition makes it difficult to achieve the goal of separation. Due to the low-energy-cost and high separation efficiency, membrane technology aroused extensive attention. This article reported three kinds of oil-water separation films to separate different oil-water mixture.1. The interpenetrating polymer network(IPN) hydrogel coated stainless steel mesh was obtained by chemical crosslinking between glutaraldehyde(GA) and the linear polymer polyvinyl alcohol(PVA). Compared with the semi-interpenetrating polymer network(semi-IPN) hydrogel coated stainless steel mesh, the IPN one had a coarser surface which improved underwater oleophobicity. By the crosslinking, contact angle of mesh increased from 141.50±0.50 o to 153.92±1.08 o. Separation efficiency was improved from99.7% to 99.8%. Furthermore, the IPN hydrogel coating had better abrasion resistance and break compressive stresswas 97.00±7.69 kPa..2. The microgel with the core-shell sructure was firstly fabricated via Pickering emulsion. Then the composite film with transmembrane structure was obtained by controlling the size of microgel and the thickness of PVA casting. With the transmembrane structure, the water flux was enhanced obviously. And the water flux of composite film was 2 times as much as PVA film. Meanwhile, the core-shell microgel provided the micro-nano structure and showed a contact angle of 142o(the one of PVA film is 133o). The microgel/PVA composite film was applied to separate surfactant-free oil-in-water emulsion, and operated at both ordinary pressure and 0.01 MPa. The flux could achieve 1000 Lm-2h-1 at the operation of 0.01 MPa. And the oil content of separated water from most tested emulsion was lower than 100 ppm.3. With certain relative humidity, the gel of cellulose acetate(CA) was prepared by the process of phase separation of CA solution and the hydrolytic condensation of silane. And the organic-inorganic composite aerogel film was obtained by the replacement of solvent and drying which was carried out at room temperature and ordinary pressure. The film had a superhydrophobic surface with contact angle of water droplet of 147.2±0.3o due to the micro-nano structure. Moreover, the submicron pore structure of aerogel can be used to separate surfactant-stable water-in-oil emulsion. At the operation of 0.01 MPa, the flux during separation was 1000-3000 Lm-2h-1 for water-in-oil emulsion with the size of about 330 nm. while the water content in filtrate was below 100 ppm.