Preparation And Application Of Poly(Vinyl Butyral)(PVB)Hollow Fiber Membranes

Membrane separation technology has been widely used in many fields for its apparent merits, such as high efficiency, simple and low energy consumption. Poly (vinyl butyral)(PVB) promises to be a novel membrane material for its good membrane forming performances, good resistance to acid, alkali and microorganism.Thermally induced phase separation (TIPS) is a promising membrane preparation method for the effective control of membrane structure. PVB hollow fiber membranes was prepared via TIPS and the influences of coagulation bath temperature (CBT), air gap and take-up speed on the structure and performance of PVB membranes were mainly studied. The prepared PVB hollow fiber membranes presented the typical asymmetric structure. The increasing of CBT, decreasing of air-gap and increasing of take-up speed could decrease the density of skin-layer and increase the pores; the permeability increased and rejection decreased correspondingly, breaking strength and elongation decreased, accordingly.PVB hollow fiber membranes used for dealing with bovine serum albumin (BSA) was studied. The fouling of BSA on PVB membrane was mainly embodied in the adsorption and deposition of pores. The membrane was fouled the most in the isoelectric point of BSA of pH=4.70, and the membrane was the slightest fouled in alkaline condition; inside-out filtration type was fouled more serious than outside-in; the fouling situation was increased with the increase of the concentration of BSA suspension and the filtration time, moreover all the adsorption and deposition of BSA particles and their aggregation occurred at the beginning of filtration within10min.Moreover, the PVB membranes were also used for processing simulated lead and zinc smelting wastewater with complexation-ultrafiltration. The order of the complex stability for the Pb2+, Zn2+, Cd2+and poly (arylic acid and maleic acid)(PMA-100) using acid-base titration and competitive complexing of binary system of heavy metal ions was Pb>Zn>Cd, these comlexation reactions could be described as the pseudo-first order reaction and the rate of complexation was Pb>Zn>Cd. Adding salt can decrease the rejection of researched metal ions for its competitive and the influence of Ca2+was more seriously than Na. Pb could be separated from Zn2+or Cd2+in smaller P/M and pH in binary system. The system of Zn2+/Cd2+could be separated easily in P/M=1.75with pH=5.0, pH=5.0was the easiest to separate for Zn2+/Cd2+once fixed P/M=1.5.