Study On The Construction And Properties Of Porphyrin Self-assembled Membrane

Porphyrins are well known functional dyes that possess high molar extinction coefficients in the visible region.They have been extensively used as sensors,nonlinear optical materials,energy conversion devices,dying waste water treatment and solar cells because of their special chemical structure and optoelectronic properties.Among many kinds of derivatives,meso-Tetraphenyl sulfonato porphyrin(TPPS)and meso-Tetra-(N-methyl-4-pyridyl)porphine(TMPyP)have been widely studied due to the supramolecular self-assembly induced by pH and salt in solution.However,immobilizing porphyrin on solid carriers is highly desirable for practical use in chiral materials,sensors and catalyst.For this reason,a growing body of research is now focusing on TPPS immobilization on various solid carriers.In this work,a smart membrane of polysulfone-graft-poly(4-vinylpyridine)(PSF-g-P4VP)blended PSF,a cation membrane of quaternary ammonium polysulfone and an anionic membrane of sulfonated polysulfone blended polysulfone were proposed by NIPS.The adsorption and self-assembly of anionic porphine(TPPS)as well as cationic porphine(TMPyP)on the above membranes were studied,and the properties of photocatalytic degradation dyes and heavy metal ions detection were explored.The main contents could be summerized as follows:The polysulfone-graft-poly(4-vinylpyridine)polymer was prepared by atom transfer radical polymerization(ATRP),and the grafted polymer was blended with PSF to fabricate the smart membrane through NIPS.The pH-responsive characteristics of the PSF-g-P4VP blended PSF membranes were measured.The hydraulic permeation results demonstrated that the pH-responsive characteristics were reversible and durable,and occurred with switching pH between 3.0 and 8.0.Water flux increased drastically from 70 to 1113 L/m-2·h at pH 8.0 as the content of PSF-g-P4VP polymer in the blend membrane increasing from 10%to 30%.The adsorption property and aggregation behavior of TPPS on PSF-g-P4VP/PSF membrane were studied.The adsorption kinetics and adsorption thermodynamics of TPPS on membrane were explored,and the influence of pH and adsorption time on adsorbing capacity and the type of aggregates were studied.Results showed that it was a chemisorption of TPPS on PSF-g-P4VP/PSF membrane,and the maximum adsorption amount was obtained at pH 2.0.The adsorption amount increased with the increase of grafting density and blending ratio.J-aggregates of TPPS were observed on the blended membrane surface below pH 2.5 owing to inductive effect of cationic P4VP units,while the J-type aggregates could be only found at pH 1.0 in aqueous solution.Quaternary ammonium polysulfone polymer was prepared by homogeneous assay method,and quaternary ammonium polysulfone membrane with spongylike pore structure was obtained by NIPS.TPPS was immobilized on the quaternized polysulfone membrane by electrostatic interaction,and the TPPS functionalized membrane was used for degradation organic dyes under the xenon lamp irradiation.The degradation rate of rhodamine B,methylene blue and methyl orange were up to 92.1%,92.1%and 94.1%,respectively.The TPPS functionalized membrane could be reused.A kind of anionic membrane(SPSF-PES membrane)was fabricated by NIPS from sulfonated polysulfone and polysulfone.Cationic type of porphyrin TMPyP was immobilized onto the SPSF-PES membrane by electrostatic-assembly,and the TMPyP functionalized SPSF-PES membrane was used for degradation rhodamine B under the xenon lamp irradiation.The degradation rate was up to 93.4%.Furthermore,TiO2 was coated on the SPSF-PES membrane surface before adsorbing TMPyP.The TMPyP/TiO2/SPSF-PES membrane was applied to degrade rhodamine B,and the degradation rate was more than 99%.Further,the TMPyP functionalized SPSF-PES membrane showed a superior color and spectral response for Cd(Ⅱ)detection.In brief,the photocatalytic performance of TPPS was enhanced after it was immobilized on the porous membrane.