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• Monolayer TMPyP@SPSf/PES membrane was prepared by electrostatic assembly strategy. • The visible light response region of TMPyP was expanded after it was immobilized. • Photocatalytic membrane reactor (PMR) exhibited excellent performance for dye degradation. • The PMR can be applied for degradation of different dyes and can be reused after regeneration. Porphyrin-based catalytic oxidation of hydrocarbon bonds is considered to be the most representative biomimetic catalysis. To mimic the biomimetic catalytic oxidation of nature under illumination of visible light, a monolayer of meso -tetrakis (1-methylpyridinium-4-yl) porphyrin immobilized sulfonated polysulfone/ polyethersulfone blend membrane (TMPyP@SPSf/PES) was prepared via a facile electrostatic assembly method. The visible light response region of TMPyP was expanded after it was immobilized on the SPSf/PES membrane surface, which resulted in the increase of the photocatalytic performance, and the Rhodamine B (RhB) degradation was increased from 30.0% to 93.4%. A photocatalytic membrane reactor (PMR) equipped with TMPyP@SPSf/PES membrane was employed for RhB treatment under continuous flow filtration coupling with photocatalysis, and the optimized degradation was up to 98.3%. Moreover, the TMPyP@SPSf/PES membrane can be reused for photocatalytic degradation of RhB after regeneration in TMPyP solution. More importantly, the TMPyP@SPSf/PES membrane can also efficiently degrade other cationic and anionic dyes (such as degradation of methylene blue 99.1%, acid fuchsin 96.8%). Finally, the oxidation mechanism and degradation pathway of RhB were further investigated by electron spin resonance (ESR), ultra-performance liquid chromatography and high-definition mass spectrometry (UPLC HDMS) and gas chromatography-Mass spectrometry (GC–MS). It was revealed that the photogenerated hole (h+), superoxide radical (·O 2 −), and singlet oxygen (1O 2) controlled the oxidation process. The degradation of RhB includes N -de-ethylate, wrecked of chromophore structures and opening-ring of benzene. [ABSTRACT FROM AUTHOR]

Several researches have been carried out to find a sustainable solution for overcoming the challenge of dyes released by industries in the environment. In this research, a photocatalytic membrane reactor (PMR) based on polysulfone (PSU) with an immobilized and suspended metal-organic framework (MOF: NH 2 -MIL125(Ti)) was applied for the decomposition of methylene blue (MB) as the model dye of textile wastewater. The MOF and the membranes were characterized through FESEM, XRD, FTIR, Raman, BET, AFM, and contact angle. The MOF incorporation with the concentration up to 0.2 wt% improved the porosity, hydrophilicity and water flux of the membrane, but in higher concentration, the system performance deteriorated due to the agglomeration of the MOF particles. Under UV illumination, MB photodegradation efficiency up to 60% was achieved with immobilized MOF. The combination of immobilized and suspended MOF as a novel strategy in the cross-flow PMR resulted in a significant MB removal efficiency boost up to 97%. Interestingly, using hybrid immobilized and suspended MOF nanoparticles resulted in a flux recovery ratio of 88% due to the self-cleaning properties of MOF nanoparticles and photo-degradation of the foulant layer. Therefore, the novel PMR has a promising potential for developing efficient membrane systems with significant flux recovery to remove dyes and other organic foulants. [Display omitted] • Foulant layer due to MB dye were successfully degraded in a photocatalytic membrane reactor by membrane activation. • In situ self-cleaning surface membrane was achieved by incorporation of immobilized and suspended NH 2 -MIL125(Ti). • Flux recovery in the fabricated PSU-MOF membranes reached to 88%. • The porosity, hydrophilicity and water flux improved by MOF incorporation. [ABSTRACT FROM AUTHOR]

Abstract: A photo-catalysis and dynamic membrane reactor system (PMR), with coated dynamic layer on polypropylene non- woven fabric material, was studied for continuous photocatalysis and retention of catalysts in a single device, in removing halogenated compound 2,4,6-Tribromophenol in water. Different dynamic layer materials such as graphite oxide, graphene oxide and nonoCaCO3 were applied to evaluate the efficiency in removing COD, 2,4,6- Tribromophenol and in debromination. The pre-coated dynamic membrane can significantly enhance the filtration performance and improve the debromination efficiency. The PMR system with dynamic layer and Fe-ZnIn2S4 photocatalyst completely removed 2,4,6-Tribromophenol when the retention time maintained 2.0h in the continuous mode. The hybrid system achieved 58%, 74% and 85% debromination when the dynamic layer materials were graphite oxide, graphene oxide and nanoCaCO3, respectively. And, the COD removal efficiencies were in the order of nanoCaCO3 (72%) > graphite oxide (51%) > graphene oxide (42%). NanoCaCO3 was found able to assist and improve debromination efficiency during UV irradiated photolysis. The combination of dynamic membrane and photocatalysis provides a new alternative for practical application of photocatalysis. [Copyright &y& Elsevier]