Polysulfone photocatalyst membrane effects of catalyst, polymeric additives and molecular imprint for selective filtration and photodegradation / Melvin Ng Hau Kwan
Membran fotomangkin mempunyai potensi yang besar dalam rawatan air sisa kerana membran dan fotomangkin boleh digabungkan dalam satu unit. Dalam kajian ini, poli(vinil alkohol) (PVA) dan polivinil pirrolidon (PVP) digunakan untuk menstabilkan 2 wt % nanozarah fotomangkin (TiO2, Mn-TiO2 and ZnO) dalam membran polisulfon (PSf) sebelum penyongsongan fasa. Bahan tambah menggalakkan pembentukan jejari liang seperti yang ditunjukkan dalam imej SEM. Penambahan PVA dan fotomangkin ke dalam membran PSf membawa penambahbaikan yang ketara dalam penurasan asid humik (HA). Penambahan PVA dan fotomangkin dalam membran PSf memeningkatkan ketelapan air sebanyak 15.5~18.1 kali ganda berbanding dengan membran PSf tulen. Membran yang mempunyai prestatsi permisahan dan penerapan yang baik diperiksa dalam ujian fotodegradasi dan semua PSf/PVP/fotomangkin menunjukkan < 15 % penurunan dalam pemangkinan foto berbanding dengan nanozarah yang bebas. TiO2 tulen diubahsuai menggunakan ‘polimer tekapan molekul’ (MIP-TiO2) sebelum dimasukkan ke dalam membran PSf. MIP-TiO2 mencapai selektivity sebanyak 2.06 dalam fotodegradasi methylene biru/metil jingga(MB/MO) apabila MIP-TiO2 diguna bawah sinaran UV selama 1 jam. MIP-TiO2 boleh digunnakan utnuk jangka masa panjang (2 jam) dan sehingga 5 kali kitaran fotodegradasi dengan seletktif MB/MO sebanyak 2.16. Penambahan MIP-TiO2 ke dalam membran PSf/PVP/MIP-TiO2 meningkatkan penelapan sehinnga 14.08 L/m2.h.bar, serta pemisahan kotoran utama (MB) secara selektif sebanyak 2.83 di bawah sinaran UV.
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Photocatalytic membranes exhibit great potential for wastewater treatment since they can combine filtration and photo degradation in a single unit. In this work, 2 wt % poly(vinyl alcohol) (PVA) and polyvinyl pyrrolidone (PVP) were used to stabilize 2 wt % of photocatalytic nanoparticles (TiO2, Mn-TiO2 and ZnO) blended into polysulfone (PSf) membrane before phase inversion. These additives affect the formation of finger-like pores as shown in the SEM images. Blending PVA and photocatalysts into PSf membrane resulted in significant improvement of humic acid (HA) rejection. The incorporation of PVP and photocatalysts into PSf membrane caused great improvement in water permeability, about 15.5~18.1 times higher than pure PSf membrane. Membranes with excellent rejection and permeation were further examined in photodegradation test, where PSf/PVP/photocatalyst showing < 15 % reduction in their photodegradation in comparison to the free nanoparticles. Pure TiO2 nanoparticles was further modified using molecular imprinting polymer (MIP-TiO2) before blending into PSf membrane. MIP-TiO2 achieved a photodegradation selectivity of methylene blue/methylene orange (MB/MO) up to 2.06 under UV irradiation for 1 h. MIP-TiO2 could be used in long duration (2 h) and up to 5 cycles of photocatalytic degradation with MB/MO selectivity of 2.16. The blending of MIP-TiO2 into PSf/PVP/MIP-TiO2 membrane further enhanced permeate flux up to 14.08 L/m2.h.bar, while retaining the major foulant MB with a selectivity of 2.83 under UV.
Polysulfone photocatalyst membrane effects of catalyst, polymeric additives and molecular imprint for selective filtration and photodegradation / Melvin Ng Hau Kwan
Polysulfone photocatalyst membrane effects of catalyst, polymeric additives and molecular imprint for selective filtration and photodegradation_Melvin Ng Hau Kwan_K4_2017_MYMY