Yatim, Nur Suhaili Mohd (2018) Synthesis Of Tio2-Pvdf Membrane With Enhanced Wetting Resistance For Membrane Distillation ApplicationS. PhD thesis, Universiti Sains Malaysia.
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Abstract
Membran penyulingan (MD) merupakan teknologi yang penting di dalam industri seperti penyulingan air laut dan rawatan sisa air kerana membran penyulingan memerlukan tenaga yang lebih rendah dan secara teorinya berkecenderungan pengotoran yang rendah. Bagi mengelakkan berlakunya pembasahan membran, kaedah rendaman dua kali diperkenalkan bagi menyesuaikan morfologi membran untuk meningkatkan keliangan, kekasaran permukaan serta kristalisasi polimer. Hidrofobisiti membran boleh ditingkatkan dengan menambah kekasaran permukaan membran melalui penambahan zarah bersaiz nano TiO2. Namun begitu, penambahan TiO2 pada membran mengurangkan keliangan disebabkan oleh penyekatan liang dan juga merendahkan hidrofibisiti akibat kehadiran kumpulan hidroksil. Masalah penghalang liang boleh diatasi dengan meminimumkan saiz zarah melalui penggunaan bahan kimia iaitu asid pada membran. Akan tetapi, sifat hidrofilik intrinsik TiO2 yang berterusan yang menyebabkan masalah pembasahan yang tidak diingini. Dengan mengurangkan saiz liang, sifat-sifat antibakteria pada membran terhadap E.Coli dapat ditingkatkan di mana masalah penyumbatan oleh bakteria pada membran dapat dikurangkan dengan menambahkan asid pengubah suai membran TiO2/PVDF. Bagi meningkatkan hidrofobisiti membran, TiO2 dirawat dengan flurosilan yang diubahsuai di bawah keadaan asid, neutral dan alkali. TiO2 yang dirawat silan pada pH 7 meningkatkan sudut sentuhan (131.7 ± 4), peningkatan penyerapan fluks (12kg/m2.h), nilai LEPw yang tinggi, pengurangan nutrien sehingga 99.65%, dan saiz liang yang lebih kecil yang dapat mengurangkan kemungkinan pembasahan liang. Membran yang paling optimum ini diuji dengan sisa air yang mempunyai kandungan pepejal yang tinggi iaitu sisa air dari kilang kertas SBR (PMSE) dan air sisa dari kilang minyak kelapa sawit (POME) selama 7 jam. Nilai fluks stabil sekitar 6 kg/m2.h untuk air sisa dari kilang kertas SBR (PMSE) boleh dicapai dan menunjukkan pembasahan membran dan rintangan penyumbatan adalah baik. Kecekapan sistem adalah sekitar 55% boleh dibandingkan dengan proses air tulen (50%). Walaubagaimanapun, membran tersebut tidak sesuai digunakan untuk merawat sisa air dari kilang minyak kelapa sawit yang kaya dengan minyak kerana fluks telah menurun dari 6 hingga 2 kg/m2.h selepas 7 jam beroperasi. Didapati bahawa sisa air dari kilang minyak kelapa sawit memberikan kecekapan terma terendah iaitu 26% berbanding dengan proses-proses lain kerana gejala pengotoran. _______________________________________________________________________________________________________ Membrane distillation (MD) has emerged as an important technology for applications in industries such as seawater desalination and wastewater treatment due to lower energy requirement and theoretically low fouling propensity. However, the main obstacle to obtain high separating efficiency in MD lies on the availability of porous hydrophobic membrane that can withstand pore wetting and membrane fouling. A dual coagulation bath method was introduced to fine tune the membrane morphology to increase its porosity, surface roughness as well as polymer crystallinity. To increase the membrane hydrophobicity, membrane roughness was induced by adding TiO2 nanoparticles. However, this brought concomitant impacts on lower porosity due to the pore blocking and it also reduces hydrophobicity due to availability of hydroxyl group. The pore blocking problem can be solved by minimizing the particle size via surface acid modification. Nonetheless, the intrinsically hydrophilic nature of TiO2 still persist which brings unwanted wetting problem. By decreasing the particle size, it was interesting to note that the antibacterial properties on membrane towards E.Coli also improved, which means that the membrane bio-fouling problem can be mitigated by incorporating acid modified TiO2/PVDF membrane. To further enhance the hydrophobicity of the membrane, TiO2 was treated with flurosilane which was modified under acid, neutral and alkaline conditions. Silanized TiO2 with pH 7 gave higher contact angle (131.7±4), higher permeation flux (12kg/m2.h), excellent nutrient removal of 99.65%, high LEPw value and smaller pore size which can reduce the possibility of pore wetting. This optimum membrane was tested for treatment of high solid content wastewater namely paper mill SBR effluent (PSME) and palm oil mill effluent (POME) for a span of 7 hours. Consistent flux around 6 kg/m2.h for paper mill SBR effluent (PMSE) could be achieved showing that the membrane wetting and fouling resistance are good. The system efficiency is around 55% which is comparable to the pure water treatment process (50%). However, the membrane is not suitable to be used for treatment of the oil-rich palm oil mill (POME) effluent as the flux dropped from 6 to 2 kg/m2.h after 7 hours of operation. It was also found that palm oil mill effluent gave the lowest thermal efficiency of 26% compared to other processes due to fouling phenomena.
| Item Type: | Thesis (PhD) |
|---|---|
| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=4719 |
| Subjects: | T Technology T Technology > TP Chemical Technology > TP155-156 Chemical engineering |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Kimia (School of Chemical Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 19 Jun 2019 08:10 |
| Last Modified: | 19 Jun 2019 08:10 |
| URI: | http://eprints.usm.my/id/eprint/44669 |
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