Abdulkarim, Abdullah Adnan (2015) Polyethersulfone-Zno Mixed Matrix Hollow Fiber Membrane with Antifouling Properties for Humic Acid Removal. PhD thesis, Universiti Sains Malaysia.
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Abstract
Satu teknik baru telah dicadangkan untuk mensintesis membran matrik bercampur (MM) berbentuk serat berongga (HF) dari formulasi yang ditentukan oleh membran kepingan rata. Untuk mencapai matlamat ini, membran kepingan rata MM yang berbeza telah disintesis daripada campuran “dope” yang mengandungi polietersulfona (PES), nanopartikel ZnO (ZnO-NPs), polivinilpirolidona (PVP), dan pelarut dimetilastamida (DMAc) menggunakan teknik pemisahan fasa. Hasil kajian ini telah menunjukkan bahawa ZnO-NPs telah meningkatkan kedua-dua hidrofilik dan kekasaran permukaan membran kepingan rata. Apabila ZnO-NPs ditambah, kebolehtelapan, penyingkiran asid humik (HA), dan sifat anti-pengotoran membran juga dipertingkatkan. Penambahan ZnO-NPs yang hidrofilik ke dalam PES boleh mengurangkan kotoran asid humik dengan syarat NPs diagih dengan seragam di dalam matrik polimer. Keputusan membran kepingan rata seterusnya telah menunjukkan bahawa nisbah ZnO-NPs kepada PVP hendaklah sama atau lebih daripada satu untuk memastikan agihan ZnO-NPs yang baik dalam matrik PES. Kontur dalaman membran serat berongga (HF) boleh diubah oleh keadaan putaran dan juga masa putaran. Formulasi optimum yang diperolehi telah digunakan dalam pembangunan membran MM HF dengan kontur dalaman yang dikawal sepenuhnya. Kajian kestabilan struktur membran HF dilakukan berdasarkan masa residensi di kawasan ruang udara (Rtm). Ketetapan kontur dalaman telah terbukti menjadi bulat sepenuhnya dengan peningkatan Rtm. Ini mungkin disebabkan oleh peningkatan dalam pemindahan jisim dalaman, kestabilan polimer, orientasi molekul, dan pelepasan tekanan. Kajian ini telah menunjukkan bahawa Rtm kritikal yang menghasilkan kontur dalaman bulat sepenuhnya adalah 0.67 s. Kemudian, membran MM HF telah disintesis pada Rtm yang sama dengan 0.82 s dan diuji menggunakan larutan sintetik HA. Penghasilan membran MM HF yang terhasil menunjukkan peningkatan dalam sifat hidrofilik, kebolehtelapan, dan sifat anti-pengotoran semasa penurasan HA. Walau bagaimanapun, sifat-sifat anti-pengotoran adalah lebih rendah daripada PES asli kerana kehadiran CaCl2. Prestasi penyingkiran membran MM HF semasa penurasan air sungai menunjukkan bahawa penggabungan 0.5 wt.% ZnONPs dapat menyahkan TOC pada kadar 26.15% berbanding hanya 6.92% menggunakan PES asli. Semasa penurasan air sungai dalam jangka masa yang lama, nisbah pemulihan fluks utama (FRR) sebanyak 96.80 % diperolehi pada 0.5 wt.% ZnO-NPs berbanding hanya 75.55% daripada FRR untuk PES asli. Ini menunjukkan bahawa membran MM HF yang diubahsuai telah berjaya dihasilkan untuk menyingkirkan HA. ________________________________________________________________________________________________________________________ A new technique was proposed to synthesize mixed matrix (MM) hollow fiber (HF) membrane from pre-determined MM flat sheet membrane formulation. To achieve this goal, different MM flat sheet membranes were synthesized from dope solution containing polyethersulfone (PES), ZnO nanoparticles (ZnO-NPs), polyvinylpyrrolidone (PVP), and dimethylacetamide (DMAc) solvent using phase separation technique. It was shown that the ZnO-NPs increased both membrane hydrophilicity and surface roughness of flat sheet membrane. Upon the addition of ZnO-NPs, the permeability, humic acid (HA) rejection, and anti-fouling property of membrane were also enhanced. The addition of hydrophilic ZnO-NPs to PES can alleviate the humic acid fouling provided the NPs are well dispersed inside the polymeric matrix. Flat sheet membrane results further indicated that the ZnO-NPs to PVP ratio should be equal to or more than unity to ensure good dispersion of ZnONPs inside PES matrix. Hollow fiber (HF) membrane inner contour could be varied by both spinning conditions as well as during the spinning time. The optimum formulation obtained was used in the development of MM HF membrane with fully controlled inner contour. Structural stability study of HF membrane was performed based on the residence time in the air gap region (Rtm). The regularity of the inner contour was proved to be fully circular with increasing Rtm. This might be due to enhancement in the internal mass transfer, polymer relaxation, molecular orientation, and stress release. It was shown that the critical Rtm that produced fully circular inner contour was 0.67 s. Subsequently, MM HF membrane was synthesized at Rtm equal to 0.82 s and tested for synthetic HA solution. The MM HF membrane showed enhancement in hydrophilicity, permeability, and anti-fouling property during HA filtration. However, the membrane antifouling properties were lower than the pristine PES due to the presence of CaCl2. The rejection performance of MM HF membranes during filtration of river water indicated that incorporation of 0.5 wt.% of ZnO-NPs was able to remove 26.15 % of the TOC compared to only 6.92 % for pristine PES. During long hours of river water filtration, ultimate flux recovery ratio (FRR) of 96.8 % was obtained at 0.5 wt.% of ZnO-NPs compared with only 75.55 % of FRR for the pristine PES. This showed that the modified MM HF membranes had been successfully developed for humic acid removal.
| Item Type: | Thesis (PhD) |
|---|---|
| Additional Information: | full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=2025 |
| Subjects: | T Technology T Technology > TP Chemical Technology > TP1-1185 Chemical technology |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Kimia (School of Chemical Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 07 Jun 2018 08:44 |
| Last Modified: | 07 Jun 2018 08:44 |
| URI: | http://eprints.usm.my/id/eprint/40721 |
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