Zubbri, Nurul Azrin (2015) Preparation And Characterization Of Lithium Orthosilicate Sorbent For Carbon Dioxide Removal. Masters thesis, Universiti Sains Malaysia.
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Abstract
Pada masa kini, dunia masih menghadapi cabaran pemanasan dan isu-isu perubahan iklim global. Setakat ini, banyak usaha telah diambil untuk mengurangkan pelepasan CO2 termasuk penggunaan penjerap yang kukuh untuk menjerap CO2. Pepejal litium ortosilikat (Li4SiO4) adalah satu daripada penjerap yang digunakan untuk menjerap CO2 pada suhu tinggi. Dalam kajian ini, Li4SiO4 telah disediakan melalui kaedah sol-gel dengan menggunakan litium nitrat (LiNO3) dan silikon etoksida (SiC8H20O4) sebagai bahan asas. Pengaruh nisbah molar Li:Si (1-5), suhu pengkalsinan (600-800°C), tempoh masa pengkalsinan (1-8 jam) dan nisbah molar H2O:Si (1-5) dikaji semasa proses sintesis penjerap. Kapasiti penjerapan oleh penjerap itu dinilai melalui beberapa ujian penjerapan CO2 dengan menggunakan Penganalisis Termogravimetri (TGA). Suhu pengkalsinan (700-800°C) dan suhu pengkarbonan (500-700ºC) diubah semasa ujian pengkarbonan. Penjerap terbaik yang mempunyai kapasiti penjerapan CO2 tertinggi dianalisa menggunakan XRD untuk mengesahkan kehadiran spesies Li4SiO4. Penjerap dengan kapasiti penjerapan CO2 tertinggi akhirnya diuji dengan beberapa ujian kitaran untuk mengkaji ketahanan penjerap melalui 10 ujian proses penjerapan-pembebasan CO2. Ciri fizikal-kimia penjerap sebelum dan selepas ujian pengkarbonan dikaji melalui analisis SEM dan XRD. Hasil kajian menunjukkan bahawa penjerap yang disediakan dengan nisbah molar Li:Si 1:1, nisbah molar H2O:Si 5:1 , pengkalsinan pada suhu 700°C selama 5 jam mempunyai kapasiti penyerapan CO2 tertinggi. Suhu pengkalsinan 800°C dan suhu pengkarbonan 700°C dipilih sebagai suhu terbaik yang menyumbang kepada kapasiti penyerapan sebanyak 7.947 CO2 mmol/g penjerap, yang juga bersamaan dengan 93% daripada hasil teori. Selepas sepuluh proses kitaran, kapasiti penjerapan CO2 oleh penjerap jatuh 16.2% dari kitaran pertama hingga kesepuluh. Penjerap Li4SiO4 telah menunjukkan potensi untuk mempunyai keupayaan penjerapan CO2 yang tinggi dan prestasi kitaran yang stabil. ________________________________________________________________________________________________________________________ Nowadays, the world is surviving the challenge of global warming and climate change issues. So far, many efforts have been undertaken to mitigate CO2 emission among which is the use of solid sorbents for CO2 capture. Solid lithium orthosilicate (Li4SiO4) is one of the sorbents used to capture CO2 at high temperature. In this research, Li4SiO4 was synthesized by sol-gel method using lithium nitrate (LiNO3) and silicon ethoxide (SiC8H20O4) as precursors. The influences of Li:Si molar ratio (1-5), calcination temperature (600–800°C), calcination time (1–8h) and H2O:Si molar ratio (1-5) were investigated during the sorbent synthesis. The sorption capacity of the developed sorbent was evaluated through CO2 capture tests performed using a Thermogravimetric Analyzer (TGA). The calcination temperature (700-800ºC) and carbonation temperature (500-700ºC) were varied during the carbonation test. The best sorbent with the highest CO2 sorption capacity was analyzed with XRD to confirm the appearance of Li4SiO4 species. The sorbent with highest CO2 sorption capacity was finally introduced to some cyclic tests to study the durability of the sorbent through ten CO2 sorptiondesorption tests. The physicochemical properties of the developed sorbent before and after carbonation tests were investigated through SEM and XRD analyses. The results showed that the sorbent prepared with 1:1 molar ratio of Li:Si, 1:1 molar ratio of H2O:Si and calcined at 700°C for 5h has the highest CO2 sorption capacity. Calcination temperature of 800ºC and carbonation temperature of 700ºC were chosen as the best values which resulted in the sorption capacity of 7.947 mmol CO2/g sorbent which is 93% of the theoretical yield. Throughout ten cyclic process, CO2 sorption capacity of the sorbent dropped about 16.2% from the first to tenth cycle which seems to be reasonable. Li4SiO4 was found to be a potential solid sorbent that has high CO2 sorption capacity besides its stable cyclic performance.
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=3075 |
| 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: | 29 Aug 2018 08:03 |
| Last Modified: | 29 Aug 2018 08:03 |
| URI: | http://eprints.usm.my/id/eprint/41583 |
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