Teh, Yong Yi (2018) Dilute Sulfuric Acid Hydrolysis Of Red Macroalga Eucheuma Denticulatum With Microwaveassisted Heating For Biochar And Bioethanol Production. Masters thesis, Universiti Sains Malaysia.
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Abstract
Eucheuma denticulatum ialah sejenis makroalga merah yang berpotensi sebagai stok suapan untuk penghasilan biotenaga kerana makroalga ini mengandungi kandungan karbohidrat yang tinggi, mudah diperolehi serta proses penghasilan hanya menggunakan tanah yang sedikit. Oleh sebab kandungan karbohidrat yang tinggi, makroalga boleh dihidrolisiskan menjadi gula mudah ditapai dan ditukar kepada bioetanol oleh mikroorganisma semulajadi. Walau bagaimanapun, pemanasan haba konvensional yang memindahkan haba dari permukaan ke pusat bahan menjadikan proses pemanasan agak lambat dan tidak cekap. Oleh itu, masa pemanasan yang berpanjangan telah mengurangkan kuantiti gula dan meningkatkan pula penghasilan produk sampingan yang boleh menjejaskan proses penapaian seterusnya. Dalam kajian ini, hidrolisis asid dengan pemanasan gelombang mikro dijalankan dalam ketuhar gelombang mikro pada frekuensi 2.45 GHz dan kuasa 800W. Dengan pemanasan dielektrik gelombang mikro, ia bukan sahaja dapat menangani masalah yang dibangkitkan di atas, malahan ia dapat meningkatkan prestasi proses hidrolisis dan menghasilkan bioarang, gula dan bahan kimia yang bernilai tinggi daripada makroalga. Tujuan utama kajian ini adalah untuk mengkaji sifat-sifat bioarang yang dihasilkan sebagai sumber biotenaga selepas makroalga melalui proses hidrolisis gelombang mikro. Proses hidrolisis dijalankan pada kepekatan asid sulfurik 0.1M dan 0.2M, suhu pemanasan antara 150-170 °C dan masa pemanasan selama 10 minit. Kualiti bioarang yang dihasilkan didapati lebih baik dengan peningkatan kandungan karbon unsur dan kandungan abu dan lembapan yang lebih rendah. Nilai kalori bioarang dapat ditingkatkan sehingga 45%, dan 39% hasil tenaga dapat dipulih kembali. Selain daripada bioarang, kepekatan gula dan produk sampingan juga ditentukan dan seterusnya ditukarkan kepada bioetanol. Hasil gula sebanyak 74.84% (51.47 g/L) dan produk 5-HMF yang berjumlah 0.20 g/L telah dicapai apabila biomassa dihidrolisiskan pada suhu 160 °C dengan kepekatan asid sulfurik 0.1M. Hasil bioetanol yang diperolehi adalah sebanyak 0.33 g/g (64.21%). Sebagai kesimpulan, hidrolisis dengan larutan acid sulfurik dalam sistem pemanasan gelombang mikro berpotensi untuk menghasilkan biotenaga, bioarang yang kaya dengan nutrien sebagai penambahbaik tanah dan bahan kimia yang bernilai tinggi. _______________________________________________________________________________________________________ Eucheuma denticulatum is a type of red macroalgae which are considered as potential feedstock for biofuel production due to high carbohydrate content, ease of availability and low arable land usage. Being such abundant in carbohydrates, macroalgae can be hydrolysed into fermentable sugars and converted to bioethanol by natural microorganims. However, the conventional thermal heating that delivers heat from the surface to center of a material is comparatively slow and inefficient. As a result, the longer heating time gives rise to a dramatic reduction of reducing sugars but higher content of by-products, consequently inhibiting the subsequent fermentation. In this study, acid hydrolysis with microwave-assisted heating of macroalga was conducted in a 2.45 GHz microwave oven with 800W of power. The rapid and efficient of dielectric heating effect of microwave-assisted heating could address aforementioned problem, enhance the hydrolysis process and co-produce biochar, reducing sugars and valuable chemicals. This study was set out to study the properties of biochar as a source of biofuel after macroalga was subjected to microwave-assisted hydrolysis. The hydrolysis reactions were operated at sulfuric acid concentrations of 0.1M and 0.2M, reaction temperatures of 150–170 °C and a heating time of 10 min. The produced biochars were characterized and it was found that biochar qualities were improved with increased elemental carbon content and lower ash and moisture contents. The calorific value of the biochar was intensified up to 45%, and 39% of energy yield was recovered. Apart from biochar, the concentrations of reducing sugars and by-product of hydrolysate were also determined and subsequently converted to bioethanol. The highest total reducing sugars were 51.47 g/L (74.84% yield) along with a low by-product 5-HMF of 0.20 g/L, when the biomass was treated under the conditions at 160 °C with 0.1M H2SO4. The ethanol yield obtained was 0.33 g/g, which corresponded to a 64.21% of yield. As a conclusion, acid hydrolysis with microwave-assisted acid hydrolysis has its great potential applications for the production of bioenergy, nutrient-rich biochar for soil amelioration and value-added chemicals.
| Item Type: | Thesis (Masters) |
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| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=4732 |
| 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: | 19 Jun 2019 09:39 |
| Last Modified: | 19 Jun 2019 09:39 |
| URI: | http://eprints.usm.my/id/eprint/44679 |
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