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Title:	Kajian penjerapan-penyahjerapan gas karbon dioksida menggunakan bahan MgO-CuO/karbon teraktif
Authors:	Wan Nor Roslam bin Wan Isahak (P62611)
Supervisor:	Mohd Ambar Yarmo, Prof. Dr
Keywords:	Penjerapan-penyahjerapan Gas karbon dioksida Adsorption
Issue Date:	7-Aug-2014
Description:	Peningkatan paras karbon dioksida (CO2) semasa dalam atmosfera telah mencapai 400 ppm merupakan masalah global yang semakin serius hingga menyumbang kepada fenomena pemanasan global dan seterusnya menyebabkan kajian penjerapan CO2 perlu dipertingkatkan. Sebanyak 36 sebatian logam oksida telah dikaji melalui kaedah pengiraan secara termodinamik dan mendapati bahawa kombinasi sebatian MgO dan CuO dipilih untuk dikaji secara mendalam disebabkan kemampuan menjerap yang baik (≈ 303 K) dan menyahjerap CO2 pada suhu yang agak rendah (523-673 K). Bahan penjerap CuO menunjukkan prestasi penjerapan CO2 yang lebih baik berbanding Cu2O. Tambahan lagi, kesan saiz zarah amat mempengaruhi kapasiti penjerapan bagi bahan MgO bersaiz nano dengan keupayaan menjerap CO2 tulen (99.8%) secara fizikal dan kimia sebanyak 23 cm3/g (1.03 mmol/g) dan 7.44 mmol/g (166.7 cm3/g). Walau bagaimanapun, pengubahsuaian bahan penjerap dengan kombinasi 25%MgO-5%CuO/B-AC mampu menjerap CO2 secara fizikal dan kimia sebanyak 75.3 cm3/g (3.36 mmol/g) dan 9.75 mmol/g (257.6 cm3/g). Pada kepekatan 15% CO2 dalam He, kapasiti penjerapan secara kimia menurun kepada 8.22 mmol/g (15.7%). Kaedah jerapan isoterma gas CO2 oleh pelbagai bahan penjerap yang dikaji menunjukkan urutan jerapan fizikal CO2 seperti berikut; 25%MgO-5%CuO/B-AC>20%MgO-10%CuO/B-AC>15%MgO-15%CuO/B-AC>30%MgO/B-AC>30% CuO/B-AC>B-AC. Dari lengkuk pertemuan, penjerapan CO2 oleh bahan penjerap optimum iaitu 25%MgO-5%CuO/B-AC mencapai kapasiti maksimum pada minit ke-6. Kadar penyahjerapan CO2 pada suhu 673 K diperolehi dalam julat pemulihan 95-98.5%. Kajian simulasi menggunakan perisian Gaussian 09 pula menjelaskan kehadiran atom Mg dalam sistem 25%MgO-5%CuO/B-AC dapat memberi kesan ketumpatan elektron yang tinggi sehingga menyebabkan interaksi CO2 yang lebih kuat terhadap bahan tersebut dengan tenaga interaksi sebanyak -216.01 kJ·mol-1. Di samping itu, kaedah penyediaan karbon teraktif (B-AC) daripada biojisim batang buluh melalui proses pengdehidratan asid sulfurik turut dikaji. Melalui kaedah ini, karbon teraktif yang mempunyai luas permukaan yang agak tinggi (1150.5 m2/g) diperolehi berbanding kaedah pemanasan (862.7 m2/g). Kaedah ini didapati lebih baik kerana melibatkan proses tanpa pemanasan dan tidak menghasilkan gas CO2 dibandingkan dengan kaedah lazim.,The recent increasing levels of carbon dioxide (CO2) in atmosphere up to 400 ppm is a serious global problems contributing to global warming and thus lead to enhanced CO2 adsorption studies. A total of 36 metal oxide compounds have been selected via thermodynamic calculations and found that the combination of MgO and CuO compounds were selected to be studied in detail due to the good CO2 adsorption ability (≈ 303 K) and desorption at a relatively low temperature (523-673 K). CuO adsorbent shows the higher CO2 adsorption capacity than Cu2O. Furthermore, the particle size greatly influences the adsorption capacity which MgO nano-sized material physically and chemically adsorbed pure CO2 (99.8 %) by 23 cm3/g (or 1.03 mmol/g) and 7.44 mmol/g (166.7 cm3/g). However, the adsorbent modification with a combination of 25%MgO-5%CuO/B-AC able to adsorb CO2 physically and chemically of 75.3 cm3/g (3.36 mmol/g) and 11.50 mmol/g (257.6 cm3/g), respectively. At a concentration of 15% CO2 in He, the chemical adsorption capacity was decreased to 9.75 mmol/g (17.9%). The CO2 adsorption isotherm of various adsorbent studied for CO2 physical adsorption was shown in sequence as follows: 25%MgO-5%CuO/B-AC>20%MgO-10%CuO/B-AC>15%MgO-15%CuO/B-AC> 30%MgO/B-AC>30%CuO/B-AC>B-AC. From breakthrough curve, the adsorption of CO2 by the optimum adsorbent, 25%MgO-5%CuO/B-AC reached maximum capacity after 6 minutes. The CO2 desorption rate at 673 K is found in the range of 95-98.5% recovery. Gaussian 09 simulation study explains the presence of Mg atoms in the 25%MgO-5%CuO/B-AC adsorbent system could affect a high electron density and resulting stronger interaction between CO2 and adsorbent with the interaction energy of -216.01 kJ·mol-1. In addition, the synthesis of activated carbon from bamboo type biomass by dehydration process using sulfuric was also studied. By this method, the activated carbon successfully produced with a relatively high surface area (1150.5 m2/g) compared with conventional method (862.7 m2/g). This kind of process carried out without heating and no any CO2 emissions compared with carbonation method.,PhD
Pages:	275
Call Number:	QD181.C1W344 2014 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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