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Polyethersulfone/cloisite15A mixed matrix membrane for gas separation
(Universiti Teknologi Malaysia, 2015) Ismail, Noor Maizura
Fabrication of mixed matrix membrane (MMM) with superior gas transport properties is challenging due to the poor dispersion of the filler in the membrane and the complicated interaction of polymer-clay surface. The purpose of this study is to develop polymer-clay based MMM for carbon dioxide (CO2) removal from methane (CH4) and to study the effects of interface voids and clay dispersion on gas separation. Asymmetric flat sheet MMM from polyethersulfone (PES) and sonicated cloisitel5A (C l5A) clay particles was prepared by a controlled fabrication parameters and phase inversion technique. The impacts of adding C15A on the MMM properties were investigated by using morphological, structural, thermal, mechanical, functional group and performance analyses. In the first phase of the study, the effect of different loading of C15A was investigated. Significant changes on the membrane morphology and thermal stability were observed for the fabricated MMMs. At 1 weight% C15A loading (PES/C15A1), MMM showed the best gas transport properties with 37% and 100% improvement on CO2 permeance and CO2/CH4 selectivity, respectively. For the second part of the study, the state of dispersion of the silicate layers in MMM was investigated by qualitative and quantitative analyses. Partial intercalated and exfoliated silicate layers in PES/C15A1 contributed to the enhancement of the membrane mechanical properties. The increase of tortuosity in MMM reduced the CH4 permeance with a significant improvement for the CO2/CH4 selectivity from 22.57 to 46.89. Particle size measurement, particle density measurement and free-path spacing measurement also demonstrated that the dispersion state in PES/C15A1 was striking with the increase in aspect ratio, dispersed single silicate layers, particle density and evidence of several tactoid classes. It was discovered that high C15A loading (5 weight%) deteriorated the PES/C15A5 performance due to the interfacial voids. Hence in the third phase, C15A was functionalized with 3-aminopropyl triethoxysilane coupling agent. Selectivity improvement was observed on the modified-C15A MMM suggesting a better interaction between the clay surface and PES matrix. From this study, incorporation of C15A has shown great C02/CH4 separation enhancement and can be regarded as potential filler for MMM
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Establishment of emission characteristics, emission factors and health risk assessment from a coal-fired power plant
(Universiti Teknologi Malaysia, 2016) Mohd. Mokhtar, Mutahharah
The objectives of this research are to investigate the emission characteristics of a coal-fired power plant (CFPP) in Malaysia and the ability of the air pollution control devices (APCDs) currently in used to comply with the limits specified in the new Environmental Quality (Clean Air) Regulations 2014 (CAR 2014) as well as to establish emission factors for the studied CFPP. The emission data are further used to evaluate the health risks of the emissions from CFPP under CAR 2014 by air dispersion modelling and health risk assessment (HRA). The studied CFPP is a 2100 MW employing APCDs of electrostatic precipitator and flue gas desulphurisation (FGD). Emissions were determined using manual and continuous stack samplings. The emission characteristics were established from the modified CFPP configuration that took into account the effects of coal quality (combustion of only sub-bituminous or bituminous coal) with FGD being in on and off modes. Each pollutant demonstrates different characteristics which would further influence the control mechanism. The study also showed that the existing APCDs were able to comply with the CAR 2014. The emission factors were established for uncontrolled and controlled emissions which would allow the estimation of the impact of emission from CFPP prior to development of new plant or expansion of existing plant as well as selection of APCDs needed to comply with emission standard. For HRA, the predicted ground level concentrations from air dispersion modelling were used as input. The HRA demonstrated different health risks for scenario of emissions from the studied CFPP under normal operation and scenario in the event that pollutants are emitted at limits specified in CAR 2014, with further assessment been given to the latter
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Carbon cryogel production from lignin, ionic liquid and liquefield oil palm frond as catalyst for esterification of levulinic acid
(Universiti Teknologi Malaysia, 2017) Mohammad Zainol, Muzakkir
Carbon cryogel synthesized from lignin, ionic liquid (IL) and mixtures of liquefied oil palm frond-ionic liquid (LOPF-IL), was used as an acid catalyst for esterification of levulinic acid in ethanol. Commercial lignin was reacted with furfural via sol-gel poly-condensation reaction at 90 °C for 30 min and the gel was freeze-dried and finally carbonized or calcined to produce carbon cryogel. Parametric study for the gel preparation was conducted to evaluate the carbon cryogel surface area and acidity. Similar parametric study was also performed on gel synthesis from IL and furfural. The selected gel condition of IL and furfural was applied for gel preparation from LOPF-IL and furfural. Nitrogen physisorption and temperature programmed desorption of ammonia measurements revealed the selected carbon cryogels obtained a large total surface area (>200 m2/g) and high acidity (>10 mmol/g). The selected carbon cryogels from lignin-furfural (CCLF), IL-furfural (CCIL) and liquefied OPF-IL-furfural (CCOPF) were further characterized using thermogravimetric analyzer, Fourier transform infrared spectroscopy, x-ray diffraction and field emission scanning electron microscopy with energy dispersive x-ray spectrometry. The phase structure of the synthesized spherical carbon cryogel was amorphous, has micro structures (microspheres) and thermally stable. The synthesized CCLF, CCIL and CCOPF were tested as catalyst in the esterification of levulinic acid. Carbon cryogels showed high potential as an acid catalyst for levulinic acid esterification with above 70.0 mol.% yield of ethyl levulinate. The kinetic studies using CCLF and CCIL revealed the esterification of levulinic acid followed pseudo-first order kinetics and have low activation energy. Meanwhile, the thermodynamic parameters conferred the reaction was endergonic and more ordered.
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Amine-functionalized kenaf as carbon dioxide adsorbent in pressure swing adsorption system
(Universiti Teknologi Malaysia, 2016) Zaini, Nabilah
Kenaf (Hibiscus Cannabinus L.) that belongs to the family of Malvaceae is abundantly grown in Malaysia since 2006 to replace tobacco plantation as it is inexpensive, easy to grow, and biodegradable. The use of kenaf as adsorbent is seen as an attractive and innovative method, and it has been used for various adsorptions. Adsorption is a promising technology that has the ability to capture carbon dioxide (CO2), the predominant contributor of global climate change. Inspired by the established and well–known amine–based absorption process of carbon capture and storage technology, the development towards new adsorbent by introducing amine functional group has been studied. Therefore, this study explores the potential of modified kenaf as adsorbent by incorporating amine functional group on the surface and investigates the CO2 adsorptive characteristics of amine–modified kenaf adsorbent using pressure swing adsorption system (PSA). The preparation of amine–modified kenaf was conducted via the incipient wetness impregnation technique. The physical and structural characteristics of amine–modified kenaf were determined via micromeritics 3 flex, field emission scanning electrons microscopy, energy dispersive x–ray, Fourier transform infrared spectroscopy, and thermogravimetric analyzer. The results show that the types of amine, amine loading concentration, and impregnation time affect the physical and structural properties of kenaf and thus affecting the capability for capturing CO2. Screening of various types of amines via PSA revealed that tetraethylenepentamine (TEPA) has recorded the highest CO2 adsorption (0.914 mmol/g). Further examination on amine loading divulged that kenaf to TEPA ratio of 1:2 presents the highest CO2 adsorption (2.086 mmol/g) with 5 hour impregnation time. To examine the utilization of amine–modified kenaf adsorbent in PSA system, pressure bed, adsorption time, and feed flowing rate were evaluated. The result revealed that these parameters affect the gas adsorption of amine–modified kenaf adsorbent. The regeneration study had shown that kenaf adsorbent could sustain the repeated adsorption/desorption cyclic operations. This study also found that physical and chemical adsorption occurred during the adsorption of CO2 on raw kenaf and amine–modified kenaf. Thus, amine–modified kenaf adsorbent has high potential to be used as low–cost CO2 agro–based adsorbent hence inducing towards innovative material in the field of gas adsorption
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Biopulping of pineapple leaf fiber using ceriporiopsis subvermispora fungus and its characterization
(Universiti Teknologi Malaysia, 2014) Mat Nayan, Nadirul Hasraf
Environmental awareness and depletion of wood resources are among vital factors that motivate researchers to explore the potential of agro-based crops as an alternative source of fiber material in paper industries. Fibers from agro-based crops are available in abundance, low cost, and most importantly its biodegradability features, which referred as "ecofriendly" materials. However, conventional pulping process which employed numerous chemical substances has resulted in a number of adverse effects on the environment. Hence, the aims of this study were to biopulp the pineapple leaf fiber (PALF) via means of Ceriporiopsis subvermispora fungus and determining its effect towards the properties of PALF fiber and paper forms. The individual fibers were characterized having good tensile properties at 0.3% of fungus treatment and favourable structural properties as characterized by Fourier transform infra-red (FTIR) spectroscopy and X-ray diffraction (XRD). It was also shown that the biopulped PALF paper achieved desirable tear index value, remarkable burst resistance and uniform morphological observations compared to the conventional chemical pulping method. On the contrary, for water absorption characteristic, the biopulped PALF paper exhibited a slight increment compared to paper produced from conventional chemical pulping. The paper making process was then optimized using design of experiment (DOE). The effects of temperature, pulping time and fungus concentration on the tear index of the PALF paper were successfully studied using response surface methodology (RSM). The DOE revealed that the pulping time had the most significant influence on the response. Optimum process conditions were obtained at pulping time of 3.15 weeks, temperature of 45°C and fungus concentration of 0.25 M which resulted in tear index of 2.485 Nm2/kg. In addition, the incorporation of corn steep liquor into the biopulping process was proven to stimulate the Ceriporiopsis subvermispora growth, thus reducing the biopulping time. However, there were no increment to the mechanical and physical properties of the PALF paper