Prof. Ir. Dr. Nor Aishah Saidina Amin

Abstract:

Transesterification is the most common method for producing biodiesel. Known as a suitable substitute to diesel fuel, the synthesis involves renewable sources as feedstock. Application of both organic and inorganic solvents in biodiesel production has been widely established. However, as the properties of conventional solvents are perpetually hazardous to human and environment, utilization of greener alternative is a better option. Among the various types of solvents available, ionic liquid seems prevalent. An ionic liquid is a combination of cations and anions, has low or negligible vapor pressure, and exists as liquid at temperature below 100 °C. The prospect of ionic liquids as green solvents in chemical processes is increasing in recent years, especially in biodiesel synthesis. This paper highlighted the properties of ionic liquids that emphasized their versatility as solvents, and the use of switchable ionic liquids as green solvents is also presented. The roles of ionic liquids in biodiesel synthesis are discussed, focusing on their pertinent capability as solvents, particularly as catalysts for transesterification reaction. Since the cost of ionic liquid may be an issue, a brief discussion about the recyclability of ionic liquids is also included.

1. Ahmad Hafiidz Mohammad Fauzi and Nor Aishah Saidina Amin (2012).An overview of ionic liquids as solvents in biodiesel synthesis. Renewable and Sustainable Energy Review, 16 (8), 5770-5786, Elsevier. (2011 I.F = 6.018)

Abstract:

This study aims to develop an optimal continuous process to produce fatty acid methyl esters (biodiesel) from waste cooking oil in a reactive distillation column catalyzed by a heteropolyacid, H₃PW₁₂O₄₀·6H₂O. The conventional production of biodiesel in the batch reactor has some disadvantage such as excessive alcohol demand, short catalyst life and high production cost. Reactive distillation combines reaction and separation to simplify the process operation. The reaction catalyzed by H₃PW₁₂O₄₀·6H₂O overcomes the neutralization problem that occurs in conventional transesterification of waste cooking oil with high free fatty acid (FFAs) and water content. Response surface methodology (RSM) based on central composite design (CCD) was used to design the experiment and analyzed four operating parameters: total feed flow, feed temperature, reboiler duty and methanol/oil ratio. The optimum conditions were determined to be 116.23 (mol/h) total feed flow, 29.9 °C feed temperature, 1.3 kW reboiler duty, and 67.9 methanol/oil ratio. The optimum and actual free fatty acid methyl ester (FAME) yield was 93.98% and 93.94%, respectively, which demonstrates that RSM is an accurate method for the current procedure.

1. Iman Noshadi, Nor Aishah Saidina Amin and Richard Parnas (2012). Continuous production of biodiesel from waste cooking oil in a reactive distillation column catalyzed by solid heteropolyacid_ Optimization using response surface methodology (RSM) Fuel, 94, 156-164, Elsevier. (2011 I.F=3.248).

Abstract:

In this work, EFB was chemically pretreated with different sodium hydroxide (NaOH) concentration. Pyrolysis was conducted in the presence of HZSM-5 after the pretreatment step to assess the effects of pretreatment process on bio-oil production. Conversions of EFB were reported to be 61wt%, 47wt% and 42wt%, after pretreatment with 5wt%, 15wt% and 25wt%, NaOH concentrations, respectively. Furthermore, the pretreatment has effectively improved the bio-oil quality by reducing or even eliminating undesired products. Besides, biomass structure was dissembled and converted to valuable compounds after upgrading the bio-oil with improved quality

1. Nor Aishah Saidina Amin, Mailin Misson, Roslindawati Haron, Mohd Fadhzir Ahmad Kamaroddin, Wan Nor Nadyaini Wan Omar and Kok-Giap Haw (2012). Bio-Oils and Diesel Fuel Derived from Alkaline Treated Empty Fruit Bunch (EFB). International Journal of Biomass & Renewables, 1 (1), 6-14.

Abstract:

In this study, liquefaction between empty palm fruit bunch (EPFB) and phenol was carried out by using sulfuric acid and H2SO2 as a catalyst. The liquefied products were reacted with formaldehyde to synthesize resin and undergo sol-gel impregnation (Sl) method before further washing, freeze-drying and carbonized to obtain carbon cryogel beads (CCBs). The CCBs then were characterized for their morphology and other physic-chemical properties such as yield, viscosity, conversion, composition, structure and porosities using Gas Chromatography Mass Spectroscopy (GC-MS), Fourier Transform Infrared Spectroscopy (FTIR), Ubblelohde capillary viscometer, pH meter, Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA). The results obtained showed that some of phenolic compounds present in liquefaction of EFB which have high potential for partially replacing phenol in phenolbrmaldehyde resin. It is envisaged that the synthesized renewable CCBs will have sufficient meso and micropores which can be employed as an absorbent for treating organic compounds (OCs) in waste water

1. B.S. Dilaeleyana, N. Norzita, S.A. Nor Aishah and K.E. Haw (2012). Synthesis and Characterization of Renewable Carbon Cryogel Beads from Empty Fruit Bunch. International Journal of Chemical and Environmental Engineering, 3 (2), 15-19, World Academy of Research and Publication.

Abstract

In this paper we are reporting the preparation and characterization of supported cobalt catalysts using a wetness impregnation method. Different cobalt catalysts loading of 0 and 10 wt% were prepared by dissolving cobalt nitrate hexahydrate in distilled water and dried in an oven at 100 °C overnight. Two selected supports of oil palm shell (OPS) activated carbon and ZSM-5 zeolite were employed and compared. Catalysts characterizations of both supports were performed by thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis and scanning electron microscope analysis (SEM). Using Scherrer equation, the cobalt metallic size was calculated. OPS activated carbon supports were further analyzed for CHNOS elemental analysis. Both supports of OPS activated carbon and ZSM-5 zeolite exhibited the successful loading of cobalt catalysts and have potential to be utilized in catalytic reactions.

1. Izirwan, I.; Mohd, A.; Amin, Saidina N. A (2013). Characterization of Oil Palm Shell Activated Carbon and ZSM-5 Supported Cobalt Catalysts. Research Journal Of Chemistry And Environment, Vol. 17(10) , 64-68. (2012 IF = 0.636)

Abstract:

In order to improve the efficiency of biodiesel production from esterification of free fatty acids, an alternative to sulfuric acid has been explored. In this study, esterification of oleic acid was performed using 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO₄]) ionic liquid for green biodiesel production. Response surface methodology (RSM) based on central composite design (CCD) was employed to study the effect of independent parameters on the process and also for single-objective optimization, while artificial neural network–genetic algorithm (ANN–GA) was utilized to simultaneously optimize the responses of the reaction (methyl oleate yield and oleic acid conversion). From the results, the predicted mathematical models for both methyl oleate yield and oleic acid conversion covered more than 80% of the variability in the experimental data. Furthermore, the linear temperature coefficient was identified as the most influential coefficient towards both responses. Higher responses were predicted for multi-objective optimization using ANN–GA compared to single-objective optimization using RSM. The optimum responses predicted using multi-objective optimization were 81.2% and 80.6% for methyl oleate yield and oleic acid conversion, respectively. The conditions to achieve optimum response were methanol–oleic acid molar ratio of 9:1, catalyst loading (0.06 mol), reaction temperature (87 °C), and reaction time (5.2 h). Furthermore, there was only small decrease in the catalytic activity of the IL after being recycled for five successive runs.

1. Ahmad Hafiidz Mohammad Fauzi and Nor Aishah Saidina Amin (2013). Optimization of oleic acid esterification catalyzed by ionic liquid for green biodiesel synthesis Energy Conversion and Management, 76, 818-827. (2012 I.F = 2.775)

Abstract:

The catalytic ozonation of sulfamethoxazole was investigated in this study using response surface methodology. The effect of four parameters pH of solution, concentration of antibiotic, ozone concentration and circulation rates was investigated on removal of sulfamethoxazole and COD of solution. The order of influence of input parameters on response was ozone concentration > pH > antibiotic concentration > circulation rates. The maximum of 80% of COD was removed at complete removal of sulfamethoxazole itself. The optimization is carried using central composite rotatable design on above mentioned four parameters. The intermediate values of pH, and circulation rates were sufficient for effective performance. The intermediate to concentrated supply of ozone was required to achieve reasonable degree of COD removal.

1. Javaid Akhtar, Nor Aishah Saidina Amin and Yasir Saleem (2013). Removal of Sulfamethoxazole Using Catalytic Ozonation: An Optimization Study. Journal of the Pakistan Institute of Chemical Engineers, 41 (1).

Abstract:

The catalytic conversion of lignocellulosic biomass to levulinic acid in ionic liquid, [EMIM][Cl] was conducted using a hybrid catalyst. The hybrid catalyst (1:1 ratio) with equal CrCl3 and HY zeolite weight ratios was synthesized using a wet impregnation method. Initially, optimization of cellulose as a model compound was carried out using two-level full factorial design (23) with two centre points. Under optimum process conditions, 46.0% of levulinic acid yield was produced from cellulose. Subsequently, utilization of lignocellulosic biomass demonstrated 15.5% and 15.0% of levulinic acid yield from empty fruit bunch (EFB) and kenaf, respectively, at the optimum conditions. Meanwhile, in the presence of ionic liquid under the same process conditions, 20.0% and 17.0% of levulinic acid were obtained for EFB and kenaf, respectively. The results indicated that ionic liquid could disrupt the covalent linkages between the biomass structures and dissolved the hollocellulose. This allowed the hollocellulose chains, accessible to the chemical transformation, to react and produce levulinic acid in presence of the hybrid catalyst. This study demonstrated that the combination of hybrid catalyst and ionic liquid has the potential to be applied for biomass conversion to levulinic acid under adequate process conditions.

1. Nazlina Ya’aini and Nor Aishah Saidina Amin (2013). Catalytic Conversion of Lignocelluloisc Biomass to Levulinic Acid in Ionic Liquid. BioResources, 8(4), 5761-5772. (2012 I.F = 1.309)

Abstract:

This study is aimed at investigating the interactive effect of reaction variables on the composition and octane number of reformat in catalytic naphtha reforming gasoline fuel. The relationship between aromatization activity and RON, with three reaction variables, namely temperature (480–510 °C), total pressure (10–30 bar) and space velocity LHSV (1.2–1.8 h⁻¹) were presented as empirical mathematical models. Experiments were performed based on the central composite rotatable design and analyzed using response surface methodology (RSM) and canonical analysis. First, the equation models are used to predict RON and aromatization activity as responses. Second, the regression analysis of RON and aromatization activity equations is obtained from the output of these developed models. Finally, the RSM is used to optimize these regression empirical models. R ² = 88.5 % for RON and 80.5 for the aromatization activity showed that RSM models fitted well with the observed data and considered to be accurate and available for predicting responses. The temperature and total pressure are the most effective variables as a linear (X ₁ , X ₂) terms and have a significant role in the responses. Numerical results also revealed that the maximum predicted RON of 105 was attained at optimum reaction temperature of 515 °C, operating pressure of 17 bar and LHSV of 2.0 h⁻¹.

1. Fawzi M. Elfghi and Nor Aishah Saidina Amin (2013). Applying Response Surface Methodology to Assess the Combined Effect f Process Variables on the Composition and Octane Number of Reformat in the Process of Reducing Aromatization Activity in Catalytic Naphtha Reforming. Reaction Kinetics, Mechanisms and Catalysis, 1-18, Springer Netherlands. (2012 I.F = 1.104)

Abstract:

In this study, a microchannel monolith photoreactor was investigated for photocatalytic CO₂ reduction with H₂O in gaseous phase using TiO₂ and indium doped TiO₂ nanoparticles. Effects of operating parameters such as monolith geometry, reaction temperature, indium loading and feed ratios were investigated to maximize yield rates. CO and CH₄ were the main products with maximum yield rates being 962 and 55.40 μmol g-catal.^-1 h^-1, respectively and selectivity being 94.39 and 5.44%, respectively. The performance of the photoreactor for CO production was in the order of In/TiO₂-monolith (962 μmol g-catal.^-1h^-1) > TiO₂-monolith (43 μmol g-catal.^-1 h^-1) > TiO₂-SS cell (5.2 μmol g-catal.^-1 h^-1). More importantly, the quantum efficiency in microchannel monolith reactor was much higher (0.10%) than that of the cell type reactor (0.0005%) and previously reported internally illuminated monolith reactor (0.012%). The significantly improved quantum efficiency indicated photon energy was efficiently utilized in the microchannel monolith reactor. A simple kinetic model based on Langmuir-Hinshelwood model, developed to incorporate coupled effect of adsorptive photocatalytic reduction and oxidation process, fitted-well with the experimental data.

1. Muhammad Tahir and Nor Aishah Saidina Amin (2013). Photocatalytic CO₂ Reduction and Kinetic Study Over In/TiO₂ Nanoparticles Supported Microchannel Monolith Photoreactor. Applied Catalysis A: General, 467, 483-496, Elsevier. (2012 I.F = 3.410)