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Papers by Mohamad Zailani Abu Bakar

Chemical engineering transactions, 2015

Natural gas contains some impurities liked acid gases (CO2 & H2S), which can affect the environme... more Natural gas contains some impurities liked acid gases (CO2 & H2S), which can affect the environment. Currently, the main focus of the research is to invent the new membranes materials for gas separation. Native polyethersulfone (PES) and PES/carbon molecular sieve (CMS) mixed matrix membranes were fabricated by solvent evaporation method using N-Methyl-2-pyrrolidone (NMP) as solvent. The final membranes were characterized in term of morphology and thermal stability by using field emission scanning electron microscopy (FESEM) and thermal gravimetric analyser (TGA). FESEM analysis of developed membranes was revealed that the final membranes have acceptable contacts between filler particles and the polymer chains with the thickness in the ranges from 51.37 µm to 67.68 µm. CMS inorganic particles were dispersed well within organic (polymer) matrix. Due to the addition of CMS the developed membrane exhibit the improved thermal stability. In the pure gas permeation, the effect of CMS load...

ASEAN Journal of Chemical Engineering, 2015

Diethanolamine (DEA) solution was used in this study to enhance the performance of polyethersulfo... more Diethanolamine (DEA) solution was used in this study to enhance the performance of polyethersulfone (PES) – carbon molecular sieve (CMS) mixed matrix membrane (MMMs). These new amine mixed matrix membranes (A3Ms) were fabricated at room temperature by using fixed concentration of PES, CMS and different concentrations (5, 10 wt. %) of DEA. The developed mixed matrix membranes were characterized by using field emission scanning electron microscope (FESEM) and thermogravimetric analyser (TGA) in order to investigate the effect of DEA addition on morphology and thermal stability. Gas performance tests were also performed to measure the permeance and selectivity. The characterization results showed that the membranes were thermally stable, dense and non-porous. The gas performance tests showed that the permeance and selectivity of A3Ms is higher than the native PES membrane. CO2 permeance increases with the increase of DEA concentration. Hence it was found that with an addition of 10% (w...

RSC Advances, 2015

Polyethersulfone (PES) as a polymer along with carbon molecular sieves (CMS) as an inorganic fill... more Polyethersulfone (PES) as a polymer along with carbon molecular sieves (CMS) as an inorganic filler and di-ethanolamine (DEA) as the third component were used to fabricate amine mixed matrix membranes (A3Ms).

Journal of Materials Science and Engineering B, 2014

Ordered mesoporous metal oxides (OMMO) SnO 2 with large surface areas and highly crystalline fram... more Ordered mesoporous metal oxides (OMMO) SnO 2 with large surface areas and highly crystalline frameworks were successfully synthesized via nanocasting routes using 3D cubic ordered mesoporous silica KIT-6 templates. The chemical and structural properties of these materials were characterized by means of XRD, N 2 adsorption-desorption SEM and TEM analyses. The present work revealed that the mesoporous SnO 2 materials exhibited well-defined and long-range periodic order of mesopores as well as highly crystalline frameworks, indicating successful replication from the mesoporous KIT-6 silica templates. Moreover, these materials demonstrated high surface area of 109 m 2 /g and high pore volume of 0.22 cm 3 /g as well as large pore size of 6.2 nm. Hence, the nanocasting route offers a versatile and simple way of creating ordered mesoporous SnO 2 with enhanced properties that may have potential applications in the field of catalysis and gas-sensing.

Journal of Physical Science

Galacto-oligosaccharides (GOS) can be synthesised via β-galactosidase (β-Gal) catalysed conversio... more Galacto-oligosaccharides (GOS) can be synthesised via β-galactosidase (β-Gal) catalysed conversion of lactose. The reaction process was carried out in the membrane reactor system to improve the conversion by partial separation of the products and galactose inhibitor. The reaction rate was determined by the concentration of the solutes on the biocatalytic membrane and it was varied by manipulating the transmembrane pressure (TMP). The yield of GOS was highest at a TMP = 0.5 bar. It was found that the formation of gel layer at higher TMP (> 0.5 bar) reduced the mass transfer of solutes through the biocatalytic membrane. Therefore, the reaction rates were decreased although the separation of galactose inhibitor was improved. Hence, it is concluded that the mass transfer of solute is the determining factor to obtain a high yield of GOS.

ASEAN Journal of Chemical Engineering

The activity and stability of chromium-exchanged beta (Cr-BEA),mordenite (Cr-MOR), and ZSM-5 (Cr-... more The activity and stability of chromium-exchanged beta (Cr-BEA),mordenite (Cr-MOR), and ZSM-5 (Cr-ZSM-5) zeolites of different Si/Alratios for volatile organic compounds (VOCS) combustion were reported. A fixed-bed catalytic reactor operated between 100 and 500°C and at a gas hourly space velocity (GHSV) of 32,000 h'! was used for the study. Methanol, ethyl acetate, methyl ethyl ketone, benzene, hexane, toluene, and xylene, all at 2,000 ppm, were selected as the VOC model compounds. Oxygenated VOCs were more reactive while showing good carton dioxide yield. Aromatics were more stable due to their resonance effect but the reactivity increased with the attachment of an electron donor group such as the methyl group. Cr-ZSM- 5(240) demonstrated the highest hydrothermal stability due to its high Si/Al ratio. Despite giving a high initial activity due to its high metal loading, Cr-BEA(25) was susceptible to coking in the long run. The high coke formation in mordenite and beta zeolites ...

Advanced Materials Research, 2015

Mesoporous SnO2 was successfully synthesized via nanocasting route using various silica matrices ... more Mesoporous SnO2 was successfully synthesized via nanocasting route using various silica matrices likely KIT-6, SBA-15 and SBA-16 as hard templates. The chemical and structural properties of these materials were characterized by means of XRD, N2 adsorption-desorption and TEM analyses. All replica products exhibited well-defined mesoporous structures and large surface areas as well as highly crystalline frameworks. Sensors were fabricated from the as-prepared mesoporous SnO2 replicas and used to test the response to 1000 ppm of ethanol vapour at different operating temperatures. The results showed that the mesoporous SnO2 sensors nanocasted from KIT-6, SBA-15 and SBA-16 silica templates exhibits excellent gas response as compared to a bulk SnO2 material, suggesting the potential application of the sensor for detecting ethanol vapour. Maximum sensitivity (~ 18.7) was reached at 300 °C using mesoporous SnO2 sensor nanocasted from KIT-6 silica. It can be explained by the large surface ar...

In this work, tungsten oxide (WO3) powder with average grain size of 50 nm was prepared using mod... more In this work, tungsten oxide (WO3) powder with average grain size of 50 nm was prepared using modified Nishide-Mizukami sol-gel method. The powder was characterized using X-Ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with transmission electron microscopy (TEM). The ethanol vapor sensing properties were investigated at different operating temperatures and gas concentrations. The WO3 pellet ethanol sensor exhibited excellent sensitivity to ethanol vapor with maximum sensitivity value of 29 at low temperature which is 200 °C. It was shown that the WO3 pellet can be reliably used to monitor high concentration of vapor above 1,500 ppm. This study demonstrated the possibility of utilizing WO3 pellet as a sensor element for the detection of ethanol vapor.

Progress in Energy and Combustion Science, 2010

Porous media combustion (PMC) has interesting advantages compared with free flame combustion due ... more Porous media combustion (PMC) has interesting advantages compared with free flame combustion due to higher burning rates, increased power dynamic range, extension of the lean flammability limits, and low emissions of pollutants. Extensive experimental and numerical works were carried out and are still underway, to explore the feasibility of this interesting technology for practical applications. For this purpose, numerical modeling

Catalysis Communications, 2003

The effect of hydrogen reduction on the activity of chromium exchanged ZSM-5 (Cr–ZSM-5) in the de... more The effect of hydrogen reduction on the activity of chromium exchanged ZSM-5 (Cr–ZSM-5) in the decomposition of ethyl acetate and benzene is reported. Reduction was performed at 400° C for 1 h while activity study was done using a reactor operated between 100 and ...

Journal of chemical …, 2004

The catalytic performance of bimetallic chromium-copper supported over untreated ZSM-5 (Cr-Cu/Z),... more The catalytic performance of bimetallic chromium-copper supported over untreated ZSM-5 (Cr-Cu/Z), ZSM-5 treated with silicon tetrachloride (Cr-Cu/SiCl 4-Z) and ZSM-5 treated with steam (Cr-Cu/H 2 O-Z) is reported. The activity is based on the combustion of ethyl ethanoate and benzene at a feed concentration of 2000 ppm and a gas hourly space velocity (GHSV) of 32 000 h −1. Due to higher reactivity and larger molecular size compared with that of water molecules, SiCl 4 reacted at the external surface of ZSM-5 crystals. Cr-Cu/SiCl 4-Z and Cr-Cu/H 2 O-Z both gave slightly lower conversion and carbon dioxide yield compared with Cr-Cu/Z. This was attributed to larger active metal crystallites formed in the mesopores and narrowing pore mouth and pore intersection by extraframework species. Cr-Cu/SiCl 4-Z and Cr-Cu/H 2 O-Z both had reduced concentration and strength of acid sites, thus making them less susceptible to deactivation by coking. The coke accumulated by these two catalysts was relatively softer and more easily decomposed in oxygen during catalyst regeneration.

Journal of Loss Prevention in the Process Industries, 2012

Batch process usually differs from the continuous process because of its time-varying variables a... more Batch process usually differs from the continuous process because of its time-varying variables and the process parameters. An early detection and isolation of faults in the process will help to reduce the process upsets and keep it safe and reliable. This paper discusses on the application of multi-layer perceptron neural network in detecting various faults in batch chemical reactor based on an esterification process that involves the reaction of ethanol and acetic acid catalyzed by sulfuric acid. A multilayer feed forward neural network with double hidden layers has been used in the neural network architecture. The detection was based on the different patterns generated between normal and faulty conditions. An optimum network configuration was found when the network produced the minimal error with respect to the training, testing and data validation.