Mohamed Nasef | Universiti Teknologi Malaysia - UTM (original) (raw)

Papers by Mohamed Nasef

Research paper thumbnail of Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

Korean Journal of Chemical Engineering, 2014

Research paper thumbnail of Radiation induced grafting of styrene onto partially fluorinated films for preparation of proton exchange membranes : the role of liquid additives

Research paper thumbnail of Preparation of composite polymer electrolytes by electron beam-induced grafting: Proton- and lithium ion-conducting membranes

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions With Materials and Atoms, Dec 1, 2007

Two classes of composite polymer electrolyte membranes, one conducting lithium ions (Li +) and th... more Two classes of composite polymer electrolyte membranes, one conducting lithium ions (Li +) and the other conducting protons (H +) were prepared using simultaneous electron beam-induced grafting. Porous poly(vinylidene fluoride) (PVDF) films were impregnated with styrene and subjected to electron beam (EB) irradiation to obtain polystyrene (PS) filled PVDF precursor films that were subsequently treated with either chlorosulfonic acid/1,1,2,2-tetrachloroethane mixture to obtain H +-conducting composite membranes or LiPH 6/EC/DEC liquid electrolyte to obtain Li +-conducting composite membranes. The properties of the obtained membranes were evaluated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and AC impedance measurements. The obtained membranes were found to achieve grafting content up to 46% with superior Li +-conductivity of 1.91 × 10 -3 S/cm and H +-conductivity of 5.95 × 10 -2 S/cm. The results of this work show that simultaneous radiation-induced grafting with EB is a promising method to prepare high quality ion-conducting membranes for possible use in fuel cells and lithium batteries.

Research paper thumbnail of Removal of metal ions from aqueous solutions using crosslinked polyethylene-graft-polystyrene sulfonic acid adsorbent prepared by radiation grafting

Crosslinked polyethylene-graft-polystyrene sulfonic acid (PE-g-PSSA) adsorbent prepared by simult... more Crosslinked polyethylene-graft-polystyrene sulfonic acid (PE-g-PSSA) adsorbent prepared by simultaneous radiation induced grafting of styrene/divinyl benzene (DVB) mixture onto low density polyethylene (PE) film followed by sulfonation was investigated for the adsorption of Co(II), Cu(II), Ni(II), Pb(II) and Ag(I) ions from aqueous solutions on batch process basis. The effects of treatment parameters such as contact time, initial metal ion concentration, pH and temperature of the solution, on the adsorption capacity of the membrane were studied. The adsorption capacity of metal ions were found to be strongly dependent on the initial metal ion concentration and pH of adsorption medium and increased in the order of Ni(II)>Co(II)>Cu(II)>Pb(II)>Ag(I). Langmuir isotherm model was found to be more fitting to the adsorption equilibrium data of all metal ions than Freundlich isotherm model. The adsorption kinetics of all tested metal ions was found to follow the pseudo-first order kinetic model. The membrane showed an interesting stability represented by five repeated adsorption/desorption cycles of heavy metal ions without any significant loss in its adsorption capacity. It can be suggested that crosslinked PE-g-PSSA membrane obtained in this work can be effectively used for the adsorption of heavy metal ions from aqueous solutions and the preference order is Ni(II)> Co(II)>Cu(II)>Pb(II)> Ag(I).

Research paper thumbnail of Preparation and Characterization of Cation Exchange Resins Based on Locally Fabricated Polythylene Pallets

... inactive graft copolymer, which has to be activated in a subsequent step to perform as a cati... more ... inactive graft copolymer, which has to be activated in a subsequent step to perform as a cation exchange resin (Nasef and Hegazy, 2004). Sulfonation ... film (Ishigaki et al., 1982;Hegazy et al., 1981, 1984; Gupta and Chapiro, 1989; Kostov, ...

Research paper thumbnail of Development of Radiation Grafted and Sulfonated Poly(tetrafluoroethylene) Membranes

Research paper thumbnail of Ion exchange technology for water and waste water treatment: principles and progress in materials development

Page 83. 5 ION EXCHANGE TECHNOLOGY FOR WATER AND WASTEWATER TREATMENT: PRINCIPLES AND PROGRESS IN... more Page 83. 5 ION EXCHANGE TECHNOLOGY FOR WATER AND WASTEWATER TREATMENT: PRINCIPLES AND PROGRESS IN MATERIALS DEVELOPMENT Mohamed Mahmoud Nasef, Hamdani Saidi Zaini Ujang ABSTRACT ...

Research paper thumbnail of Effect of liquid additives on graft copolymerization of styrene onto perirradiated poly(Ethylene-Co-tetrafluoroethylene) films

Research paper thumbnail of Ion Exchange Technology I

Research paper thumbnail of The Preparation and Characterization of Chitosan / Poly (Vinyl Alcohol) Blended Films

E-Journal of Chemistry

In this study, chitosan and PVA were blended at different proportions (considering chitosan as th... more In this study, chitosan and PVA were blended at different proportions (considering chitosan as the main component) in solution forms. The chemical structure and the morphology of the obtained blend films were investigated using FTIR and field emission scanning electron microscope (FESEM). The thermal stability of the blend films were also studied using thermal gravimetric analysis (TGA). Our results showed that chitosan and PVA form a compatible blend and their films displayed homogenous and smooth surface properties compared to their individual pure components. The blending of PVA with chitosan at all proportions was found to highly enhance the swelling of the obtained films compared to that of pure chitosan one.

Research paper thumbnail of Preparation and Characterization of Chitosan/Agar Blended Films: Part 2. Thermal, Mechanical, and Surface Properties

E-Journal of Chemistry

Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar ... more Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the major component) in solution forms. The thermal stability of the blended films was studied using thermal gravimetric analysis (TGA). It was revealed that chitosan and agar form a compatible blend. Studying the mechanical properties of the films showed a decrease in the tensile strength and elongation at break with increasing agar content. Blending of agar with chitosan at all proportions was found to form hydrogel films with enhanced swelling compared to the pure chitosan one. Static water contact angle measurements confirmed the increasing affinity of the blended films towards water suggesting that blending of agar with chitosan improves the wettability of the obtained films.

Research paper thumbnail of Improved Methanol Barrier Property of Nafion Hybrid Membrane by Incorporating Nanofibrous Interlayer Self-Immobilized with High Level of Phosphotungstic Acid

ACS Applied Materials & Interfaces, 2015

High level of phosphotungstic acid (PWA) was self-immobilized on electrospun nylon nanofiberous s... more High level of phosphotungstic acid (PWA) was self-immobilized on electrospun nylon nanofiberous sheet to fabricate highly selective methanol barrier layer for sandwich structured proton conducting membranes. Simple tuning for the assembly conditions of central layer and thickness of outer Nafion layers allowed obtaining different composite membranes with superior methanol barrier properties (namely, P = 3.59 × 10(-8) cm(2) s(-1)) coupled with proton conductivities reaching 58.6 mS cm(-1) at 30 °C. Comparable activation energy for proton transport and more than 20 times higher selectivity than Nafion 115 confirm the effectiveness of the central layer and resulting membranes for application in direct methanol fuel cells (DMFCs). When tested in DMFC single cell, the performance of hybrid membrane was far better than Nafion 115 especially at higher methanol concentrations.

Research paper thumbnail of Eco-safe and expeditious approaches for synthesis of quinazoline and pyrimidine-2-amine derivatives using ionic liquids aided with ultrasound or microwave irradiation

Journal of Molecular Liquids, 2014

ABSTRACT Green approaches for efficient synthesis of quinazoline- and pyrimidine-2-amine derivati... more ABSTRACT Green approaches for efficient synthesis of quinazoline- and pyrimidine-2-amine derivatives were established based on the one-pot and three-component condensation of guanidine carbonate, cyclic ketones and aldehydes. These approaches involve the evaluation of the activity of several acidic ionic liquids (ILs) as organocatalysts under solvent-free medium in the microwave and as solvents and catalysts in the ultrasound irradiations. Reactions were evaluated for a number of substituted aldehydes and cyclic ketones on the basis of variation of parameters including type and amount of ILs, reaction temperature and time. Compared to the ultrasound method, the solvent-free procedure in the microwave was found to be more efficient in terms of both chemical yield and reaction time. Catalyst recyclability, simplicity, and time-saving aspects of the reaction suggests that these methods present real alternatives to conventional reaction protocols.

Research paper thumbnail of Sustainable alternative protocols for the multicomponent synthesis of spiro-4H-pyrans catalyzed by 4-dimethylaminopyridine

Journal of Industrial and Engineering Chemistry, 2015

ABSTRACT Green approaches to the synthesis of spiro-4H-pyrans are reported based on the one-pot a... more ABSTRACT Green approaches to the synthesis of spiro-4H-pyrans are reported based on the one-pot and three-component condensation via a domino Knoevenagel/Michael/cyclization sequence. These approaches involve evaluation of the activity of several organocatalysts in water as a reaction media and also under solvent-free in both microwave irradiation and ball milling conditions. Extensive experiments were carried out to optimize the reaction parameters including type and amount of catalyst, reaction temperature and time. Microwave irradiation in presence of 4-dimethylaminopyridine (DMAP) was observed as the best procedure with good yields, short reaction time, environmental friendliness, and convenient operation.

Research paper thumbnail of New CO2 adsorbent containing aminated poly(glycidyl methacrylate) grafted onto irradiated PE-PP nonwoven sheet

Radiation Physics and Chemistry, 2014

ABSTRACT A new CO2 adsorbent containing triethylamine (TEA) was prepared by radiation induced gra... more ABSTRACT A new CO2 adsorbent containing triethylamine (TEA) was prepared by radiation induced grafting of glycidyl methacrylate (GMA) onto polyethylene coated polypropylene (PE-PP) non-woven sheet followed by amination reaction. The degree of grafting (DOG%) was controlled by variation of monomer concentration and absorbed dose. The incorporation of aminated poly(GMA) was investigated by Fourier transform infrared (FTIR) and scanning electron microscope (SEM). The adsorbent with DOG of 350% and amination yield of 60% exhibited CO2 adsorption capacity of 4.52 mol/kg at ambient temperature and pressure.

Research paper thumbnail of Tuning N-methyl- d -glucamine density in a new radiation grafted poly(vinyl benzyl chloride)/nylon-6 fibrous boron-selective adsorbent using the response surface method

RSC Adv., 2015

ABSTRACT A new adsorbent containing boron-selective groups was prepared by radiation induced graf... more ABSTRACT A new adsorbent containing boron-selective groups was prepared by radiation induced grafting of vinylbenzyl chloride (VBC) onto nylon-6 fibers followed by functionalisation with N-methyl-D-glucamine (NMDG). The density of glucamine loaded in the adsorbent was tuned by optimisation of the reaction parameters such as NMDG concentration, reaction temperature, reaction time and degree of grafting using response surface methodology (RSM) employing Box-Behnken design (BBD). The optimum parameters for achieving the maximum glucamine density (1.7 mmol/g) in the adsorbent are 10.6%, 81 oC, 47 min and 121% for NMDG concentration, reaction temperature, reaction time and degree of grafting (DG), respectively. The deviation between the optimum experimental and predicted glucamine density is found to be 1.2% suggesting the reliability of RSM in predicting the yield and optimising the functionalisation reaction parameters. The chemical composition, morphology and structure of NMDG-containing fibrous adsorbent were studied using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The thermal properties were determined using differential scanning calorimetry (DSC) and the thermal stability was evaluated by thermogravimetric analysis (TGA). Considering the physico-chemical properties of the fibrous adsorbent and preliminary results of boron adsorption, it can be suggested that this adsorbent is a promising candidate for boron removal.

Research paper thumbnail of Modification of nylon-6 fibres by radiation-induced graft polymerisation of vinylbenzyl chloride

Radiation Physics and Chemistry, 2015

ABSTRACT Modification of nylon-6 fibres by radiation-induced graft copolymerisation (RIGP) of vin... more ABSTRACT Modification of nylon-6 fibres by radiation-induced graft copolymerisation (RIGP) of vinylbenzyl chloride (VBC) using the preirradiation method was investigated. A number of grafting parameters such as type of solvent, total dose, monomer concentrations, reaction temperature and reaction time were studied to obtain desired degree of grafting (DG). The DG was found to be a function of reaction parameters and achieved a maximum value of 130 wt% at 20 vol% VBC concentration in methanol, 300 kGy dose, 30 °C temperature and 3 h reaction time. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to evaluate the chemical, morphological and structural changes that occurred in the grafted fibres, respectively. Thermogravimetric analysis (TGA) was also applied to determine the thermal stability, whereas differential scanning calorimeter (DSC) and universal mechanical tester were used to analyse respective thermal and mechanical properties of the grafted fibres. The results of these analyses provide strong evidence for successful grafting of VBC onto nylon-6, and the variation in the properties of the grafted fibres depends on DG.

Research paper thumbnail of Ultrasound-assisted regioselective ring opening of epoxides with nitrogen heterocycles using pyrrolidonium and imidazolium-based acidic ionic liquids

Research on Chemical Intermediates, 2015

ABSTRACT Imidazolium and N-methyl-2-pyrrolidonium ionic liquids under ultrasound irradiation were... more ABSTRACT Imidazolium and N-methyl-2-pyrrolidonium ionic liquids under ultrasound irradiation were developed as a green and expeditious approach for C--alkylation and N-alkylation of the nitrogen heterocycles including indoles and imidazoles with aliphatic and aromatic epoxides. Ionic liquids were used with a dual role of catalyst and solvent. The highest yield (85 %) was obtained with N-methyl-2-pyrrolidonium dihydrogen phosphate [H-NMP]H2PO4 as a pyrrolidonium ionic liquid under ultrasound at 50 kHz, with a reaction time of 60 min and reaction temperature of 60 °C. The combination of ionic liquids and ultrasonic irradiation was found to be an effective, green and eco-friendly method for alkylation of indoles and imidazoles.

Research paper thumbnail of Journal of Nuclear Science Malaysia

Research paper thumbnail of In-Situ Continuous Production of Hydrogen Gas from Molasses Using Mutated Enterobacter aerogenes ADH43 for Fuel Cell Application

Iranica Journal of Energy & Environment, 2011

The performance of the continuous stirred tank reactor (CSTR) for the in-situ production of hydro... more The performance of the continuous stirred tank reactor (CSTR) for the in-situ production of hydrogen gas (H ) integrated with a polymer electrolyte membrane fuel cell (PEMFC) was investigated. Facultative 2 anaerobe fermentation of Enterobacter aerogenes ADH-43 was conducted into CSTR 50 rpm of agitation speed, 37°C of temperature, 6.3 of pH and 0.15; 0.3; 0.45; 0.60 hG of dilution rate. Bio-H produced was assessed after 1 2

Research paper thumbnail of Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

Korean Journal of Chemical Engineering, 2014

Research paper thumbnail of Radiation induced grafting of styrene onto partially fluorinated films for preparation of proton exchange membranes : the role of liquid additives

Research paper thumbnail of Preparation of composite polymer electrolytes by electron beam-induced grafting: Proton- and lithium ion-conducting membranes

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions With Materials and Atoms, Dec 1, 2007

Two classes of composite polymer electrolyte membranes, one conducting lithium ions (Li +) and th... more Two classes of composite polymer electrolyte membranes, one conducting lithium ions (Li +) and the other conducting protons (H +) were prepared using simultaneous electron beam-induced grafting. Porous poly(vinylidene fluoride) (PVDF) films were impregnated with styrene and subjected to electron beam (EB) irradiation to obtain polystyrene (PS) filled PVDF precursor films that were subsequently treated with either chlorosulfonic acid/1,1,2,2-tetrachloroethane mixture to obtain H +-conducting composite membranes or LiPH 6/EC/DEC liquid electrolyte to obtain Li +-conducting composite membranes. The properties of the obtained membranes were evaluated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and AC impedance measurements. The obtained membranes were found to achieve grafting content up to 46% with superior Li +-conductivity of 1.91 × 10 -3 S/cm and H +-conductivity of 5.95 × 10 -2 S/cm. The results of this work show that simultaneous radiation-induced grafting with EB is a promising method to prepare high quality ion-conducting membranes for possible use in fuel cells and lithium batteries.

Research paper thumbnail of Removal of metal ions from aqueous solutions using crosslinked polyethylene-graft-polystyrene sulfonic acid adsorbent prepared by radiation grafting

Crosslinked polyethylene-graft-polystyrene sulfonic acid (PE-g-PSSA) adsorbent prepared by simult... more Crosslinked polyethylene-graft-polystyrene sulfonic acid (PE-g-PSSA) adsorbent prepared by simultaneous radiation induced grafting of styrene/divinyl benzene (DVB) mixture onto low density polyethylene (PE) film followed by sulfonation was investigated for the adsorption of Co(II), Cu(II), Ni(II), Pb(II) and Ag(I) ions from aqueous solutions on batch process basis. The effects of treatment parameters such as contact time, initial metal ion concentration, pH and temperature of the solution, on the adsorption capacity of the membrane were studied. The adsorption capacity of metal ions were found to be strongly dependent on the initial metal ion concentration and pH of adsorption medium and increased in the order of Ni(II)>Co(II)>Cu(II)>Pb(II)>Ag(I). Langmuir isotherm model was found to be more fitting to the adsorption equilibrium data of all metal ions than Freundlich isotherm model. The adsorption kinetics of all tested metal ions was found to follow the pseudo-first order kinetic model. The membrane showed an interesting stability represented by five repeated adsorption/desorption cycles of heavy metal ions without any significant loss in its adsorption capacity. It can be suggested that crosslinked PE-g-PSSA membrane obtained in this work can be effectively used for the adsorption of heavy metal ions from aqueous solutions and the preference order is Ni(II)> Co(II)>Cu(II)>Pb(II)> Ag(I).

Research paper thumbnail of Preparation and Characterization of Cation Exchange Resins Based on Locally Fabricated Polythylene Pallets

... inactive graft copolymer, which has to be activated in a subsequent step to perform as a cati... more ... inactive graft copolymer, which has to be activated in a subsequent step to perform as a cation exchange resin (Nasef and Hegazy, 2004). Sulfonation ... film (Ishigaki et al., 1982;Hegazy et al., 1981, 1984; Gupta and Chapiro, 1989; Kostov, ...

Research paper thumbnail of Development of Radiation Grafted and Sulfonated Poly(tetrafluoroethylene) Membranes

Research paper thumbnail of Ion exchange technology for water and waste water treatment: principles and progress in materials development

Page 83. 5 ION EXCHANGE TECHNOLOGY FOR WATER AND WASTEWATER TREATMENT: PRINCIPLES AND PROGRESS IN... more Page 83. 5 ION EXCHANGE TECHNOLOGY FOR WATER AND WASTEWATER TREATMENT: PRINCIPLES AND PROGRESS IN MATERIALS DEVELOPMENT Mohamed Mahmoud Nasef, Hamdani Saidi Zaini Ujang ABSTRACT ...

Research paper thumbnail of Effect of liquid additives on graft copolymerization of styrene onto perirradiated poly(Ethylene-Co-tetrafluoroethylene) films

Research paper thumbnail of Ion Exchange Technology I

Research paper thumbnail of The Preparation and Characterization of Chitosan / Poly (Vinyl Alcohol) Blended Films

E-Journal of Chemistry

In this study, chitosan and PVA were blended at different proportions (considering chitosan as th... more In this study, chitosan and PVA were blended at different proportions (considering chitosan as the main component) in solution forms. The chemical structure and the morphology of the obtained blend films were investigated using FTIR and field emission scanning electron microscope (FESEM). The thermal stability of the blend films were also studied using thermal gravimetric analysis (TGA). Our results showed that chitosan and PVA form a compatible blend and their films displayed homogenous and smooth surface properties compared to their individual pure components. The blending of PVA with chitosan at all proportions was found to highly enhance the swelling of the obtained films compared to that of pure chitosan one.

Research paper thumbnail of Preparation and Characterization of Chitosan/Agar Blended Films: Part 2. Thermal, Mechanical, and Surface Properties

E-Journal of Chemistry

Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar ... more Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the major component) in solution forms. The thermal stability of the blended films was studied using thermal gravimetric analysis (TGA). It was revealed that chitosan and agar form a compatible blend. Studying the mechanical properties of the films showed a decrease in the tensile strength and elongation at break with increasing agar content. Blending of agar with chitosan at all proportions was found to form hydrogel films with enhanced swelling compared to the pure chitosan one. Static water contact angle measurements confirmed the increasing affinity of the blended films towards water suggesting that blending of agar with chitosan improves the wettability of the obtained films.

Research paper thumbnail of Improved Methanol Barrier Property of Nafion Hybrid Membrane by Incorporating Nanofibrous Interlayer Self-Immobilized with High Level of Phosphotungstic Acid

ACS Applied Materials & Interfaces, 2015

High level of phosphotungstic acid (PWA) was self-immobilized on electrospun nylon nanofiberous s... more High level of phosphotungstic acid (PWA) was self-immobilized on electrospun nylon nanofiberous sheet to fabricate highly selective methanol barrier layer for sandwich structured proton conducting membranes. Simple tuning for the assembly conditions of central layer and thickness of outer Nafion layers allowed obtaining different composite membranes with superior methanol barrier properties (namely, P = 3.59 × 10(-8) cm(2) s(-1)) coupled with proton conductivities reaching 58.6 mS cm(-1) at 30 °C. Comparable activation energy for proton transport and more than 20 times higher selectivity than Nafion 115 confirm the effectiveness of the central layer and resulting membranes for application in direct methanol fuel cells (DMFCs). When tested in DMFC single cell, the performance of hybrid membrane was far better than Nafion 115 especially at higher methanol concentrations.

Research paper thumbnail of Eco-safe and expeditious approaches for synthesis of quinazoline and pyrimidine-2-amine derivatives using ionic liquids aided with ultrasound or microwave irradiation

Journal of Molecular Liquids, 2014

ABSTRACT Green approaches for efficient synthesis of quinazoline- and pyrimidine-2-amine derivati... more ABSTRACT Green approaches for efficient synthesis of quinazoline- and pyrimidine-2-amine derivatives were established based on the one-pot and three-component condensation of guanidine carbonate, cyclic ketones and aldehydes. These approaches involve the evaluation of the activity of several acidic ionic liquids (ILs) as organocatalysts under solvent-free medium in the microwave and as solvents and catalysts in the ultrasound irradiations. Reactions were evaluated for a number of substituted aldehydes and cyclic ketones on the basis of variation of parameters including type and amount of ILs, reaction temperature and time. Compared to the ultrasound method, the solvent-free procedure in the microwave was found to be more efficient in terms of both chemical yield and reaction time. Catalyst recyclability, simplicity, and time-saving aspects of the reaction suggests that these methods present real alternatives to conventional reaction protocols.

Research paper thumbnail of Sustainable alternative protocols for the multicomponent synthesis of spiro-4H-pyrans catalyzed by 4-dimethylaminopyridine

Journal of Industrial and Engineering Chemistry, 2015

ABSTRACT Green approaches to the synthesis of spiro-4H-pyrans are reported based on the one-pot a... more ABSTRACT Green approaches to the synthesis of spiro-4H-pyrans are reported based on the one-pot and three-component condensation via a domino Knoevenagel/Michael/cyclization sequence. These approaches involve evaluation of the activity of several organocatalysts in water as a reaction media and also under solvent-free in both microwave irradiation and ball milling conditions. Extensive experiments were carried out to optimize the reaction parameters including type and amount of catalyst, reaction temperature and time. Microwave irradiation in presence of 4-dimethylaminopyridine (DMAP) was observed as the best procedure with good yields, short reaction time, environmental friendliness, and convenient operation.

Research paper thumbnail of New CO2 adsorbent containing aminated poly(glycidyl methacrylate) grafted onto irradiated PE-PP nonwoven sheet

Radiation Physics and Chemistry, 2014

ABSTRACT A new CO2 adsorbent containing triethylamine (TEA) was prepared by radiation induced gra... more ABSTRACT A new CO2 adsorbent containing triethylamine (TEA) was prepared by radiation induced grafting of glycidyl methacrylate (GMA) onto polyethylene coated polypropylene (PE-PP) non-woven sheet followed by amination reaction. The degree of grafting (DOG%) was controlled by variation of monomer concentration and absorbed dose. The incorporation of aminated poly(GMA) was investigated by Fourier transform infrared (FTIR) and scanning electron microscope (SEM). The adsorbent with DOG of 350% and amination yield of 60% exhibited CO2 adsorption capacity of 4.52 mol/kg at ambient temperature and pressure.

Research paper thumbnail of Tuning N-methyl- d -glucamine density in a new radiation grafted poly(vinyl benzyl chloride)/nylon-6 fibrous boron-selective adsorbent using the response surface method

RSC Adv., 2015

ABSTRACT A new adsorbent containing boron-selective groups was prepared by radiation induced graf... more ABSTRACT A new adsorbent containing boron-selective groups was prepared by radiation induced grafting of vinylbenzyl chloride (VBC) onto nylon-6 fibers followed by functionalisation with N-methyl-D-glucamine (NMDG). The density of glucamine loaded in the adsorbent was tuned by optimisation of the reaction parameters such as NMDG concentration, reaction temperature, reaction time and degree of grafting using response surface methodology (RSM) employing Box-Behnken design (BBD). The optimum parameters for achieving the maximum glucamine density (1.7 mmol/g) in the adsorbent are 10.6%, 81 oC, 47 min and 121% for NMDG concentration, reaction temperature, reaction time and degree of grafting (DG), respectively. The deviation between the optimum experimental and predicted glucamine density is found to be 1.2% suggesting the reliability of RSM in predicting the yield and optimising the functionalisation reaction parameters. The chemical composition, morphology and structure of NMDG-containing fibrous adsorbent were studied using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The thermal properties were determined using differential scanning calorimetry (DSC) and the thermal stability was evaluated by thermogravimetric analysis (TGA). Considering the physico-chemical properties of the fibrous adsorbent and preliminary results of boron adsorption, it can be suggested that this adsorbent is a promising candidate for boron removal.

Research paper thumbnail of Modification of nylon-6 fibres by radiation-induced graft polymerisation of vinylbenzyl chloride

Radiation Physics and Chemistry, 2015

ABSTRACT Modification of nylon-6 fibres by radiation-induced graft copolymerisation (RIGP) of vin... more ABSTRACT Modification of nylon-6 fibres by radiation-induced graft copolymerisation (RIGP) of vinylbenzyl chloride (VBC) using the preirradiation method was investigated. A number of grafting parameters such as type of solvent, total dose, monomer concentrations, reaction temperature and reaction time were studied to obtain desired degree of grafting (DG). The DG was found to be a function of reaction parameters and achieved a maximum value of 130 wt% at 20 vol% VBC concentration in methanol, 300 kGy dose, 30 °C temperature and 3 h reaction time. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to evaluate the chemical, morphological and structural changes that occurred in the grafted fibres, respectively. Thermogravimetric analysis (TGA) was also applied to determine the thermal stability, whereas differential scanning calorimeter (DSC) and universal mechanical tester were used to analyse respective thermal and mechanical properties of the grafted fibres. The results of these analyses provide strong evidence for successful grafting of VBC onto nylon-6, and the variation in the properties of the grafted fibres depends on DG.

Research paper thumbnail of Ultrasound-assisted regioselective ring opening of epoxides with nitrogen heterocycles using pyrrolidonium and imidazolium-based acidic ionic liquids

Research on Chemical Intermediates, 2015

ABSTRACT Imidazolium and N-methyl-2-pyrrolidonium ionic liquids under ultrasound irradiation were... more ABSTRACT Imidazolium and N-methyl-2-pyrrolidonium ionic liquids under ultrasound irradiation were developed as a green and expeditious approach for C--alkylation and N-alkylation of the nitrogen heterocycles including indoles and imidazoles with aliphatic and aromatic epoxides. Ionic liquids were used with a dual role of catalyst and solvent. The highest yield (85 %) was obtained with N-methyl-2-pyrrolidonium dihydrogen phosphate [H-NMP]H2PO4 as a pyrrolidonium ionic liquid under ultrasound at 50 kHz, with a reaction time of 60 min and reaction temperature of 60 °C. The combination of ionic liquids and ultrasonic irradiation was found to be an effective, green and eco-friendly method for alkylation of indoles and imidazoles.

Research paper thumbnail of Journal of Nuclear Science Malaysia

Research paper thumbnail of In-Situ Continuous Production of Hydrogen Gas from Molasses Using Mutated Enterobacter aerogenes ADH43 for Fuel Cell Application

Iranica Journal of Energy & Environment, 2011

The performance of the continuous stirred tank reactor (CSTR) for the in-situ production of hydro... more The performance of the continuous stirred tank reactor (CSTR) for the in-situ production of hydrogen gas (H ) integrated with a polymer electrolyte membrane fuel cell (PEMFC) was investigated. Facultative 2 anaerobe fermentation of Enterobacter aerogenes ADH-43 was conducted into CSTR 50 rpm of agitation speed, 37°C of temperature, 6.3 of pH and 0.15; 0.3; 0.45; 0.60 hG of dilution rate. Bio-H produced was assessed after 1 2