Arshad Ahmad

Universiti Teknologi Malaysia | UTM · Department of Chemical Engineering

A series of fibrous aminated adsorbents for CO2 adsorption were prepared by covalent incorporation of poly (glycidyl methacrylate) (PGMA) by graft copolymerization of GMA onto electron beam (EB) irradiated polyethylenepolypropylene (PE/PP) fibrous sheets and subsequent amination with ethylenediamine (EDA), diethylenetriamine (DETA), or tetraethylen...

Directly synthesising dimethyl ether (DME) from CO2 hydrogenation is a promising technique for efficiently utilising CO2 as a feedstock to produce clean fuel. The main challenges in this process are the low CO2 conversion and DME selectivity of the catalyst and its deactivation over time due to sintering, aggregation, coke formation, and water adso...

The effect of copper (Cu) content on Cu oxide loaded onto carbon nanotube (CuO/CNT) catalyst on mechanistic, kinetics, and photonic efficiency of photodegradation of p-chloroaniline (PCA) under visible (VIS) and ultraviolet (UV) light irradiation have been detailed explored. For low-loading (1-5 wt%) CuO/CNT, the photodegradation performed better u...

Emission of carbon dioxide (CO 2 ) becomes a main concern in battling issues of global warming. The strategy to reduce the concentration of CO 2 could be achieved by implementing carbon capture and storage (CCS) technology such as adsorption by solid adsorbents. In this work, hydrazone containing adsorbent was prepared by radiation induced grafting...

Dihydrogen (H2), commonly named ‘hydrogen,’ is considered as a promising renewable fuel that does not emit carbon dioxide upon combustion. Nonetheless, since hydrogen is actually mainly produced from fossil fuels, sustainable methods such as water splitting are required. For that, metal oxide semiconductors have been explored as photoelectrode mate...

Hydrogen is a zero-carbon footprint energy source with high energy density that could be the basis of future energy systems. Membrane-based water electrolysis is one means by which to produce high-purity and sustainable hydrogen. It is important that the scientific community focus on developing electrolytic hydrogen systems which match available en...

Two novel types of anion exchange membranes (AEMs) having imidazolium-type functionalised nanofibrous substrates were prepared using the facile and potentially scalable method. The membranes’ precursors were prepared by graft copolymerization of vinylbenzyl chloride (VBC) onto syndiotactic polypropylene ( syn -PP) and polyamide-66 (PA-66) nanofibro...

Preparation and optimization of tetraethylenepentamine (TEPA) content in polyethylene/polypropylene (PE/PP) grafted with poly(glycidyl methacrylate) (PGMA) adsorbent for CO2 capture were investigated. The amination reaction parameters such as solvent type, amine to solvent ratio and reaction time were optimized using the Taguchi method to maximize...

The performance and cost of the membranes have always been crucial for the utilization of electrochemical energy devices. This article presents the properties and the performance of two commercially available and low-cost perfluorinated sulfonic acid membranes of GN115 and GN212C for vanadium redox flow battery (VRFB) application in comparison with...

Porous membrane with enhanced proton conductivity is designed and prepared for vanadium redox flow battery (VRFB). The membrane is composed of ultra height molecular weight polyethylene (UHMWPE) grafted with poly(vinylbenzyl chloride) (PVBC) at different degrees of grafting (DOG). Subsequently, the membrane is functionalized with graphene oxide (UH...

Performances of Pressure swing adsorption (PSA) dependent on the type of adsorbent and efficiency of the regeneration cycle. In this work, a model describing CO 2 mixture flow, mass and heat transfer with multi-component adsorption model are developed in Aspen Adsorption environment to compare the performance of PSA cycles with three different adso...

In this study, ligands originated from glycidyl methacrylate (GMA) and vinyl benzyl chloride (VBC) monomers were grafted onto fibrous polyethylene/polypropylene (PE/PP) substrate and the resulting grafted copolymers were functionalized with ethylenediamine (EDA). The changes in the chemical structure and crystallinity of the aminated adsorbents wer...

Graphene oxide (GO) was functionalized onto both sides of grafted porous polyethylene/polypropylene (PEPP) membrane sheet through sonication and simple immersion. Graphene oxide is a trending material in the field due to its excellent properties such as highly resistant to alkaline/acidic and strong mechanical strength, low cost and easily accessib...

Modification of polyethylene coated polypropylene by radiation-induced graft copolymerization (RIGP) of N-vinylformamide film followed by hydrolysis was studied to produce polyvinylamine (PVAm) containing adsorbent for CO 2 adsorption. A number of grafting parameters such as irradiation dose, monomer concentration, and reaction temperature were inv...

The CO 2 adsorption performance of poly (chloromethyl styrene) (PCMS) grafted on polyethylene coated polypropylene (PE/PP) fibrous polymer substrate and followed by amination with monoethanolamine (MEA) was investigated using gravimetric sorption system. The chemical, structural and morphological changes in the aminated adsorbents were evaluated us...

A highly active and robust fibrous spherical ZSM‐5‐supported nickel catalyst with different promoters (Mg, Ca, Ta, Ga) have been synthesised by microemulsion method for dry reforming of methane (DRM). The structural framework provided by the unique fibrous spherical ZSM‐5 aided confinement of Ni particles. Catalytic activity was improved by homogen...

Biomass agricultural waste has great potential for meeting part of the world energy need and is completely environmentally friendly. One conversion method is thermochemical processes and specifically, pyrolysis. Pyrolysis converts the lignocellulose waste to fuel and essential chemicals into three products: biogas, bio-oil, and biochar. However, pe...

Hydrogen is an interesting energy source alternative to fossil fuel which commonly produced from a non-renewable resource such as methane. Alternatively, ethanol is an attractive resource option for producing hydrogen because of its renewability. Assessing both alternatives is important for selection of better and sustainable option. In this work,...

This paper examines the impact of sensor and actuator failures in the operation of a multivariable distillation column. Several failure scenarios are evaluated including failures of sensors and actuators in various scales of magnitudes and durations. The results obtained illustrate the ability of process controllers in suppressing the impact of the...

High momentum release of jet fire can be very intense, and the released heat can be very high, depending on the source capacity. One of the key parameters in characterizing the jet fire is the radiative fraction. The previous study has correlated the radiative fraction to the source using a Froude number basis. Nevertheless, the flame mechanism and...

Today, about 95 % of hydrogen gas supply is produced from steam methane reforming process, which uses substance from fossil fuel origin. This unsustainable source of hydrogen production also leads to greenhouse gases emission. Hence, this paper presents the promising future of exploiting an alternative to water electrolysis; the elevated temperatur...

The steam reforming of gasified biomass tar model that consists of phenol, toluene, naphthalene, and pyrene over Ni/dolomite/La2O3 (NiDLa) catalyst was performed in a fixed bed reactor. The effect of reaction temperature (500-900 °C), steam to carbon (S/C) molar ratio (0.5-2.5), and gas hourly space velocity (GHSV) (8,000-22000 h-1) on hydrogen (H2...

A copper chloride (CuCl) electrolyzer that constitutes of composite proton exchange membrane (PEM) that functions at medium-temperature (>100 °C) is beneficial for rapid electrochemical kinetics, and better in handling fuel pollutants. A synthesized polybenzimidazole (PBI) composite membrane from the addition of ZrO2 followed with phosphoric acid (...

Sudden release of combustible/flammable materials at high pressure could result in the occurrence of a jet fire in the processing industry. Understanding the jet fire phenomenon and its mechanism could assist practitioners and researchers to predict the radiant energy transfer caused by the jet fire. Due to the dynamics of jet fire occurrence, the...

A composite membrane of polybenzimidazole (PBI) and sulfonated polyether ether ketone (SPEEK) based electrolyzer that operates at higher working temperature above 80 ⁰C is advantageous for faster electrochemical kinetics, higher current exchange density and more resistance to fuel impurities. A high-temperature copper chloride-based composite membr...

Low conductivity and stability of anion exchange membranes limited the durability and performance of corresponding fuel cells despite their unique advantages in compared to the proton exchange membrane fuel cells. In this work, we present a simple and efficient method to fabricate highly durable anion exchange membranes from commercial porous hydro...

The separation of an azeotropic mixture such as ethanol/ethyl acetate in distillation process can be enhanced by ultrasound wave. The application of ultrasound wave creates bubble cavitation in the mixture and shifts the vapour-liquid equilibrium favouring the separation of the azeotropic mixture. This study investigates the formation of bubbles in...

A fibrous silica zeolite Y (HY@KCC‐1) catalyst with a high surface area of 568 m2/g and unique core‐shell morphology was successfully synthesized via a modified KCC‐1 synthesis method. Characterization of the catalysts was achieved with X‐ray powder diffraction (XRD), field emission scanning microscope (FESEM), N2 adsorption/desorption, and 2,6‐dim...

The removal of boron from aqueous solutions using nanofibrous adsorbent containing grafted poly(glycidyl methacrylate) with glucamine ligand was investigated in a batch equilibration mode. Particularly, the equilibrium isotherms, kinetics, thermodynamics of boron adsorption onto a newly prepared chelating adsorbent obtained by radiation-induced gra...

The global expansion of industry and technology has brought various environmental issues especially in atmospheric pollution and global warming. These resulted in various R&D activities on renewable energy resources and devices. Developing high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) is one of them. Over the past decades, this...

Early and accurate fault detection and diagnosis (FDD) minimises downtime, increases the safety and reliability of plant operation, and reduces manufacturing costs. This paper presents a robust FDD strategy for a nonlinear system using a bank of unknown input observers (UIO). The approach is based on structure residual generation that provides not...

Graphene oxide (GO) has attracted tremendous attention in membrane-based separation field as it can filter ions and molecules. Recently, GO-based materials have emerged as excellent modifiers for vanadium redox flow battery (VRFB) application. Its high mechanical and chemical stability, nearly frictionless surface, high flexibility, and low cost ma...

This paper discusses the procedure of integrating importance measures into fault tree analysis. Importance measures (IM) are analytical tools developed to quantitatively appraise the contribution of a plant component towards the overall risk. As part of safety assessment, this method can be used to rank and identify the root cause of undesired even...

The paper presents a study for investigating i) the effect of amination of poly(GMA)-grafted polyethylene/polypropylene (PE/PP) substrates with trimethylamine (TMA) and ethylenediamine (EDA) and ii) their impact on carbon dioxide (CO2) adsorption capacity of the obtained adsorbents. The chemical, structural, and morphological changes of the aminate...

Low permeability layers of poly(1-vinylimidazole) were polymerised and deposited onto both sides of electrospun polyethersulfone (PES) nanofibrous sheet radiofrequency plasma. The layers not only act as an efficient fuel barrier layer but also impart high and stable proton conductivity, as well as better chemical and dimensional stabilities. Typica...

Ultrasound application has been reported to assist chemical processes as a result of various physiochemical effects during acoustic cavitation phenomena in a liquid. In this study, acoustic pressure distribution in ethanol solution induced by ultrasonic waves in a sonoreactor was investigated using COMSOL Multiphysics software. The variations of ac...

The removal of carbon dioxide (CO 2 ) from natural gas is a practical measure in dealing with problems such as CO2 emissions into the atmosphere and reducing the cost of gas processing operations. Adsorption is a promising technology currently used, specifically pressure swing adsorption (PSA) method. In this paper, the adsorption column packed wit...

Torrefaction of pelletised oil palm empty fruit bunches (OPEFBs) is a promising pretreatment technique for improving its solid biofuel properties and energy recovery potential. Therefore, this paper investigates the torrefaction of OPEFB pellets to examine the effects of temperature and purge gas flow rate on mass yield (MY), energy yield (EY), and...

The search of new membranes for vanadium redox flow battery with low vanadium ions permeation rates, high ion conductivity, excellent proton conductivity, low area resistance, chemical stability, and low cost is on a soaring demand. In this work, a simple modification method is applied to improve the performance of commercially available low-cost m...

The search for highly vanadium selective membrane for vanadium redox flow battery (VRFB) is fast growing to accelerate the commercialization of VRFB. Currently, VRFB is challenged by high vanadium permeability through the membranes lowering the battery performance. In this paper, a simple and effective strategy for improving the vanadium barrier pe...

Performance of acid/PBI membranes declines at high temperature operation of fuel cell. • Durability significantly increases using pyridine-PBI and phosphonated graphene oxide. • Proton conductivity at dry conditions compares well to Nafion under 100% humidity. • A peak power density shows above 75% improvements after adding phosphonated filler. A B...

Pelletization and torrefaction are promising pre-treatment techniques for improving the solid biofuel properties of oil palm empty fruit bunches (OPEFB) for efficient energy recovery. Therefore, this paper seeks to perform a preliminary analysis of the torrefaction of OPEFB pellets in a stainless steel horizontal fixed bed tubular reactor (FBT). It...

: Early and accurate fault detection and diagnosis (FDD) may minimize downtime, increase the safety of plant operations, and reduce manufacturing costs. This paper presents a fault detection and diagnosis for a nonlinear system using a bank of unknown input observers (UIO). The proposed approach was able to identify sensors fault even with the pres...

An electrochemically reduced graphene oxide was grown on carbon felt surface in a simple one-step electrodeposition process of graphene oxide and it was employed as a positive electrocatalyst of vanadium redox flow battery. The electrodeposited graphene-based nanocomposite on carbon felt presented outstanding electrochemical redox reversibility tow...

Polybenzimidazole (PBI) was studied as an ionomer binder at varying ratios (1–7) in a 20–40 wt% Pt–Pd/C cathode-coupled catalyst layer for the oxygen reduction reaction (ORR) in a high-temperature proton exchange membrane fuel cell (HT-PEMFC). Catalytic activity was examined by CV and LSV, while the properties of the catalysts were characterized by...

Nanofibrous poly(vinylidene fluoride) (PVDF) sheets were produced by electrospinning and grafted with oxirane groups using radiation induced grafting of glycidyl methacrylate (GMA) followed by treatment with N-methyl-D-glucamine (NMDG). The NMDG density in the nanofibers was tuned by optimization of the immobilisation reaction variables using respo...

Preparation of polyurethane (PU) nanofibers with enhanced hydrophilic properties was carried out by electrospinning of PU followed by modification of the obtained PU nanofibrous scaffold with 2-hydroxyethyl methacrylate (HEMA) by radiation induced grafting (RIG) method. The effect of electrospinning parameters on fibre diameters was optimized using...

A novel polyoxometalate-based electrode is developed by incorporating phosphotungstic acid (PWA) in Nylon-6,6 nanofiber followed by carbonization. Developed PWA-carbon nanofiber (PWA-CNF) showed the characteristics of dual-scale porosity of micro- and mesoporous substrate with surface area of around 684 m2g−1. The compound exhibited excellent stabi...

In this study, we proposed an innovative and versatile method for preparation of highly stable and conductive supported ionic liquid (IL) membranes for proton exchange fuel cell applications. Novel covalently supported dual acidic IL membranes were prepared by radiation induced grafting of 4-vinyl pyridine (4-VP) onto poly(ethylene-co-tetrafluoroet...

A highly durable proton exchange membranes (PEM)s based on covalently supported ionic liquid (IL) bearing sulfonic acid imidazolium groups were successfully fabricated. The membrane preparation involved radiation induced grafting of 1-vinyl imidazole (1-VIm) onto poly(ethylene-co-tetraflouroethene) (ETFE) film, followed by covalent immobilization o...

Malaysia generates significant quantities of lignocellulosic wastes through the production of crude palm oil (CPO). Over the years, the accumulation of the oil palm wastes (OPW) have become an environmental burden. These problems can be addressed by pretreatment and valorisation of OPW in bioenergy as envisioned in the National Biomass Strategy (NB...

The effect of significant parameters on the tuning of electrochemical reduction of graphene oxide (GO) and its electrochemical behavior toward ferri/ferrocyanide as a redox couple was investigated for the first time through a systematic methodical procedure. Reduced graphene oxide (rGOs) modified electrodes were prepared by electrodeposition on the...

Fault detection and isolation is absolutely important task for improving the reliability and safety of process industries in order to achieve their product quality requirements. This paper is focusing on the problem of the robust fault detection and isolation of multicomponent distillation process in the presence of modeling uncertainties and unkno...

Amorphous TiO2 (AT) was successfully prepared via the sol-gel technique, using different titanium sources followed by incorporation of copper via the electrochemical method to give CuO/TiO2 (CAT) catalysts. The catalysts were characterized via XRD, N2 physisorption, FTIR, TEM, EDX, XPS, ESR and UV–Vis DRS. The results verified that the use of diffe...

Crude Palm Oil (CPO) production in Malaysia generates significant wastes which present numerous environmental challenges. These can be addressed by the pretreatment and valorization of oil palm wastes (OPW) for energy utilization as outlined in the National Biomass Strategy (NBS-2020). However, the inefficiency of current conversion techniques such...

Microwave-assisted spray drying process provides an intensified form of energy for moisture removal and offers potential applications for producing thermally sensitive powders in foods, cosmetics and pharmaceuticals industries. The process produces powder at lower drying air temperatures that are impractical under conventional spray drying, with pr...

BIOMANETICS is a software developed for biomass devolatilization kinetics computation. Devolatilization kinetics reveal the rate a biomass decomposes when heat is applied, a very important step in the thermochemical process. Thermochemical processes such as pyrolysis, gasification, combustion and torrefaction, convert biomass to environmentally fri...

Development of more efficient electrodes is essential to improve the competitiveness of vanadium redox flow battery (VRFB) systems. Covalent functionalization of carbon structure in graphene oxide with phosphonic acid groups was carried out to enhance the electrode wettability. The phosphonated graphene oxide (P-GO) was characterized and found disp...

Anion exchange membranes (AEM) have gained significant interest in electrochemical energy devices with a unique set of benefits. However, none of the commercial AEMs behave ideally under alkaline operation condition and developing proper membranes is one of the major hurdles to the durability and performance of anion exchange membrane fuel cells. H...

Tremendous research efforts have been dedicated towards development and utilization of sustainable alternative energy resources. Depletion of fossil fuels and the rising environmental concerns such as global warming are among the reasons that necessitated such. Hydrogen (H2) has been widely considered a clean fuel for the future, with the highest m...

Heteropolyacids (HPAs) are a class of inorganic materials that have been widely used as additives to enhance the performance of fuel cell membranes, recently. This chapter covers the use of HPAs in the preparation of proton exchange membranes (PEM) for polymer electrolyte membrane fuel cells (PEMFCs). The fundamental aspects of HPAs and their corre...