Mohamed Aroua

Sunway University, Department of Science and Technology, Faculty Member

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Process optimization and kinetics of microwave assisted transesterification of crude glycerol for the production of glycerol carbonate

Sustainable Energy and Fuels, 2021

The production of glycerol carbonate (GC) from industrial grade crude glycerol was catalyzed by c... more

Absorption of CO 2 into aqueous mixtures of glycerol and monoethanolamine

Journal of Natural Gas Science and Engineering, Sep 1, 2016

The solubility of CO 2 in aqueous solutions 30 wt% monoethanolamine (MEA) mixed with various glyc... more The solubility of CO 2 in aqueous solutions 30 wt% monoethanolamine (MEA) mixed with various glycerol concentrations was measured. The CO 2 absorption was performed at three different temperatures (313, 323, and 333 K), and pressures ranging from 500 to 1500 kPa with concentrations of glycerol in the mixture varying from 0 to 20 wt%. Correlations of solubility as a function of CO 2 partial pressure were obtained with deviation of less than 2% over the pressure range investigated. The CO 2 loading at various temperatures, pressures, and concentrations showed an agreement to the general trend of absorption (i.e., increasing the equilibrium loading with decreasing the temperature and increasing the pressure). The solubility of the MEA solution increased by adding glycerol up to a level of 10% at lower pressures. The findings showed that 5 wt% glycerol in the mixture was the concentration that yielded the optimum CO 2 solubility as it could increase the CO 2 solubility of MEA at low pressures and approximately maintain its capture performance at high pressures. It confirmed that the solvent is suitable for the absorption of CO 2 under low pressures (below 1000 kPa) and can be applied in low-pressure CO 2 absorption processes such as post-combustion CO 2 capture.

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Microwave Assisted Solvent-Free Catalytic Transesterification Of Glycerol To Glycerol Carbonate

As a by-product of the biodiesel industries, glycerol has been vastly generated which surpasses t... more As a by-product of the biodiesel industries, glycerol has been vastly generated which surpasses the market demand. It is imperative to develop an efficient glycerol valorization processes in minimizing the net energy requirement and intensifying the biodiesel production. In this study, base-catalyzed transesterification of glycerol with dimethyl carbonate using microwave irradiation as heating method to produce glycerol carbonate was conducted by varying grades of glycerol, i.e. 70%, 86% and 99% purity, that is obtained from biodiesel plant. Metal oxide catalysts were used with varying operating parameters including reaction time, DMC/glycerol molar ratio, catalyst weight %, temperature and stirring speed. From the study on the effect of different operating parameters it was found that the type of catalyst used has the most significant effect on the transesterification reaction. Amidst the metal oxide catalysts examined, CaO gave the best performance. This study indicates the feasib...

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Fluoride removal by low-cost palm shell activated carbon modified with prawn shell chitosan adsorbents

International Journal of Environmental Science and Technology, 2021

Hydrofluoric acid is used in large volumes during solar panels manufacturing for cleaning purpose... more Hydrofluoric acid is used in large volumes during solar panels manufacturing for cleaning purpose. It results in the generation of wastewater containing high concentrations of fluoride. Chemical precipitation is commonly used to remove most of fluoride from the wastewater. It reduces fluoride concentration to ~ 20 mg/L, whereas the discharge standard is set to 2 mg/L. Adsorption is preferable when dealing with diluted wastewater. This study evaluated the adsorption of fluoride using two low-cost adsorbents: granular palm shell activated carbon and its modification with the prepared chitosan of prawn shells. The effects of pH, dosage, contact time and initial fluoride concentration were studied in batch mode adsorption experiments. The highest removal efficiencies of fluoride by two adsorbents comprised 46% and 55%, respectively, at pH 2 and pH 7. The contrasting behavior of the two adsorbents in relation to pH is attributed by the adsorbents surface charge associated with the surface functional groups identified by FTIR. The adsorption isotherm modeling showed better fit to the Langmuir model for both adsorbents. Adsorption kinetics results fitted well into the pseudo-second-order kinetics model suggesting chemisorption mechanism of fluoride removal.

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Selection of Tubular Membrane Separation based on the Resistance Performance

Proceedings of the International Conference on Natural Resources and Technology, 2019

Processing of fruits (such as pink guava) to produce fruit juices results in high amount of waste... more Processing of fruits (such as pink guava) to produce fruit juices results in high amount of waste materials that still contain valuable by-products (e.g. antioxidants or polyphenols). Analysis of hydrodynamic resistances that considers gel layer formation as the main fouling mechanism and permeate flux decline was studied. Using tubular membrane FP 100 and ES 404 performed the experiments, with a molecular weight cutoff of 100 kDa and 4 kDa respectively. Results showed that the permeate fluxes for both of the membranes increased by increasing the Trans Membrane Pressure (TMP) and it would decrease with time. All of the resistances increased with TMP meanwhile the mass transfer of polyphenols did not affect the TMP. All the TMP resulted in similar fouling values for both membranes.

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Starch as novel water soluble biopolymer in removal mixtures heavy metal ions via polymer enhanced ultrafiltration

6TH INTERNATIONAL CONFERENCE ON ENVIRONMENT (ICENV2018): Empowering Environment and Sustainable Engineering Nexus Through Green Technology, 2019

Four heavy metals Zn (II), Pb (II), Cr (III) and Cr (VI) were selected in this work was tested th... more Four heavy metals Zn (II), Pb (II), Cr (III) and Cr (VI) were selected in this work was tested through a Polymer Enhanced Ultrafiltration (PEUF) system. The effects of pH, polymer concentration and metal ions feed concentration were the main focus and influenced the performance of PEUF system. A conventional water-soluble polymers was selected, namely polyethylene glycol (PEG), and an unmodified starch as biopolymer is proposed as an alternative binding reagent for four selected metal ions used for heavy metals removal from wastewater. Speciation profiles of Zn (II), Pb (II), Cr (III) and Cr (VI) species were obtained using available software to identify the soluble complexes of Zn (II), Pb (II),Cr (III) and Cr (VI) ions and hydroxides ions (OH-) present in various charged ions, either as anions or cations, at certain pH range. Investigation through experimental works was done using ultrafiltration systems obtained by laboratory ultrafiltration bench scale equipped with 10 kDa polysulfone hollow fiber membrane. The main operating parameter, namely the effects of pH, polymer composition and metal ions concentrations, were significantly affected by the rejection coefficient conducted at constant pressure and flowrate. Unmodified starch and PEG as binding polymers performed complexation interactions due to physical attraction of metal ions to the polymer on the molecular surface with high possibility of chemical occurrence. Rejection values were high at pH 7 for Zn (II) and Cr (III) ions corresponding to higher rejections with unmodified starch. Pb (II) ions obtained high rejections when tested with PEG whenever carried out in mixed metal ions solutions. The rejection of these metal ions by starch in this study is found to be influenced by granule structure that generally behaved in a non-ionic manner.

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The Study of Carbon Dioxide Removal in Membrane Module by Single and Mixture of Alkanolamine Aqueous Solutions

Journal of Applied Membrane Science & Technology, 2017

This work presents an investigation on the performance of CO2absorption into aqueous alkanolamine... more This work presents an investigation on the performance of CO2absorption into aqueous alkanolamine solution using a hollow fiber membrane gas–liquid contactor. Aqueous solution of ethanolamine (MEA), diethanolamine (DEA), 2–amino–2–methyl–1–propanol (AMP) and piperazine anhydrous (PZ) were chosen as the absorption liquids. A microporous hollow fiber membrane made of polyvinylidene fluoride (PVDF) was used as the medium for gasliquid absorption process. In this study, the operating temperature is fixed at 30°C, while the flowrate of CO2 and alkanolamine were in the range of 1000–5000 ml/min and 50–280 ml/min respectively. The feed gas was introduced directly to the shell of the module at 1–1.5 bar and the liquid flowed through the fiber lumen side. The CO2 transfer through the membrane was found to be reaction controlled and dependent on the type of amine used. The use of piperazine as an accelerator in the mixture of the absorption liquids gives a good impact on increasing the perfor...

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Crude biodiesel refining using membrane ultra-filtration process: An environmentally benign process

Egyptian Journal of Petroleum, 2015

Ceramic membrane separation system was developed to simultaneously remove free glycerol and soap ... more Ceramic membrane separation system was developed to simultaneously remove free glycerol and soap from crude biodiesel. Crude biodiesel produced was ultra-filtered by multichannel tubular membrane of the pore size of 0.05 lm. The effects of process parameters: transmembrane pressure (TMP, bar), temperature (°C) and flow rate (L/min) on the membrane system were evaluated. The process parameters were then optimized using Central Composite Design (CCD) coupled with Response Surface Methodology (RSM). The best retention coefficients (%R) for free glycerol and soap were 97.5% and 96.6% respectively. Further, the physical properties measured were comparable to those obtained in ASTMD6751-03 and EN14214 standards.

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Correlation and measurement of density and viscosity of aqueous mixtures of glycerol and N-methyldiethanolamine, monoethanolamine, piperazine and ionic liquid

Journal of Molecular Liquids, 2016

The density and viscosity of aqueous mixtures of glycerol and N-Methyldiethanolamine (MDEA), glyc... more

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Microstructures, interactions and dynamics properties studies ofN-methyldiethanolamine + guanidinium triflate ionic liquid + water tertiary system at the standard temperature

Molecular Simulation, 2015

In order to understand the phase equilibrium behavior of aqueous ionic liquids (ILs) guanidinium ... more In order to understand the phase equilibrium behavior of aqueous ionic liquids (ILs) guanidinium triflate [gua][OTf] solution (binary solvent) at 7 different molar fractions of water ranged from 0.1 to 0.7 at 440.15 K classical molecular dynamic simulations were performed. The simulations measured changes in different properties such as density, structural, bonding properties (radial distribution function, water clustering and hydrogen bonding) and dynamic property (diffusion coefficient). The analysis of radial distribution and spatial distribution functions revealed a significant long-range structural correlation between IL and water. Water molecules intercalated in the coordination shell of both ions, thus

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Cleaner Production A Do It Yourself Manual

Project on the Formulation of Emission Factors for Industrial Pollutants in Malaysia

Application of Neural Networks to Predict Biodiesel Density

In this study a new approach based on Artificial Neural Networks (ANNs) has been designed to pred... more In this study a new approach based on Artificial Neural Networks (ANNs) has been designed to predict the density of various vegetable oil-based ethyl esters and palm oil-based methyl esters biodiesel. The experimental densities data measured at various temperatures from 15°C to 90 °C at 1 °C interval were used to train the networks. The present work, applied a three layer back propagation neural network with nine neurons in the hidden layer. The results from the network are in good agreement with the measured data and the average absolute percent deviation was 0.29, 0.35, 0.72, 0.54, 0.68 and 0.72 % for the palm oil methyl esters and the ethyl esters of palm, canola, com and ricebran oil,respectively. The results of ANNs have also been compared with the results of theoretical estimations.

Waste to Biodiesel: Direct and Indirect Routes to Your Fuel Tank

Event though the price of fossil fuel now is lower than what it was six months ago, there is no g... more Event though the price of fossil fuel now is lower than what it was six months ago, there is no guarantee that the price will remain low and may even set new price record because the oil reserves are declining. Biodiesel is one of the promising sustainable energy sources that can be a serious contender for fossil fuel if the raw materials can be obtained at an economically viable level. Efforts are underway to identify such raw materials and source from waste is definitely one of the main candidates. Some waste such as waste frying oil, bleaching earth and coffee ground are examples of waste that can be used to produce biodiesel at varying technical difficulties directly. However any other waste containing C, H, Nand P sources can be also potentially used for producing biodiesel indirectly, after transformation process involving microbes. For example,algae that grows on a C,H, Nand P sources from domestic and industrial wastewater (food,rubber, palm oil industries) and CO2 (from combustion of fuel) can be a source of raw material for biodiesel production. In this work, various challenges and opportunities available for producing biodiesel from waste sources, directly and indirectly are conceptually discussed.

RBD palm olein-based methyl/ethyl esters

Reactive extraction of solid coconut waste to produce biodiesel

Journal of the Taiwan Institute of Chemical Engineers, 2013

Biodiesel is an alternative diesel fuel produced using transesterification method where edible or... more Biodiesel is an alternative diesel fuel produced using transesterification method where edible or non edible oil and alcohol reacts in the presence of catalyst. Biodiesel is expensive than fossil fuels because of higher raw material and production costs. Solid coconut waste is an alternative raw material from waste and suitable for biodiesel production to lower the production cost. Solid coconut waste is produced after coconut milk extraction and may still contain 17-24 wt% extractable oil content. This study introduces reactive extraction of solid coconut waste for biodiesel production. Effects of catalyst amount, KOH (0.8-2.0%), temperature (55-65 8C) and mixing intensity (500-900 rpm) were studied to optimize the reactive extraction. Based on the Response Surface Methodology (RSM), the optimum condition was found to be 2.0 wt% of KOH catalyst, 700 rpm of mixing intensity and reaction temperature, 62 8C where resulted in 88.5% of biodiesel yield.

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Coconut waste as a source for biodiesel production

2010 2nd International Conference on Chemical, Biological and Environmental Engineering, 2010

Biodiesel industry needs a cheaper and economical viable raw material that can replace the curren... more Biodiesel industry needs a cheaper and economical viable raw material that can replace the currently used vegetable oil. Obtaining cheaper raw materials are one of the continuous targets of many biodiesel producing facilities since 70 to 95 % of the production costs are attributed to raw materials. One of the main options is to use waste material from animal and plant sources. In this study, coconut waste is used to produce biodiesel using methanol and KOB. The oil content in coconut waste varies from 10-11 wt%. The highest yield, 64 % is achieved with 5 wt% of KOB within 3 hr by mixing raw material and methanol.

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Solvent free enzymatic transesterification of crude jatropha oil in packed bed reactor

2010 2nd International Conference on Chemical, Biological and Environmental Engineering, 2010

In this study, we produce biodiesel from jatropha oil through enzymatic synthesis in a re circula... more In this study, we produce biodiesel from jatropha oil through enzymatic synthesis in a re circulated packed bed reactor (PBR). A solvent free system by three stepwise addition of one equivalent molar methanol in each step was chosen for this study. The enzyme was Lipozyme 1M, a 1,3 regiospecific immobilized lipase from Mucor miehei. Initially, we scrutinized the appropriate amount of lipase by varied the lipase dosage from 5% to 20% based on Jatropha oil weight. Constant operating condition for all experiment was set to temperature of 45° C, PBR flow rate of 5 ml/min and 3 molar equivalent of methanol. The highest biodiesel yield of 54% was obtained at 10% of lipase dosage. We have also examined the effect of methanol addition time by conduct an experiment with one equivalent molar of methanol. The maximum conversion was found at 24 hours. However, a subsequent experiment carried out based on profile from those experiment, could only gave a biodiesel yield of 51 %. Afterwards, we observe the lipase stability in PBR solvent free system.

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Control of pH during water denitrification in an upflow bio-electrochemical reactor (UBER) using a pumparound system

Separation and Purification Technology, 2010

In this study a new reactor design is proposed to control the pH during the bio-electrochemical d... more In this study a new reactor design is proposed to control the pH during the bio-electrochemical denitrification process. A previously developed UBER was modified by including a pumparound system. With the pumparound system a portion of the treated water is continuously withdrawn from the UBER into a CO 2 sparging bottle to decrease its pH to about 6.1 ± 0.1, before being returned to the cathode zone where denitrification process takes place. Continuous denitrification was studied with a HRT of 24 h applying an electric current in the range of 15-25 mA. The effects of circulation flow rate (F c) on the pH and on the concentrations of nitrate and nitrite ions in the effluent were investigated. The pumparound system succeeded to stabilize the cathode pH around 7-8 through alteration of circulation flow rate (F c). Complete denitrification with no trace of nitrite was therefore achieved at circulation flow rate of 0.7 mL/min and electric current 25 mA. A further investigation in absence of bicarbonate sodium resulted in a satisfactory nitrate treatment showing that the carbon dioxide gas dissolved in the CO 2 sparging bottle supplied enough carbon for the autohydrogenotrophic microorganisms.

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Improvement of autohydrogenotrophic nitrite reduction rate through optimization of pH and sodium bicarbonate dose in batch experiments

Journal of Bioscience and Bioengineering, 2009

Accumulation of nitrite intermediate in autohydrogenotrophic denitrification process has been a c... more Accumulation of nitrite intermediate in autohydrogenotrophic denitrification process has been a challenging difficulty to tackle. This study showed that further growth of "true denitrifying" bacteria and adaptation to nitrite led to a faster reduction of nitrite than nitrate as a solution to circumvent nitrite accumulation. Moreover, two effective parameters namely pH and bicarbonate dose were optimized in order to achieve a better reduction rate. Sodium bicarbonate dose ranging from 20 to 2000 mg/L and pH in the range of 6.5-8.5 was selected to be examined employing 0.2 g MLVSS/L of reacclimatized denitrifying bacteria. Eleven runs of experiments were designed considering the interactive effect of these two operative parameters. A fairly close reduction time less than 4.5 h (N 22.22 mg NO 2 −-N/g MLVSS/h) was gained for the pH range between 7 and 8. The highest specific nitrite reduction rate at 25 mg NO 2 −-N/g MLVSS/h was achieved applying 1000 mg NaHCO 3 /L at pH 7.5 and 8. The pH was found to be the leading parameter and bicarbonate as the less effective parameter on nitrite reduction removal. Central composite design (CCD) and response surface design (RSM) were employed to develop a model as well as define the optimum condition. Using the experimental data, the developed quadratic model predicted optimum condition at pH 7.8 and sodium bicarbonate dose 1070 mg/L upon which denitrifiers managed to accomplish reduction within 3.5 h and attained the specific degradation rate of 28.57 mg NO 2 −-N/g MLVSS/h.

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