Now showing 1 - 10 of 32
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Sulfur dioxide removal by calcium-modified fibrous KCC-1 mesoporous silica: kinetics, thermodynamics, isotherm and mass transfer mechanism

2022-04-01 , Hanif M.A. , Naimah Ibrahim , Khairuddin Md Isa , Umi Fazara Md Ali , Tuan Abdullah T.A. , Jalil A.A.

The removal of sulfur dioxide from industrial flue gas through dry flue gas desulfurization method commonly involves the use of adsorption process with porous sorbent. The efficiency of this process is highly dependent on the adsorption capacity and the adsorption rate of SO2 onto the sorbent materials. The use of KCC-1 mesoporous silica modified with calcium metal additives (Ca/KCC-1) in SO2 adsorption is examined in a fixed bed reactor system. The adsorption capacity of Ca/KCC-1 is found to be critically governed by the reaction temperature and inlet SO2 concentration where low values of both parameters are favorable to achieve the highest adsorption capacity of 3241.94 mg SO2/g sorbent. SO2 molecules are adsorbed on the surface of Ca/KCC-1 by both physisorption and chemisorption processes as assumed by the Avrami kinetic model. Thermodynamic study shows that the process is exothermic and spontaneous in nature, and changes from an ordered stage on the surface of KCC-1 towards an increasingly random stage. The process is well explained by Freundlich isotherm model indicating a slightly heterogeneous process and moderate adsorption capacity. The adsorption stage is limited by film diffusion at the initial stage and by intraparticle diffusion during the transfer of SO2 into the network of pores before adsorption takes place on the active sites.

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The impact of ionic strength and pH on the interaction of Pseudomonas putida to minerals and electrical potential of surfaces

2022-02-01 , Zuki F.M. , Edyvean R.G.J. , Umi Fazara Md Ali , Pourzolfaghar H. , Gafri H.F.S. , Bzour M.I.

The impacts of the acidity and ionic strength of the solutions were evaluated on the electrical potential of the surfaces as well as the interaction of Pseudomonas putida to quartz and hematite. Zeta potential analysis was performed using the streaming potential technique. Experimental results were performed by the flow cell method. Finally, the extended Derjaguin–Landau–Verwey– Overbeek (XDLVO) theory has been applied to describe bacterial-mineral attachment in terms of the sum of repulsive acid-base and electrostatic interaction energies, and attractive van der Waals interaction energies. The results indicate that the zeta potential is obviously influenced by the presence of bacteria, electrolyte concentration, and pH regions. At higher ionic strengths, charge effects on the bacterial cell surface increase adherence by suppressing the thickness of the diffuse double layer. At pH 5–6, at all ionic strengths, the bacteria adhered more on the surfaces of the minerals. Hematite coupons represented the greatest adhesion at pH 5–6 and an ionic strength 0.1 M. XDLVO theory for the attachment of P. putida to the minerals also confirmed the experimental outcomes. The information obtained in this study is of fundamental significance for the understanding of the survival and transport of bacteria in water distribution, groundwater, and soil systems.

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Adsorption of ammonium from wastewater treatment plant effluents onto the zeolite; A plug-flow column, optimisation, dynamic and isotherms studies

2022-01-01 , Khamidun M.H. , Ali Fulazzaky M. , Al-Gheethi A. , Umi Fazara Md Ali , Muda K. , Hadibarata T. , Mohammad Razi M.A.

The current work aimed to investigate the removal mechanism of NH4+ from wastewater treatment plant effluent (WWTPE) onto the zeolite in the plug-flow column reactor (PFCR). The adsorption process was optimised as a function of length (2–15), time (0.5–202 min), and accumulation (0.05–2.4 mg/g) using response surface methodology (RSM). The optimal operating parameters for the adsorption were recorded after 134.89 min with 1.52 mg/L of zeolite with 6.685 cm of the column length where the predicted and actual removal was 99.79 vs. 98.00% of NH4+ from WWTPE. The bed depth service time (BDST), Thomas, and Yoon-Nelson models were used to explain the adsorption behaviour. In contrast, the mass transfer factor (MTF) model was carried out to determine the internal and external removal mechanism. The findings revealed that PFCR exhibited an efficiency for removing NH4+ from WWTPE. The dynamic adsorption behaviour was satisfactorily described by the BDST, Thomas, and Yoon-Nelson models. These findings confirmed that the empirical models had verified the suitable of PFCR for removing NH4+ from WWTPE.

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Study on characterization of bio-oil derived from sugarcane bagasse (Saccharum barberi) for application as biofuel

2022-04-01 , Ahmad S.F.K. , Umi Fazara Md Ali , Isa K.M. , Subash Chandra Bose Gopinath

Lignocellulosic biomass especially, sugarcane bagasse Saccharum barberi sp., appears to be a more suitable material for partial substitution of transport fuel (diesel) than Saccharum officinarum sp., due to its structural similarity to transport fuel (diesel). Besides that, less research has been implemented on this type of species. Bio-oil can be implemented as biodiesel by processing it further using chemical reactions such as hydrodeoxygenation and cracking with zeolite catalyst. Hence, the purpose of this study is to determine the compatibility of pyrolytic bio-oil produced from Saccharum barberi sp. in comparison with S. officinarum sp. for use as transport fuel (diesel) in automotive applications. This purpose can be accomplished by comparing the oil’s bio-physiochemical properties for both species. The experiment is conducted on a bench-scale on which bio-oil of Saccharum barberi sp. is secured from the catalytic pyrolysis process at a temperature of 500°C and heating rate of 50°C/min with the addition of ZSM-Zeolite catalyst. Thermogravimetric analysis of Saccharum barberi sp. reveals that cellulose is more reactive than lignin, evidenced by the high percentage of weight loss at temperatures ranging from 251°C to 390°C. The high contents of carbon (40.7%) and hydrogen (6.50%), as well as slight traces of sulphur (0.08%) and nitrogen (0.85%), in bio-oil (Saccharum barberi sp.) indicate that it is conceivable to be partially used for replacement in biofuel production. Overall physiochemical properties reveal that Saccharum barberi sp. shows more potential than S. officinarum sp. Gas chromatography–mass spectrometry analysis reveals that bio-oil consists of high amounts of aromatic hydrocarbon (26.2%), phenol (14.8%) and furfural (13.0%) in comparison to S. officinarum sp.

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Adsorption of carbon dioxide (CO2) by activated carbon derived from waste coffee grounds

2021-05-24 , Lim H.K. , Umi Fazara Md Ali , Razi Ahmad , Aroua M.K.

Currently, three are several agricultural bio-based materials have been successfully utilized as gas adsorbents. In this study, waste coffee grounds (WCGs) have been selected as a potential precursor of Carbon Dioxide (CO2) adsorbents. The preparation parameters for activated carbon derived from WCGs were optimized using Response Surface Methodology (RSM). The optimized preparation parameters were found to be 1:3.67 impregnation ratio of acid, 533oC of carbonization temperature and 1.13 hours of activation time, which resulted in 23.6 wt% of yield. The physical and chemical characteristics of WCGAC in terms of surface morphology, carbon content, ash content and yield were also investigated. The CO2 breakthrough time using WCGAC were carried out at the temperatures of 30, 40, and 60°C. It was found that WCGAC shows a longer CO2 breakthrough times (5 mins) and a higher adsorption capacity (4.33 mg CO2/g adsorbent) at 30oC.

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Gasification char residues management: Assessing the characteristics for adsorption application

2023-09-01 , Anis Atikah Ahmad , Ahmad M.A. , Umi Fazara Md Ali , Ken K.

Due to the world-wide energy crisis and economic issues, biomass has become a resource of global interest as an alternative to activated carbon (AC) produced using non-renewable feedstock (i.e. coal-based). The production of AC from biomass has been determined to be sustainable owing to the abundance of biomass resources on Earth. Biomass gasification has significantly gained market interest and was predicted to reach a value of USD 126 billion by 2023. A critical concern for the existing commercial gasification plants is the handling of char residues, which represent approximately 10% of the initial feedstock mass and are presently treated as waste. The conversion of these chars into AC that can be used for adsorption applications is a possible alternative. This review article focuses on evaluating the characteristic of the gasification char (GC) that is used for adsorption processes. The current AC production method was briefly reviewed. In addition, recent studies on adsorption using GC were explored and summarised.

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Comparative Performance of Catalytic and Non-Catalytic Pyrolysis of Sugarcane Bagasse in Catatest Reactor System

2020-04-30 , Faraheen Kabir Ahmad S. , Umi Fazara Md Ali , Khairuddin Md Isa , Alina Rahayu Mohamed , Sataimurthi O.

Catalytic pyrolysis is a favourable process used to enhance the quality of bio-oil. Based on reviews from previous research there are only scarce of studies on the comparison of catalytic and non-catalytic pyrolysis of biomass such as rice husk, olive husk and corncob. In this study, sugarcane bagasse was selected as it has not been explored much yet. The target of this research is to compare the impact of catalytic and non-catalytic pyrolysis of sugarcane bagasse in terms of the yield, properties, and also the compositions of bio-oil. Catalytic and non-catalytic pyrolysis was executed in catatest bed reactor at temperatures 400°C to 550°C with the aids of ZSM-5 zeolite catalyst. Bio-oil from catalytic and no-catalytic pyrolysis which gives the maximum yield was used to be studied further in terms of the properties and chemical compositions. The result shows that the maximum yield of bio-oil was accomplished from catalytic pyrolysis at temperature 500°C which was 21.4%. The properties and composition of bio-oil from catalytic pyrolysis shows better result compare to non-catalytic pyrolysis.

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Oil palm waste-derived reduced graphene oxide (rGO) for dynamic adsorption of dye in a fixed-bed system

2024-01-01 , Mohd Ali Jinnah S.N.H. , Umi Fazara Md Ali , Subash Chandra Bose Gopinath , Naimah Ibrahim , Razi Ahmad , Mohamed Zuki F.

This study focuses on investigating the dynamic adsorption of Rhodamine B (RhB) from reduced graphene oxide (rGO) derived from oil palm waste. The synthesis of rGO from palm kernel shell (PKS) was achieved through double oxidation and carbonization method, resulting in a yield of 73.5 wt%. The reduction of oxygen-containing functionalities process using PKS was confirmed by FTIR spectroscopy, microscopic evaluation, and X-ray diffraction analyses. Laboratory-scale fixed-bed experiments were conducted with various process parameters. Both PKS and rGO were used as adsorbents, and a comparison was made based on breakthrough curve analysis, adsorption capacity and percentage removal of dye. The adsorption kinetics of RhB on PKS and rGO were best described by the non-linear Yoon-Nelson model, with a high adsorption capacity of 88.32 mg/g and 195.24 mg/g respectively. Using both PKS and rGO, the maximum adsorption capacity was observed when using 10 cm bed depth column, inlet dye concentration of 5 mg/L, flow rate of 12 mL/min and pH of 7. PKS exhibited good dye removal with an efficiency of 66.54%. Meanwhile, the exothermic behavior highlighted the potential of utilizing rGO for maximum dye removal, achieving an efficiency of 90.35%. This study justifies rGO as a cost-effective superior dye removal adsorbent, providing new prospect for large-scale dye removal.

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Production of fuel grade anhydrous ethanol: A review

2021-05-24 , Lee Y.H. , Chen C.H. , Umi Fazara Md Ali , Mohd Irfan Hatim Mohamed Dzahir

Alcoholic fermentation of fermentable carbon sources like molasses and table sugar using yeast are typical route in producing alcohol particularly known as bioethanol (C2H5OH). The key challenge encountered in bioethanol production process is to eliminate the impurity presence within the bioethanol which mainly water. Distillation is an energy extensive process which commonly used to recover ethanol up to 95% purity due to the presence of azeotropic composition. The distillation will no longer appropriate for further purification once the azeotrope composition has reached. Nonetheless, to be able to use as a viable fuel for gasoline engine or for any other utilizations where the purity is a major concern, further dehydration steps are needed producing an absolute ethanol. Few studies have been investigated on various dehydration methods for producing anhydrous ethanol, including azeotropic distillation, extractive distillation, adsorption, membrane pervaporation, and solvent extraction process. This review offers an insight into currently used technology on the ethanol dehydration methods and the future prospect on the continuous improvement particularly on the process energy requirement and efficiency will be discussed.

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Surface alkali promotion of carbon dioxide hydrogenation for conservation of carbon sources: Cyclic voltammetry study

2020-01-01 , Tan S.Y. , Naimah Ibrahim , Umi Fazara Md Ali , Sara Yasina Yusuf , Aroua M.K.

Conversion of CO2 captured from biogas upgrading process into useful chemicals or fuels e.g. methane is an attractive route towards conservation of carbon sources. Sustainable hydrogenation route could be achieved by combining the process with hydrogen generated from water electrolysis. In this work, cyclic voltammetry was used as preliminary technique to probe the electrochemical behaviour of Na-modified Pt/YSZ as model catalyst under CO2 hydrogenation. The reaction is irreversible and the voltammogram features are not easily distinguishable under reaction conditions. The increase in cathodic peak height and the decrease in peak potential with addition of sodium at low coverage (0.32%) indicated that the charge transfer reaction was enhanced and thus the methanation reaction could be electrochemically promoted given sufficient amount of H2 flow. However, increasing Na coverage was found to decrease the current hysteresis possibly due to formation of sodium compounds such as carbonates or oxides that populate the three-phase-boundary (tpb) active sites, thus deactivating the catalyst.