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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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Microplastics and nanoplastics: Recent literature studies and patents on their removal from aqueous environment

2022-03-01 , Muhammad Adli Hanif , Naimah Ibrahim , Farrah Aini Dahalan , Umi Fazara Md Ali , Masitah Hasan , Jalil A.A.

The presence of microplastics (MP) and nanoplastics (NP) in the environment poses significant hazards towards microorganisms, humans, animals and plants. This paper is focused on recent literature studies and patents discussing the removal process of these plastic pollutants. Microplastics and nanoplastics can be quantified by counting, weighing, absorbance and turbidity and can be further analyzed using scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, surface-enhanced Raman spectroscopy and Raman tweezers. Mitigation methods reported are categorized depending on the removal characteristics: (i) Filtration and separation method: Filtration and separation, electrospun nanofiber membrane, constructed wetlands; (ii) Capture and surface attachment method: coagulation, flocculation and sedimentation (CFS), electrocoagulation, adsorption, magnetization, micromachines, superhydrophobic materials and microorganism aggregation; and (iii) Degradation method: photocatalytic degradation, microorganism degradation and thermal degradation; where removal efficiency between 58 and 100% were reported. As these methods are significantly distinctive, the parameters which affect the MP/NP removal performance e.g., pH, type of plastics, presence of interfering chemicals or ions, surface charges etc. are also discussed. 42 granted international patents related to microplastics and nanoplastics removal are also reviewed where the majority of these patents are focused on separation or filtration devices. These devices are efficient for microplastics up to 20 μm but may be ineffective for nanoplastics or fibrous plastics. Several patents were found to focus on methods similar to literature studies e.g., magnetization, CFS, biofilm and microorganism aggregation; with the addition of another method: thermal degradation.

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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 , Muhammad Adli Hanif , 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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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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Advancement in recycling waste tire activated carbon to potential adsorbents

2022-12-01 , Umi Fazara Md Ali , Hussin F. , Subash Chandra Bose Gopinath , Aroua M.K. , Khamidun M.H. , Jusoh N. , Naimah Ibrahim , Syahirah Faraheen Kabir Ahmad

Waste tires have been identified as one of the contributors to environmental problems and the issue of inadequate landfill spaces. The lack of consistent and systematic approaches such as specific regulations/laws or mechanisms of waste management to waste tires, limited application of technology for recycling waste tires and lack of awareness on the impacts of waste tires problem, make waste tires a source of environmental pollution. Various researches have been conducted on recycling waste tires into polymer bends, and materials to harden concretes, fuels and adsorbent. Researchers suggested that pyrolysis is the current trend of recycling waste tire to harvest the saleable pyrolysis oil and the recycled carbon black. Therefore, this review attempts to compile relevant knowledge about the potential of adsorbent derived from waste tires to be applied in the removal of various types of pollutants like heavy metals, organic pollutants, dye and air/gaseous pollutant. Studies were carried out on revealing the properties and the characteristics of activated carbon derived from waste tire as effective adsorbent which influence the application performance at liquid or gas phase. In addition, the challenges in the production of activated carbon derived from waste tire were discussed.

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EVALUATION OF PHENOL FORMALDEHYDE RESIN SYNTHESIZED FROM SUGARCANE BAGASSE BIO-OIL UNDER OPTIMIZED PARAMETERS

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

Bio-oil from biomass is considered as a potential substitute to partially replace phenol in the preparation of phenol formaldehyde resin as replacement to the commercial phenol which high in cost. However, the percentages of bio-oil substitutions need to be determined to ensure that the performance is good as the commercial ones. The aim of this research is to identify the optimum conditions for synthesizing phenol formaldehyde resin (PF) and determines the percentages of bio-oil substitutions by manipulating the synthesizing variables such as formaldehyde to phenol (F/P) catalyst ratio (NaOH/P), catalyst ratio and duration using one-factor-at-time method. The effect of each manipulated variables on shear strength was compared to the Chinese National Standard for PF resin shear strength. Bio-based phenolic resins are synthesized using the optimum conditions by replacing 10, 20, 30 and 40% of phenol with bio-oil from the pyrolysis of sugarcane bagasse. The results obtained shown that the optimum conditions to synthesize phenol formaldehyde resin is at F/P molar ratio of 2.0, catalyst ratio of 0.6 and duration of 3 hour. The results of bio-based phenolic resins bonding performance shows that substitution percentage of bio-oil up to 20% at most gives good performance compared to the pure PF resin.

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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.