Razi Ahmad
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Preferred name
Razi Ahmad
Official Name
Razi, Ahmad
Alternative Name
Ahmad, Razi
Ahmad, R. B.
Ahmad, R.
Ahmad, R. Badlishah
Main Affiliation
Scopus Author ID
54419444500
Researcher ID
B-9254-2012

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  • Publication
    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.
  • Publication
    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.
  • Publication
    Potential of pretreated palm kernel shell on pyrolysis
    ( 2023-01-01)
    Razi Ahmad
    ;
    Ragunathan Al Santiagoo
    ;
    Abdul Ghapar Ahmad
    ;
    Syakirah Afiza Mohammed
    ;
    Wan Ahmad W.A.M.
    ;
    Vikneswaran Vijean
    ;
    Ibrahim N.R.
    The impact of pretreatment on palm kernel shell (PKS) with torrefaction for the possibility of pyrolysis is discussed in this study. PKS samples were torrefied at different holding times of 30 and 60 minutes at temperatures of 200, 225, 250, 275, and 300 °C. In a fixed-bed reactor with a constant nitrogen flow rate of 500 ml/min, torrefaction pretreatment was carried out. The elemental composition, mass, and energy yield, as well as proximate analysis, were all performed on the pretreated PKS. The optimised pretreated PKS was pyrolyzed next at a temperature of 400 to 550 °C in a fixed-bed reactor. The outcomes demonstrated that the pretreated PKS had a significant mass and energy yield at a temperature of 250 °C and a holding time of 30 min. PKS's calorific value and carbon content both rose after pretreatment. However, the oxygen and moisture content decreased for pretreated PKS. The maximum bio-oil production of 58% was achieved during the pyrolysis of pretreated PKS at a temperature of 500 °C. At higher temperature of 550 ℃, the bio-oil decreased due to secondary cracking reaction. Consequently, the pretreated PKS has greater potential as effective feedstock for successive proses particularly pyrolysis for bio-oil production.
  • Publication
    Effect on product Yield and Tar composition through co-gasification of pretreated palm kernel shell and Mukah Balingian coal
    (IOP Publishing, 2020)
    Razi Ahmad
    ;
    Mohd Azlan Mohd Ishak
    ;
    Nur Nasulhah Kasim
    ;
    Khudzir Ismail
    In this study, co-gasification of palm kernel shell (PKS) and Mukah Balingian (MB) coal was carried out in a fixed bed reactor. The effect of sample pretreatment of both samples were explored via co-gasification towards product yields and tar composition. Results indicated that, pretreated blending samples produced higher gas yield with lower tar and char yield than the untreated blending samples. This was due to low moisture and oxygenated components of the pretreated samples prior to co-gasification. The tar composition of the pretreated blending samples showed increasing in the aromatic and aliphatic alkane, whereas, noticeable decreasing of phenol and carbonyl. Thus, pretreated of PKS and MB coal have prominence influence on the distribution of product yields and tar composition through co-gasification.
  • Publication
    Torrefaction of palm kernel shell using conventional and microwave irradiation pretreatment
    (IOP Publishing, 2020)
    Razi Ahmad
    ;
    M A M Ishak
    ;
    N N Kasim
    ;
    K Ismail
    This study describes the properties of torrefied palm kernel shell (PKS) by conventional and microwave irradiation (MI) pretreatment. In conventional pretreatment, the untreated PKS was torrefied using fixed bed reactor at temperature of 210, 230, 250, 270 and 290 °C for 60 min of holding time. In MI pretreatment, the untreated PKS was irradiated with microwave power of 200, 300, 450 and 600 W for 8 min of holding time. The torrefied samples were analysed for mass and energy yield, energy density, calorific value and proximate and ultimate analysis. The results showed that, the properties of torrefied samples were improved with increasing torrefaction temperature and microwave power. The mass and energy yield, moisture, volatile matter and oxygen content of torrefied PKS decreased, whereas, the calorific value, energy density and carbon content increased with increasing torrefaction temperature and microwave power. The torrefaction temperature of 270 °C and microwave power of 450 W were appropriate to upgrade the PKS properties. Therefore, the change in properties of torrefied PKS revealed the potential of applying pretreatment prior to further thermal conversion such as pyrolysis and gasification.
  • Publication
    A review on enhancement of oil palm solid waste through torrefaction
    (Springer, 2023-09)
    Nur Rahimah Ibrahim
    ;
    Razi Ahmad
    ;
    Mohd Azlan Mohd Ishak
    Biomass is one of the renewable energy sources and is easily obtained in Malaysia. Due to the substantial amount of biomass waste generated by agricultural activities, Malaysia actually has great potential for biomass power generation. The oil palm industry is the largest contributor to biomass waste in Malaysia, particularly oil palm solid waste. The raw oil palm solid waste produced low-quality products during thermochemical conversion. Thus, the torrefaction process is one of the approaches to improve the characteristics of raw oil palm solid waste. Therefore, the objectives of this study are to review the production and characteristics of solid biofuel from oil palm solid waste via the torrefaction process. Torrefaction is a thermal conversion method of biomass in the low-temperature range of 200–300 °C. Different reaction conditions such as temperature and reaction time lead to several characteristics of biofuel products. The solid fuel of pretreated oil palm solid waste has enhanced overall quality and its characteristics after torrefaction.
  • Publication
    Optimization studies of coal organic sulfur removal using Potassium Carbonate and Ethylene Glycol as a deep eutectic solvent
    (Malaysian Institute of Chemistry (Institut Kimia Malaysia), 2023-06-29)
    Syarifah Nursyimi Azlina Syed Ismail
    ;
    Mohd Azlan Mohd Ishak
    ;
    Khudzir Ismail
    ;
    Wan Izhan Nawawi
    ;
    Nur Nasulhah Kasim
    ;
    Asnida Yanti Ani
    ;
    Azil Bahari Alias
    ;
    Razi Ahmad
    Combustion of coal emits sulfur dioxide gas into the atmosphere. When reacting with water vapour, this gas produces sulfuric acid, also known as acid rain, causing environmental destruction, and endangering human health. One option to address these issues is to remove the sulfur from coal before combustion. Physical and chemical pre-treatments using oxidizing or reducing agents easily remove inorganic sulfur from coal, namely pyrite and sulfate sulfur. However, organic sulfur is hard to remove unless a particular reagent is applied to break the carbon-sulfur bonds to release the sulfur from the coal matrix. This study reports the utilization of a mixture of potassium carbonate and ethylene glycol (K2CO3:EG) under sonication to extract organic sulfur from coal. The ultrasonic shockwave separates sulfur from the coal's macromolecular structure by breaking the chemical connections that hold sulfur to coal. CCD-RSM experimental design was presented to overcome traditional methods that make finding the optimal standard difficult and time-consuming. The effects of molar ratio, temperature, and extraction time on the removal of organic sulfur in coal were investigated, and sonicating coal at 40 °C for 60 minutes with 1:16 K2CO3:EG was found to be the ideal parameter. The changes to the thiophene and organic sulfate FTIR peaks may serve as a preliminary measure of the effectiveness of K2CO3:EG in coal desulfurization. This research shows that solvent-pre-treated coal may be safe and environmentally advantageous, two goals of the 2030 Agenda for Sustainable Development.
  • Publication
    Desulfurization and optimization of high sulfur Jambi province coal by ultrasonic-assisted process using Peroxyacetic Acid (PAA) treatment
    (Semarak Ilmu Publishing, 2025-06)
    Razi Ahmad
    ;
    Nurul Fatihah Nazua
    ;
    Syarifah Nursyimi Azlina Syed Ismail
    ;
    Mohd Fauzi Abdullah
    ;
    Mohd Azlan Mohd Ishak
    ;
    Wan Izhan Nawawi Wan Ismail
    ;
    Khudzir Ismail
    ;
    Muslim Darbi Abdulrrahman
    The desulfurization process of high-sulfur coal from Jambi Province, Indonesia was investigated using peroxyacetic acid (PAA) as mild oxidising agent by ultrasonic wave. This study reports the utilization of a mixture of acetic acid and 6% hydrogen peroxide (CH3COOH: H2COOH) under sonication to extract organic sulfur from coal. The ultrasonic shockwave separates sulfur from the coal's macromolecular structure by breaking the chemical connections that hold sulfur to coal. The optimum concentration, temperature, and processing time for the coal desulfurization process were determined using the Central Composite Design-Response Surface Methodology (CCD-RSM) to overcome the traditional methods that make finding the optimal standard difficult and time-consuming. Sonicating coal at 30 ËšC for 30 minutes with 70:30 (CH3COOH: H2COOH) was found to be the ideal parameter. Results shows that all inorganic and some of the organic sulfur could be removed from the coal using mild conditions without severely affecting the coal microstructure as observed in the FESEM-EDX. Through the FTIR analysis, the organic sulfur structural parameters show the relative abundance of aliphatic sulfur (thiol, thiophene and sulfone) and organic matters in these coals decreased after the coal treated by PAA.To clarify its chemical effect, the production regularities of hydroxyl radical under ultrasonic field was determined using the iodine release method. Experimental results also showed that the production rule of hydroxyl radical was consistent with the desulfurization degree. These findings confirmed that the synergistic action of physical and chemical effects of the ultrasonic played an important role in this desulfurization process, which could serve as a reference for further optimizing the coal desulfurization process.
  • Publication
    The direct and catalytic pyrolysis of rice straw
    ( 2010)
    Razi Ahmad
    A study of the catalytic pyrolysis on rice straw was carried out in a fixed-bed reactor. The work objectives were to determine the influences of pyrolysis parameters i.e pyrolysis temperature, heating rate and holding time on distribution of product yield. The optimization process was analyzed by employing central composite rotatable design (CCRD) in response surface methodology (RSM). The catalysts used in this research were zeolite ZSM-5 and dolomite. The catalytic pyrolysis was carried out based on optimized condition of bio-oil yield. The characterization of pyrolysis product between non-catalytic and catalytic pyrolysis were investigated, by elemental, spectroscopic and chromatographic techniques. The char yield produced from pyrolysis process was high at low heating rates, while the gas yield produced was high at higher temperature and longer holding time. The experimental value of the optimum bio-oil yield was 27.62% as compared to the predicted value which bio-oil yield was 27.87% at pyrolysis temperature of 450 oC, heating rate of 77.63 oC/min and holding time of 2.61 min by using optimization process in the Design Expert (DOE) software. The chemical characterization studies of uncatalysed bio-oil derived from pyrolysis of rice straw contained considerable amounts of carbonyl and oxygenated compound, resulting in higher oxygen content in elemental composition and low pH value. Used of zeolites ZSM-5 and dolomite caused an increase in gas yields and a decrease in bio-oil yields. The product yields and the quality of the produced bio-oil were affected by the used of catalyst. The major improvement in the quality of liquid product with the use of catalyst was the increase of phenol concentration (useful chemicals) and the reduction of some corrosive acids which are undesirable compound in bio-oil. Dolomite catalyst having the most impacts than zeolite ZSM-5 in removing some of aldehyde and ketone compounds which are responsible for the thermal or storage stability. The influence of the zeolite ZSM-5 and dolomite catalyst used in this study caused only enhancement of liquid production in terms of quality but not the bio-oil produced.
      2  29
  • Publication
    Electro-oxidation as Tertiary Treatment Techniques for Removal of Palm Oil Mill Effluent
    ( 2020-07-09)
    Che Zulzikrami Azner Abidin
    ;
    Fahmi Muhammad Ridwan
    ;
    Abdul Haqi Ibrahim
    ;
    Nazerry Rosmady Rahmat
    ;
    Farah Mohamed Hussein N.
    ;
    Razi Ahmad
    The production of palm oil, though, results in the generation of huge quantities of polluted wastewater normally referred as palm oil mill effluent (POME). It gives adverse impacts to the environment, particularly if it is not properly treated. POME are known to have various types of liquids, residual oil and suspended solid as it has very high strength waste in its untreated form. Although conventional biological processes are normally efficient for the degradation of pollutants occurring in wastewater, most of these compounds are not effectively removed. As a result, further treatment is needed to meet more stringent discharge standards of Department of Environment (DOE), Malaysia. This research focused on treatment of POME by using electro-oxidation process (EO). It was done to identify the performance of EO process for colour, chemical oxygen demand (COD), suspended solids (SS), and Ammoniacal-nitrogen NH3-N) removal as well as the relative effects of different operational parameters such as pH, type of electrodes and contact time. The pH was varied between 3 and 11, using Ferum (Fe) and Aluminium (Al) electrode, and contact time from 0 to 120 min. The most suitable pH, contact time and type of electrode were pH 3, 120 min and Aluminium electrode, respectively. Therefore, EO process at specified level can be used as an efficient and effective post-treatment technology to meet the standard regulatory requirements.
      5  34