Malaysian Journal of Chemical Engineering and Technology
The Malaysian Journal of Chemical Engineering and Technology (MJCET) (e-ISSN: 2682 8588) is a peer-reviewed research article from various fields published semi-annually in an open-access international refereed journal. MJCET will be accepting research papers in the fields of chemical engineering. Publication is free of charge. MJCET has been recently indexed in MyCite starting from the volume and issues of 2023 onwards. CLICK HERE TO SUBMIT MANUSCRIPT
Effect of Drying Temperature on Synthesised Zinc Oxide Microparticles from Mango Seed Extract
Zinc oxide (ZnO) is known for its antimicrobial activity, UV protection, and applications in environmental fields. However, the green synthesis of ZnO is often affected by processing conditions, especially drying temperature. This study investigates the effect of drying temperatures at 60, 70, and 80 °C on ZnO synthesis using mango seed extract (MSE) as a natural reducing agent. Zinc acetate dihydrate (ZA) and zinc nitrate hexahydrate (ZN) were used as precursors to supply Zn²⁺ ions during synthesis. ZA samples produced higher extraction yields, with a maximum of 37.80% at 60 °C. All ZN samples powders appeared finer and brighter in colour. SEM images showed that ZA samples formed larger rod-like agglomerates, while ZN samples produced more uniform and less clustered particles with spherical or flower-like shapes. EDX confirmed the presence of only zinc and oxygen, with ZN samples showing more consistent Zn to O ratios across all temperatures. Zeta potential analysis indicated that ZN samples had more stable negative surface charges ranging from −22 to −25 mV. In contrast, ZA sample showed fluctuating values with a strong positive charge at 80 °C. Particle size analysis showed that ZN sample at 70 °C had the smallest and most uniform size of 1.454 µm, while ZA sample at 70 °C showed the largest particles. XRD confirmed that all samples followed the wurtzite crystal structure. Crystallite size increased with temperature in ZA samples but decreased slightly in ZN samples. FTIR analysis confirmed Zn–O stretching and showed fewer organic residues in ZN samples. UV-Vis results indicated that ZA had consistent absorption peaks and band gap values between 4.53 and 4.61 eV. ZN showed a strong band gap of 4.54 eV at 60 °C but dropped significantly at higher temperatures. Overall, ZN at 70 °C produced ZnO with the best morphology and surface stability, while ZA at 70 °C showed better optical performance and consistent band gap behaviour.
Copyright (c) 2025 Nurainul Kamalia Iskandar Hussein, Rabiatul Adawiyah Abdol Aziz, Siti Fatma Abd Karim, Ummi Kalthum Ibrahim https://creativecommons.org/licenses/by-sa/4.0
Characterization of the chemical composition of extracted oil palm frond (OPF) fibres using TAPPI standard methods and Wise’s method
Malaysia is the second largest exporter of oil palm, with over 5 million hectares of plantations that produce a large amount of waste materials like palm oil mill waste, empty fruit bunches, fronds, trunks, shells and fibres. Extracting cellulose fibres (CFs) from oil palm fronds (OPF) waste is a smart strategy in managing oil palm plantation waste. Therefore, this study was aimed to extract OPF fibres and determine the actual percentage weight content of the cellulose, hemicellulose and lignin from the extracted OPF fibres. The first part of the study is to extract OPF fibres from Malaysia OPF using direct chemical method. A mixture of 3.2 mol/L nitric acid and 60 mmol/g hydrogen peroxide was used to break down the complex structure of OPF at temperature of 50 °C for 48 h. Meanwhile, in the second part of the study, the percentage weight of the lignin, hemicellulose and cellulose in the extracted OPF were determined using the TAPPI 222, Wise’s Method and TAPPI 203 respectively. Additionally, Fourier Transform Infrared Spectroscopy (FTIR) analysis was conducted to characterize and identify the functional groups present in the extracted OPF fibres. The yield of successful extracted OPF fibres using direct chemical treatment is 51.3 ± 0.7%. Meanwhile, the analysis result shows that the extracted OPF fibres contained 7 ± 0.5 wt% of lignin, 32 ± 4.1 wt% of hemicellulose and 37 ± 4.5 wt% of cellulose. The actual content of lignin, hemicellulose and cellulose in the extracted OPF fibres is useful to guide for suitable commercial sustainable applications based on the required strength.
Copyright (c) 2025 Nur Ain Razak , Suffiyana Akhbar, Sakinah Mohd Alauddin https://creativecommons.org/licenses/by-sa/4.0
Comparative Study on Natural Insect Repellent Properties of Euphorbia hirta and Plectranthus amboinicus
Growing concern over the health and environmental risks of synthetic repellents like DEET and permethrin has spurred interest in natural, plant-based alternatives. Although many plants have long been used in Malaysia for traditional medicine and pest control, scientific evidence of their repellent potential remains limited. Therefore, this study aims to (1) evaluate the insect repellent efficiency of Euphorbia hirta (E. hirta) and Plectranthus amboinicus (P. amboinicus) against hematophagous insects, ants and (2) characterise the bioactive compounds responsible for their repellent properties. The active compounds of phenolic, terpenoids, thymol, and carvacrol from the plants were extracted using ethanol via Soxhlet extraction and concentrated using a rotary evaporator. Repellence tests were conducted at a 10% concentration, with formulations prepared based on terpenoid-to-phenolic ratios of 3:2, 1:1, and 2:3. Results revealed that P. amboinicus contained high levels of thymol (41.9%) and carvacrol (28.5%), while E. hirta showed notable amounts of quercetin (4.5%) and kaempferol (3.2%). P. amboinicus exhibited stronger repellence against ants at higher terpenoid-to-phenolic ratio of 3:2, whereas E. hirta demonstrated effective repellence even at lower ratio of 1:1, with minimal ant attraction. Overall, both plants showed promising insect repellent activity, with P. amboinicus being more effective at higher concentrations. These findings emphasise the attractiveness of plant-based repellents as sustainable pest control solutions, reducing reliance on synthetic chemicals and promoting eco-friendly practice.
Copyright (c) 2025 Hanis Nur Nabilah Hazri, Arbanah Muhammad, Nur Hazirah Rozali Annuar, Siti Rahika Abdul Halim https://creativecommons.org/licenses/by-sa/4.0
A Study on the Effectiveness of Eggshell as an Abrasive Agent in Toothpaste
Growing concerns about the safety of synthetic ingredients in dental products have led to the search for natural alternatives. This study explores the potential of using eggshell as a calcium-rich byproduct of the food industry as a sustainable toothpaste ingredient. Eggshell powder, with its high content of calcium carbonate, was used in addition to a toothpaste base and its physicochemical properties were analysed using FTIR, XRD, and XRF. The formulated toothpaste was then tested for % calcium content, pH, foaming ability, and abrasiveness, with results compared to a commercial toothpaste. The eggshell-based toothpaste had 93.51 % calcium, a slightly alkaline pH of 8.05 and produced 14 mL of foam. The value was roughly 16.7 % more than that produced by the commercial one, which was 12 mL. Its moderate abrasiveness mimics the cleaning performance of conventional formulations, which suggests safe and effective cleaning performance. These results demonstrate that the eggshell powder can be used as a viable and eco-friendly alternative to synthetic fillers in toothpaste that would have functional properties while helping to reduce waste from the food industry.
Copyright (c) 2025 Nur Azurah Zuraikha Mohd Zulkarnain, Harumi Veny, Farah Hanim Ab Hamid, Rozana Azrina Sazali, Sri Rizki Putri Primandani, Zulkifli Abd Rashid, Azil Bahari Alias https://creativecommons.org/licenses/by-sa/4.0
A qualitative risk assessment for ammonium nitrate facilities: Correlating to historical data
The commercial fertiliser industry produces five primary chemicals which include phosphate, ammonia, urea, ammonium nitrate (AN), and nitric acid. The AN is widely used in agriculture but has been associated with numerous accidents due to inadequate post-accident investigations and management. A qualitative risk assessment is crucial for identifying and managing risks in such hazardous industries. This research demonstrates the application of a Process Hazard Analysis (PHA) method, specifically the Hazard and Operability Study (HAZOP), using Microsoft Excel. This research analyses AN manufacturing process facility located in the United States (US) as the US is a major global producer and consumer of AN and plays a significant role in the fertiliser and industrial explosives supply chain. The selected study nodes include raw material production unit, the product processing neutraliser, and AN storage unit. The key elements of the HAZOP study, including guide words, process parameters, causes, consequences, safeguards, risk ratings, and recommendations, were documented in Microsoft Excel. A total of eighteen deviations were identified, with the highest overall risk associated with the product processing neutraliser. In the manuscript, further discussion is focused primarily on the neutraliser, as it was identified as the highest risk. Historical accident data showed that the transportation unit had the highest accident frequency, alongside storage and manufacturing. The HAZOP methodology proved effective for identifying potential hazards and improving safety in AN facility. This approach allows the process safety management team to proactively address operational problems and enhance overall industry safety.
Copyright (c) 2025 Mimi Nur Farrahida Ahmad Sabri, Rafeqah Raslan https://creativecommons.org/licenses/by-sa/4.0
Sensitivity Analysis of Reaction Kinetics in Saponification of Ethyl Acetate and Sodium Hydroxide in Continuous Stirred Tank Reactor (CSTR)
Continuous stirred-tank reactors (CSTRs) are integral to industrial chemical processes due to their uniform mixing and steady-state operation. The saponification of ethyl acetate with sodium hydroxide is a widely used model reaction for studying kinetics in CSTRs. Understanding the sensitivity of reaction kinetics to operating conditions is critical for enhancing reactor performance, ensuring consistent product quality, and minimizing inefficiencies. Reaction kinetics in a CSTR are influenced by reactant concentrations, temperature, and flow rate. Misidentifying or poorly optimizing these parameters can result in suboptimal performance and reduced conversion efficiency, posing challenges for industrial applications. This study conducts a detailed sensitivity analysis to identify the key parameters influencing the saponification reaction in a CSTR. It quantifies how variations in these parameters affect conversion efficiency and overall reaction performance, providing actionable insights for process optimisation. A reaction kinetics model was selected and validated using robust pilot-plant experimental data. Parameters, including reactor temperature, were systematically analysed through numerical simulations to assess their sensitivity and impact on system performance. The validated model demonstrated strong agreement with experimental results, yielding RMSE values ranging from 0.0007 to 0.0013 and R² values between 0.9996 and 0.9999 across 30, 40, 50, and 60 °C. Maximum deviation remained below 0.6 %, highlighting the model’s predictive accuracy and industrial applicability. Sensitivity analysis showed the greatest marginal benefit between 30 and 40 °C, with a peak sensitivity ratio of 0.00072, indicating that small temperature adjustments in this range have the greatest impact on the final conversion of ethyl acetate. This study sets itself apart from classical saponification research by integrating pilot-plant data with MATLAB-based analysis, offering a validated dataset and a meaningful contribution to chemical reaction engineering.
Copyright (c) 2025 Sherif Abdulbari Ali, Nur Hannani Mohamad Azehar https://creativecommons.org/licenses/by-sa/4.0
Formulation of Polymer Composite from Starch/PVA and Crosslinking with Silica from Rice Husk Ash for Polymer Flooding
This research project focuses on the creation of a polymer composite by combining potato starch, polyvinyl alcohol (PVA), and silica from rice husk ash (RHA) for polymer flooding in enhanced oil recovery (EOR). This study aims to overcome the limitations of the polymer use for EOR, such as polymer degradation, shear-thinning behaviour, and viscosity control of the polymer. The polymer blend of starch/PVA was crosslinked with silica from RHA, which is expected to enhance the shear-thinning behaviour and control the viscosity of polymer solutions. The investigation involves varying silica concentration to observe its impact on shear rate and viscosity. The methodology includes the extraction of silica from rice husk and the preparation of the polymer composite solution, followed by characterisation of the polymer using Fourier Transform Infrared Analysis and viscosity analysis. The polymer composite was expected to withstand the harsh conditions in the reservoir, which can help to enhance the oil recovery. The polymer composites showed stability in viscosity as the temperature rose, indicating high thermal stability, with no effects from the salinity in 2.5% and 5% saline concentration. In conclusion, the presence of silica, particularly 3%, can improve the rheological properties of biopolymer solutions, making them more stable under reservoir conditions such as high salinity and temperature.
Copyright (c) 2025 Muhammad Afiq Iqmal Mohd Yunan, Norin Zamiah Kassim Shaari https://creativecommons.org/licenses/by-sa/4.0
HF-free dry gel synthesis of MIL-100(Fe) for adsorptive removal of salicylic acid in wastewater treatment
This study reports an HF-free dry-gel conversion route to synthesise MIL-100(Fe) and evaluate its performance for adsorptive removal of salicylic acid from wastewater. Comprehensive characterisation of the material was conducted using XRD, FT-IR, FESEM and zeta potential. The dry gel conversion method successfully produced MIL-100(Fe) with an amorphous structure with an average particle size of 27 μm. Adsorption experiments achieved a maximum salicylic acid removal efficiency of 82.62% across the tested range (10 to 50 µg/mL), corresponding to an adsorption capacity of 80.93 mg/g at 120 minutes. Significant reductions in FT-IR peaks associated with carboxylic acid O–H stretching vibrations were observed, particularly in regions 3600 to 4000 cm−1 and 2500 to 3600 cm−1. These changes indicate strong interactions between the carboxyl groups of salicylic acid and the active sites on the MIL-100(Fe) surface, confirming effective adsorption and removal of salicylic acid. These findings demonstrate that MIL-100(Fe) synthesised through a hydrofluoric acid-free dry gel conversion route is an effective and environmentally benign adsorbent for the removal of pharmaceutical pollutants from wastewater.
Copyright (c) 2025 Wan Nuraishah Wan Ishak, Nurul Syafiqah Mohd Sabri, Ying Pei Lim, Huey Ling Tan https://creativecommons.org/licenses/by-sa/4.0
Preliminary GC-MS Profiling of Bioactive Compounds in Muntingia calabura from the Rural Area of Bukit Besi
Muntingia calabura is a medicinal plant commonly found along roadsides in Malaysia and is traditionally believed to possess various therapeutic activities. Although it has been widely utilised in traditional medicine and several pharmacological properties have been reported, most studies have relied on crude extracts without detailed characterisation of the bioactive constituents. Therefore, the present study aimed to identify the bioactive compounds in the fruit, leaves, and stem bark using Gas Chromatography-Mass Spectroscopy (GC-MS). Each part of the plant was extracted using the Soxhlet technique and hexane and petroleum ether as a solvent. GC-MS analysis revealed seven (7) compounds using petroleum ether and ten (10) compounds in hexane extract in fruit parts; ten (10) compounds in petroleum ether and seventeen (17) compounds using hexane in leaf parts; and ten (10) compounds in petroleum ether and fifteen (15) compounds using hexane in stem bark parts. The prime compound found in fruit is 2-Methyl-Z, Z-3,13-octadecadienol (64.27%) using petroleum ether, while it is L-(+)-Ascorbic acid 2,6-dihexadecanoate (29.95%) when using hexane. For leaves, both solvents showed a similar most extracted compound, which is 9-Octadecenoic acid, 1,2,3-propanetriyl ester (42.29% with petroleum ether and 25.34% with hexane). In stem bark, the most extracted compound is 2-Methyl-Z, Z-3,13-octadecadienol (29.88%) (fatty alcohol) for petroleum ether, while for hexane extract, it is 2H-1-Benzopyran-6-ol,3,4-Dihydro-2,5,7,8-Tetramethyl-2-(4,8,12-Trimethyl Tridecyl) (31.88%). These findings indicate the diverse bioactive compound was found in different parts of Muntingia calabura, emphasising the need for further pharmacological and biological studies to validate its therapeutic claim.
Copyright (c) 2025 Nur Syukriah Ab Rahman, Muhammad Hazim Ahmad, Qistina Liyana Othman, Nur Hanisah Mohamad Nizam, Nurizzati Mohd Daud https://creativecommons.org/licenses/by-sa/4.0
Valorisation of Waste Glass in Eco-friendly Clay Brick: Influence on Physico-mechanical Properties and Water Absorption
Clay bricks are widely used as building material all around the world. Natural clay is experiencing a constant reduction due to its continual use in the manufacturing of clay bricks. The depletion of clay resources has become a global issue, prompting many countries to limit the use of natural clay. This research study investigates the effect of waste glass addition on the physical-mechanical and water absorption properties of eco-friendly clay bricks, incorporating 0, 5, 10, 15, and 20 wt% of waste glass into the clay. The temperature of 900 °C was used for the firing process of clay bricks. Compressive strength, linear shrinkage, bulk density, apparent porosity and water absorption of the eco-friendly clay bricks were tested. Incorporating 20 wt% waste glass into clay bricks improved mechanical and physical properties: compressive strength (+29.4%), bulk density (+11.3%), apparent porosity (−16.0%), and water absorption (−24.6%). The digital micrographs demonstrated a reduction in the porosity with the addition of waste glass. This study revealed that the addition of waste glass induced the formation of a glass-phase fused bond with the body of clay when subjected to high temperature. Waste glass can be added to clay brick as a partial substitute for natural clay, improving the physical-mechanical and water absorption properties of clay bricks.
Copyright (c) 2025 Kai Ying Chew , Mohd Fadhil Majnis, Mustaffa Ali Azhar Taib , Ayu Haslija Abu Bakar, Maliza Ismail Jamail https://creativecommons.org/licenses/by-sa/4.0
Synergistic effects of ultrasonic irradiation and PEG demulsifiers on oil-in-water emulsion separation
A crude oil exporter like Malaysia continues to face challenges related to oil-in-water (O/W) emulsions. These emulsions are typically generated during extraction and transportation processes, leading to difficulties in effective separation. This study investigates the synergistic effects of ultrasonic irradiation and polyethylene glycol (PEG) 1500 demulsifiers on the separation efficiency of model diesel-based O/W emulsions. The emulsions were prepared using Tween 60 as a stabiliser, followed by treatments involving PEG 1500 and varying ultrasonic exposure for 5, 10, 30, and 60 s. A series of bottle tests and particle size analyses were conducted to evaluate demulsification performance and droplet size distribution. The findings revealed that the combination of ultrasonic treatment and PEG 1500 effectively enhanced emulsion destabilisation compared to chemical treatment alone. The optimal demulsification efficiency was achieved at 10 s of ultrasonic exposure (Sample D), which produced the highest oil separation percentage and the most balanced phase separation. However, prolonged irradiation beyond 30 s led to over-dispersion, droplet fragmentation, and re-emulsification thereby reducing separation efficiency. The present particle size distribution results supported these finding where excessive ultrasonic irradiation yielded smaller and overly stable droplets resistant to coalescence.
Copyright (c) 2025 Nur Ainin Sofiya Mat Yajid, Muhammad Shafiq Mat Shayuti, Siti Aisyah Ghazali, Tengku Amran Tengku Mohd, Azzah Nazihah Che Abdul Rahim, Suriatie Mat Yusuf https://creativecommons.org/licenses/by-sa/4.0
Formulation and Evaluation of Natural Lip Balm: Exploring the Synergistic Benefits of Beetroot and Kaempferia galanga Linn
Growing consumer concern over synthetic additives has intensified interest in plant-based lip care. This study formulated and evaluated a dual-extract lip balm using beetroo (Beta vulgaris) pigment and Kaempferia galanga Linn (KGL) essential oil as natural colourant and bioactive agents. Twenty-two formulations were prepared from coconut oil, beeswax, and candelilla wax, with varying beetroot:KGL ratios (0.5–2.5 g). Each formulation was assessed for pH (n=3), melting point, greasiness index, surface homogeneity, and accelerated colour stability (30 days at 40 °C/75 % RH and 4 °C). Among all tested formulations, F7 exhibited the most favourable balance of non-greasy texture, stable pH, and good melting point, supporting its potential as a safe and natural cosmetic alternative.
Copyright (c) 2025 Nurhaslina Che Radzi, Afiqah Dayana Ahmad Kamarul https://creativecommons.org/licenses/by-sa/4.0
Effect of Salinity and Alkalinity on Dynamic Adsorption of Anionic Surfactant and Oil Recovery in Alkaline-surfactant-polymer Flooding using a Sand Pack Model
Alkaline-surfactant-polymer (ASP) flooding is a widely used enhanced oil recovery (EOR) method, but it has reliability issues, particularly surfactant adsorption that reduces efficiency. Surfactant adsorption becomes complex in the presence of alkaline and polymer, which exhibit uncertain behaviour at varying salinity and alkalinity. This study investigates the impact of brine and alkaline concentrations on the adsorption of anionic surfactant and the corresponding oil recovery in ASP flooding. The ASP formulation consisted of 2,000 ppm sodium dodecyl sulphate (SDS), 500 ppm partially hydrolysed polyacrylamide (HPAM) and 10,000 to 30,000 ppm sodium carbonate (Na2CO3) as the surfactant, polymer and alkaline, respectively. Sodium chloride (NaCl) was prepared at concentration 10,000 to 30,000 ppm to investigate the effect of salinity. Quartz sand (150 to 250 μm) was packed into a sand pack model for dynamic adsorption and oil recovery tests. The critical micelle concentration (CMC) of SDS was determined to be 2,200 ppm using the Du Noüy ring method. Adsorption was measured using a UV-Vis spectrophotometer. In dynamic adsorption, as salinity increases from 10,000 ppm to 30,000 ppm, surfactant adsorption increases as much as 10% from 0.69 mg/g to 0.76 mg/g. Meanwhile, surfactant adsorption decreases as much as 22% from 0.69 mg/g to 0.54 mg/g with increasing alkalinity from 10,000 to 30,000 ppm, respectively. The highest oil recovery of 75% original oil in place (OOIP) was achieved at 10,000 ppm brine and 30,000 ppm alkaline, which also exhibited the lowest adsorption. In conclusion, alkaline concentration has been the most determining factor, which has significant impact in minimising the surfactant adsorption, while enhancing the oil recovery in ASP flooding.
Copyright (c) 2025 Nur Sarah Mohd Noor, TENGKU AMRAN TENGKU MOHD, Mohd Zaidi Jaafar https://creativecommons.org/licenses/by-sa/4.0
Physical, Thermal and Microstructural Effect of CO2 in Carbonic Acid on Mortar
Existing studies have shown current methods of carbon dioxide infusion are limited to slow carbonation rates and lack of carbon dioxide penetration. This study aims to tackle these problems by proposing a new method of infusion by adding carbon dioxide via liquid directly during mixing process. This study also investigates the thermophysical behaviour of mortar subjected to liquid-phase CO₂ infusion, focusing on its effects on mechanical strength, hydration, and carbonation processes. Mortar specimens were prepared and infused with carbonic acid during mixing, followed by compressive strength testing, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results indicate that liquid-phase CO₂ infusion increases calcium carbonate (CaCO₃) formation, as confirmed by SEM observations of calcite crystallisation. Compressive strength measurements showed that 100% infusion CO₂ mortar does surpass normal mortar mixture showing potential in this method. TGA revealed that the amount of CO₂ retained or released is highly dependent on the mixing and curing conditions, but higher infusion does results in high amount of calcite form, with hydration dynamics significantly influencing the final strength. This is supported by SEM results showing more calcium carbonate formed for all samples but also the formation of pores due to high water content inside mortar.
Copyright (c) 2025 Muhammad Irfan Khumaini Kamaruhisam, Miradatul Najwa Muhd Rodhi, Mohd Fadzil Arshad, Mohd Syazwan Mohd Syukor, M Ghaddaffi M Noh https://creativecommons.org/licenses/by-sa/4.0
Evaluating the feasibility of chitosan-based carbon quantum dots in xerogel matrix for CO2 removal
This study investigates the feasibility of using xerogel as a support matrix to stabilise chitosan-based carbon quantum dots (CCQDs) for CO₂ adsorption. After being hydrothermally treated for 24 hours at 180°C, CCQDs were immobilised in xerogel matrices with different ratios of CCQDs to solution. Tests for CO₂ adsorption were carried out at 30°C, 100 mL/min flow rate, and 5% CO₂ concentration. The CCQD-X 1:50 sample had the maximum adsorption capacity, at 80.28 mg/g. The existence of hydroxyl, carbonyl, and C–O functional groups that promote CO₂ binding was verified by FTIR analysis. According to TGA measurements, CCQD-X 1:1 demonstrated exceptional thermal stability by retaining the largest residual mass of 40% at 950°C. With a surface area of 0.1864 m²/g for CCQD-X 1:50, BET analysis validated mesoporous properties, while FESEM pictures showed a heterogeneous xerogel surface shape. CHNS elemental analysis confirmed that nitrogen and sulfur were successfully incorporated, increasing the adsorbent's affinity for CO₂ through polar and basic surface functions. Overall, the results show that CCQDs supported by xerogel have better stability and functional characteristics, which makes them a viable and sustainable adsorbent for effective CO₂ collection applications.
Copyright (c) 2025 Nur Ainaa Mohd Hasyim Chan, Norhusna Mohamad Nor https://creativecommons.org/licenses/by-sa/4.0
Ramification of alcohols towards microalgae fatty acid esters recovery via direct transesterification
Alcohols are commonly utilised for methyl or ethyl esters production in the transesterification of biodiesel production; a non-petroleum-based energy sources which is mostly cited as mono-alkyl esters. The substantial needs of high reactant concentration and catalyst have diverted studies towards direct transesterification (DT). Traditional physicochemical disruption towards microalgae cells which aims for free fatty acids collection commonly goes all along with the DT which reducing a lot of cost and chemical dependency. The aimed fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) were transesterified using freshly harvested Chlorella sp. 15g/L HCDs of wet microalgae and alcohol with ratio of 1:3 microalgae oil to alcohol were used in utilising the DT. This method could provide higher reaction rate as well as a shorter reaction time and promoting a higher purity of biodiesel. The objective of this study is to observe the effect of ethanol and methanol as acylation agent in producing biodiesel via direct transesterification of Chlorella sp. The Fourier-Transform Infrared Spectroscopy (FTIR) and Gas Chromatography Mass Spectrometry (GC/MS) were used to determine the purity and the characteristics of the alcohol affecting the DT. The biodiesel from methanol solvent provides higher purity product since it was more soluble and less dense compared to the ethanol, which enhanced the reactivity of DT. The final mass of FAME was lower compared to FAEE; 1.528 gram and 2.691 gram, respectively. This is due to the simple structure of methanol, which enhanced the bond breaking as well as vaporisation at a lower temperature. Final FAME product was characterised as butenoic acid, 3-methyl-, methyl ester with purity of 37.84 %, and FAEE product was a 9-octadecenoic acid (Z)-, methyl ester with purity of 15.75 %. In conclusion, direct transesterification using methanol was more effective than ethanol due to its molar ratio.
Copyright (c) 2025 Muhammad Syafiq Abu Hassan, Aina Irdina Mohd Yusmadi, Nik Raikhan Nik Him https://creativecommons.org/licenses/by-sa/4.0
Solvent selection for efficient phenolic extraction from palm kernel cake using microwave-assisted techniques
This study investigated the recovery of phenolic compounds from palm kernel cake (PKC) using microwave-assisted extraction (MAE), focusing on the effects of solvent type and liquid-to-solid ratio on extraction efficiency. MAE was performed under constant microwave power (300 W) and extraction time (25 minutes), while varying the solvent types (ethanol, methanol, and water) and liquid-to-solid ratios (20:1, 30:1, and 40:1). Among the solvents tested, ethanol achieved the highest extraction yield (45%) and total phenolic content (TPC) of 0.086 mg GAE/g dry oil, while water produced the lowest yield (10%) and TPC (0.052 mg GAE/g dry oil). Regarding the liquid-to-solid ratio, the highest extraction yield (48%) was observed at a 40:1 ratio. However, the highest TPC was obtained at a 30:1 ratio, emphasising the dilution effect at higher solvent volumes. These findings demonstrate that optimising both solvent selection and liquid-to-solid ratio is critical for maximising phenolic recovery from PKC. Moreover, the use of ethanol, a food-grade and biodegradable solvent, coupled with MAE technology, provides a sustainable and cost-effective approach for the valorisation of agricultural by-products. The optimised process offers potential applications in the food, nutraceutical, and pharmaceutical industries.
Copyright (c) 2025 Ellisa Natasya Rosli, Norhusna Mohamad Nor, Siti Hawa Mat Yaman https://creativecommons.org/licenses/by-sa/4.0
Microwave irradiation synthesis of carbon nanotubes: Advances, purification techniques, and scalability prospects
Carbon nanotubes (CNTs) has been a subject of extensive research and development due to their exceptional properties. This article provides an overview of CNT production techniques, focusing on conventional methods such as arc discharge and chemical vapor deposition (CVD), as well as the emerging alternative, microwave (MW) irradiation technique. The MW irradiation technique offers a promising alternative with potential advantages in terms of energy efficiency and economical aspect. The article also discusses various purification techniques, mainly categorised into chemical and physical purification, underlining their advantages and challenges. Scalability of these production methods are also extensively discussed to explore the potential for scaling up MW irradiation technique, suggesting new alternative for achieving cost-effective and high-quality CNT production on an industrial scale. This review aims to provide insights into the current state of CNT production advancement and identify future opportunity for research and development in this field.
Copyright (c) 2024 Muhamed Nor Iqmal Hafizi Kamaruddin, Siti Shawalliah Idris, Atikah Kadri, Noor Fitrah Abu Bakar https://creativecommons.org/licenses/by-sa/4.0
Evaluation of poly aluminium chloride (PAC) and polyacrylamide (PAM) in coagulation-flocculation processes for sewage wastewater treatment
The increasing population and industrial activities in Malaysia are putting strain on the country’s sewage wastewater treatment, leading to environmental pollution and public health risks. Indah Water Konsortium Sdn. Bhd. has been commissioned assigned with sewage treatment plant (STP) operation which uses biological process of Sequence Batch Reactor (SBR). Meanwhile, research on chemical process for the sewage treatment using poly aluminium chloride (PAC) and polyacrylamide (PAM) that acted as coagulant and flocculant respectively, in Jar Test method was carried out. The purpose of this research was to evaluate the possible improvement of chemical process on suspended solids removal beyond the capabilities of the existing SBR system. These two chemicals were varied in dosage amount, and used to ensure the suspended solids are bound together to form a bigger floc and settle out. Turbidity, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Suspended Solid (TSS) and pH value were analysed to meet the standard B limit set by the Department of Environment (DOE). Results showed that the most effective impact of coagulant and flocculant was the treated wastewater in Jar 5 using only 16 mg/L of PAC and 0.04 mg/L of PAM were used as coagulant and flocculant, respectively, resulting the value of the turbidity, pH, COD, BOD, and TSS was 2.00 NTU, pH 6.22, 2.00 mg/L, 5.22 mg/L, and 2.00 mg/L, respectively.
Copyright (c) 2024 Siti Halwa Othman, Noor Fauziyah Ishak, Muhammad Iqhmal Borhan https://creativecommons.org/licenses/by-sa/4.0
A review of game-based learning in fuel cell education for secondary students
The need for fuel cell education is now critical since fuel cell exposure can build future economies, human capital, and environmental consciousness, as fuel cell is the future green technology. This can be communicated through educational programs that guarantee the transfer of knowledge is relevant and transparent. This paper provides an overview of the need to prepare our students, who will be the next generation of potential fuel cell users and designers, for the impending widespread adoption and use of hydrogen fuel cell technology. To ensure that the learning process is interesting and inspiring, mobile games are demonstrating their promise as useful instruments for assisting fuel cell teaching. With the application of various game design elements, game-based learning has been demonstrated to boost cognitive growth, learning experiences, learning engagement, and motivation. As a result, research must continue to focus on the creation of fuel cell education modules for secondary students that use mobile games as learning tools. By integrating game-based learning into fuel cell education, we can inspire and empower the next generation of professionals to drive the transition towards sustainable energy future.
Copyright (c) 2024 Nur Fadhilah Abdul Jalil, Umi Azmah Hasran, Siti Fadzilah Mat Noor, Muhammad Helmi Norman https://creativecommons.org/licenses/by-sa/4.0
Advanced logging technologies in reservoir crossflow detection
Crossflow exists when there are zones with dissimilar pressure properties allowed to communicate during production. Reservoir fluid from a high-pressure zone will flow preferentially to a low- pressure zone except if the production parameters are well controlled. In a multi-layer producing reservoirs, the crossflow is often related to a poor cement bonding that creates unwanted conduits behind casing. The reservoir crossflow can cause several production problems including zonal allocation, production performance and reservoir variables, potential reduction in recovery factor, and sanding problem. Several cased-hole logging tools have been introduced to detect the crossflow including Production Logging Tool (PLT), High Precision Temperature (HPT) and Spectral Noise Logging (SNL). The technology evolvement is meant to ameliorate the previous tools in crossflow detection. This paper discussed the advanced technologies in crossflow detection starting from the beginning.
Copyright (c) 2024 Zaim Zakwan Zainal Abidin, Wan Zairani Wan Bakar, Tengku Amran Tengku Mohd https://creativecommons.org/licenses/by-sa/4.0
SigmaXL optimisation of oil spill removal from water using orange peels bio-adsorbent
Traditional methods for oil spill cleanup, such as chemical dispersants and mechanical recovery, are often expensive and can harm marine ecosystems. If orange peels (OP) prove to be a cost-effective alternative, it could save money for companies and governments involved in oil spill response efforts. Response surface methodology (RSM) optimisation conducted in this study, with dosage ranging from 0.2 – 0.4 g and time from 41 – 50 min, identified OP particles of BSS 100 sieve size as an effective adsorbent for oil spill mop up. Using the basic SigmaXL features in Excel, a design of experiments (DOE) based on central composite design (CCD) indicates that the maximum adsorption capacity of OP is 34.17 g/g. This capacity is characterised by its limonene content, which enhances its sorption ability under optimal conditions of 0.2 g and 50 min. As such, a quadratic model, whose reliability is described by F, p-value, T and mean square (MS) model significance parameters, illustratively satisfy the predicted response variable at R2 = 0.8988. As a result, the residual plots show a uniform distribution of residuals, while the 3D surface and contour plots indicate connection between the input and output variables. SigmaXL not only gives the optimal combinations but allows for further optimum variable predictions outside the boundaries chosen at 95% confidence and prediction intervals. This study also shed light on resource and time management with respect to OP utilisation for oil sorption, which is the sole aim of selecting the two factors analysed to minimise cost.
Copyright (c) 2024 Abdulhalim Musa Abubakar, Halleluyah Daniel Diriki, Lukman Buba Umdagas, Kishan Chand Mukwana, Wisdom Chukwuemeke Ulakpa, Tahiru Saka, Kamran Khan, Afaque Ahmed Bhutto https://creativecommons.org/licenses/by-sa/4.0
Photoelectrochemical characterisation of direct and pulse electrodeposited copper on fluorine-doped tin oxide glass
Electrodeposition (ED) is applied in several applications since it is one of the most user‐friendly and cost-effective techniques. The increasing popularity of this technique is due to its capacity to control the morphology and chemical composition of the target materials. Copper (Cu) is one of the metals that can be discovered in the greatest abundance on earth. It has been used as an alternative to noble metals to improve the photo electrochemical (PEC) activity for hydrogen generation. This research involved the electrochemical deposition of Cu metal onto fluorine-doped tin oxide (FTO) glass using direct and pulse ED. The objective of this study is to investigate the PEC performance of Cu metal electrodeposited on FTO glass by evaluating its efficiency under light illumination. The deposition of the Cu films was successful, resulting in a thin layer of Cu films onto the FTO. The PEC response of metallic Cu was analysed by doing an LSV study on the thin films, in relation to the ED technique, applied voltage, ED time, and pulse cycle. The results show that the FTO/Cu −0.8 V samples produced via pulse ED have the highest PEC activity. The deposition of strongly adhering and improved morphology of Cu thin film is important especially for interconnect in semiconductor applications.
Copyright (c) 2024 Nur Azlina Adris , Lorna Jeffery Minggu, Rozan Mohamad Yunus, Khuzaimah Arifin, Muhamad Azuwa Mohamed, Mohammad B. Kassim https://creativecommons.org/licenses/by-sa/4.0
Beauty beware : Unmasking the hidden treats of heavy metals in Malaysia cosmetics
Cosmetics have progressed into an essential part of daily routines due to their widespread use, commonly through topical application. However, many cosmetic products contain heavy metals which can accumulate and pose health risks over time. Concerns on product safety including ingredient monitoring have been raised as regular cosmetic use exposes consumers to potentially harmful chemicals. Understanding consumer perceptions is crucial for informed decision-making, yet research on user perception of cosmetics and heavy metal contents in the Malaysian market remains limited. This study focused on assessing heavy metal contents in face cream products from various brands as heavy metals pose a significant concern. The concentration of heavy metals in cosmetic products was analysed by using inductively coupled plasma-optical emission spectrometry (ICP-OES) and atomic absorption spectroscopy (AAS). The results indicate that 4440 ppm of mercury is present in Brand B, which is particularly alarming. These findings underscore the prevalence of unauthorised local products with higher-than-permissible levels of heavy metals, highlighting the need for stricter monitoring and regulation.
Inductively Coupled Plasma Optical Emission Spectrometry
Copyright (c) 2024 Syahirah Adila Abdul Latif, Farah Hanim Ab Hamid, Harumi Veny, Rozana Azrina Sazali https://creativecommons.org/licenses/by-sa/4.0
Quantitative accident analysis on two different bioethanol production plant
The purpose of this study is to examine the expected percentage of fatalities caused by three significant equipment mishaps at a recently built facility in Selangor, Malaysia. This study investigated the possibility of (1) various events occurring in terms of toxicity, thermal radiation, and overpressure, and (2) the percentage of fatalities resulting from the release of chemical mixtures from two ethanol plants: the reference plant (Plant 1) and Plant 2. The major equipment includes a combustor reactor operating at 700 °C and 1 bar for both Plants 1 and 2, a gasification reactor operating at 700 °C (Plant 1) and 900 °C (Plant 2) at 20 bar, and a bioreactor operating at 37 °C and 1 bar for both Plants 1 and 2. To model the process and determine the mass density, mass fraction, and volume fraction of the mixture, Aspen Plus software was utilized. ALOHA and MARPLOT software were used to compute the quantity of toxicity, heat radiation, overpressure, and the affected area. The main equipment comprises a combination of carbon dioxide, carbon monoxide, hydrogen, ethanol, ethanoic acid, and water, with water considered non-harmful. The release of a chemical mixture was postulated and simulated using three-hole size scenarios: 10 mm, 25 mm, and 160 mm. The findings indicated that Plant 2 experienced the highest percentage of fatalities, 86.77%, resulting from the ethanol fireball incident during nighttime through a 25 mm leak.
Copyright (c) 2024 Muhammad Saber Khairunnizam, Mohd Aizad Ahmad, Zulkifli Abdul Rashid, Nur Adlina Azhari https://creativecommons.org/licenses/by-sa/4.0
Purification of Geobacillus thermodenitrificans Thermostable Lipase
The demand for a structured method in producing high quality lipases has tremendously increased lipase purification technology within specific range of its original function. Crude lipase enzyme produced by a locally isolated Geobacillus thermodenitrificans (LGT) has demonstrated a notable potential for various bio-deinking capacities and other enzymatic actions based on the credential amount used. The enzyme production was set up in an airlift fermenter system using a cultivation medium prepared from (w/v) 1.25% glucose and yeast extract, 0.75% NaCl and 0.10% olive oil. Fermentation was accomplished in 24 hours with an air flow rate of 1.00 L/min. Physical parameters were maintained at 7.0% (v/v) inoculum size and pH 6.8. The extracted extracellular crude lipase was purified to homogeneity using four-step procedures. The acetone precipitation, Sephadex G-100 filtration chromatography and double steps of DEAE Sefarose CL-6B anion with exchange chromatography has resulted a final yield of 25.00%. The molecular weight of the purified enzyme was estimated to be 33.5 kDa using an SDS-PAGE analysis. The lipase enzyme has a high potential to be further used for many industrial purposes and has been purified with 22.1-fold protein. The above functional reported characteristics of the LGT was considered a modest quality taking into consideration of its ability to stand high temperature range.
Copyright (c) 2024 Nik Raikhan Nik Him, Muhammad Syafiq Abu Hassan https://creativecommons.org/licenses/by-sa/4.0
Antimicrobial properties of citrus waste-infused used cooking oil (UCO) shellac
The used cooking oil (UCO) and leftover citrus were combined to create a UCO shellac infused with potent antimicrobials. By converting oil and citrus waste into a value-added product, this process significantly contributes to waste reduction efforts. The efficiency of the shellac formulation was demonstrated by assessing the bactericidal activity of shellac made from UCO infused with orange (Citrus sinensis), lemon (Citrus limon), and key lime (Citrus aurantifolia) peel waste. Fourier-Transform Infrared Spectroscopy (FTIR) analysis revealed that the UCO shellac infused with citrus waste contained functional groups such as hydroxyl, alkyne, carboxylic acid, conjugated acid, aromatic ring, and primary alcohol, which contribute to its antimicrobial properties. Among the formulations evaluated, the lemon-infused UCO shellac had the highest ascorbic acid content (0.9 mg/L). When compared with other shellac formulations, including UCO infused with orange or lime waste, as well as a control shellac, the lemon-infused UCO shellac proved to be the most effective in inhibiting bacterial growth on the agar plate. On the plate treated with the lemon-infused UCO shellac, bacterial colonies started to form and begin expanding after 96 hours of culturing. This indicates that the infusion of discarded lemon peel into UCO yielded the shellac with the strongest antibacterial properties.
Citrus Waste; Used Cooking Oil; Infused Oil Infused-UCO Paint;Antimicrobial Activity
Copyright (c) 2024 Miradatul Najwa Muhd Rodhi, Nur Zahirah ‘Ainaa’ Mohd Asri , Abdullah Farhan Rozi, Harumi Veny, Fazlena Hamzah https://creativecommons.org/licenses/by-sa/4.0
An overview of catalyst development for enhanced green hydrogen production
The persistent release of greenhouse gases, primarily due to the heavy reliance on fossil fuels in transportation and energy-intensive industries, necessitates urgent research into sustainable alternatives. These sectors, regarded as the foundation of civilisation, make significant contributions to environmental degradation. In response, hydrogen (H2) emerges as a promising energy source capable of meeting global energy needs while reducing harmful emissions. This article provides a comprehensive overview of cutting-edge H2 production technologies, focusing on a critical issue within this landscape: the use of precious metals in catalysts. While precious metals such as platinum have excellent catalytic activity, their scarcity and high cost make widespread implementation difficult. A careful review of catalyst support materials to improve overall performance and stability is also provided. It explores the wider field of catalysts for producing green H2, including needs, recent findings, theoretical effectiveness, and developing approaches to lessen reliance on precious metals. The article concludes with perspectives on the future, promoting a better understanding of the complex interplay between catalyst design, sustainability, and green H2 production.
Copyright (c) 2024 Wei Shi Ng, Nurulfasihah Azhar, Nur Rabiatul Adawiyah Mohd Shah, Nurul Nabila Rosman, Nur Ubaidah Saidin, Masliana Muslimin, Rozan Mohamad Yunus https://creativecommons.org/licenses/by-sa/4.0
Optimising of operation conditions for carbon nanotube production using pyrolysis coupled with catalytic chemical vapor deposition
Sewage sludge holds great potential for producing carbon nanotubes (CNTs) due to their abundance, renewability, and low-cost carbon source. The objective of this study is to investigate the production of CNTs through two-stage processes i.e. pyrolysis and catalytic chemical vapor deposition (CCVD) of sewage sludge-derived vapor. The central composite design (CCD) model of response surface methodology (RSM) was conducted to predict and optimise the yield of CNTs from sewage sludge vapour. The statistical results indicate that the optimal conditions are a catalyst loading of 0.5 and a temperature of 800 °C. The catalyst loading has the greatest impact on CNTs yield, as evidenced by the F-value in the ANOVA. The actual CNTs yield under these optimal conditions was 30.53%, which is in close agreement with the predicted value of 33.60%. A quadratic model was employed to investigate the relationship between temperature and catalyst load on the deposition yield of CNTs. The CNTs were then characterised using Raman Spectroscopy, X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscopy (TEM). The optimised CNTs had an outer diameter of 25.2 nm, and inner diameters of 3.2 nm. This research contributes to the advancement of the CNTs production from sewage sludge.
Copyright (c) 2024 Mohd Syazwan Mohd Ghazali, Mohd Saufi Md Zaini, Siti Zaharah Roslan, Syed Shatir A. Syed-Hassan https://creativecommons.org/licenses/by-sa/4.0
Enhancing antibacterial property: Tetraethyl orthosilicate influence on quaternised chitosan/PVA film
As a food packaging material, a biofilm barricades the food from contaminants. A film formulated from biopolymers with antibacterial properties is useful and holds high potential as a food packaging alternative since biopolymers are degradable, compostable, and made from renewable resources. Chitosan has been reported to demonstrate antimicrobial properties which are efficient against gram-positive and gram-negative bacteria. However, in its pure form, chitosan has poor solubility in most solvents and is limited to acidic environments only. Thus, in this study, chitosan was quaternised using hexadecyl trimethyl ammonium bromide to enhance its hydrophilicity and its antibacterial effectiveness. A film was formulated with a blend of quaternised chitosan with polyvinyl alcohol and tetraethyl orthosilicate. The FTIR results revealed the presence of peaks around 1400 cm-1 representing the asymmetric bending of the trimethylammonium group and 950 cm-1 corresponding to the quaternary ammonium group which show the success of the quaternisation process and the crosslinking with tetraethyl orthosilicate (TEOS) results in improving the hydrophilicity of the film. By using the technique of diffusion on the disc examined against E. coli, it was observed that all formulated films regardless of the presence of TEOS have antibacterial properties. The fabricated films can be used as food packaging alternative materials.
Copyright (c) 2024 Mohd Akasyah Sulaiman, Norin Zamiah Kassim Shaari https://creativecommons.org/licenses/by-sa/4.0