Malaysian Journal of Chemical Engineering & Technology

A novel combined-mode design for A MEMS-based micro passive direct methanol fuel cell

2024-04-27T01:21:32+08:00

A small-scale micro direct methanol fuel cell was developed by utilizing silicon substrate-based electrode plates, where the flow field plate was fabricated with micro-electro-mechanical system technology. Modelling work was carried out to assist in designing the anode and cathode plates to obtain the required configuration and geometric dimensions for the microfabrication process. A novel combined-mode anode plate was developed with an active-mode grid design and a passive-mode porous design for the flow field while the cathode plate was developed with a passive-mode design of square window-shaped through holes in a staggered arrangement. Silicon etching methods were used to form the desired flow field structures on the electrode plates with an active area of 1 cm². The single cell was assembled by incorporating the electrode plates and membrane electrode assembly. A study on the feasibility and effectiveness of the new micro fuel cell was conducted. The performance test resulted in a maximum power density value of 1.86 mW/cm² at a voltage of 138.7 mV.

Antimicrobial properties of citrus waste-infused used cooking oil (UCO) shellac

2024-09-06T04:54:06+08:00

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.

Air pollution index evaluation based on haze phenomena in East Malaysia using Giovanni satellite database

2024-04-08T09:06:16+08:00

This work evaluates air pollution related to haze phenomena in Malaysia from 2000 to 2019. The main objective of this work is to evaluate the relationship between the Air Pollution Index (API) during haze occurrences using the Giovanni satellite database. The collected data of the API was denoted as ground-based data, while that of GIOVANNI was denoted as satellite-based data. The air pollutants targeted in the study include PM_2.5, SO₂, CO, and O₃. Sarawak and Sabah were chosen as the study areas due to the high levels of hazardous haze pollutants observed in these regions. The data analysis utilised a linear regression approach to examine the correlation and relationship between ground-based and satellite-based measurements. Factors contributing to haze occurrence were also investigated by gathering meteorological data from GIOVANNI, including wind speed and surface temperature. The analysis's correlation coefficient (R) values range from weak, moderate and strong, with all p-values below 0.05, indicating statistical significance. Notably, wind speed shows a strong negative correlation with API, with an R-value of −0.8750, demonstrating an inverse relationship between the two variables. Similarly, temperature exhibits a moderate negative correlation with API, reflected in an R-value of −0.7270. The findings indicate a strong inverse relationship between the factors and haze pollution, with correlations from the GIOVANNI database serving as a benchmark for identifying causes of high API during haze.

Beauty beware : Unmasking the hidden treats of heavy metals in Malaysia cosmetics

2024-09-11T16:04:59+08:00

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.

Enhancing antibacterial property: Tetraethyl orthosilicate influence on quaternised chitosan/PVA film

2024-05-02T04:56:30+08:00

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.

Optimising of operation conditions for carbon nanotube production using pyrolysis coupled with catalytic chemical vapor deposition

2024-08-12T05:43:27+08:00

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.

SigmaXL optimisation of oil spill removal from water using orange peels bio-adsorbent

2024-09-19T04:29:04+08:00

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.

Quantitative accident analysis on two different bioethanol production plant

2024-09-10T04:05:22+08:00

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.

Optimisation of chemical treatment parameters for enhanced yield of cellulose nanofibres from Semantan Bamboo (Gigantochloa scortechinii)

2024-02-16T07:51:34+08:00

Semantan bamboo (Gigantochloa scortechinii) is one of available bamboo in Malaysia and an ideal source for cellulose based nanofibres. However, research on this bamboo has been moderately studied. Therefore, this study conducted a direct and simple chemical treatment using nitric acid and hydrogen peroxide which motivated by previous studies to extract cellulose nanofibre from Semantan bamboo. The Semantan bamboo was used in powder form with particle size in the range of 250 μm to 425 μm. The parameters of the chemical treatment which are temperature, duration of treatment and concentration of nitric acid and hydrogen peroxide were varied. The yield percentage of extracted Semantan bamboo cellulose nanofibres was determined and its functional groups was characterised using Fourier-transform infrared (FTIR) spectroscopy. The findings found the optimum that 76% of extracted Semantan bamboo cellulose nanofibres was obtained at treatment condition of 50 ℃, 48 hours and concentration of HNO₃ and H₂O₂ at 3.2 mol/L and 60 mmol/g, respectively.

A brief overview on finite element analysis for mechanics of proton exchange membrane fuel cell

2024-04-29T02:47:24+08:00

Hydrogen energy is an ideal alternative for energy-intensive industrial processes, long-distance transportation, and enabling the integration of decentralized renewable energy sources like solar and wind power. Many countries have implemented strategies for the development of hydrogen energy. Proton exchange membrane fuel cells (PEMFC) are a highly efficient hydrogen conversion technology that can be utilised in a variety of applications, including backup power systems, portable electronics, and transportation, due to its high-power density and simple architecture. Finite element analysis (FEA) is a prominent numerical tool to simulate and to predict the mechanical behaviour of PEMFC under operating conditions. The main goal of this paper is to conduct a review on the utilisation of FEA in improving the performance of PEMFC. The FEA utilisation to evaluate the geometrical design of PEMFC end plate is first discussed, followed by fatigue life of PEMFC stack. Finally, the design optimisation of PEMFC performed in various investigations is also reported. Well validated FEA is found to be a powerful tool to evaluate the mechanics of PEMFC. It can be integrated with modern optimisation methods to improve the performance of PEMFC.

An overview of catalyst development for enhanced green hydrogen production

2024-08-19T11:15:46+08:00

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.

Photoelectrochemical characterisation of direct and pulse electrodeposited copper on fluorine-doped tin oxide glass

2024-09-11T18:11:59+08:00

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.

A review of game-based learning in fuel cell education for secondary students

2024-09-30T17:15:40+08:00

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.

Advanced logging technologies in reservoir crossflow detection

2024-09-27T02:38:45+08:00

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.

Microwave irradiation synthesis of carbon nanotubes: Advances, purification techniques, and scalability prospects

2024-10-23T09:08:47+08:00

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.

Evaluation of poly aluminium chloride (PAC) and polyacrylamide (PAM) in coagulation-flocculation processes for sewage wastewater treatment

2024-10-01T00:12:37+08:00

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.

Purification of Geobacillus thermodenitrificans Thermostable Lipase

2024-09-10T00:07:48+08:00

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.