Malaysian Journal of Bioengineering and Technology

Mechanical and Thermal Properties of Cellulose Nanocrystal/Graphene Nanoplatelet Reinforced Polylactide Acid Biocomposites

2024-11-24T04:33:49+00:00

In this research, cellulose nanocrystal (CNC) and graphene nanoplatelet (GNP) were introduced as hybrid nanofillers at a total loading level of 5wt.% in poly(lactic) acid (PLA) as matrix material. PLA-CNC/GNP biocomposites were successfully fabricated with the utilisation of compression moulding to study the effect of CNC and GNP on the mechanical and thermal properties of the biocomposites. The produced PLA-CNC/GNP biocomposite materials, including pure PLA for comparison purposes, were characterised by mechanical and thermal properties. Overall, the results of the flexural properties showed that the PLA biocomposite had a formulation of 2.5 wt.% CNC and 2.5 wt.% GNP contributed significantly to the enhancement of flexural strength and the modulus, up to 47% and 76%, respectively. The thermal properties also seem to be optimally improved as the thermal stability of the biocomposite samples was analysed accordingly. Overall, the incorporation of CNC and GNP with 5 wt.% of total hybrid filler loading showed a favourable impact on the mechanical and thermal properties of PLA biocomposite for environmentally friendly automotive components.

Mechanical Properties of Annealed Soda Lime Silica Glass with Various Potassium Salt by Ion Exchange

2024-12-12T13:33:37+00:00

This work studied the effect of ion exchange parameters on the glass properties. The regular soda lime silica glass was annealed at 600 ºC for 16 hours, followed by the chemical treatment process. The chemical treatment was carried out using different types of potassium salts at two different temperatures. Different ion exchange media in salt paste were prepared using KNO₃, KCl, and K₂SO₄ and heat treated at 425 ºC and 465 ºC for 4 hours. The mechanical properties of the glass before and after ion exchange treatment were analyzed using the 3-point bending and Vickers hardness method. The results show the highest flexural strength was obtained after the annealed glass was treated with KCl for 4 hours at 425 ºC. Meanwhile, treatment with KNO₃ at 425 ºC resulted in the highest Vickers hardness strength and glass fracture toughness compared to samples treated with other potassium salts. From both characterization techniques, the K₂SO₄ salt medium showed the lowest flexural strength, hardness, and fracture toughness values. Additionally, ion exchange treatment at 465 ºC reduced the glass's mechanical properties as higher treatment temperatures lead to surface structure stress relaxation.

Study on the Performance of Polymer Inclusion Membrane for Gold Extraction

2024-12-12T13:51:24+00:00

The efficiency of polymer inclusion membranes (PIMs) for gold extraction, particularly using Aliquat-336 as a carrier, has been extensively studied. The membrane was fabricated by combining poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) with dioctyl phthalate (DOP) and varying concentrations of Aliquat-336 (5, 10, 15, 20, and 25 wt.%). The optimal formulation, incorporating 20 wt.% Aliquat-336 (M5), demonstrated significant improvements in ion exchange capacity (IEC) extraction rates, achieving an impressing 1.697 meq/g and 95.96% extraction efficiency, respectively.

From Light to Heavy: Addressing Gaps in Rare Earth Element Extraction at the Lynas Advanced Materials Plant

2024-12-16T07:33:56+00:00

The Lynas Advanced Materials Plant (LAMP) in Kuantan, Malaysia, exemplifies sustainable practices in rare earth element (REE) separation processes through its efficient solvent extraction techniques using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEH/EHP or P507) and di-2ethylhexyl-phosporic acid (D2EHPA or P204) to separate REEs from monazite ore sourced from Mt. Weld, Australia. LAMP achieves a remarkable 99% yield for light REE separation in areas such as lanthanum, cerium, praseodymium, and neodymium. It faces challenges separating heavy REEs due to the low content in its concentration to be cost-effective. This limitation underscores the need for improved solvents or alternative methods like ion exchange to enhance heavy REE recovery, particularly yttrium, gadolinium, terbium, and dysprosium, which is of interest to Malaysia to separate its non-radioactive heavy REE from ion-adsorbed clay. Insights from LAMP's processes offer valuable lessons in developing robust REE separation strategies that align with global demand, green technology, and environmental and social impact.

Advances in Membrane Technology for Gold Extraction: A Comprehensive Review

2024-12-16T08:25:45+00:00

This comprehensive review investigates recent advancements in separation technologies for gold extraction, focusing on sustainable and efficient methods to address environmental concerns associated with traditional practices. The study explores innovative techniques such as hydrometallurgical methods, biocyanidation, biosorption, and membrane technology, evaluating their mechanisms and environmental implications. Significant trends in gold extraction have emerged over the past five years, as revealed by a comprehensive review of numerous studies. One such trend is the increasing adoption of non-toxic leaching agents like thiocyanate, which show comparable recovery rates to cyanide while posing lower environmental risks. Additionally, advancements in bioleaching through engineered microbial strains have demonstrated improved gold solubilization efficiencies, with reported increases of up to 25% in recovery rates. Membrane technologies, particularly composite and nanostructured membranes, have emerged as promising alternatives for selective gold ion separation, offering enhanced permeability and selectivity. The integration of these advanced technologies into hybrid systems further enhances overall recovery rates, with efficiencies of over 95% when combining biological and physical separation methods. This review concludes that the future of gold extraction lies in the combination of these innovative technologies, which improve recovery efficiencies and address critical environmental concerns. The ongoing research in this field is vital for the development of sustainable gold recovery processes that meet both economic and ecological demands. By examining the mechanisms, efficiencies, and environmental impacts of these methods, this paper highlights the future potential of separation technologies in sustainable gold recovery.

Advancements and Challenges in Wire Arc Additive Manufacturing – A Review

2024-12-18T02:28:32+00:00

Wire arc additive manufacturing (WAAM) is a groundbreaking advancement in 3D metal printing, enabling efficient and cost-effective production of large, complex components using gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW). Suitable for metals like stainless steel, aluminium, and titanium alloys, WAAM involves layer-by-layer deposition of molten metal using an electric arc to melt wire feedstock. Despite its benefits, WAAM faces challenges with thermal cycles and microstructural inconsistencies, affecting component strength and ductility. Recent studies focus on microstructural analysis and mechanical properties, revealing varied microstructures due to distinct heat cycles. Research indicates consistent hardness across WAAM-fabricated components, with variations based on microstructural constituents. Optimizing the WAAM process involves understanding these characteristics and refining welding parameters. Advances in WAAM technology promise significant improvements in manufacturing efficiency, cost-effectiveness, and component quality across various industries.

Effect of Silver Complex on Graphene Oxide Alginate (GOAlgAg) for Antibacterial Studies

2024-12-18T07:04:39+00:00

The effect of the silver complex on graphene oxide and its antibacterial studies was reported in this work. Graphene oxide (GO) has a high specific surface area and is well-known for being an ideal substrate material for growing silver nanoparticles. The simplified Hummer's method was chosen to prepare GO and Silver nanoparticles (AgNPs), which have been decorated on the surface of GO during the reduction of silver complex solution [Ag(NH₃)₂OH] in GO aqueous solution. The obtained nanocomposite was analyzed by using Ultraviolet-visible spectrophotometry (UV-Vis) and X-ray diffraction (XRD). The antibacterial performance against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (B. subtilis) was investigated using the disk agar diffusion method. The diameter of the inhibition zone indicates the effectiveness of GOAlgAg in preventing these bacteria from growing while displaying the nanocomposite as a promising material for antibacterial-related applications. The best antibacterial properties were found in a sample of 5.0:2.5ml GOAlgAg, which shows the highest inhibition zone, 0.85cm toward Escherichia coli and 1.03cm toward B. subtilis.

Advances in Biohydrogen Production: Techniques, Challenges, and Future Prospects

2024-11-17T06:04:09+00:00

Progressing to sustainable and renewable energy sources is essential for addressing climate change and reducing reliance on fossil fuels. Biohydrogen production, which is the production of hydrogen via biological processes, can be one solution since it provides high-value energy and environmental benefits. This review aims to provide summary information about the three basic strategies involved in biohydrogen production: dark fermentation, photo fermentation, and microbial electrolysis cells (MECs). Dark fermentation is the fermentative conversion of organic matter via anaerobic microbes into hydrogen and other products. While this approach is simple and could work with diverse waste substrates, scalability is limited due to low hydrogen yields and the need for substrate pretreatment. Photosynthetic bacteria employ light to transform organic substrates into hydrogen. Photosynthetic bacteria use light to convert organic substrates into hydrogen, indicating that this process could complement dark fermentation. However, its dependence on light and low efficiency present significant challenges. Microbial electrosynthesis (MEC) converts hydrogen into energy by reducing it from carbon dioxide and using electroactive bacterium combined with an external voltage to produce gas from organic matter that is well-aligned but complex with wastewater treatment while also facing costs that make them highly operational. These technologies are likely to see improvements in genetic engineering, new designs for reactors, and the use of them with other industrial processes to improve productivity and profitability. Ongoing research and development are essential to realize large-scale, practical methods for biohydrogen production. This review covers the potential of biosynthetic and anaerobic approaches in this field.

Effect of Polyvinyl Alcohol (PVA), Cellulose Nanocrystals (CNC), and ?-Polylysine (?-PL) Biocomposites for Fresh Chillies Coating Application

2024-12-19T13:40:22+00:00

The rising demand for fresh fruits and vegetables has resulted in considerable issues in post-harvest preservation, especially with weight loss and rotting. This study examines the efficacy of a biodegradable biocomposite coating made from polyvinyl alcohol (PVA), cellulose nanocrystals (CNC), and ?psilon polylysine (?-PL) in prolonging the shelf-life of chilies. The investigation specifically analyses the post-harvest performance of chilies with and without stems when treated with 17 solutions of PVA/CNC/?-PL biocomposite suggested by the Response Surface Method (RSM). The fresh chilies were dipped into the PVA/CNC/?-PL biocomposite solution for 30 seconds, weight loss inspection of the chilies was evaluated in 21 days, and stored in the chiller at 9 °C. Findings demonstrate that stemless chilies coated with the nanocomposite experience markedly reduced weight loss, which gains the lowest weight loss results of 5.92 % during storage in comparison to their stem chilies, the lowest weight loss result is 17.5 %. The protective layer significantly diminished moisture loss and preserved fruit firmness, hence enhancing freshness duration. The stemless chilies, coated with the PVA/CNC/?-PL nanocomposite, exhibited enhanced preservation properties, indicating that the lack of stems, along with the coating formulation, improves the fruit's resistance to dehydration and decay. This work demonstrates that PVA/CNC/?-PL nanocomposites may serve as a novel, eco-friendly approach to diminish waste and enhance the shelf-life of fresh products. The results suggest favorable consequences for sustainable agriculture, minimizing food waste and enhancing supply chain logistics. Future research may investigate the scalability of this method and its applicability to other perishable fruits and vegetables.

A Review of Enzymatic Pretreatment of Lignocellulosic Biomass for Bioenergy Conversion

2024-12-08T16:06:40+00:00

Lignocellulosic biomass, composed of cellulose, hemicellulose, and lignin, is an abundant and renewable resource with immense potential for sustainable bioenergy production. The methodology could potentially lead to a reduction in fossil fuel reliance and greenhouse gas emissions. However, its complex structure poses significant challenges for conversion, and effective pretreatment technologies are needed to make the sugars more accessible for fermentation. Enzymatic pretreatment for biomass is turning into a promising biofuel production route because it requires less energy and has a lower environmental impact. This method improves biomass solubilization, sugar release, and volatile fatty acid production by reducing particle size and increasing substrate solubilization. Key enzymes such as cellulases, hemicellulases, and ligninolytic enzymes are critical to breaking down the complex structure of lignocellulose. The efficiency of enzymes has improved dramatically over the years due to advances in enzyme discovery, molecular modifications, and production. Enzymatic saccharification has been advanced by approaches that include solid-state fermentation, enzyme immobilization, and optimization of reaction conditions. Enzymatic pretreatment is not free from drawbacks as it also requires high enzyme loadings because of lignin recalcitrance, and, while using the so-called hydrothermal pretreatment, harsh conditions to advantage are unavoidable due to high solids loading. As a response, improved methods such as flow-through hydrothermal pretreatment or combined techniques are being investigated to increase sugar digestibility and decrease the formation of inhibitory products. Future directions should focus on finding novel pretreatment methods that are sustainable and cost-effective for large-scale applications. Through methods including sulfite pretreatment and enzyme engineering combined with CRISPR-Cas gene editing and artificial intelligence techniques, subprocesses of bioconversion can be optimized to improve the overall process. Enzymatic pretreatment has excellent potential to improve the stages of bioenergy production and provide sustainable energy solutions.

A Review on Microwave Processing Technique in the Synthesis of CaCu3Ti4O12

2024-12-22T03:07:33+00:00

Microwave heating has a high potential technique to be used as an effective substitute for traditional furnace heating techniques in today's ceramic industries, including the synthesis of promising very high dielectric materials with relative permittivity, e_r = 10⁵of CaCu₃Ti₄O₁₂ (CCTO). The microwave processing approach employs microwave radiation to heat materials more efficiently and uniformly to promote uniform densification. Hence, this approach improved the material’s characteristics tremendously compared to the traditional furnace. As microwave heating lowers the reaction times, it has the potential to save both money and energy compared to conventional heating techniques. In CCTO processing, microwave energy was commonly used to replace the heating technique in the calcination stage, sintering stage, or both. This review delves into the historical development and advancements in microwave processing methods within ceramic manufacturing, particularly focusing on CCTO electroceramics. The aim is to assess the viability of microwave processing as a complete substitute for conventional furnace heating techniques in the production of CCTO.

Outside Front Cover - Journal name, Cover image, Volume issue details, ISSN, Copyright, Preface, Editorial Board, Acknowledgement for Reviewers, Table of Contents

2024-12-29T09:22:23+00:00