ASEAN Journal of Chemical Engineering

Translucent Polyvinylidene Difluoride Membrane Incorporated with Titanium Dioxide and Mesoporous Siliceous Phosphotungstic Acid Photocatalyst for Methylene Blue Removal from Wastewater

2025-12-31T21:05:19+07:00

Photocatalytic oxidation is an effective method for degrading organic pollutants in air and water, but suspended photocatalysts, such as titanium dioxide (TiO₂), face challenges including recovery difficulties, a large band gap, and a low surface area. In this study, titanium oxide and mesoporous siliceous phosphotungstic acid (TiO₂-MPTA) were incorporated into polyvinylidene difluoride (PVDF) membranes as an alternative to bare TiO₂ for methylene blue (MB) removal. Both opaque (O-PVDF/TiO2-MPTA) and translucent (T-PVDF/TiO₂-MPTA) membranes were fabricated with TiO₂ loadings of 0.5–2.5 wt.% via blending, with translucency designed to enhance light penetration for improved photocatalytic activity. Membranes were characterized by SEM, FTIR, and UV-vis-NIR spectroscopy to assess morphology, chemical composition, and optical properties. Photocatalytic performance was strongly dependent on TiO₂-MPTA content. Neat T-PVDF and O-PVDF showed negligible MB removal (~0.8% and ~0.7%, respectively) due to the absence of a photocatalyst. MB degradation increased with loading, reaching 74% for T-PVDF/1.5TiO₂-MPTA and 59% for O-PVDF/1.5TiO₂-MPTA, before declining at 2.5 wt.% due to catalyst agglomeration. The translucent T-PVDF/1.5TiO₂-MPTA membrane outperformed its opaque counterpart by 15%, highlighting the role of light penetration. Enhanced performance is attributed to the mesoporous structure and high surface area (154–625 m²/g) of MPTA-Si, which provides abundant active sites, promotes photon absorption, and reduces electron-hole recombination. These results demonstrate that PVDF/TiO₂-MPTA nanocomposite membranes, particularly translucent membranes with optimized loading, are promising for efficient photocatalytic removal of organic dyes from wastewater.

Utilization of Liquid Anaerobic Digestate using Recirculating Hydroponic Planting System

2026-01-02T07:34:04+07:00

A hydroponic planting technique employing organically treated anaerobic digestion digestate liquid fertiliser is becoming popular. This study examines the biological treatment of digestate from food processing waste anaerobic digestion using Cosmoball® uncoated and activated carbon-coated plastic media. In a pilot-scale recirculating hydroponic system (RHS), ammonia-to-nitrate conversion and plant development were assessed at varying digestate ammonia concentrations. Bench tests suggest that AC-coated Cosmoball^® successfully treats digestate. After 21 days, the nitrate level reached 80 ppm, and 100% ammonia elimination and over 90% of the carbon oxygen demand (COD) were observed. The RHS maintained 116-ppm nitrate but reduced COD treatment to only 62–66%. High pH at the start of the RHS trial required pH control until day 40, after which it stabilised at 6.8. 15-ppm ammonia additions caused a substantial pH drop. Maintaining the pH at 5.8 on the RHS boosted plant growth. Finally, AC-coated media improves nitrification and produces plant-growth nitrate.

Development and Assessment of the Synergistic Inhibition Efficiency of IA/AMPS Copolymers for Inhibiting CaCO₃ and CaSO₄ Co-production in Oilfield Scale

2026-01-02T07:31:49+07:00

Polycarboxylate-scale inhibitors (PSI) are widely utilised in managing oilfield mineral scales, not only due to their high complexation, increased dispersion, and high thermal stability, but also due to their environmental compatibility, as they are phosphorus-free. However, they are effective in inhibiting only one specific scale. Thus, new non-phosphorus multifunctional SI is in demand immediately, where the scale can be made up of a combination of two or more minerals. Itaconic acid/ 2-acrylamido-2-methylpropane sulfuric acid (IA/AMPS) novel copolymer is synthesised via a free radical polymerisation to inhibit the CaCO₃ and CaSO₄ scales. The functional groups believed to be effective in inhibiting the scales were characterised using FTIR. The IA/AMPS performance was investigated to determine the optimal synthesis parameters/ conditions for the dispersion property. Results show that the best conditions for IA/AMPS copolymer preparation included a 1:2 molar ratio of IA to AMPS, 7% of initiator dosage and monomer total mass, a 4:1 molar ratio of ammonium persulfate (APS) to sodium bisulfite, 90 °C of reaction temperature, and 7 hours of the reaction period. Based on the qualitative observations, the IA/AMPS scale inhibitor effectively reduces the formation and surface adherence of both CaCO₃ and CaSO₄ scales. It significantly lowers the scale density and promotes the formation of less adherent, finer particles, especially under elevated temperatures. The combined effect of IA/AMPS and heat demonstrates a synergistic inhibition, particularly evident in the complete prevention of CaSO₄ scale at 80 °C.

Balancing Relief Gas and Assist Gas Flows for Efficient Flare Gas Combustion in Onshore Gas Facility

2025-12-31T21:09:07+07:00

This study investigates the interplay between relief gas and assists gas flows in onshore gas facilities, focusing on their impact on flare gas combustion efficiency. The primary objectives of this study are to analyze how relief gas flow rate, CO₂ and H₂S compositions, and the mixed-gas flow ratio influence the assist gas requirement, the mixed-gas calorific value, the flare gas composition, and the overall gas mix ratio. Additionally, the study evaluates flare gas monitoring to ensure compliance with environmental regulations. The comprehensive analysis aims to enhance the understanding of these variables’ interactions and their effects on gas systems, contributing to improved industrial sustainability and efficiency. Increasing relief gas flow reduces assist gas demand, raises the mixed-gas calorific value and SO₂ concentration, and lowers CO₂ levels. Higher CO₂ content in the relief gas decreases the calorific value and increases CO₂ concentration without significantly affecting relief gas flow. Increasing H₂S content raises the calorific value and SO₂ concentration while reducing CO₂. A higher gas-mix flow ratio also lowers CO₂ and increases SO₂, with the minimum LHV of 300 BTU/SCF occurring at a ratio of 10.69. Monitoring results confirm that all flare emissions remain within government regulatory limits.

The Tear and Tensile Strengths of Silica Fly Ash Reinforced Natural Rubber Vulcanizate

2026-01-02T07:27:15+07:00

This study investigated the enhancement of tear and tensile strengths in natural rubber (NR) vulcanizates reinforced with silica fly ash. The focus was on evaluating the tear and tensile strengths of the composites to improve their performance across various industrial applications. NR, known for its elasticity and flexibility, is often reinforced with fillers to enhance its mechanical properties. Silica fly ash, a by-product of coal combustion, was utilized as a reinforcing agent due to its high silica content and fine particle size. A series of NR composites was prepared by incorporating silica fly ash at weight percentages ranging from 10 to 40 parts per hundred parts of NR (phr). The vulcanization process was optimized to ensure uniform dispersion of the fly ash particles within the NR matrix. The resulting vulcanizates were then subjected to standardized testing to measure their tear and tensile strengths. Results indicated a significant improvement in both tear and tensile strengths with the addition of silica fly ash, particularly at an optimal filler loading. The tear and tensile strengths of the NR vulcanizate with 30 phr silica fly ash (optimal filler loading) were 84.3 N/mm and 29.0 MPa, which were much higher than those of the tear and tensile strengths of the NR vulcanizate with no silica fly ash; 41.2 N/mm and 19.0 MPa, respectively. The 100% modulus, maximum, and delta torque for NR/silica fly ash vulcanizate were higher than those of unfilled NR vulcanizate. The study concludes that silica fly ash is a viable, cost-effective filler for NR, offering substantial improvements in mechanical properties. This finding not only promotes the use of industrial waste but also opens avenues for developing high-performance rubber composites for diverse applications.

Steam Explosion of Palm Oil Mesocarp Fiber: A Simulation Study

2026-01-02T07:23:43+07:00

Palm oil mesocarp fiber (POMF), a lignocellulosic biomass generated in large quantities during palm oil production, is a potential feedstock for sugar production via steam explosion. In this study, the steam explosion of POMF was simulated using Aspen Plus® to evaluate the effects of POMF composition, steam explosion temperature (110–220°C), and residence time (3.5–20 min) on cellulose and hemicellulose conversions as well as on the yields of sugars and degradation products. Variations in POMF composition had no significant impact on cellulose or hemicellulose conversion, nor on the resulting product yields. Across all samples, glucose yields remained constant at approximately 14%, while xylose yields remained stable at approximately 6%. Furfural and 5-HMF yields were minimal at ~0.5% and ~0.2%, respectively. In contrast, product yields were highly sensitive to steam explosion temperature. Glucose yield increased moderately from ~12.7 to ~14.3% at intermediate temperatures before declining sharply between 170 and 210°C. Xylose increased from 0.47 to 10.1% as the temperature rose from 130 to 160°C, then decreased substantially at higher temperatures. At elevated temperatures, sugars became unstable and degraded, leading to significant increases in furfural and 5-HMF formation above 160°C. Residence time had a stronger influence than temperature. Prolonged exposure intensified sugar degradation, with glucose decreasing from ~14.1 to 2.3% and xylose decreasing to 1.4% as residence time increased from 3.5 to 20 min. Correspondingly, furfural and 5-HMF yields increased gradually with time, indicating enhanced secondary degradation pathways. Overall, the Aspen Plus® model successfully described the steam explosion behavior of POMF over a wide range of process conditions. While POMF composition exerted minimal influence, both steam explosion temperature and residence time strongly affected sugar release and the formation of degradation products.

Sustainable Auto-Oxidation of Glucose to Ethyl Formate in Ethanol: Pathways for Hydrogen Storage and Future Energy Applications through Formic Acid Derivatives

2026-01-02T07:21:47+07:00

Formic acid, as the simplest carboxylic acid, holds significant potential as a hydrogen carrier due to its high storage efficiency and ease of transport. Its sustainable production from renewable feedstocks, such as glucose, offers promising prospects, particularly for resource-rich countries like Indonesia. Previous studies have demonstrated the feasibility of producing formic acid by oxidizing glucose with hydrogen peroxide, which can be generated directly from air in water via manganese (Mn)-catalyzed oxidation, thereby circumventing harmful Fenton reactions. In this context, copper (Cu⁺) and manganese (Mn²⁺) ions have been recognized as effective catalysts for this oxidation process. This study investigates the auto-oxidation of glucose into formic acid or ethyl formate, employing air as the oxidant and Cu(II)-Mn(II) acetate as the catalytic system. The experimental variables included the Cu:Mn ratios (1:10 and 1:20), the Mg:Cl ratios in the drying agents, specifically magnesium chloride (MgCl₂) and calcium chloride (CaCl₂), in proportions of 1:1 and 1:2, and the %TEOA volume as the chelating agent. The primary objective was to assess the effects of these variations on ethyl formate yield. In the experimental setup, glucose was combined with the catalytic mixture, amine, drying agents, and a base in ethanol. Air was injected into the system, and the mixture was distilled to approximately 78°C. Titrimetric analysis revealed that the optimal reaction conditions were achieved with a Cu:Mn ratio of 1:10, a Ca:Mg ratio of 1:1, and a 50 % volume of TEOA, resulting in a 4.32% yield of ethyl formate after 2.5 hours of reaction time. These findings underscore the potential for efficiently and sustainably producing ethyl formate or formic acid via a green catalytic oxidation process.

Biomimetic Hydrolysis of Water Hyacinth Cellulose to Glucose

2026-01-02T06:36:12+07:00

. Water hyacinth (Eichhornia crassipes), an aquatic plant notorious for its disruptive impact on aquatic ecosystems, contains significant amounts of cellulose, hemicellulose, lignin, protein, and ash. Despite its reputation as an aquatic weed, this plant shows promise for valorization through efficient biomass utilization technologies. Fractionation of its lignocellulosic components into lignin, hemicellulose, and cellulose is critical for enabling their selective processing and conversion into valuable products. Among these, cellulose hydrolysis plays a pivotal role, converting cellulose into glucose, a fundamental building block for biofuels and other bioproducts. Common hydrolysis methods, which typically rely on acids or enzymes, face numerous technical challenges, including inefficiencies and environmental concerns. This study explores an innovative approach by developing a biomimetic hydrolysis process, inspired by enzymatic systems, for cellulose derived from water hyacinth. Piperazinium dihydrogen sulfate [H₂-Pip]²⁺(HSO₄⁻)₂ was employed as the catalyst, with manganese (Mn) as co-catalyst. Experiments were conducted at three temperatures (50°C, 76.5°C, and 85°C) and at different catalyst concentrations (0.122 M and 0.244 M), with glucose concentration measured after 1, 3, and 5 hours of reaction. Results demonstrated a degree of cellulose hydrolysis of 0.40% per 1°C increase in the absence of Mn, which increased to 0.53% with Mn at 50°C. Furthermore, higher temperatures consistently yielded greater hydrolysis efficiency and glucose production. Doubling the catalyst concentration resulted in 1.3 and 1.75-fold increases in glucose yield at 50°C and 85°C, respectively, and longer reaction times further increased overall yield. These findings highlight the potential of biomimetic hydrolysis as an effective strategy for converting water hyacinth cellulose into glucose, offering an environmentally sustainable alternative to conventional hydrolysis methods.

Hydrolytic Extraction and Biomimetic Catalysis of Hemicellulose from Water Hyacinth Holocellulose Using Glutamic Acid

2025-12-31T21:14:29+07:00

The increasing demand for sustainable energy has intensified research into biomass-based alternatives. Water hyacinth (Eichhornia crassipes), a fast-growing aquatic plant with high hemicellulose content, presents a promising lignocellulosic feedstock for biofuel production. However, conventional hydrolysis methods often require extreme conditions and generate inhibitory by-products. This study investigates the application of glutamic acid, a dicarboxylic amino acid, as a biomimetic catalyst for the hydrolysis of hemicellulose extracted from water hyacinth holocellulose. Hydrolysis reactions were conducted at controlled temperatures (40°C, 60°C, and 80°C), with catalyst concentrations of 1.5 mM and 22 mM, and reaction durations of 1, 3, and 5 hours. The catalyst was introduced by post-temperature stabilization, and all experiments were performed in duplicate to ensure reproducibility. The results demonstrated a positive correlation between temperature, catalyst concentration, and hydrolysis efficiency. The highest xylose yield of 3.14% and a conversion of 43.0% were achieved at 80°C with 22 mM glutamic acid after 5 hours. These findings suggest that glutamic acid can facilitate hemicellulose hydrolysis under mild conditions, though further optimization is needed to improve yield and scalability.

State of the Art Mapping of the Initiating Event Identification Methods by Bibliometric Analysis

2026-01-02T07:15:17+07:00

Probabilistic Safety Assessment (PSA) can be used to evaluate the safety of Nuclear Power Plants (NPPs). To improve NPPs’ safety, reactor safety technology is always developing. Each technology will have a different hazard that can cause an Initiating Event (IE). Of course, this development will affect IE. IE is the event that can affect normal operation and have the potential to cause worst-case conditions when the mitigation system does not work properly. A comprehensive, detailed bibliometric analysis of NPP PSA and IE remains absent from the literature. The objective of this paper is to discuss existing research and identify future trends through bibliometric analysis and a literature review in the PSA and IE domains. The search criteria include the keywords, publication period, publication type, and language. Ninety-five scientific papers were identified during the first screening and were included in the bibliometric analysis. The Bibliometric analysis will represent the keyword network using VOSviewer 1.6.20. The second screening stage is used to strengthen the analysis and generate 43 articles as objects for the literature review. The results showed that the topic of identifying and developing identification methods has not been widely discussed and has become an important research topic. The results of this analysis strengthen the research hypothesis that developing IE methods for new technology NPPs, including High Temperature Gas Cooled Reactors (HTGRs), is feasible.

Leaching Co(II), Mo(VI), and Al(III) Ions from Spent Catalyst Co-Mo/γ–Al2O3 using Organic Acid

2026-01-02T07:12:40+07:00

The disposal of spent catalysts must be managed to prevent environmental pollution caused by the heavy metal content in the material. This work investigates the leaching performance of spent catalyst Co-Mo/γ–Al₂O₃ using an organic acid as the solvent. The leaching process was designed by varying several operating conditions. The particle size was varied at -40+80, -80+120, and -200 mesh, while pulp density was varied at 5, 10, and 20% (wt/v). This experiment used four types of acid, i.e., citric acid, lactic acid, formic acid, and acetic acid. This operation lasted 22 days. The sampling process was conducted periodically during the leaching process. Among the four investigated organic acids, lactic acid provided the highest metal ion recovery. Under that operating condition, the recovery percentage of Co(II), Mo(VI), and Al(III) ions was 50.81, 67.68, and 58.00%, respectively. Furthermore, this work also observed the applicable mechanism during the leaching process through a kinetic study. That study showed that the internal diffusion and chemical reaction steps simultaneously controlled the leaching rate.

Cellulose-Based Materials for Neural Tissue Engineering: From Scaffolds to Interfaces - A Review

2025-12-31T21:16:57+07:00

Cellulose and its derivatives have emerged as versatile natural polymer platforms for neural tissue engineering due to their intrinsic biocompatibility, low cytotoxicity, and tunable biodegradability. Recent advances demonstrate that cellulose-based materials can be engineered to reproduce key structural and physicochemical features of the neural extracellular matrix, including polysaccharide-rich architectures and fibrillar topographies that support neuronal adhesion, alignment, and network formation. Bacterial cellulose, nanocrystalline cellulose, methylcellulose, ethyl cellulose, and their composite systems exhibit hydrogel-forming capability and abundant chemically active functional groups, enabling chemical modification, injectability, and controlled delivery of bioactive agents. Importantly, the incorporation of conductive fillers or chemical modification strategies has enabled electrically active cellulose-based scaffolds with conductivities spanning approximately 7.8 × 10⁻⁷ to 0.49 S cm⁻¹, while largely preserving cytocompatibility, positioning these materials as promising candidates for electrically responsive scaffolds and long-term neuronal interfaces. Despite these advances, challenges remain in achieving precise control over mechanical properties, degradation kinetics, and long-term electrical stability under physiological conditions. This review critically examines the progress in cellulose-derived materials for neural tissue engineering and neuronal interface fabrication, with an emphasis on material composition, fabrication methodologies, structure-property-function relationships, and current limitations, and outlines future directions for the rational design of multifunctional cellulose-based neural biomaterials.

Renewable Electricity Production from Tofu Wastewater and Palm Oil Mill Effluent (POME) via Microbial Fuel Cell

2026-01-02T07:05:29+07:00

Microbial fuel cell (MFC) technology is a renewable energy solution that offers multiple benefits, including environmental friendliness, direct electricity generation, and wastewater treatment. In wastewater treatment, MFCs convert organic matter into electricity while simultaneously treating wastewater. This study investigated a double-chamber MFC using tofu wastewater and palm oil mill effluent (POME) as substrates. A carbon-based material served as the electrode in a membrane electrode assembly (MEA). The results revealed that the MFC generated voltages of 546 mV and 876 mV for tofu wastewater and POME, respectively. The highest power and current densities measured were 12.45 mW/m² and 25.87 mA/m² for tofu wastewater, and 25.22 mW/m² and 52.8 mA/m² for POME. Furthermore, the chemical oxygen demand (COD) removal efficiencies were 52.7% for tofu wastewater and 56.7% for POME. These findings demonstrate the potential of MFC technology for power generation using tofu wastewater and POME, making it a promising approach for sustainable energy and wastewater treatment.

Enhanced Polysaccharide Extraction from Chlorella pyrenoidosa Using Microwave-Assisted Technique and Response Surface Methodology Approach

2026-01-02T07:03:32+07:00

Microalgal polysaccharides represent a high-value class of bioactive macromolecules with growing demand in pharmaceutical, nutraceutical, and functional food industries. Yet, inefficient and unsustainable extraction technologies severely constrain their industrial exploitation. Chlorella pyrenoidosa is a particularly attractive biomass source due to its rapid growth and high polysaccharide content, but its highly recalcitrant cell wall remains a major barrier to efficient recovery. The objective of this study was to optimize microwave-assisted extraction (MAE) conditions to maximize polysaccharide yield from Chlorella pyrenoidosa and to evaluate the effects of critical process variables using response surface methodology (RSM). Accordingly, a Box–Behnken experimental design was employed to systematically model and optimize the effects of extraction temperature, solid-to-liquid ratio, and irradiation time. Under optimized conditions (60 °C, 1:80 g/mL, 10 min), a maximum polysaccharide yield of 60.22% was achieved. The quadratic regression model exhibited excellent predictive accuracy (R² = 0.9893, p < 0.05), as confirmed by ANOVA. Compared with conventional extraction methods, the optimized MAE process delivered markedly higher extraction efficiency, substantial reductions in processing time and solvent usage, and superior alignment with green chemistry principles. Collectively, this work provides a scalable and industrially relevant green extraction framework that advances the valorization of microalgal biomass and supports the transition toward sustainable biorefinery platforms.

Sustainable Biomass Production of Euglena gracilis Cultivated in Dairy Farm Wastewater: A Growth and Lipid Yield Assessment

2025-12-31T21:19:15+07:00

Dairy farming has a detrimental effect of wastewater that can pollute the environment, leading to eutrophication from increased nitrogen and phosphorus levels. Microalgae have significant potential for treating such wastewater. This study aimed to examine the influence of dairy farm wastewater concentrations on Euglena gracilis, particularly its growth, biomass, and lipid production and to develop a growth model for it. This study cultivated Euglena gracilis in Cramers & Myers (CM) medium for 18 days with wastewater concentrations of 0%, 10%, 25%, and 50%. The highest cell density, biomass, and lipid content were 64.5 x 10⁴ cells/mL, 0.560 g/L, and 0.175 g/L, respectively, in the 0% wastewater treatment. The 10% concentration yielded the best results, achieving a cell density, biomass, and lipid content of 27.0 x 10⁴ cells/mL, 0.290 g/L, and 0.127 g/L, respectively. The mathematical approach used shows that the Gompertz Model growth curve produces better simulation data than the Logistic Model. The Gompertz Model can describe Euglena gracilis cultivation with higher accuracy by accounting for the lag phase. Optimal wastewater concentration, to increase microalgae productivity, is an important aspect that can support a circular bioeconomy by using biomass as a raw material for high value products.