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Effect of Diethanolamine (DEA) Solvent Flow Rate on the CO2 Absorption-Desorption Process Using a Hollow Fiber Membrane Contactor
Full text linkOne of the primary objectives in decarbonization is the separation of CO₂ from industrial gas mixtures, particularly in application such as biogas purification and flue gas treatment. A dual-layer crossflow membrane module was utilized under both circulation and batch operating modes with a 30% DEA solution. This study investigates the influence of solvent flow velocity on CO₂ separation performance using a hollow fiber membrane contactor with a 30% DEA solvent. the process was evaluated under two operating modes: batch and solvent circulation. Key variables measured include the solvent flow rate (40–160 mL/min), operating temperature (30–50°C), and sweep gas flow rate (100–300 mL/min). The results indicate that under continuous operation with a solvent flow rate of 160 mL/min, a temperature of 30°C, and a sweep gas flow rate of 100 mL/min, 50.42% of the CO₂ was successfully removed. In contrast, the batch system, under identical conditions achieved only a 27.8% removal rate. The superior performance in circulation mode is attributed to the continuous renewal of the solvent, which sustains a stable concentration gradient and minimizes mass transfer resistance. These findings underscore the potential of membrane-based systems with optimized solvent circulation for efficient and stable CO₂ capture in industrial applications
Effect of Stearic Acid on Barrier and Mechanical Properties of Edible Films Based on Carboxymethyl Cellulose (CMC), Konjac Glucomannan (KGM), and κ-Carrageenan (κCarr)
Full text linkThe development of edible films using natural polysaccharides presents a sustainable alternative to synthetic packaging materials. This study aimed to enhance the barrier properties of edible films composed of carboxymethyl cellulose (CMC), konjac glucomannan (KGM), and κ-carrageenan (κCarr) by incorporating stearic acid (SA). Films were prepared by blending the biopolymers with SA at varying concentrations (0.1–0.5% w/w) and characterized for their structural, physical, and mechanical properties. Fourier-transform infrared (FTIR) spectroscopy confirmed molecular interactions between SA and the polysaccharide matrix, evidenced by reduced O–H absorption bands and intensified –CH₂– peaks. SA incorporation increased film thickness and moisture content but reduced tensile strength, elongation at break, solubility, and water vapor permeability (WVP). Although the WVP of SA-modified films did not meet the Japanese Industrial Standard at the tested concentrations, the observed trend suggests that higher SA levels could further improve barrier performance. The optimal formulation (0.5% SA) demonstrated enhanced hydrophobicity, acceptable water activity, and moderate tensile strength and opacity. These findings indicate that stearic acid can effectively modify the functional properties of polysaccharide-based edible films, advancing their potential as eco-friendly food packaging materials. Further optimization of SA concentration is recommended to achieve industrial moisture barrier standards
Utilization of Coconut Shell and Coffee Grounds as Briquettes Using the Carbonization Method
Full text linkBiomass-based briquettes offer a renewable energy alternative that can help reduce CO₂ emissions. Coconut shells and coffee grounds are promising waste materials due to their high calorific value. This study aimed to optimize the composition and carbonization time in producing briquettes from these two materials. The briquettes were prepared following SNI 01-6235-2000 and export briquette standards. The process included drying, carbonization at 300 °C for 60, 90, 120, 150, and 180 minutes, sieving, mixing, molding, and drying. Coconut shells and coffee grounds were mixed at weight ratios of 9:1, 8:2, 7:3, 6:4, and 5:5 with a total of 46.5 grams and 8.5 grams of adhesive. Briquette quality was evaluated based on moisture content, ash content, volatile matter, density, calorific value, and fixed carbon. The 9:1 composition yielded the highest calorific value of 6,472 cal/g, while a carbonization time of 90 minutes produced the best calorific value of 6,504 cal/g. The results show that a high proportion of coconut shells with limited coffee grounds and optimal carbonization time can produce briquettes with high energy potential, suitable for use as an alternative fuel
Optimization of Palm Frond Pulping Using a Soda-Anthraquinone Process in a Circulating Digester: A Sustainable Approach
Full text linkOil palm fronds, typically discarded after pruning, have potential as a raw material due to their lignocellulosic content. This study optimizes the soda-anthraquinone pulping process using a circulating digester. It investigates the effects of cooking temperatures (140, 150, and 160°C), cooking times (120, 180, and 240 minutes), and NaOH concentrations (10%, 15%, and 20%) with 0.1% anthraquinone, employing Response Surface Methodology (RSM) based on Central Composite Design (CCD). Analysis with Design Expert 13 software revealed significant impacts on yield (19.01-31.00%), kappa number (9.24-15.69), and viscosity (2.91-34.45 cP). Optimal conditions were 140°C, 120 minutes, and 10% NaOH, yielding 30.57% pulp, kappa number of 13.87, and viscosity of 24.03 cP. This research underscores the environmental benefits of utilizing palm fronds, contributing to waste reduction and circular economy practices, and demonstrates the potential for industrial scalability, offering a sustainable alternative to traditional pulping methods
Comparative Analysis of CO₂ Content in Biogas and Synthetic Gas Using Chittick Titration Validated by Gas Chromatography
Full text linkThis study aimed to validate the Chittick titration method for measuring carbon dioxide (CO2) content using gas chromatography (GC) as the reference method. Two types of gas samples were analyzed: synthetic CO2/N2 gas with a theoretical composition of 40:60 and biogas produced by anaerobic fermentation. Analyses were conducted in parallel using both methods to compare CO2 measurements. For synthetic gas, the Chittick titration recorded an average CO2 content of 39.11%, whereas GC recorded 40.52%. For biogas, Chittick titration produced 30.16%, whereas GC measured 31.40%. The differences between the methods were 0.81% for synthetic gas and 1.55% for biogas, with relative errors of 2.00% and 3.45%, respectively. The t-test results showed statistically significant differences (p < 0.05) between the methods for both gas types. However, the observed deviations remained within practically acceptable limits for small-scale laboratory applications. These findings suggest that Chittick titration is a practical and cost-effective alternative for estimating CO2 content, particularly in laboratories with limited access to gas chromatography equipment. This study is expected to serve as a useful reference for educational institutions and small laboratories that are seeking to develop simple gas analysis methods with adequate validity
Combination Process of Rice Husk Ash Coagulation and Electrocoagulation for Palm Oil Mill Effluent Treatment
Full text linkPalm oil mill effluent (POME) poses a significant environmental threat due to its high organic and inorganic load. This study introduces a novel integration of rice husk ash (RHA) coagulation and electrocoagulation (EC) for sustainable POME remediation. Thermally treated at 500 °C for two hours, RHA was characterized via FTIR, revealing active silica-based functional groups conducive to charge neutralization and adsorption. Treatment experiments employed 9.3 g/L RHA and aluminum electrodes spaced 20 mm apart under varying currents of 10, 15, and 20 A over 15, 30, and 45 minutes. At the highest tested condition (9.3 g/L RHA, 20 A, 45 minutes), the integrated process achieved 78% total solids (TS) and 43% chemical oxygen demand (COD) removal, surpassing individual RHA coagulation removed 34% TS and 17% COD, while EC alone achieved 43% TS and 18% COD removal. The superior performance stems from synergistic flocculation, adsorption, and electroflotation. Compared to conventional methods, the combined RHA–EC system offers faster treatment, lower chemical and energy demands, and improved sustainability. These findings suggest a scalable solution for decentralized POME treatment, particularly in resource-limited palm oil-producing regions
Modelling Urea and Creatinine Concentration Distribution in Hollow Fiber Membranes for Hemodialysis Applications
Full text linkHumans are dynamic creatures who continue to follow developments over time. This development also has a big impact on changes in habits and has an impact on the health of everyone, which needs special attention in this era of globalization. One of the treatments for kidney failure patients is kidney function replacement therapy, namely haemodialysis. Haemodialysis therapy is a high technology to replace the function of the kidneys in removing metabolic waste (air, sodium, potassium, hydrogen, urea, creatinine, uric acid and other substances) through a semi-permeable membrane as a separator for blood and dialysate fluid in an artificial kidney (dialyzer). where the processes of diffusion, osmosis, and ultrafiltration occur. In this study, a hollow fiber type dialyzer was used which consisting of three main components: the shell (which directs dialysate flow), the porous membrane, and the tube (which carries blood). In general, this research will be carried out theoretically by developing a mathematical model of mass transfer in hollow fiber membranes in the haemodialysis process to study the distribution of urea and creatinine concentrations in the tube, membrane, and shell axial and radial section, the effect of pore area of membrane on urea and creatinine clearance, and the influence of dialysate flowrate on urea and creatinine clearance. The mathematical modeling successfully illustrates the distribution of urea and creatinine concentrations within the hollow fiber membrane both axially and radially, with a concentration decrease from blood to dialysate, influenced by diffusion and convection mechanisms. Simulation results indicate that increasing dialysate flowrate enhances haemodialysis efficiency, but its effect diminishes after reaching a certain threshold. Meanwhile, increasing the membrane surface area from 1.3 m² to 1.8 m² results in only a slight reduction in the urea concentration from 16.67 mol/m³ to 16.62 mol/m³ and creatinine from 8.85 mol/m³ to 8.83 mol/m³, demonstrating that membrane surface area has a smaller impact
Enhancing Fuel Oil from Polyethylene Waste: A Comparative Study of Catalyst Efficiency in Thermal Pyrolysis
Full text linkThe growing accumulation of polyethylene (PE) plastic waste poses a significant environmental challenge, necessitating effective recycling and waste management solutions. Thermal pyrolysis has emerged as a promising method for converting plastic waste into valuable hydrocarbons. This study presents a comparative analysis of catalyst efficiency in the thermal pyrolysis of PE waste, with a focus on maximizing product yield and optimizing chemical composition. Various catalysts were evaluated to assess their impact on the degradation process, product distribution, and overall conversion efficiency. The research utilized 100 grams of PE waste in the form of 2 cm pellets. The catalysts tested—activated carbon, HZSM-5, and low-rank coal (LRC)—were each added at 10% of the plastic\u27s weight. The experiments were conducted under varying conditions of time (30, 60, 90, 120, 150, and 180 minutes) and temperature (350, 450, 550, and 650°C). The thermal pyrolysis setup included an integrated furnace with glass column fractionation and four trays for collecting liquid pyrolysis products. Key parameters such as total yield, °API and calorific value were analyzed and compared to those of conventional fuel oil. The results demonstrated that the LRC catalyst outperformed both activated carbon and HZSM-5, achieving a yield of 61.10% at 650°C for 180 minutes. The pyrolysis product obtained using the LRC catalyst exhibited properties—such as °API and calorific value—comparable to those of conventional gasoline. This study highlights the potential of catalytic pyrolysis in managing plastic waste effectively, offering a viable approach to reducing plastic pollution while producing valuable hydrocarbon products. The findings underscore the importance of catalyst selection in optimizing pyrolysis outcomes, providing valuable insights for sustainable plastic waste managemen
Fabrication and Characterization of Psf-TiO2/GO Membranes for Photocatalytic Decomposition of Dyes in Batik Liquid Waste
Full text linkOne of the important processes in making batik cloth is dyeing which requires large amounts of water. Liquid waste from washing and rinsing batik cloth produces color from residual dye and can be the main source of water pollution. One method of removing dyes is the ultrafiltration process using Membrane Technology for photocatalytic decomposition. In this research, polysulfone (PSf) membrane uses addition of different TiO2 compositions (1, 1.5, 2, 3, and 5 wt.%) and graphene oxide (GO) of 0.5 wt.% composition as photocatalyst. The photocatalyst can store energy therefore the photocatalytic process can be performed in a visible light environment. To identify the best composition of photocatalysts, photocatalytic performances were tested by the removal of methyl violet as dye along with characterization of the membranes for the morphological and physicochemical properties using FTIR, SEM, XRD, and DMA. The highest performance under visible light was shown by a membrane containing 5 wt.% TiO2, which provided a permeate flux of 22.97 L m-2 h-1 and dye removal of up to 89.84%. The findings indicated that the PSf membrane matrix\u27s stability and photocatalytic enhanced potential are driven by the cooperative interaction between TiO2 and GO nanoparticles, which function as photocatalysts
Green Extraction of Microcrystalline Cellulose from Cabbage Waste (Brassica Oleracea L.) via Steam Explosion Under Pressurized and Non-Pressurized Nitrogen (N2)
Full text linkAgricultural residues such as cabbage waste (Brassica oleracea L.) are rich in cellulose and offer promising potential for sustainable microcrystalline cellulose (MCC) production. This study aims to extract and characterize MCC from cabbage waste using an environmentally friendly approach that combines high-speed blending, low-concentration oxalic acid hydrolysis (0–2% w/v), and steam explosion at 130 °C for 15 minutes, under both pressurized and non-pressurized nitrogen (N₂) atmospheres. The application of pressurized N₂ significantly improved delignification efficiency and preserved cellulose crystallinity. The optimal treatment (2% oxalic acid with N₂) yielded a cellulose content of 79.18%, with hemicellulose and lignin contents reduced to 15.28% and 0.10%, respectively. FTIR analysis confirmed the effective removal of non-cellulosic components, while XRD analysis revealed a crystallinity index 66%, which is high compared to typical MCC values from other biowastes (~50–60%). SEM revealed clean and well-dispersed fiber morphology. These results indicate that oxalic acid combined with N₂-assisted steam explosion is an effective and eco-friendly method for producing MCC. This approach minimizes chemical use and oxidation, making it suitable for pharmaceutical excipients, biodegradable composites, and other green material applications. Overall, the process aligns with circular economy principles and contributes to the Sustainable Development Goals (SDGs)