Chemical and Natural Resources Engineering Journal (Formally known as Biological and Natural Resources Engineering Journal)

OPTIMIZATION AND ADSORPTION STUDIES OF LEAD REMOVAL USING MODIFIED MACROPHYTE BIO-ADSORBENT

2025-11-05T09:29:11+08:00

Lead contamination in wastewater presents a major environmental and public health concern due to its toxicity, persistence, and non-biodegradable nature. Although conventional treatment methods such as chemical precipitation and membrane filtration are commonly used, they often come with drawbacks including high operational costs, energy demands, and secondary pollution. As a sustainable alternative, this study investigates the potential of Azolla, an aquatic macrophyte, as a low-cost and eco-friendly bio-adsorbent for lead removal from contaminated water. The Azolla biomass was pre-treated with hydrochloric acid for five hours to improve its surface area and activate functional groups. Its lignocellulosic structure, rich in hydroxyl and carboxyl groups, supports effective lead adsorption via complexation and ion exchange mechanisms. A 2-Level Factorial Design was used to optimize key adsorption parameters including pH, contact time, and initial lead concentration. The highest removal efficiency of 93.69% was achieved at pH 10, a lead concentration of 250 ppm, and a contact time of 10 minutes. Adsorption isotherm analysis indicated that the process followed the Freundlich isotherm model, suggesting multilayer adsorption on a heterogeneous surface with multiple binding sites. These findings demonstrate the effectiveness of Azolla as a promising bio-adsorbent for lead removal. Further research is recommended to explore its long-term performance and scalability for industrial wastewater treatment applications.

INVESTIGATING ADSORPTION ISOTHERMS AND KINETICS, AND ECOTOXICITY OF ACTIVATED CARBON FROM CARBON-FIBER REINFORCED POLYMER (CFRP)

2026-01-14T12:03:51+08:00

This study presents the synthesis of activated carbon (AC) from carbon fiber reinforced polymer (CFRP) waste as a sustainable adsorbent for wastewater treatment. Characterization by FTIR, SEM, and XRD confirmed the development of functional groups, a porous morphology, and a predominantly amorphous carbon structure in AC, with minor graphitic domains in CFRP. Adsorption tests using the methylene blue (MB) dye showed good performance, with the Langmuir isotherm resulting in the best-fitted model (adjusted R² = 0.88), indicating monolayer adsorption and pseudo-first-order kinetics (adjusted R² = 0.96). Thus, confirming concentration-dependent adsorption of MB by AC, produced from CFRP. Ecotoxicity evaluation using brine shrimp assay revealed an LC50 of 33.11 mg (or 3311 mg/L), suggesting moderate toxicity. These findings demonstrate that AC derived from CFRP exhibits strong adsorption efficiency with acceptable ecological risk, providing a viable pathway to convert CFRP waste into valuable materials for environmental remediation.

IN SILICO CHARACTERIZATIONS OF DEGRADATIVE ENZYME FROM LANDFILL LEACHATE METAGENOME FOR POTENTIAL POLYCHLORINATED BIPHENYL (PCB) BIOREMEDIATION

2025-08-05T14:34:15+08:00

The characterization of enzyme structure and function was essential for understanding biochemical pathways and developing effective biotechnological applications, particularly in environmental bioremediation. Traditional experimental methods for protein analysis were often labor-intensive and limited by the inability to culture certain microorganisms. In this study, an in silico approach was employed to predict the structure and function of a putative degradative enzyme identified from metagenomic analysis of landfill leachate. Using a combination of bioinformatics tools, including sequence alignment, domain annotation, secondary structure prediction and three-dimensional (3D) structural modeling, the target enzyme was analyzed for its catalytic potential and stability. Conserved motifs and active sites were identified, suggesting its involvement in the degradation of xenobiotic compounds such as polychlorinated biphenyls (PCBs). The 3D structure model revealed a typical fold associated with oxygenase or dehydrogenase activities, with predicted metal-binding sites critical for catalyses. These findings demonstrate the power of computational methods to accelerate the discovery and characterization of novel enzymes, especially from unculturable microbial communities. This approach provides a valuable foundation for future functional validation, protein engineering and the development of environmentally sustainable biocatalysts.

OPTIMIZING FORMULATION AND SYNTHESIS CONDITIONS OF RED PALM OIL (RPO)-BASED NANOEMULSIONS STABILIZED BY TWEEN 80

2026-01-14T12:03:56+08:00

Nanoemulsion is an important class of nanomaterial that offers several advantages due to its improved stability and dispersibility in aqueous systems. In this preliminary study, oil-in-water nanoemulsions were synthesized using red palm oil (RPO). RPO was chosen for its high insoluble vitamin E content, a potent antioxidant that can reduce oxidative stress by neutralizing free radicals. The most suitable emulsifier, optimal formulation, and synthesis conditions to produce stable nanoemulsions were evaluated. A laser beam penetration test based on the Tyndall effect and light-scattering principles was used to confirm the presence of nanoemulsions qualitatively. The results indicate that Tween-80 produced the most stable and translucent nanoemulsion. The optimal formulation was found to have a weight ratio of 10:15:74:1 for RPO: Tween 80: water: glycerin. The optimal synthesis conditions were using the high-speed homogenizer at 15000 rpm for 40-minute synthesis time. The resulting nanoemulsions demonstrated stability suitable for further studies (e.g., physicochemical characterization, scale-up, and additional functionalization) for food and beverage applications.

CARBON NANOTUBE-CHITOSAN THIN FILM ON QCM (QUARTZ CRYSTAL MICROBALANCE) FOR DETECTION OF IPA (ISOPROPYL ALCOHOL)

2025-08-01T11:51:04+08:00

This study presents the development of a quartz crystal microbalance (QCM) sensor coated with a multi-walled carbon nanotube–chitosan (MWCNT-COOH/CS) composite for the detection of isopropyl (IPA) vapor, a common volatile organic compound (VOC). The composite was synthesized via glutaraldehyde crosslinking to enhance bonding between carboxyl-functionalized MWCNTs and chitosan, followed by sonication and stirring to ensure uniform dispersion. Material characterization was carried out using Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and field-emission scanning electron microscopy (FESEM), confirming successful integration and interaction between MWCNTs and CS. Static QCM analysis showed that the MWCNT-COOH/CS composite achieved a balanced frequency shift of approximately 106 Hz with a response time of ~40 seconds, outperforming standalone CS and MWCNT layers in terms of response speed and signal stability. Dynamic measurements across IPA concentrations from 300 to 700 ppm revealed a linear frequency shift trend with a correlation coefficient (R²) of 0.9713. Compared with similar sensors reported in the literature, the developed composite exhibits promising sensitivity, faster response time, and ease of fabrication, suggesting strong potential for real-time VOC monitoring applications.

INFLUENCE OF THE PROCESS PARAMETER ON CHLORELLA VULGARIS CULTIVATION FOR CO2 SEQUESTRATION AND PROTEIN PRODUCTION

2025-09-04T11:08:47+08:00

Microalgae, known for their high photosynthetic efficiency, offer a promising approach for CO? sequestration and the production of high-value products such as single-cell proteins (SCP). However, low CO? solubility in water and strain-specific tolerance limit CO₂ fixation efficiency. This study aimed to optimise CO? fixation and SCP production in freshwater Chlorella vulgaris using the Taguchi Orthogonal Array method. Key parameters, namely light (5-15 kLx), CO? concentration (1–5%), and nitrogen content (0–1 g/L), were investigated in a 2-L Schott glass bottle. Process validation was performed within the same system, and a comparative assessment was subsequently conducted against a 2-L flat-panel photobioreactor (FPPBR) to determine any differences in cultivation performance. Results showed that biomass productivity had a greater influence on CO? fixation (9.049%) and protein yield (45.78%) than CO? concentration or nitrogen content. Notably, the flat-panel PBR achieved superior growth performance (47.67%), highlighting the importance of reactor design. Logistic growth modelling with the Taguchi growth rate equation provided the best fit for the experimental data (R² between 0.6-0.93). These findings provide valuable insights for enhancing microalgae CO? capture and SCP production, although further refinement of cultivation systems and kinetic models is necessary.

ADVANCING OZONE TECHNOLOGY: APPLICATIONS IN HAND SANITIZERS, COSMETICS, AND COMPUTATIONAL FLUID DYNAMICS (CFD) MODELLING FOR ENHANCED PERFORMANCE

2025-11-24T12:11:17+08:00

Ozone technology has emerged as a revolutionary tool in disinfection, cosmetics, and process optimization. This review highlights advances in ozone applications, focusing on its role as a disinfectant in hand sanitizers and cosmetic formulations, and on its optimization using Computational Fluid Dynamics (CFD) modelling. Ozone-based hand sanitizers provide an effective, skin-friendly alternative to alcohol-based products, addressing concerns about dryness and irritation while ensuring broad-spectrum antimicrobial activity. In cosmetics, ozonated oils are recognized for their healing, moisturizing, and antimicrobial properties and are used in diverse skincare formulations. The integration of CFD modelling has significantly improved the efficiency of ozone systems by enabling precise predictions of ozone mist behavior, ensuring safety and optimal disinfection in various environments. This review highlights the potential of ozone technology as a sustainable and versatile solution for enhancing public health and safety while paving the way for innovative applications in multiple industries.