Indonesian Journal of Environmental Management and Sustainability

Exploration of Weak Acid Solvent Usage in the Separation of Aluminum (Al) from Multilayer Plastic Waste

2025-06-11T06:26:19+00:00

Multilayer plastic waste is difficult to biodegrade, causing environmental problems. An alternative to processing multilayer plastic waste is to separate aluminum from the polymer using a delamination process with acid solvents. In this study, a combination of chemical (acid solvents), thermal (90^oC), and mechanical (stirring at 300 rpm) methods was employed to evaluate the efficiency of delamination of multilayer plastic packaging. Several weak acid solvents, including acetic acid, citric acid, and formic acid, were tested at a concentration of 30% and a reaction time of 10 minutes. The method involved immersing cut multilayer plastic samples into acid solutions under controlled conditions, followed by filtration and drying to recover the aluminum layer. The best result was obtained using 30% formic acid, which successfully separated and recovered 0.940 g or 87% of aluminum from a 1.08 g multilayer sample. This process demonstrates an effective, relatively low-cost approach to enhance the recyclability of multilayer plastic waste, contributing to a more sustainable plastic waste management strategy.

Photocatalytic Degradation of Diazinon in Aqueous Solutions Using ZnO Under Visible Light Irradiation: An Advanced Oxidation Process Approach

2025-05-15T07:39:36+00:00

Diazinon is a commonly used organophosphate insecticide in agriculture, but its persistence in water and soil presents significant health and environmental concerns. This study investigates the photocatalytic removal of diazinon from aqueous solutions using zinc oxide (ZnO) nanoparticles activated by visible light irradiation. ZnO was chosen due to its excellent photocatalytic properties, including a direct band gap (~3.1 eV), strong oxidative capability, chemical stability, and non-toxic nature, making it a superior candidate for visible-light-driven environmental remediation. Photocatalytic degradation under sunlight was also assessed for comparison. Key operational parameters, such as photocatalyst dosage, solution pH, initial diazinon concentration, and irradiation time, were systematically optimized. The highest degradation efficiency degradation was achieved with 20 mg of ZnO, neutral pH, 30 mg/L an initial concentration, and 60 minutes of irradiation. Kinetic analysis revealed that the process followed zero-order reaction kinetics (k = 1.118; R² = 0.9962). Notably, visible light irradiation was more effective than sunlight in degrading diazinon. These findings provide important details about the potential of ZnO nanoparticles as an efficient, low-cost, and environmentally friendly photocatalyst for remediating pesticide-contaminated water under sustainable energy conditions.

Evaluation of Stainless-Steel Mesh 304 Cathode Performance in a Microbial Fuel Cell for Tofu Wastewater Treatment

2025-05-15T04:26:49+00:00

Currently, tofu wastewater (TWW) is one of the major environmental issues that must be addressed. When discharged untreated TWW into natural water bodies or soil, it poses a serious threat to the environment. Therefore, effective treatment of TWW is crucial before to disposal. As an advanced bio-electrochemical technology, the microbial fuel cell (MFC) offers a promising approach to reduce pollutants while simultaneously generating electricity. However, the choice of cathode material is crucial for enhancing MFC performance. This study aims to evaluate the performance of an MFC using an SSM-304 cathode with TWW as the target substrate. Several characteristics of TWW including pH, chemical oxygen demand (COD), biological oxygen demand (BOD), total solids (TS), total dissolved solids (TDS), and total suspended solids (TSS), were analyzed before and after MFC treatment. Additionally, the performance of the MFC system was further evaluated based on voltage output (V), current density (J), coulombic efficiency (CE), and MFC efficiency (?MFC). The results show that COD and BOD were reduced by 69.56% and 64.00%, while TS, TDS, and TSS increased by 48.79%, 32.24%, and 45.15%, respectively. The MFC system with SSM-304 produced a voltage of 167 mV, a current density of 267.2 mA/m², a coulombic efficiency of 3.35%, power density of 27.89 mW, and MFC efficiency of 10.43%. Overall, this study demonstrated the potential of MFCs for simultaneous wastewater treatment and energy recovery.

Acid-Activated Natural Clay for Fe(III) Adsorption: An Integrated Study of Mechanisms, Kinetics, and Thermodynamics

2025-06-11T06:22:14+00:00

The increasing contamination of water by Fe(III) ions from industrial activities, particularly in nickel-producing regions such as Morowali, presents serious environmental and public health concerns. Among various treatment approaches, adsorption stands out as an efficient and cost-effective method, especially using natural clay modified by acid treatment. This study aims to investigate the characterization, adsorption kinetics, and thermodynamic behavior of Fe(III) removal using acid-modified natural clay (NC) derived from Morowali. The clay was activated using sulfuric acid (H₂SO₄), followed by physicochemical characterization and batch adsorption experiments to assess its removal performance. Adsorption kinetics were analyzed using Pseudo-First Order (PFO), Pseudo-Second Order (PSO), Intraparticle Diffusion (IPD), and Liquid Film Diffusion (LFD) models to elucidate the adsorption mechanism. Furthermore, thermodynamic parameters such as Gibbs free energy (deltaG), enthalpy (deltaH), and entropy (deltaS) were calculated to determine the nature of the adsorption process. The results showed that NC exhibited a considerable adsorption capacity for Fe(III), with PSO providing the best kinetic fit, indicating chemisorption control. Thermodynamic analysis confirmed the spontaneous and endothermic nature of the process. These findings demonstrate the potential of acid-modified clay from Morowali as a low-cost and locally available adsorbent, contributing to sustainable water treatment strategies in industrial regions.

Hydrochar Derived from Pennisetum setaceum for Congo Red Adsorption: A Low-Cost Bioadsorbent from Invasive Grass

2025-08-01T07:18:46+00:00

This study investigates the adsorption performance of hydrochar derived from Pennisetum setaceum (PS) through hydrothermal treatment at 250°C for various reaction times (1-4 hours) for the removal of Congo Red (CR) dye from aqueous solutions. The materials were characterized using FTIR, XRD, SEM–EDS, BET, and pHpzc analysis to evaluate changes in functional groups, crystallinity, morphology, elemental composition, and surface charge. FTIR spectra confirmed the presence of oxygen-containing functional groups (O-H, C=O, C-O-C, C-O), while XRD patterns indicated a transition from amorphous to partially crystalline structures, followed by re-amorphization at longer reaction times. SEM images revealed a progressive increase in porosity and surface roughness, accompanied by an increase in carbon content, as shown by EDS. BET analysis of HPS-4 further confirmed its mesoporous structure with a surface area of 9.316 m²/g, which supports enhanced adsorption performance. Adsorption experiments demonstrated that the optimum pH for CR removal by HPS-4 was 5, with a maximum capacity of 51.674 ± 5.468 mg/g. Kinetic studies followed the pseudo-first-order model, and equilibrium data fitted well with the Langmuir isotherm, indicating monolayer adsorption. Thermodynamic analysis showed the process was spontaneous and exothermic (?H° = ?44.07 kJ/mol). The proposed adsorption mechanism involves a combination of electrostatic attraction, hydrogen bonding, and ?–? interactions between CR molecules and the aromatic structure of hydrochar. However, regeneration tests indicated a significant decrease in efficiency after the third cycle. These findings suggest that hydrochar from Pennisetum setaceum is a promising adsorbent for anionic dye removal, with optimal performance achieved under controlled hydrothermal conditions.

Driving Factors Influencing Watershed Management and Sustainability: A Systematic Review

2025-06-02T04:30:15+00:00

Watershed management and sustainability have gained significant global attention due to escalating environmental, socioeconomic, and governance challenges. This study presents a Systematic Literature Review (SLR) aimed at identifying and synthesizing key driving factors that influence watershed management and sustainability. A comprehensive search was conducted exclusively in the Scopus database, covering publications from 2013 to 2023. Through PRISMA-based screening and thematic analysis of 193 relevant studies, a total of 37 driving factors were identified. These factors were classified into three main domains: biophysical (7 factors), socio-economic (13 factors), and institutional (17 factors). The findings reveal that institutional factors are most prominently emphasized, followed by socio economic and biophysical dimensions. This synthesis provides a holistic understanding of the complex and interconnected elements that drive watershed sustainability. The insights derived are intended to inform future research, support evidence-based policymaking, and strengthen integrated watershed management practices across diverse geographic and socio-political contexts. The search employed multiple keyword combinations, including ”watershed”, ”catchment”, ”river basin”, ”drivers”, ”influencing factors”, and ”determinants”, ensuring broader thematic coverage within the Scopus database.