CHEMICA: Jurnal Teknik Kimia

Optimization of H2O2/COD and Fe3+/H2O2 Ratios in Combined Electrocoagulation-Fenton System for Petrochemical Wastewater Treatment

Iqbal Syaichurrozi — 2026-08-31

Petrochemical wastewater is characterized by a high organic load and complex composition, which can limit the effectiveness of conventional biological treatment and necessitate advanced treatment technologies. This study evaluated an integrated electrocoagulation–Fenton process for petrochemical wastewater treatment, focusing on optimizing the H2O2/COD and Fe3+/H2O2 ratios and assessing their effects on COD degradation kinetics. Electrocoagulation was initially conducted under previously optimized conditions of 5 V, initial pH 7, and 60 min, followed by Fenton oxidation at pH 3. The H2O2/COD ratio was varied at 5, 10, 15, and 20 g/g, while the Fe3+/H2O2 ratio was adjusted to 0, 0.013, 0.02, and 0.04 g/g. The optimum H2O2/COD ratio of 15 g/g achieved a COD removal efficiency of 48.14%. Further optimization identified an Fe3+/H2O2 ratio of 0.02 g/g as the optimal condition, yielding the highest COD removal efficiency of 88.75%. The achieved removal efficiency is comparable to the upper end of the range reported for integrated electrocoagulation–Fenton treatment of refractory industrial wastewater. Kinetic analysis showed that both first-order and second-order models adequately described COD degradation; however, the second-order model provided a slightly better fit, with R² values of 0.98–0.99. This result suggests that the oxidation process was governed primarily by interactions between oxidizing species and organic pollutants rather than simple first-order degradation. Overall, optimizing oxidant and catalyst dosages substantially improved the integrated electrocoagulation–Fenton process, demonstrating its potential as an effective treatment strategy for petrochemical wastewater and providing practical operating conditions for advanced wastewater treatment applications.

Effect of Cellulose-to-Starch Ratio and Sorbitol Concentration on the Mechanical, Physical, and Biodegradation Properties of OPEFB-Based Bioplastics

Eka Cahya Muliawati — 2026-09-01

The extensive use of conventional plastics, which are difficult to degrade, has driven the development of environmentally friendly bioplastics derived from oil palm empty fruit bunches (OPEFB). The independent variables were the OPEFB Cellulose-to-Starch ratio (1:2, 1:1, and 2:1) and sorbitol concentration (5%, 10%, 20%, and 30% w/w) in OPEFB-derived cellulose matrices reinforced with cellulose nanocrystals (CNC) and polyvinyl alcohol (PVA). The bioplastics were prepared using the solution casting method. The results indicate that the optimal formulation for water resistance was achieved at a 2:1 cellulose-to-starch ratio with 5% sorbitol, yielding the lowest water absorption of $2.56\% \pm 0.12\%$ and an outstanding water resistance of $97.44\%$. Conversely, the highest tensile strength of $44.16 \pm 1.45 \text{ MPa}$ was obtained at a 1:2 ratio with 30% sorbitol. The highest biodegradability in the soil burial test was observed at 30% sorbitol, with a maximum weight loss of $66.16\% \pm 2.11\%$ within 14 days. FTIR analysis confirmed the typical preservation of polysaccharide functional groups. At the same time, SEM observations at higher magnification revealed a well-distributed nanostructure with a controlled porous morphology that effectively balances mechanical performance and accelerated microbial degradation.

Utilization of Microcrystalline Cellulose (MCC) from Kepok Banana Pseudostem (Musa acuminata) as A Filler and Glycerol as A Plasticizer in Starch-Based Bioplastics from Cassava Peels (Manihot esculenta)

Erlikasna Sembiring — 2026-08-31

The use of agricultural residues as renewable reinforcing materials offers a sustainable strategy to enhance the performance of biodegradable bioplastics. This study aims to characterize Microcrystalline Cellulose (MCC) derived from the pseudostem of kepok banana and to analyze its effects on the characteristics and mechanical properties of bioplastics. In this study, 10 g of starch was used, with MCC concentrations of 0%, 2.5%, 5%, 7.5%, 10%, and 15% (%w/w) and glycerol at 20%, 30%, and 40% (%v/w) relative to the mass of starch. The process of isolating MCC from kepok banana pseudostem is by hydrolysis with 50% H2SO4. The highest tensile strength value was 2.5 MPa in bioplastics filled with 5% MCC and 30% glycerol, with an elongation percentage of 7.92% and a Young's modulus of 48.68 MPa. FTIR analysis of bioplastics showed C-H, -OH, and C=C functional groups, confirming the presence of starch and cellulose. The addition of 5% MCC can increase tensile strength, as supported by SEM test results showing a denser, non-porous, non-cracked bioplastic surface. The results of the biodegradation test using the soil burial method, with an MCC-to-glycerol ratio of 5:30, showed 20% degradation in 15 days. The open-air test method yielded 12.5% degradation. These results demonstrate that MCC derived from kepok banana pseudostem can effectively enhance the mechanical performance of cassava peel starch-based bioplastics while providing a sustainable approach for the valorization of agricultural residues.

Comparative Study of Sulfuric Acid and Cellulase Enzymatic Hydrolysis of Cassava Stem Cellulose for Bioethanol Production

Firda Mahira Alfiata Chusna — 2026-08-31

Bioethanol production from lignocellulosic biomass is influenced by the effectiveness of the hydrolysis process in producing fermentable sugars. This study aimed to compare the effects of acid hydrolysis and enzymatic hydrolysis on glucose conversion and bioethanol content produced from cassava stems. Acid hydrolysis was carried out using H2SO4 at concentrations of 1 M, 2 M, and 3 M, while enzymatic hydrolysis used varying enzyme dosages of 1 g, 2 g, and 3 g. The hydrolyzed sugars were fermented with Saccharomyces cerevisiae, and the bioethanol was separated by distillation and analyzed for its composition. All experiments were conducted in triplicate, and data were analyzed using Welch's independent t-test. The results showed that enzymatic hydrolysis produced higher glucose concentration and glucose conversion after fermentation than acid hydrolysis. However, acid hydrolysis produced a significantly higher bioethanol content (78–90±2%) than enzymatic hydrolysis (10–28±1%) (p = 0.002). These findings indicate that under the operating conditions used, acid hydrolysis is more effective at producing bioethanol, whereas enzymatic hydrolysis is more effective at producing fermentable sugars. This study concluded that the hydrolysis method influences glucose conversion and bioethanol yield. Further research is needed to optimize enzymatic hydrolysis, fermentation, and distillation conditions and evaluate the combination of acid pretreatment and enzymatic hydrolysis to increase bioethanol production.

Photoelectrocatalytic Green Hydrogen Production from Coconut Water Waste Using Carbon-MgO Nanocomposite-Modified Electrodes

Abdul Haris Watoni — 2026-08-29

Hydrogen is considered a promising alternative to fossil fuels; however, conventional water electrolysis requires substantial energy input and may have limited environmental efficiency. This study investigates the synthesis of carbon–magnesium oxide (C–MgO) nanocomposites mediated by red dragon fruit (Hylocereus polyrhizus) peel extract for enhancing green hydrogen production from coconut water waste through photoelectrocatalysis. The nanocomposite was synthesized using a hydrothermal method and characterized using UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). UV–Vis analysis indicated good optical stability, with a main absorption band at 400–500 nm and a band gap energy of 2.48–2.66 eV, indicating suitability for visible-light-driven photoelectrocatalysis. FTIR analysis confirmed the presence of –OH, C=C, C=O, and Mg–O functional groups. XRD results revealed the characteristic diffraction pattern of C–MgO with a cubic crystal structure and an average crystallite size of 17.41 nm. These physicochemical properties contributed to improved photoelectrocatalytic hydrogen production. Conventional electrolysis of coconut water produced hydrogen at a rate of 0.3636 mL/min, whereas photoelectrocatalysis using a C–MgO 1:3-modified electrode achieved a production rate of 3.1489 mL/min. The incorporation of carbon and MgO into the electrode modifier increased the hydrogen production rate by 766.03% compared with conventional electrolysis. Overall, the results demonstrate that the biosynthesized C–MgO nanocomposite effectively enhances visible-light-driven photoelectrocatalytic hydrogen production from coconut water waste, offering a promising approach for waste valorization and sustainable green hydrogen generation.