Nitrogen (N) is an essential macronutrient required for plant growth; however, its absorption efficiency remains relatively low due to significant nitrogen loss to the environment. To overcome this limitation, the development of slow-release fertilizers (SRF) is crucial, enabling controlled, gradual nutrient release. This study aims to develop and evaluate a cellulose-modified mesoporous silica matrix as an encapsulation material for Urea-Ammonium Nitrate (UAN) fertilizer, a liquid formulation containing urea, ammonium, and nitrate. The material was synthesized using the sol-gel method with variations including pure silica, non-calcined silica-cellulose, silica-cellulose calcined at 550°C and 700°C, and cross-linking with glutaraldehyde. Characterization techniques included Fourier Transform Infrared Spectroscopy (FTIR) for functional group identification, Scanning Electron Microscopy combined with Energy Dispersive X-ray (SEM-EDX) for morphology and elemental composition, and Gas Sorption Analyzer (GSA) for surface area and pore size analysis. The results showed that the silica-cellulose composite calcined at 550°C (SSCGK550) had the highest fertilizer release value of 893.7 ppm. Plant growth test results show that plants treated with SSCGK550 had the highest growth, with a length of 8 cm and 8 leaves per stem by day 15, whereas plants treated with conventional fertilizer (control) showed a lower growth response, with an average height of 5 cm and only 3 leaves per stem by day 15. These findings demonstrate the success of encapsulating UAN fertilizer in a silica-cellulose matrix and highlight its potential as an efficient slow-release fertilizer to support sustainable agriculture.
Antibacterial edible films based on natural extracts have gained attention as sustainable alternatives for food packaging. Leaf extract of Trema orientalis contains bioactive compounds, including flavonoids, phenolics, alkaloids, terpenoids, and saponins, with potential antibacterial activity. The extract was obtained using ethanol and characterized by LC–MS, which identified 16 compounds, with an extraction yield of 16.45%. Edible films were prepared using a polyvinyl alcohol (PVA)–polyethylene glycol (PEG) matrix and characterized by FTIR, SEM, and physical–mechanical analyses. The incorporation of the extract improved the film properties, including thickness, water resistance, and tensile strength. Antibacterial activity against S. aureus and E. coli increased with extract concentration, reaching a maximum inhibition zone of 13.3 ± 0.58 mm at 60% extract concentration. Molecular docking against DNA gyrase B of E. coli (6F86) and S. aureus (4URM) identified compound 5 (−8.04 kcal/mol) and compound 13 (−7.94 kcal/mol) as the strongest-binding compounds toward their respective target proteins, indicating their potential contribution to the antibacterial activity of the extract. Toxicity evaluation using the Brine Shrimp Lethality Test (BSLT) yielded an LC50 value of 1976 ppm, indicating that the extract was non-toxic. These findings demonstrate that Trema orientalis extract-based edible films exhibit promising antibacterial properties and have potential as environmentally friendly active food packaging materials.
The discharge of laundry wastewater containing surfactants and phosphates represents a growing environmental concern, particularly in areas where wastewater is released without adequate treatment. This study evaluates sulfuric acid–activated rice husk ash (RHA) as a low-cost adsorbent for removing surfactants and phosphates from real laundry wastewater. FTIR and XRD analyses indicated that the main silica-related functional groups and framework of RHA were largely retained after acid activation, while SEM observations suggested a rougher and more heterogeneous surface morphology. Batch adsorption experiments using real laundry wastewater showed that surfactant and phosphate removal were influenced by adsorbent dosage and contact time. The optimum dosage was 3 g for surfactant removal and 4 g for phosphate removal, while the optimum contact time for both contaminants was 30 min. Controlled isotherm experiments using separate single-solute surfactant and phosphate standard solutions indicated that the adsorption behavior of both contaminants was better described by the Freundlich model, suggesting adsorption on heterogeneous surface sites. Kinetic analysis using real laundry wastewater showed rapid uptake, with the Elovich model providing the best overall fit for both surfactant and phosphate adsorption. These findings suggest that sulfuric acid–activated RHA is a promising, simple, and affordable biomass-derived adsorbent for laundry wastewater treatment, although further studies involving surface area analysis, regeneration, reusability, column operation, and cost performance are required to support practical application.
Larvicides are a class of insecticides that chemically control the growth of dengue vectors. Although synthetic larvicides remain effective for mosquito control, their prolonged and excessive use may contribute to insecticide resistance and potential environmental impacts. In alternative literature, silver nanoparticles can be used to reduce these negative impacts, as they exhibit larvicidal activity. Organic waste, such as plumeria leaves that have fallen, wilted, and lost economic value, can serve as a bioreductor in the synthesis of silver nanoparticles. Green synthesis of silver nanoparticles was carried out by mixing the water extract of plumeria leaves with a 1 mM AgNO3 solution at a 1:9 (v/v) ratio. The concentration of the plumeria leaf water extract used was 1%, and the heating temperature was 60°C. Silver nanoparticles were characterized using a UV-Vis spectrophotometer, PSA, TEM, and SEM-EDS, and their larvicidal activity was tested. Silver nanoparticles provide a maximum wavelength of 430 nm. The TEM and SEM-EDS characterization results show irregular spherical shapes, as well as square and triangular shapes, and PSA confirmed an average particle size of 72.39 nm with a zeta potential of −21.51 mV. Biosynthesized silver nanoparticles exhibit larvicidal activity with an LC50 of 13 ppm.
This study utilizes green nanotechnology by employing Trema orientalis leaf extract (TO-EE) as a natural bioreductant to synthesize silver nanoparticles (AgNPs-TO) and apply them in biopolymer film-based food packaging. AgNPs were synthesized using a stirrer method and characterized by UV-Vis, FTIR, XRD, PSA, and TEM. UV-Vis confirmed nanoparticle formation with a λmax at 430 nm (SPR). FTIR indicated phenolic and carbonyl groups in the reduction of Ag+ to Ag0. XRD showed a face-centered cubic silver structure with minor AgCl presence. PSA revealed an average size of 56.46 nm with high polydispersity (>0.5), while TEM showed spherical, heterogeneous particles. Antioxidant activity (DPPH) showed IC50 values of 128.40 µg/mL (AgNPs-TO) and 75.59 µg/mL (TO-EE). Anti-photooxidation tests in a linoleic acid system demonstrated that AgNPs-TO and BP/AgNPs-TO films suppressed hydroperoxide formation. Preliminary BSLT screening showed an LC50 <1000 ppm, and 5 ppm AgNPs were selected for incorporation into the biopolymer film. The additional AgNPs-TO also affects the physical properties of the biopolymer film. These results indicate that AgNPs-TO are promising as active agents in environmentally friendly food packaging.
The development of environmentally friendly bioadditives has attracted growing attention for improving diesel fuel quality. This study comparatively investigated the role of oxygenated compounds in essential oils from Cymbopogon nardus and Cymbopogon citratus as natural bioadditives. The essential oils were obtained by hydrodistillation and characterized for yield, moisture content, density, kinematic viscosity, and volatile compound composition using gas chromatography–mass spectrometry. The essential oils were then blended with diesel fuel at five additive concentrations (0.2, 0.4, 0.6, 0.8, and 1.0% (v/v)), with neat diesel (0% (v/v)) serving as the control. The resulting blends were evaluated for density, kinematic viscosity, distillation characteristics, and ignition quality, as indicated by the Calculated Cetane Index (CCI). The results revealed that C. citratus essential oil contained a higher proportion of oxygenated compounds than C. nardus. The optimal bioadditive concentration was determined to be 0.8% (v/v) for C. nardus and 0.6% (v/v) for C. citratus, based on a balance between statistically significant CCI improvement and maintaining density and kinematic viscosity within diesel fuel specifications. At these optimal concentrations, the CCI increased from 45.5 for neat diesel to 46.3 for C. nardus and to 46.9 for C. citratus, respectively, while density and kinematic viscosity remained within diesel fuel specifications. These findings suggest that variations in essential oil composition may contribute to the observed differences in fuel properties and support the potential use of essential oils rich in oxygenated compounds as sustainable bioadditives for diesel fuel applications.
Caffeine is a type of alkaloid found in coffee, tea, and chocolate. Caffeine consumption is generally safe and offers benefits such as increased alertness and concentration; however, excessive consumption can potentially lead to caffeine poisoning or overdose, which can be harmful to health and even life-threatening. Analytical determination of caffeine is generally performed using conventional techniques such as HPLC and UV-Vis spectrophotometry. An alternative analytical method with potential, but has not yet been widely explored, is cyclic voltammetry. In this study, a cyclic voltammetry method for caffeine analysis was developed using a working electrode modified with a molecularly imprinted polymer to enhance electrode sensitivity. Bulk polymerization was used to produce the molecularly imprinted polymer (MIP), whose characteristics were then analyzed using SEM and FTIR instruments. The optimal electrode composition was obtained at a ratio of 1:2:2 (KCl: agar powder: MIP), which resulted in a cathodic peak current (Ip,c) of −1.45 × 10−3 A at pH 5. Higher conductivity facilitates easier electron transfer, which in turn results in a higher peak current. The application of this method to the analysis of caffeine in ground coffee types A, B, and C resulted in caffeine contents of 17.46 ppm, 12.87 ppm, and 13.78 ppm, respectively. The voltammetric method showed a limit of detection (LoD) of 2.26 ppm and a limit of quantitation (LoQ) of 7.53 ppm. These results indicate that the molecularly imprinted polymer-modified electrode is an effective tool for analyzing caffeine using the cyclic voltammetry method.
Ammonia is a toxic pollutant parameter in petrochemical wastewater and can impair the quality of aquatic environments. This experimental study evaluated the kinetics of ammonia biodegradation by an Effective Microorganisms-4 (EM4) consortium using the Monod model approach, focusing on molasses concentration as an external carbon source and the effect of microbial acclimatization. This experiment was conducted in aerobic batch systems with initial ammonia concentrations of 10, 30, and 50 ppm and the addition of 5% and 10% molasses. Mixed Liquor Suspended Solids (MLSS) and pH were monitored to evaluate environmental dynamics and biomass growth. The results showed that increasing the molasses concentration from 5% to 10% increased the maximum specific growth rate (μmax) from 6.29 to 7.17 day−1 and decreased the half-saturation constant (Ks) from 23.22 to 14.01 mg/L; therefore, a lower Ks indicates higher apparent substrate affinity. The acclimatization further improved the kinetic response, yielding higher μmax and lower Ks than the non-acclimated system, alongside higher MLSS and a faster pH decrease consistent with more intensive biodegradation activity. Overall, these results confirm that the combination of microbial acclimatization and sufficient molasses addition can enhance the kinetic performance of ammonia biodegradation by EM4.
Biosurfactants are surface-active compounds synthesized by microorganisms. These compounds offer several advantages, including low toxicity, high compatibility, and biodegradability. Biosurfactants can be isolated relatively quickly, a property that renders them potentially applicable in industrial settings. One type of microorganism that produces biosurfactants is endophytic bacteria, which live within plant tissues. The present study focuses on the characterization of biosurfactants produced by endophytic bacteria isolated from geothermal ferns in the area around the Gedong Songo hot spring in Semarang Regency. Isolate 9 (D9) demonstrated the optimal oil-spreading capability and was consequently selected for further production and characterization. The optimal growth curve for biosurfactant production by isolate D9 (BS-D9) occurred in the early stationary phase, approximately 132 hours post-inoculation, with an oil-spreading diameter of 5.1 centimeters. The emulsification index (E24) of BS-D9 reached 95%, which is nearly equivalent to SDS at 1000 ppm, suggesting a high emulsification capacity. The methylene blue test indicated that BS-D9 is an anionic biosurfactant, whereas the negative Biuret test result indicated that it does not belong to the lipopeptide group. Fourier-transform infrared (FTIR) spectroscopy indicates that BS-D9 falls within the glycolipid category. This classification is supported by a distinctive absorption peak corresponding to glycosidic bonds, potentially of the rhamnolipid type. Rhamnolipids are widely recognized for their high emulsification efficiency, stability, and environmental compatibility, making them attractive for various industrial applications. These results indicate that BS-D9 has potential applications as a surface-active agent with environmentally friendly properties.
Breast cancer is one of the most prevalent diseases among women and ranks among the top five leading causes of cancer-related deaths worldwide. Current therapeutic approaches remain suboptimal in addressing the highly aggressive progression of cancer cells. A simple method to initiate the drug discovery process is Quantitative Structure-Activity Relationship (QSAR) analysis. Previous experimental studies have reported that cyanopyridine derivatives exhibit potent inhibitory effects on PIM-1 kinase, a key regulator in MCF-7 human breast cancer cells. In this study, we performed QSAR analysis on structurally modified cyanopyridine derivatives to design novel anti-breast cancer agents. The research methodology included: (1) molecular geometry optimization using the PM3 semi-empirical method, (2) calculation of QSAR descriptors (hydrophobic, electronic, and steric parameters), and (3) rational molecular design based on the derived QSAR model. Optimizations and calculations were performed using HyperChem software. Multiple Linear Regression (MLR) analysis and external validation generated the best QSAR equation for Model 1: log (1/IC50) = 151.273 + 1884.726qC1 − 4663.478qC4 + 5431.564qC5 + 1501.074qN7 + 592.015qO10. This model exhibits better core statistical metrics, with an R = 0.868, R2 = 0.753, SEE = 0.272, R2ext = 0.9342, and Q2ext = 0.8717. In addition, statistical parameters of the Y-scrambling test indicate the robustness of the best QSAR model (average Rscramble = 0.3881; average R2scramble = 0.1558). A promising drug candidate was identified based on antiproliferative activity predicted by the best QSAR model. A subsequent in silico evaluation comprehensively assessed their pharmacokinetic and toxicity profiles. The results revealed that synthesized and designed derivatives successfully satisfied most critical pharmaceutical criteria. The pharmacokinetic profile of this compound was comparable to the native ligand (VRV), as well as established reference drugs like tamoxifen and doxorubicin. 2-[4-(5-Cyano-6’-fluoro-1-methyl-6-oxo-1,6-dihydro-[2,3’]bipyridinyl-4-yl)-2-methoxy-phenoxy]-N-phenyl-acetamide (8M) was considered the best potential drug candidate due to its high anti-breast cancer efficacy and relatively low toxicity. The molecular docking study demonstrates that the binding affinity of the designed cyanopyridine derivatives for the PIM-1 kinase receptor was in the range of −9.5 to −9.7 kcal·mol−1, which is comparable to that of doxorubicin (10.0 kcal·mol−1). Moreover, these values surpass the binding affinity of the native ligand (9.2 kcal·mol−1) and tamoxifen (8.0 kcal·mol−1). This finding was further corroborated by molecular dynamics simulations, which demonstrated the stability of the interactions. Therefore, these designed compounds have potential as novel anti-breast cancer drugs.
This study reports the synthesis and evaluation of a biodegradable slow-release fertilizer based on microcrystalline cellulose (MCC) extracted from coconut husk waste from Seluma Regency, Bengkulu Province. MCC was prepared through sequential acid washing, alkaline delignification, bleaching, and acid hydrolysis. A composite fertilizer was synthesized by incorporating maleate-containing polymer segments into MCC through limited radical grafting and/or esterification, followed by incorporation of polydihydroxymethylurea potassium phosphate (PDMU–KP) using citric acid as an interaction agent. Fourier transform infrared (FTIR) analysis indicates the presence of carbonyl, amide, and phosphate-related functional groups associated with the composite structure. Scanning electron microscopy (SEM) revealed a dense and agglomerated composite morphology with a rough, layered surface and crystalline aggregates, while energy-dispersive X-ray (EDX) analysis verified the presence of C, N, O, P, and K elements within the copolymer matrix. X-ray diffraction (XRD) analysis showed a reduction in cellulose crystallinity after copolymerization, indicating the formation of a polymer composite. Nutrient release tests conducted in distilled water for 28 days demonstrated controlled and differential release behavior governed by polymer swelling and matrix relaxation processes. Phosphate exhibited a maximum release concentration of 0.398 mg/L on day 7, followed by a gradual decrease to 0.058 mg/L by day 28. In contrast, nitrogen release occurred more gradually, reaching a maximum concentration of approximately 3.08 mg/L on day 14 before declining at later stages. These results indicate that the MCC-g-PMA/PDMU–KP copolymer provides sustained nutrient release with distinct release maxima for phosphorus and nitrogen, highlighting its potential as a cellulose-based slow-release fertilizer designed to improve nutrient use efficiency and reduce nutrient losses, derived from locally available coconut husk waste.
Indonesia’s limited fossil fuel reserves, coupled with increasing national energy demand, highlight the need for alternative and renewable fuel sources. Biomass-derived bio-oil produced through pyrolysis represents a promising solution that can both reduce dependence on petroleum-based fuels and mitigate environmental pollution from underutilized biomass waste. This study investigates the production of bio-oil from candlenut shells and coffee shells through pyrolysis at varying temperatures (250, 350, and 450°C), conducted with and without a NiCl2 catalyst. The bio-oil was characterized for yield, density, and viscosity. The highest bio-oil yields from non-catalytic pyrolysis were achieved at 450°C, amounting to 39.14% for candlenut shells and 41.80% for coffee shells. Catalytic pyrolysis using NiCl2 enhanced the bio-oil yield, producing up to 55.78% (candlenut shells at 450°C) and 58.05% (coffee shells at 350°C). Density measurements showed the highest values in catalytic pyrolysis at 250°C, while the lowest densities were observed in non-catalytic pyrolysis at 450°C. Viscosity followed a similar trend, decreasing with increasing temperature and the presence of the catalyst. FTIR analysis confirmed the presence of functional groups including C–O, C=O, C=C, C≡C, C–H, and O–H. Overall, this study demonstrates the potential of candlenut and coffee shell waste as feasible feedstocks for bio-oil production, offering alternative renewable energy sources for future applications.
Tofu wastewater contains high concentrations of phosphate (PO43−) and ammonium (NH4+), which can cause eutrophication if discharged without proper treatment. One promising method for nutrient recovery and wastewater remediation is struvite (MgNH4PO4·6H2O) precipitation, which simultaneously removes phosphate and produces a slow-release fertilizer. This study investigates the effect of pH variation (8, 9, and 10) and molar ratios of Mg2+:NH4+:PO43− (1:1:1, 4:1:1, and 1:4:1) on phosphate removal efficiency, product yield, and morphological characteristics of the formed crystals. Experiments were conducted with a reaction time of 60 minutes under controlled pH conditions. The results revealed that both pH and molar ratio significantly affected the phosphate precipitation process. The highest phosphate removal efficiency of 89.94% was obtained at pH 9 with a 4:1:1 molar ratio, indicating that excess Mg2+ under moderately alkaline conditions favored struvite formation. In contrast, the highest calculated product yield was observed at pH 8, showing that the condition giving maximum mass-based recovery was not identical to the condition giving maximum phosphate removal efficiency. At pH 10, phosphate removal efficiency decreased, most likely due to the formation of competing Mg(OH)2 precipitates, which reduced the availability of free Mg2+ for struvite crystallization. Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) analysis showed that the struvite crystals exhibited block-like morphologies with irregular surfaces and an average size of 20–50 μm. Although nutrient-release kinetics were not directly measured in this study, the observed crystal size may influence dissolution behavior based on the surface-area effect reported in the literature, supporting the potential application of the recovered struvite as a slow-release fertilizer. Overall, the findings demonstrate that pH 9 and the molar ratio of 4:1:1 represent the optimal conditions for struvite production from tofu wastewater, offering an environmentally sustainable approach to nutrient recovery and contributing to circular economy practices in agriculture.
This study reports on activated carbon/magnetite nanocomposite modified with povidone for the adsorption applications of heavy metal (lead) ions. The synthesis routes used in this study were coprecipitation, activated carbon activation, and ex-situ methods. The data analysis results showed that the activated carbon/magnetite nanocomposite modified with povidone had a crystallite size of 9.45 nm with a single-phase inverse cubic spinel structure. The activated carbon/magnetite nanocomposite modified with povidone showed successful synthesis with the appearance of octahedral and tetrahedral Fe–O lattice vibrations (440 and 550 cm–1), O–H (3200–3395 cm–1), C=O (1655 cm–1), and C–N (1182 cm–1) functional groups. Furthermore, the activated carbon/magnetite nanocomposite modified with povidone exhibited a chunky and spherical morphology, with a particle size of 39.91 nm. The nanocomposite had a large specific surface area and pore volume, namely 129.237 m2/g and 0.198 cm3/g, respectively, thus providing many active sites for adsorption. Interestingly, the nanocomposite was superparamagnetic, facilitating its separation from the solution after adsorption. The adsorption efficiency of this nanocomposite was 71.01% with an adsorption capacity of 29.6415 mg/g in 180 minutes at a volume of heavy metal solution of 25 mL with a theoretical concentration of 100 ppm, adsorbent dose of 0.05 g, pH 5, and room temperature, and followed with pseudo-second order adsorption kinetics model. The resulting removal efficiency is better than magnetite/povidone, which has a removal efficiency of 70%.
Meloxicam (MLX) is a class II BCS non-steroidal anti-inflammatory drug (NSAID) with low solubility and manufacturing challenges due to its needle-like crystal habit, which causes poor flowability and high elasticity. These mechanical characteristics often trigger capping and lamination during direct compression. This study aims to perform physicochemical characterization and mechanical property evaluation of MLX co-crystals with fumaric acid (FUM) co-former, synthesized using the ultrasound-assisted solution co-crystallization (USSC) method. The co-crystals were synthesized at a 1:1 molar ratio in ethanol solvent using ultrasonication. Characterization was performed using a polarizing microscope, PXRD, DSC, and FTIR, followed by evaluation of flow properties, compressibility, and tabletability. The results of PXRD, DSC, and FTIR analyses confirmed the formation of a new co-crystal phase via intermolecular hydrogen-bonding interactions. A morphological transformation was observed from a needle habit to a more isodiametric or plate-like habit. The MLX-FUM co-crystal showed significant improvements in flow rate (0.134 g/sec), angle of repose (33.86°), and compressibility index (38.92%) compared to pure MLX. Tabletability analysis showed a fivefold increase in tensile strength (2.70 MPa) at a pressure of approximately 2.94 MPa (30 kg/cm2), which correlated with a decrease in elastic recovery from 3.18% to 1.96%. This study concludes that co-crystal synthesis by USSC holistically improves the mechanical profile of MLX, showing an improved mechanical profile that demonstrates potential for tablet manufacturing processes using the direct compression method.
This study aimed to synthesize and characterize chitosan/poly(vinyl alcohol) (PVA)-based polymer electrolyte membranes modified with bentonite and LiOH using the solvent casting method. The chitosan:PVA composition was varied from 10:90 to 90:10 to evaluate its effects on the physical, mechanical, thermal, morphological, and electrochemical properties of the membranes. Characterization was conducted through thickness, tensile strength, and porosity measurements, as well as Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy (SEM–EDX), Thermogravimetric Analysis–Derivative Thermogravimetry (TGA–DTG), and Cyclic Voltammetry (CV). The results showed that the membrane with a chitosan:PVA ratio of 10:90 exhibited the highest tensile strength of 19.86 MPa, whereas the membrane with a ratio of 30:70 achieved the highest porosity of 20.49%, which facilitated ion transport and enhanced electrochemical performance. FTIR analysis confirmed intermolecular interactions among chitosan, PVA, bentonite, and LiOH through the O–H, N–H, C=O, Si–O, and Li–O functional groups. SEM–EDX analysis revealed that carbon and oxygen were the predominant elements, while calcium, sodium, silicon, and lithium were also detected, consistent with the membrane composition. Cyclic voltammetry demonstrated typical capacitive behavior, with the current response increasing as the scan rate increased. Meanwhile, TGA–DTG analysis indicated gradual thermal degradation, with the primary decomposition occurring between 350°C and 550°C, demonstrating good thermal stability. Overall, the chitosan/PVA–bentonite composite membrane doped with LiOH shows strong potential as an environmentally friendly polymer electrolyte membrane for energy storage applications, particularly lithium-ion batteries.
Chitosan-HPMC-methylparaben hydrogel film has been successfully synthesized. Chitosan, a key component with desirable characteristics for the production of hydrogel films, has some shortcomings that can be overcome by adding HPMC, a commonly used gelling agent that improves the physical properties of hydrogel films, and methylparaben, which enhances mechanical properties and antibacterial activity. The physical properties test of the hydrogel film, i.e., the solubility and swelling test, showed that the addition of HPMC reduced the solubility ratio and increased the swelling ratio in the chitosan hydrogel film. The addition of methylparaben relatively increases the antibacterial activity, tensile strength, and elongation of chitosan-HPMC-methylparaben hydrogel films. The chitosan-HPMC-methylparaben dry film exhibits a tensile strength of 19.56 MPa and an elongation of 1.98%. Surface morphological characterization of the hydrogel film through SEM tests showed that the chitosan-HPMC-methylparaben hydrogel film has granules on its surface, whereas the chitosan-HPMC hydrogel film has a smooth texture with a flat surface. The addition of methylparaben reduces the degree of crystallinity and produces an amorphous phase. The chitosan-HPMC-methylparaben hydrogel film shows strong activity against S. aureus and E. coli. Based on these results, the hydrogel film can be considered an antibacterial material for wound dressings, although elongation still needs to be improved.
This study presents the verification of the APHA Standard Method 5220 D for determining chemical oxygen demand (COD) in wastewater using a spectroscopic closed-reflux colorimetric system. Both the low range (LR: 0–90 mg O2/L) and high range (HR: 90–700 mg O2/L) methods were verified to ensure their suitability for wastewater monitoring in the industrial estate, with the LR method applied to effluent samples and the HR method applied to influent samples. Method performance was evaluated using linearity, sensitivity, limit of detection (LOD), limit of quantification (LOQ), limit of linearity (LOL), precision, accuracy, and measurement uncertainty for both LR and HR COD levels. The calibration curves exhibited excellent linearity, with coefficients of determination (R2) of 0.9991 (LR) and 0.9996 (HR). The LOD (3Syx/b) and LOQ (10Syx/b) values were 3.34 and 11.14 mg O2/L for LR, and 15.48 and 51.59 mg O2/L for HR, respectively. Precision testing produced %RSD values of 2.88% (LR) and 1.37% (HR), both meeting acceptance criteria based on ⅔ CV Horwitz. Accuracy evaluation using potassium hydrogen phthalate (KHP) standards yielded recoveries of 97.50–106.02% (LR) and 98.83–102.92% (HR), consistent with Association of Official Analytical Chemists (AOAC) requirements. Measurement uncertainty was assessed by combining contributions from calibration, precision, accuracy, and instrumental factors, resulting in expanded uncertainties of ±3.83 mg O2/L for LR and ±13.87 mg O2/L for HR (k = 2). The findings confirm that the method is reliable and suitable for routine COD analysis in wastewater monitoring.
The increasing utilization of biosolar fuels with high FAME (Fatty Acid Methyl Ester) content requires systematic quality evaluation to ensure compliance with fuel quality standards. This study evaluated biosolar fuels with different FAME fractions (B0, B40, B50, B60, and B100), with B40–B60 representing the main blending range and B0 and B100 serving as reference fuels. Fuel quality was assessed based on color, density, flash point, cetane number, distillation characteristics, total acid number (TAN), sulfur content, and water content, with reference to the Indonesian B40 diesel fuel specification under the Cetane Number 48 (CN 48) category as stipulated in Kepdirjen No. 384.K/MG.06/DJM/2024. The results showed that increasing FAME concentration produced a lighter fuel color and increased density from 839.7 kg m−3 (B0) to 876.5 kg m−3 (B100). Flash point increased from 55.6°C (B0) to 80.0°C (B100), while cetane number increased from 47.1 (B0) to 54.9 (B60), indicating improved fuel safety and ignition quality. Distillation temperatures increased with increasing FAME fraction due to the lower volatility of biodiesel components. The Total Acid Number increased from 0.09252 to 0.27320 mg KOH g−1, whereas sulfur content decreased from 0.06622 to 0.00492 % (m/m), reflecting the inherently low sulfur composition of biodiesel. Water content increased substantially from 153.664 mg kg−1 (B0) to 901.970 mg kg−1 (B100) due to the hygroscopic nature of FAME. Activated zeolite treatment, applied at a dosage of 6 g per 500 mL fuel based on preliminary laboratory practice and adsorption conditions applied during the experimental design, reduced water content by approximately 9–24%; however, several blends remained above the allowable limit of 380 mg kg−1. The relatively low flash point observed for B100 may indicate the presence of residual light components originating from production or handling processes and should therefore be interpreted as a limitation of the tested sample rather than a general biodiesel characteristic. These findings indicate that while biodiesel blending improves several fuel properties, effective moisture control remains essential for maintaining the quality and stability of high-FAME biosolar fuels.
Dayak onion (Eleutherine americana (L.) Merr) is known to have potential as an inflammatory pathway modulator as it contains active compounds such as eleutherine, isoleutherine, and eleutol. They are known to have anti-inflammatory, antioxidant, and anti-cancer activities. This study explored the potential of Eleutherine americana (L.) Merr bioactive compounds as COX-2 enzyme inhibitors using an in silico approach. The data were obtained using Lipinski’s rule of 5, ADMET profile prediction, molecular docking, and molecular dynamics simulation. The molecular docking results showed that eleutherin, isoeleutherin, and elecanacin had strong binding affinities of −8.09, −8.19, and −8.06 kcal/mol to the active site of COX-2 with amino acid residues SER530, ALA527, SER353, HIS90, PHE518, LEU384, and PHE381. Meanwhile, MD analysis showed that eleutherin formed stable RMSD Cα interactions at a distance of 1.4 Å for 100 ns with COX-2, while isoeleutherin showed slight fluctuations of 2.5 Å at 75 ns with an average radius of gyration of 24 Å. The findings demonstrate potential for further development, particularly in the exploration of new herbal-based drug discovery using Eleutherine americana (L.) Merr, and can be studied further in vitro and in vivo to validate the drug candidate as a COX-2 inhibitor in anti-inflammatory therapy.
