Science and Technology Indonesia

Spectrophotometry vs Digital Image Colorimetry: Analytical Challenges, Standardization, and Emerging Intelligent Frameworks

Faja Manafiaddin, Nazriati, Hadi Nur — Sun, 21 Jun 2026 00:00:00 +0000

Colorimetric analysis provides a rapid and cost-effective approach for monitoring chemical reactions and determining analyte concentrations. This review examines the strengths and limitations of conventional spectrophotometric methods, known for high precision but high cost and low portability, against digital image colorimetry (DIC). DIC, utilizing smartphones and other portable imaging devices, offers advantages in portability, low operational cost, and alignment with Green Analytical Chemistry principles. However, its analytical performance is often influenced by illumination variability, differences between imaging devices, color-space selection, and calibration strategies. This paper reviews recent developments in DIC, including hardware platforms, color-space transformations, and advanced data processing approaches used to improve analytical performance. Furthermore, to evaluate analytical reliability, this review introduces a novel fuzzy logic-based qualitative reasoning framework. Using a Mamdani-type inference system, the model evaluates the complex interactions between four key variables: lighting stability, device consistency, color-space robustness, and calibration strength. The framework demonstrates that DIC can achieve a "Good" analytical reliability score when lighting is moderately controlled, color-space selection is robust, and calibration strategies are sufficiently strong. However, uncontrolled device variability remains a limiting factor preventing systems from reaching an "Excellent" reliability category, highlighting the ongoing need for methodological standardization in digital colorimetric technologies.

Clustering in Chemical Characteristics and Contaminant Metal Levels of Indonesian Sago Starch: A Comprehensive Analysis of Purity and Quality

Sun, 21 Jun 2026 00:00:00 +0000

Indonesia has the most sago plantations in the world, which means that sago can be used for a wide range of things, including food, animal feed, fuel, fiber, and fertilizer. However, Indonesian sago starch can’t be used more widely in either domestic or international markets because there isn’t enough information about its chemical composition and contaminant levels. This study examines the chemical composition and heavy metal levels of sago starch from various regions of Indonesia. The results show that the chemical properties of sago starch vary from province to province. For example, the carbohydrate content ranges from 84.26% to 94.93%, while the fat and protein content are relatively low. There are also reports of differences in the amounts of amylose and amylopectin. The levels of heavy metals are very low and meet international safety standards, which means that Indonesian sago starch is safe to eat. Sago starch from Indragiri Hilir, Banjarmasin, and Lingga exhibits chemical properties similar to those from Meranti, Indonesia’s primary sago-producing region, suggesting their potential as alternative sources. The appropriate amounts of amylose and amylopectin in these areas make it suitable for food products that require very high flexibility. These results support improving the use of sago starch and help raise the quality and safety standards for Indonesian sago products.

Temperature Estimation of Geothermal Systems and Subsurface Model Based on Geochemical of Lake Ranau

Mochammad Malik Ibrahim, Agung Harijoko, Wiwit Suryanto — Sun, 21 Jun 2026 00:00:00 +0000

The geothermal potential of the Lake Ranau area comes from the remnants of magmatic activity from Mount Seminung. Geothermal manifestations in this area are in the form of hot springs that are thought to emerge through geological structures. This research aims to determine the approximate temperature of the geothermal system and subsurface model based on the analysis of chemical geothermometer method. The chemical geothermometer method can be used to indirectly predict the temperature of the subsurface geothermal system. Geothermal fluid manifestations in Kota Batu Village were chemically sampled by collecting three samples (LP 1, LP 2, and LP 3) and in Lombok Village by collecting three samples (LP 4, LP 5, and LP 6). Chemical geothermometers used in the research are silica, Na/K, K/Mg and Na-K-Ca geothermometers. The results of chemical geothermometer calculations on 6 samples of geothermal fluid manifestation locations, the estimated temperature of the subsurface geothermal system in the research area ranges from 177.0 - 285.6 ⁰C and is included in the geothermal system with medium to high enthalpy. The subsurface model based on the calculation results of various chemical geothermometers about geothermal system components such as cap rock, reservoir rock, heat source, geological structure, thermal fluid and surface manifestations.

Construction of Binary Linear Codes from Zero Divisor Graphs

Vira Hari Krisnawati, Ardi Nur Hidayat, Muhammad Husnul Khuluq — Sun, 21 Jun 2026 00:00:00 +0000

Binary linear codes play an essential role in communication systems by ensuring reliable data transmission. One approach to constructing binary linear codes is through graph theory. In this paper, we study the construction of binary linear codes derived from the incidence matrices of zero divisor graphs of the rings Z(pᵅ) and Z(pᵅqᵝ), where p, q are prime numbers and α, β ≥ 1 are integers. We analyze the parameters of the resulting binary linear codes, such as their length, dimension, and minimum distance. Furthermore, we investigate some examples of the constructed codes. To justify their theoretical and practical relevance, we perform an optimality analysis comparing the constructed codes with classical bounds. All evaluated codes strictly satisfy the Hamming sphere-packing bound. This work offers a new contribution to the study of linear codes by combining ideas from algebra, graph theory, and coding theory.

Molecular Interaction and Crystalline Structure Reorganization of C. esculenta and M. leucadendra Extract-Loaded CS/PVA Electrospun Nanofibers

Atina Atina, Idha Royani, Assa Idah, Miksusanti Miksusanti, Fitri Suryani Arsyad — Sun, 21 Jun 2026 00:00:00 +0000

Understanding the molecular-to-structural evolution of extract-loaded electrospun systems is essential for rationally designing biofunctional nanomaterials. In this study, chitosan/polyvinyl alcohol (CS/PVA) electrospun nanofibers incorporated with Colocasia esculenta (CE) and Melaleuca leucadendra (ML) extracts were systematically investigated to elucidate the correlation between precursor solution interactions and resulting fiber morphology. Raman and UV-Visible spectroscopy were employed to probe molecular interactions and electronic transitions in electrospinning solutions. Extract incorporation induced vibrational band broadening and intensity suppression in Raman spectra, accompanied by increased absorbance and a red shift in UV–Visible spectra, particularly in the ML-containing system, indicating enhanced hydrogen bonding and greater electronic delocalization. Following electrospinning, structural characterization using XRD, FTIR, and SEM revealed progressive crystallinity reduction, peak shifting toward lower diffraction angles, hydrogen-bond-driven band broadening, and morphological evolution from smooth 90.86 ± 1.87 nm fibers (CS/PVA) to thicker 111.89 ± 2.96 nm fibers (CS/PVA/CE) and 118.48 ± 2.98 nm fibers (CS/PVA/ML). No separate crystalline extract phase was detected, confirming molecular-level dispersion within the polymer matrix. The ML-modified system exhibited the highest degree of amorphization and structural reorganization. These results establish a direct structure–property–function relationship, demonstrating that extract-induced modulation of intermolecular interactions governs crystalline organization, electrospinning dynamics, and nanofiber morphology. This study provides mechanistic insight into crystallinity engineering in plant-extract-loaded polymer systems and offers a scalable strategy for designing advanced bioactive electrospun nanomaterials.

Physicochemical Properties and Water Filtration Performance of Electric Field Fabricated Polyvinylidene Fluoride Membranes

Sun, 21 Jun 2026 00:00:00 +0000

This study investigated the use of an electric field-assisted phase inversion method (15 kV) to tailor the properties of PVDF membranes with a thickness of 3 mm. The electric field significantly altered membrane formation, producing porous structures compared to the dense morphology of untreated membranes. Increasing the PVDF concentration (25–35%) reduced the pore size from 11.54 µm to 5.27 µm, resulting in more uniform structures. Surface analysis indicated that the membranes remained relatively smooth, with smaller surface features at higher polymer concentrations. The mechanical properties improved substantially, with the tensile strength increasing from 12.28 MPa to 43.21 MPa and higher stiffness observed. FTIR results revealed enhanced β-phase formation under the electric field, indicating improved chain alignment, supported by increased crystallinity from XRD. In terms of filtration performance, the permeability reached 55.32 L/m²·h·bar, while turbidity rejection exceeded 90% for all treated membranes. These results demonstrate a promising approach for high-performance PVDF membranes and strong potential as composite base materials.

LEDs with Organized InGaN Nanopylons Generating within Green, Yellow, as well as Blue Region

Phan Xuan Le, Nguyen Huy Khiem — Sun, 21 Jun 2026 00:00:00 +0000

The creation of structured settings for InGaN/GaN (I/G) nano-pylon diodes emit illumination (LED) within the green, yellow, as well as blue (GYB) spectrum regions using molecular beam epitaxy has been described. Compared with InGaN (planar) sheets of identical structure and thickness, the gadget’s working area, including one nano-pylon InGaN part for titularly identical element as well as lengthiness between 250 and 500 nm, would be unaffected by prolonged problems. Electroluminescent hue ranges indicate a minor blue change with rising power (nearly non-existent in the yellow gadget) and line wideness that are marginally wider than those of modern InGaN quantum wells. InGaN was also utilized in a phosphor-transmuted white LED (WLED) to enhance its optical attributes such as scattering, lumen, and color rendition. It was found that InGaN has its own advantages and limitations. It was found that adjusting the InGaN discharge to 460 nm would benefit the lumen and color rendition of the WLED under a particle size of 9 µm, while a 450-nm discharge would promote scattering, both of which better match the human sight.

Zagreb-Based Indices of Line Graph of Prime Coprime Graph for Integers Modulo Group

Abdurahim, Mamika Ujianita Romdhini, Jihadil Qudsi — Sun, 21 Jun 2026 00:00:00 +0000

In this paper, we investigate the line graph of the prime coprime graph associated with the integers modulo group. Explicit general formulas are derived for the first Zagreb index, the second Zagreb index, and the hyper-Zagreb index of the considered structures. A comparative analysis is performed between the newly obtained results and previously reported findings, highlighting structural differences and index growth behaviour under the line-graph transformation. Furthermore, a statistical analysis is conducted to explore the quantitative relationship between the prime coprime graph and its corresponding line graph with respect to the computed Zagreb-based indices. The results provide deeper insight into the structural complexity of algebraically defined graphs and clarify how degree-based topological descriptors evolve under graph transformations.

The Utilization of Beta, Sigmoid, and Linear Fuzzy Membership Functions Discretization to Classify AISI 1045 Surface Roughness Levels Using the Ensemble of Multiple Naïve Bayes

Sun, 21 Jun 2026 00:00:00 +0000

Currently, researchers in various fields are using fuzzy discretization for decision-making. Discretization construction for numerical data involving a combination of fuzzy membership functions is significant because it can affect the performance of the model used. Classification of AISI 1045 surface roughness with satisfactory performance is needed to improve efficiency and extend the service life of AISI 1045 products. This study utilizes three fuzzy membership functions: beta, sigmoid, and linear in constructing fuzzy discretization on machining factors and tangential roughness levels to classify the axial roughness level of AISI 1045. Classification is performed using an ensemble of single naïve Bayes methods integrated with fuzzy discretization. These single methods are distinguished based on the combination of fuzzy membership functions used in the discretization. The results of the study show that the integration of fuzzy discretization through a combination of fuzzy membership functions, namely beta, sigmoid, linear, and fellow beta functions in the MNB method provides different performance, even the performance of MNB with fuzzy discretization using a combination of beta and sigmoid is almost the same or not statistically significantly different from the performance of the ensemble method. However, the ensemble method built provides the best performance for classifying the surface roughness level of AISI 1045, with Accuracy, Precision, Recall, F1-score, AUC, Balanced Accuracy, and G-Mean of 85.42%, 55.33%, 73.14%, 62.63%, 71.71%, 81.71%, and 81.04%, respectively.

Shearing Stress-Induced Lipid Accumulation in Chlorella Cultivated in CO₂-Enriched Medium Modified with NaOH

Sun, 21 Jun 2026 00:00:00 +0000

Chlorella can produce MUFA and PUFA, such as linolenic acid, with an ideal ω-3: ω-6 ratio content (1:1). This study investigates the effects of centrifugation-induced shear stress on lipid metabolism and fatty acid composition in Chlorella sorokiniana and Chlorella vulgaris cultivated in CO₂-enriched TAP medium modified with NaOH as an inorganic carbon source. Shear stress was applied during the exponential growth phase to assess its influence on biomass productivity, biochemical composition, and lipid accumulation under nutrient-rich (P1) and nutrient-deficient (P2) conditions. Results revealed that C. sorokiniana showed superior adaptability to shear stress compared to C. vulgaris, showing a 64.7% increase in lipid content and maintaining higher unsaturated fatty acid (UFA) proportions, particularly polyunsaturated fatty acids (PUFAs). In contrast, nutrient deprivation in P2 promoted saturated fatty acid (SFA) accumulation as an energy storage adaptation. Biomass recovery in P1 indicated the need for nutrient availability in sustaining growth following mechanical treatments. The fatty acid profile of C. sorokiniana was dominated by UFA (67.2%), including ω-3 and ω-6 PUFAs, whereas C. vulgaris showed a higher SFA (42.2%). These findings suggest that moderate shear stress can stimulate lipid biosynthesis and improve the nutritional quality of microalgal lipids without compromising cell viability, provided sufficient nutrients are available. The combination of shear stress induction and optimized nutrient management offers a promising strategy to enhance microalgal lipid production for functional food and nutraceutical applications.

Modeling and Forecasting of Sulfur Dioxide (SO₂) Emissions in Several ASEAN Countries (Using State Space Multivariate Time Series Analysis)

Sun, 21 Jun 2026 00:00:00 +0000

Sulfur dioxide (SO₂) emissions (ton/year) produced from coal combustion, household heating, motor vehicles, and volcanic eruptions, has been considered as a dangerous air pollutant that causes many respiratory diseases and increases the mortality rate. Many studies have been conducted generally in developed countries and industrialized countries that are aware of the adverse effects of increasing SO₂emissions in the air. Many studies have been conducted to measure the level of air pollution caused by SO₂ emissions and research on the relationship of SO₂ emissions with public health and mortality rates. The problem in this study is how to build the best State Space Multivariate Time Series model for SO₂ emissions data in several ASEAN countries, Indonesia, Thailand, Philippines and Malaysia. This study aims to build the best State Space Multivariate Time Series model that fits the data and uses the best state space model for forecasting SO₂ emissions for the next few years. The analysis method that will be used is State Space Multivariate Time Series Analysis (Autoregressive Vector modeling, and State Space Model). The results show that SO₂ emissions in Indonesia are significantly influenced by emission conditions in Indonesia four years earlier and SO₂ emissions in Malaysia two and four years earlier; SO₂ emissions in Thailand are significantly influenced by SO₂ emission conditions in Thailand and the Philippines one year prior; SO₂ emissions in the Philippines are significantly influenced by SO₂ emission conditions in Thailand one years prior and SO₂ emission conditions in the Philippines four years prior; SO₂ emissions in Malaysia are significantly influenced by SO₂ emissions conditions in Indonesia two, three, and five years prior, SO₂ emissions conditions in Malaysia four years prior, SO₂ emissions conditions in Thailand and Philippines five years prior. Forecasting results using the state space model indicate a downward trend in SO₂ emissions in Indonesia, Thailand, the Philippines, and Malaysia over the next ten years.

Effect of Deformation by Wire Drawing on the Mechanical and Electrical Properties of Aluminum

Sun, 21 Jun 2026 00:00:00 +0000

This research investigates the influence of cold wire drawing on the electromechanical properties of high-purity (99.7%) aluminum conductors. Aluminum wires were subjected to progressive plastic deformation, with cross-sectional reduction rates ranging from 11.25% to 88.44%. The results demonstrate that mechanical deformation significantly enhances the ultimate tensile strength, reaching a peak value of 116.14 MPa and a Vickers hardness of 57.63 HV at the maximum reduction rate. Conversely, a marked reduction in elongation at break was observed, indicating a loss of ductility due to intense work hardening. Regarding electrical performance, the study reveals that electrical resistivity increases by only 0.87% over the full deformation range, while electrical conductivity exhibits a proportional decline. This degradation in transport properties is physically attributed to the increased density of lattice defects (dislocations) acting as electron scattering centers. These findings highlight the critical trade-off between mechanical reinforcement and electrical efficiency, providing essential data for the optimization of high-performance conductors for power transmission.

Numerical Solution of the Gardner Equation Using the Method of Lines and an Improved Fifth-Order Runge-Kutta Scheme

Dismahayuna Pratyamifta Naisya Putri, Ummu Habibah — Sun, 21 Jun 2026 00:00:00 +0000

The Gardner equation is a nonlinear partial differential equation that arises in the modeling of nonlinear dispersive wave phenomena. Analytical solutions of this equation are limited to specific cases, which motivates the development of reliable numerical approaches. This study presents a numerical scheme based on the Method of Lines combined with an Improved Runge-Kutta method of order five to solve the Gardner equation. Spatial discretization is performed using second-order central finite difference schemes, which transform the governing equation into a system of ordinary differential equations. The resulting system is integrated in time using the fifth-order Improved Runge-Kutta method to achieve high accuracy and computational efficiency. Simulations targeting solitary pulse and kink-like wave solutions reveal that the MOL-IRK5 scheme consistently outperforms the classical MOL-RK4 method. The numerical results show strong agreement with the exact solutions at all observed time levels. Wave profiles are preserved during propagation, and no spurious oscillations are observed. Global error measures, including the maximum error, mean absolute error, and root mean square error, remain small throughout the simulation interval, indicating stable numerical performance. The results demonstrate that the proposed MOL-IRK5 scheme provides accurate and efficient approximations for different types of Gardner equation solutions. The numerical approach presented in this study offers a reliable framework for solving nonlinear dispersive equations and can be extended to more complex mathematical models in applied science and engineering.

Product Development of Diffusion Solution from Citrus reticulata Blanco Essential Oil

Tran Thien Hien, Nguyen Nam Do, Mai Huynh Cang — Sun, 21 Jun 2026 00:00:00 +0000

The aim of this study was to develop a diffuser solution product from Citrus reticulata Blanco essential oil, which was recovered by hydrodistillation. The hydrodistillation process was influenced by factors such as: raw material grinding time (grinding for 40s); raw material/solvent ratio (1/3 g/mL); raw material moisture content (70%), and extraction time (120 min) with an essential oil content of 0.254 mL/g dw. Using gas chromatography-mass spectrometry (GC-MS), 21 chemical components in Citrus reticulata essential oil were identified, of which the main compound was limonene, accounting for 94.64%. Thanks to its biological activities, Citrus reticulata essential oil is widely used in the field of developing household care products, including diffuser solutions. The results showed that with the IPM base oil content of 25%, the essential oil content of 40%, and the emulsifier PEG-40 of 20% combined with 96% ethanol at a content of 5%, preserved in a dark glass bottle to bring a product with good sensory scores in terms of uniformity, scent, and volatility. The diffuser solution product created helps to utilize the by-product material from Citrus reticulata peel to produce essential oil, contributing to increasing the usage value of the Citrus reticulata tree. This study is novel in that it combines hydrodistillation-process selection with the formulation of a passive diffuser solution from Citrus reticulata peels by-products, thereby connecting essential-oil recovery with aroma-delivery design in a single product-oriented workflow.

Bioactivity Study of Russelia equisetiformis Ethanol Extract as an MCF-7 Breast Cancer Cells Inhibitor with In vitro and In silico Approaches

Sun, 21 Jun 2026 00:00:00 +0000

Russelia equisetiformis has been used in traditional medicine, but its molecular mechanisms against breast cancer remain unexplored. This study aimed to investigate the cytotoxic potential of R. equisetiformis ethanol extract and elucidate its molecular interactions through a combined in vitro and in silico approach. Cytotoxicity evaluation using the Resazurin assay demonstrated the extract’s activity against MCF-7 breast cancer cells with an IC50 value of 352.60 ± 0.23 ????g/mL. To understand the underlying mechanism, the identified bioactive compounds that passed the druglikeness test were analyzed using molecular docking against the Progesterone Receptor (PDB ID: 2W8Y) and Estrogen Receptor-alpha (PDB ID: 3ERT). Docking analysis revealed that these compounds form binding interactions with target receptors, providing insight into their potential mechanism of action, albeit with lower affinity compared to standard drugs (tamoxifen and anastrozole). Importantly, ADMET prediction using ProTox 3.0 highlighted apigenin, kaempferol, isokaempferide, and kaempferol 3-O-rhamnoside as the most promising primary candidates, demonstrating inactivity against hepatotoxicity, carcinogenicity, and cytotoxicity. These findings provide initial scientific evidence for the potential anticancer properties of R. equisetiformis compounds, indicating that all four compounds are safe and viable bioactive candidates for further development as non-toxic therapeutic agents.

Engineering the Anatase-Rutile Phase Composition of TiO2 through H2O2 Addition and Its Photocatalytic Activity

Sun, 21 Jun 2026 00:00:00 +0000

The synthesis of mixed-phase anatase–rutile TiO₂ has been carried out to improve its light response and photocatalytic activity. The synthesis of mixed-phase TiO₂ was performed through a sol–gel method in an alkaline solution and followed by a hydrothermal process in an autoclave at a temperature of 150 °C for 3 h. A 60 mL of 0.5 M HNO₃ was then added into the TiO₂ precipitate, followed by the addition of various amounts (0 mL, 10 mL, and 20 mL) of 30% H₂O₂. The suspension was homogenized by sonication for 30 min to obtain an anatase–rutile mixed phase. The resulting mixed-phase TiO₂ was further labeled as A0, A1, and A2, respectively. The High-Score analysis showed that the phase composition of TiO₂ was 9.4% anatase and 90.6% rutile (A0); 17% anatase and 83% rutile (A1); and 49.6% anatase and 50.4% rutile (A2). The diffuse reflectance spectra showed a shift in the band gap energy from 3.17 eV (fully anatase TiO₂) to 2.75–2.86 eV in A0, A1, and A2 mixed-phase TiO₂. These results suggested that the photocatalytic activity of A1 and A2 mixed-phase TiO₂ would occur in the early visible-light region (λ > 400 nm). The photocatalytic examination of the mixed-phase TiO₂ under LED and UV irradiation resulted in a decrease in rhodamine-B (Rh-B) concentration of up to 92%. However, the photocatalytic activity of mixed-phase TiO₂ did not outperform that of fully anatase TiO₂, which achieved a 98% reduction in Rh-B concentration.

Structural Modification of Bentonite by Rice Husk Biochar for Enhanced Methylene Blue Removal under Visible Irradiation

Neza Rahayu Palapa, Elsa Irma Esthomihi Manurung, Yulizah Hanifah, Davin Philo — Sun, 21 Jun 2026 00:00:00 +0000

The development of sustainable and low-cost materials for wastewater treatment remains an important environmental challenge. In this study, a bentonite-biochar (Bnt–Bc) composite was prepared through structural modification of bentonite using rice husk–derived biochar followed by KOH-assisted activation. The physicochemical properties of the materials were systematically characterized using XRD, BET, FTIR, SEM, and UV–Vis diffuse reflectance spectroscopy. The results revealed that biochar incorporation modified the interlayer structure of bentonite, resulting in reduced crystallinity, pore structure alteration, and the introduction of additional oxygen-containing functional groups. These structural changes contributed to improved surface reactivity and enhanced interaction with dye molecules. The performance of the materials was evaluated for methylene blue (MB) removal under Visible Light irradiation. The Bnt–Bc composite exhibited significantly higher removal efficiency compared to pristine bentonite and biochar, achieving up to 98% MB removal within 150 min. Kinetic analysis indicated that the removal process followed a pseudo-first-order model. The enhanced performance is attributed to the combined effects of improved adsorption capacity, surface functional groups, and photo-assisted degradation under Visible Light irradiation. This study demonstrates that biochar modified bentonite composites derived from agricultural waste represent a promising and environmentally friendly material for dye-contaminated wastewater treatment.

Nano-Enhanced Tri-Organotin (IV) Complexes from a Ciprofloxacin Hybrid: Synthesis, Characterization, and Superior Antifungal Activity

Aliyaa Dhahir Mohsin, Angham G. Hadi, Rana A. K. Al-Refaia — Sun, 21 Jun 2026 00:00:00 +0000

Organotin (IV) compounds are of significant interest in both the chemical and medicinal sectors. Among these, tri-organotin (IV) derivatives (R3SnX) stand out due to their potent biological activity and their distorted trigonal bipyramidal geometry. The present study details the synthesis, nano-formulation, and improved antifungal activity of three new tri-organotin (IV) complexes. These complexes have been synthesized from a hybrid ligand, formed from ciprofloxacin and 5-aminosalicylic acid, followed by modification of the carboxylate functional group with chloroacetic acid. These compounds have been completely characterized by FT-IR, multinuclear NMR spectroscopy (¹H, ¹³C, ¹¹⁹Sn), and CHNS analysis. To enhance their biological activity, the synthesized complexes have been nano-formulated with triangular silver nanoparticles (AgTNPs). The antifungal activity of both pure and nano-formulated complexes has been investigated against Fusarium spp. In vitro antifungal assays against Fusarium spp. revealed that the triphenyltin complex (T3) was the most active among the pure compounds, achieving a 20% inhibition rate at 2 mg/mL, attributed to its high lipophilicity and aromatic content. Remarkably, the nano-formulated version (AgTNPs-T3) demonstrated a significant synergistic effect, increasing the inhibition rate to 55% at the same concentration, a 2.75-fold enhancement compared to the unmodified complex. This superior performance is attributed to the high surface area-to-volume ratio and sharp vertices of the AgTNPs, which facilitate better membrane penetration and ROS generation.

Preparation of Carrageenan/Chitosan/Curcumin Hydrogel Films: Physicochemical Characterization and In Vitro Evaluation as a Promising Diabetic Wound Dressing

Sun, 21 Jun 2026 00:00:00 +0000

Wound dressings with their physical characteristics that can maintain moisture and their active content which possesses antibacterial and antioxidant properties, represent a crucial solution in addressing the delayed healing of diabetic wounds. For this purpose, in this work we prepared hydrogel films made from a combination of carrageenan, chitosan, and curcumin, and subsequently evaluated their performance for potential application as the diabetic wound dressings. There were three hydrogel film formulations fabricated using 0.5% chitosan, 0.05% curcumin, and carrageenan at varying concentrations of 1%, 1.5%, and 2%, which were subsequently designated as A1, A2, and A3, respectively. These films were examined for physical parameters, chemical profiles, antibacterial activity against Staphylococcus aureus and Escherichia coli, and antioxidant activity (DPPH assay). The A2 film formulation demonstrated optimal characteristics, as evidenced by a high swelling capacity of 1439.67 ± 20.36%, an appropriate moisture content of 20.63 ± 0.49%, a film pH of 6.23 ± 0.31%, favorable degradation behavior of 93.27 ± 1.36%, and a film thickness of 0.20 ± 0.001 mm. This formulation also demonstrated superior antibacterial activity against Staphylococcus aureus and Escherichia coli, accompanied by strong antioxidant activity (IC₅₀ = 74.52 ppm). Such results indicate that the carrageenan/chitosan/curcumin hydrogel film, particularly formulation A2, is a promising smart hydrogel dressing candidate for diabetic wound applications.

PVA/PVP Dissolving Microneedle Arrays Loaded with Parameria laevigata Extract: Formulation and Characterization for Transdermal Anti-Acne Therapy

Sun, 21 Jun 2026 00:00:00 +0000

Despite the well-documented antimicrobial and antioxidant properties of Parameria laevigata (kayu rapet) bark, its incorporation into a dissolving microneedle (DMN) platform for transdermal acne therapy has not been previously investigated. This study developed and characterized PVA/PVP-based DMN arrays loaded with P. laevigata extract as a minimally invasive delivery system targeting acne-associated pathogens. Ultrasonic-assisted extraction in 95% ethanol yielded a phytochemical-rich extract (8.68%) containing flavonoids, tannins, saponins, and alkaloids, with strong antioxidant activity (DPPH IC50 = 40.98 ± 4.32 ppm; ABTS IC50 = 46.92 ± 3.25 ppm; FRAP = 70.24 ± 6.41 mg AAE/g extract) and moderate antibacterial activity against Acne vulgaris-associated bacteria Staphylococcus aureus and Cutibacterium acnes at 100–150 ppm (inhibition zone: 8.22–8.46 mm). Eight DMN formulations were fabricated at a fixed 30% w/w PVA/PVP total polymer concentration with 5% extract loading. The optimized formulation (F2) produced a complete 49-needle pyramidal array with adequate mechanical integrity for stratum corneum penetration, confirmed polymer–extract physicochemical compatibility by FTIR, and exhibited Korsmeyer–Peppas release kinetics with a diffusion-controlled mechanism reaching 56.48% cumulative release over 24 h. These findings establish P. laevigata-loaded DMN arrays as a viable proof-of-concept platform for transdermal acne therapy, warranting further ex vivo permeation and in vivo efficacy validation.

Comparative Valuation of Employee Stock Options Using CRR and Enhanced American Models with Vesting and Exit Effects

Dara Puspita Anggraeni, Abdurakhman, Noorma Yulia Megawati — Sun, 21 Jun 2026 00:00:00 +0000

Employee stock options (ESOs) are required to be measured at grant-date fair value under existing accounting standards, yet classical lattice models typically assume frictionless exercise behavior. In practice, ESO contracts incorporate vesting restrictions, employee exit risk, and behavioral exercise triggers that can materially affect valuation outcomes. This study provides a structural comparison between the Cox-Ross-Rubinstein (CRR) American model and the Enhanced American (EA) framework within a unified binomial setting in which the probabilistic return process constant to isolate employment-related frictions. An analytical dominance result is established, showing that EA valuations remain strictly below the CRR American benchmark under these frictions. Numerical experiments confirm the theoretical ordering and quantify its economic magnitude: under moderate frictions, valuation gaps remain limited to approximately 2-3%, whereas under high exit intensity and conservative trigger thresholds, the discount expands substantially to approximately 65-69%, particularly for long-dated and near-the-money contracts. Heatmap analysis across volatility and dividend regimes further demonstrates that this dominance ordering persists under economically relevant parameter variations. The findings indicate that employment-related frictions constitute a materially significant component of ESO valuation and that model choice within fair-value measurement frameworks can meaningfully influence reported compensation expenses.

The Locating-Chromatic Number of Disjoint Union of Cycles

Sun, 21 Jun 2026 00:00:00 +0000

Chartrand et al. introduced the idea of the locating-chromatic number of connected graphs in 2002. Let c be a disconnected graph H with k-coloring. Let S_i be the set of all vertices that get color i and let Phi be the partition of V(H) induced by c. The color code C_Phi(v)=(d(v,S_1), d(v,S_2), ..., d(v,S_k)) of a vertex v, where d(v,S_k)=min{d(v,x)} . The locating k-coloring of H is denoted by c if all vertices in H have unique distinct color codes. Welyyanti et al. in 2014 expanded on this idea so that it also applies to unconnected graphs. In this work, for n=>3 and m=>2, we calculate the locating-chromatic number of the disjoint union of cycles, represented by mC_n.

Semiparametric Path Analysis with Truncated Spline: A Simulation Study with Double Resampling Inference

Sun, 21 Jun 2026 00:00:00 +0000

This study proposes a semiparametric path analysis framework that integrates truncated spline modeling with resampling-based inference to capture both linear and nonlinear relationships within a unified structure. The motivation arises from the limitation of conventional path analysis, which relies on linearity assumptions that are often violated in empirical data, as indicated by the Ramsey RESET test. To address this issue, a truncated spline approach is employed to flexibly model nonlinear relationships, while statistical inference is conducted using double resampling techniques. A simulation study is performed to evaluate the performance of resampling methods under varying conditions. The results show that for a sample size of n=200 with a single nonlinear relationship, the double jackknife method provides more stable and efficient estimates compared to alternative approaches. This finding motivates its application in the empirical analysis. The empirical results, based on data from East Java, Indonesia, reveal that technology access has a significant direct effect on both financial knowledge and financial literacy. A nonlinear relationship is identified between technology access and financial literacy, characterized by a threshold effect captured through truncated spline modeling. However, the indirect effect through financial knowledge is found to be statistically insignificant. Overall, the proposed approach offers a flexible and robust framework for modeling complex causal relationships and improves inference accuracy in semiparametric path analysis.

Development of a Potential Prebiotic Film Based on Sago Flour and Kepok Plantain Peel Starch with Prebiotic Properties to Support Lactobacillus plantarum Growth

Sun, 21 Jun 2026 00:00:00 +0000

Innovative prebiotic carriers that can be directly integrated into foods are increasingly sought for functional food development. This study developed prebiotic starch films using sago flour and starch from kepok plantain (Musa paradisiaca) peel, designed as intrinsic prebiotic components rather than packaging. Films were formulated with 1%, 3%, and 5% plantain peel starch and characterized for physicochemical properties, morphology, and their prebiotic effect on Lactobacillus plantarum. Higher starch concentrations increased film thickness (0.13–0.18 mm) and moisture content (11.42–16.24%), while significantly decreasing water solubility (55.31–41.14%) (p < 0.05). Tensile strength was low (0.17–0.27MPa) and elongation high (89.28–178.10%). FTIR confirmed polysaccharide functional groups; SEM revealed heterogeneous fibrous structures. Resistant starch in films (1.89–3.76%) was lower than raw starch (38.91%) due to gelatinization. The 5% starch film supported the highest L. plantarum viability (26 × 10⁸ CFU/mL), compared to 3% (23 × 108 CFU/mL) and 1% (21 × 10⁸ CFU/mL), demonstrating that plantain peel starch acts as an effective intrinsic prebiotic without commercial prebiotics. The composite film shows potential as active packaging or a probiotic carrier in functional foods, although mechanical and water barrier optimization is still required.

The Transportation Planning for Cost Optimization in Cold-Chain Distribution: A Case Study

Chatchai Sutikasana, Sanit Pattane, Sasiwimon Wongwilai, Weenakorn Ieosanurak — Sun, 21 Jun 2026 00:00:00 +0000

Cold chain logistics for perishable goods faces increasing challenges in balancing product quality and cost efficiency. This study proposes a mixed integer linear programming (MILP) model that jointly optimizes transportation and inventory decisions in temperature-controlled supply chains by incorporating both transportation and perishability-related holding costs within a multi-node distribution network. A real-world case study based on a ten-node cold chain system in Thailand is used to validate the model. The results indicate that the proposed approach effectively determines routing structures, shipment quantities, and vehicle utilization while accounting for product deterioration. Compared with experience-based planning, the proposed model reduces total logistics cost by 8.02%, primarily through improved transportation efficiency. These findings demonstrate the importance of integrating routing decisions with perishability considerations and highlight the model’s potential as a practical decision-support tool for cold chain logistics operations.

Synergistic Integration of Multi-Sensor Satellite Data and Gradient Boosting Machine Learning for High-Resolution PM₂.₅ Estimation during Tropical Peatland Fires

Sun, 21 Jun 2026 00:00:00 +0000

Tropical peatland and forest fires are critical contributors to regional haze and public health crises, yet ground-based monitoring in these regions remains sparse. This study develops a robust framework for estimating surface PM₂.₅ concentrations during extreme fire events (2021–2025) by integrating multi-sensor satellite observations with in-situ data through a Hist Gradient Boosting Regressor (HGBR) approach. To enhance predictive accuracy, we implemented advanced feature engineering, including 1–3 days of exogenous lags, rolling statistics (3 and 7-day windows), and aerosol–meteorological interaction variables. Our analysis of multiple pollutants (PM₂.₅, NO₂, SO₂, CO, HC, and O₃) reveals that during active fire periods, the Air Quality Index (AQI) frequently escalated to "Unhealthy" and "Hazardous" levels. The proposed HGBR model demonstrated high fidelity in representing spatiotemporal variability, achieving a coefficient of determination (R² = 0.72), with an RMSE of 14.26 μg/m³ and MAE of 8.49 μg/m³ (n = 339). These results validate the efficacy of machine learning-driven satellite monitoring in bypassing the limitations of fragmented ground station networks. This framework offers a scalable solution for operational air quality forecasting and early warning systems in fire-prone equatorial regions.

Interlinkage of Drought, Fire Severity, Vegetation Degradation, and Hydrological Response in Peatland Ecosystems

Mokhamad Yusup Nur Khakim, Azhar Kholiq Affandi, Erni, Mardia Ulfa — Sun, 21 Jun 2026 00:00:00 +0000

Peatlands, as fragile ecosystems, are vulnerable to deforestation and altered hydrological regimes. The objectives of this study were to evaluate the effects of deforestation on runoff, drought, and fire severity in nine Peat Hydrological Units (KHG) in South Sumatra, Indonesia, in 2014–2025. The deforestation map was created by analyzing the Landsat-8 image through Spectral Mixture Analysis (SMA) and the Normalized Difference Fraction Index (NDFI). The runoff was modeled using the Soil Conservation Service-Curve Number (SCS-CN) method based on downscaled land cover, CHIRPS, GLDAS, and MODIS data. The drought condition was evaluated using the Vegetation Health Index (VHI), and fire severity was evaluated based on the Relativized Burn Ratio (RBR). The findings indicate that in 2015, the most significant deforestation occurred with the value of NDFI decreasing by > 0.25. In 2015, the highest annual rainfall during the study was 1828 mm, with an anomaly of 1-m topsoil moisture reaching −11.35 mm. Extreme drought (VHI < 0.1) occurred in > 35% of the area of S. Merang – S. Ngirawan and S. Lalan – S. Merang watersheds. Also, the 2015 fires had the largest area of moderate and high (RBR > 0.27) compared to the 2019 and 2023 fires. Deforestation also increased hydrologic response in the watershed as the annual runoff coefficient increased from 13% in 2015 to 15% in 2016 due to a decrease in infiltration from vegetation loss. As a conclusion, this study showed that deforestation increased runoff, drought conditions and peat fires. Our findings are important for evidence-based strategies on fire mitigation and hydrological management in tropical peatlands.

Initial Assessment of a Dual-Bioactive Hydrogel Incorporating Phagocytosis-Stimulating and Tissue-Regenerative Proteins for Enhanced Wound Healing

Sun, 21 Jun 2026 00:00:00 +0000

Wound healing is a complex process that can be impaired by various factors. Hydrogel is a recommended choice for keeping the skin moist and enhancing wound healing. Hydrogel can contain bioactive compounds to improve wound healing effectiveness further. Phagocytosis activating protein (PAP) and thrombospondin (TSP) can stimulate macrophage and promote cell proliferation. They had the potential to enhance wound healing when incorporated into a hydrogel. This study aims to evaluate the effect of PAP and TSP hydrogel on irritation and wound healing efficacy in a rat model. This experiment is conducted using a full-thickness wounds model in rats. The hydrogel formulations with PAP and/or TSP were applied to the wounds for 21 days. The wound contraction, histology, and TGF-β1 expression were measured. The results showed that low-dose PAP hydrogel had the best wound healing performance among all groups, with high TGF-β1 levels in the early phase and low levels in the late phase. Low-dose TSP hydrogel had similar but weaker effects than low-dose PAP hydrogel. There was no sign of skin irritation for all formulations. Hydrogel containing a low dose of PAP or TSP is a promising formula for further developing new wound dressing materials. It also opens an opportunity to cure some challenging to-treat wounds, such as diabetic and burn wounds.

Effect of Plant Age and Altitude on the Essential Oil Composition of Cinnamomum cullilawan from Maluku, Indonesia

Sun, 21 Jun 2026 00:00:00 +0000

Cinnamomum cullilawan Blume from Maluku is a potential source of essential oil for pharmaceutical, cosmetic, food, and natural product-based industries. This study evaluated the effects of plant age and elevation on the yield and chemical composition of C. cullilawan essential oil. Bark samples were collected from four different locations (n = 4), representing plant ages of 8, 10, 15, and 20 years and different elevation gradients. Essential oils were extracted by steam distillation and analyzed using gas chromatography–mass spectrometry (GC–MS). Statistical analyses included linear regression, Analysis of Variance (ANOVA), partial t-test, and Principal Component Analysis (PCA). The essential oil yield ranged from 0.84% to 1.83%, with the highest yield obtained from 20-year-old plants (1.83%). ANOVA showed that plant age and elevation had a significant simultaneous effect on essential oil yield (p = 0.04), with significant partial effects of plant age (p = 0.026) and elevation (p = 0.034). GC–MS analysis revealed that eugenol and linalool were the dominant compounds. The highest eugenol content was found in 8-year-old plants (92.35%), whereas samples from higher elevation showed the highest linalool content (24.45%) and the lowest safrole content (0.76%). Statistical analysis indicated that eugenol (p = 0.03), safrole (p = 0.038), linalool (p = 0.047), and terpineol (p = 0.038) were significantly influenced by plant age and elevation, while other minor compounds showed no significant effect (p > 0.05). PCA showed that the first two principal components accounted for 83.14% of the total variation. These findings indicate that ontogenetic and ecological factors influence essential oil yield and chemical composition and may contribute to shifts in the relative dominance of phenylpropanoid and terpenoid compounds, providing a scientific basis for optimizing cultivation and standardizing C. cullilawan essential oil quality.

Development of a Natural Antifungal Shampoo Containing Clove Bud Oil (Syzygium aromaticum): Formulation and in Vitro Evaluation

Afia Khaira, Tantri Nareswari, Refsya Azanti Putri, Achmad Gus Fahmi — Sun, 21 Jun 2026 00:00:00 +0000

Dandruff affects approximately 50% of the global population during their lifetime. Clove bud oil (Syzygium aromaticum) (CBO), which is currently utilized mainly in the cigarette industry, has potential as an anti-dandruff agent because of its antifungal activity. This study aimed to optimize cocamide DEA and sodium lauryl sulfate (SLS) concentrations in CBO shampoo formulations and to evaluate the preliminary antifungal activity of the optimum formulation against Candida albicans as a model fungal organism, compared with a commercial ketoconazole shampoo (Ketomed®). CBO quality was characterized through organoleptic evaluation, specific gravity determination, ethanol solubility testing, Thin Layer Chromatography (TLC), and GC–MS analysis. GC–MS confirmed eugenol (76.88%) and β-caryophyllene (16.18%) as the major constituents of the oil. The shampoo formulations were prepared using the emulsification method followed by a two-stage surfactant optimization process. The first optimization identified 8% cocamide DEA as the optimum concentration, producing a viscosity of 3915 ± 59 cPs and foam height of 10.43 ± 0.20 cm. The second optimization demonstrated that 8% SLS provided the most favorable physicochemical characteristics and washing performance. The optimum formulation exhibited antifungal activity against C. albicans with an inhibition zone of 24.06 ± 3.01 mm, compared with 32.50 ± 1.44 mm for Ketomed®, which corresponded to approximately 74% relative antifungal efficacy. These findings suggest that CBO shampoo possesses promising potential as an antifungal anti-dandruff formulation while also providing an alternative value-added utilization of clove oil. This study was limited to in vitro evaluation against a single microorganism, C. albicans, and further in vivo and clinical studies remain necessary to confirm the efficacy and safety of the developed formulation.

Land Cover Classification Using LAPAN-A3 and Sentinel-2 Imagery in Google Earth Engine: A Machine Learning-Based Comparative Analysis

Sun, 21 Jun 2026 00:00:00 +0000

Open-source satellite imagery such as Sentinel-2 has been widely proven reliable for various geospatial applications. However, achieving geospatial independence remains crucial for any country to reduce reliance on foreign data sources and strengthen national sovereignty in Earth observation capabilities. In this context, Indonesia initiated a microsatellite development program in 2007, which has now reached its third generation with LAPAN-A3. Despite these efforts, LAPAN-A3 is still considered an experimental satellite, and further evaluation is required before it can be fully adopted for operational applications. This study evaluates the performance of LAPAN-A3 imagery for land cover mapping using machine learning approaches and compares its performance with the well-established global dataset Sentinel-2. Two widely used classifiers, Random Forest (RF) and Support Vector Machine (SVM), were implemented within the Google Earth Engine (GEE) platform and tested using different combinations of spectral features. The results show consistent improvements in classification performance when additional spectral features are incorporated for both LAPAN-A3 and Sentinel-2 datasets. In all feature configurations, RF outperforms SVM, achieving higher Overall Accuracy (OA) and Kappa coefficients. Although Sentinel-2 generally yields slightly better results, LAPAN-A3 demonstrates promising performance despite its experimental nature. These findings highlight the potential of LAPAN-A3 as a national remote sensing asset that can contribute to Indonesia’s long-term goal of achieving geospatial independence and strengthening domestic Earth observation capabilities.

Root-Derived Phytochemicals from Inula confertiflora for Antioxidant and Antibacterial Activities

Sun, 21 Jun 2026 00:00:00 +0000

Inula confertiflora, a medicinal herb indigenous to Ethiopia, often used in traditional treatments for inflammatory and pain-related conditions. The root of I. confertiflora was soaked with n-hexane, ethyl ether, and acetone solvents. The proportion of crude extracts derived from ethyl ether extracts was 1.4 times higher than that of n-hexane and 1.2 times higher than that of acetone. Analytical detection results of crude extracts confirmed that I. confertiflora contained a variety of different preliminary phytochemicals. The higher concentrations of total flavonoids and other polar phytoconstituents present in the ethyl ether extracts were associated with greater radical-scavenging effectiveness in the DPPH solution. More than half of the bacterial growth efficiency was restricted by phytochemicals derived from I. confertiflora root extracts using non-polar, medium-polar, and high-polar solvents. It is crucial to note that medium-polar extracts of I. confertiflora root decreased the inhibitory effect on the development of both gram-positive and gram-negative bacterial strains at a concentration of 100 μg/mL using acetone as the solvent. Additionally, they exhibited improved radical scavenging against a DPPH solution. Moreover, molecular docking simulation clearly revealed that I. confertiflora extracts have a strong binding affinity toward four key bacterial target proteins (LasB (-7.9kcal/mol), PBP2a (-8.0kcal/mol), FabH (-11.3kcal/mol), and MurA1 (-4.7kcal/mol)). Collectively, these findings suggest that I. confertiflora extracts exhibit substantial potential as antibacterial agents by targeting diverse and functionally important bacterial proteins.

Polysaccharide-Stabilized Butterfly Pea Flower (Clitoria ternatea) Anthocyanin as Natural Photosensitizer against MRSA: In Silico and In Vitro Evaluation

Sun, 21 Jun 2026 00:00:00 +0000

Butterfly pea flower (Clitoria ternatea) anthocyanins have potential as natural photosensitizers for photothermal–photodynamic therapy (PTT/PDT) against Methicillin-resistant Staphylococcus aureus (MRSA), but their inherent instability under pH and thermal stress limits therapeutic utility. This study evaluated polysaccharide-based stabilization systems for butterfly pea anthocyanin extract (BPFE) and assessed their photosensitizer performance through in silico and in vitro approaches. Dried flower extraction using 60% ethanol with 30-minute maceration and 45-minute ultrasonic-assisted extraction yielded a total anthocyanin content of 5.037 ± 0.395 mg CGE/L with a photothermal efficiency of 52.34 ± 7.93% at 450 nm and 22.21 ± 2.35% at 550 nm. Molecular docking against penicillin-binding protein 2a or PBP2a (PDB: 1MWU) showed that all 18 screened compounds demonstrated binding affinities of −7.4 to −11.1 kcal/mol. The extract at 8% produced an inhibition zone of 10.67 ± 0.94 mm against S. aureus (p < 0.0001), establishing the minimum inhibitory concentration. Among six polysaccharide stabilization systems evaluated, the freeze-dried konjac glucomannan system (F-KJC) demonstrated the most consistent pH stability and lowest thermodynamic degradation (23.85% vs. 39.80% for BPFE over six freeze-thaw cycles), supported by FTIR evidence of non-covalent hydrogen bonding. Singlet oxygen quantum yield of F-KJC (Φ = 0.4740) exceeded BPFE (Φ = 0.3014). Under 550 nm irradiation, F-KJC significantly inhibited MRSA growth compared with non-irradiated controls, while 450 nm irradiation did not produce a statistically significant photothermal enhancement. These findings support polysaccharide stabilization, particularly the freeze-dried konjac system, as a viable strategy for enhancing the photosensitizer performance of butterfly pea anthocyanins against MRSA.

Unravelling the Potential of Wild Endemic Sumatran Turmeric (Curcuma sumatrana Miq.) as a Candidate of Herbal Medicine for Neurodegenerative Diseases

Sun, 21 Jun 2026 00:00:00 +0000

Neurodegenerative diseases pose significant health challenges, while synthetic drugs are often associated with detrimental side effects. Hence, the search for herbal medicines is warranted. Curcuma sumatrana is traditionally used by Minangkabau people as a herbal medicine, but it remains scientifically underexplored. This study aims to evaluate its neuroprotective potential through phytochemical profiling, computational analyses, and biological assays. LC-MS/MS-QTOF profiling identified 13 compounds in the rhizome extract, predominantly terpenoids. In silico analyses predicted antioxidant, anti-inflammatory, and antineurodegenerative activities, while drug-likeness assessment suggested favorable bioavailability for all identified compounds. Furthermore, molecular docking targeting neurodegeneration-associated proteins revealed strong interactions of compounds namely brefeldin A, nigakilactone K, genistein, and 8-epi-loganic acid-6’-O-β-D-glucoside with MAPK1, TNF-α, BACE1, and CASP3, respectively. In addition, the extract exhibited notable antioxidant activity in the DPPH assay and ameliorated monosodium glutamate-induced cognitive impairment, hippocampal neurodegeneration, and elevated brain malondialdehyde levels in mice. Hence, C. sumatrana is a promising herbal medicine for neurodegenerative diseases, plausibly acting through the modulation of neurodegeneration-related pathways and antioxidant mechanisms. These findings provide a foundation for future drug discovery by identifying bioactive compounds with potential applications in the management of neurodegenerative disorders.

Adsorption of Malachite Green Dye onto Bagasse Ash-Based Silica Aerogel/MgO Composite: Kinetic, Isotherm, and Thermodynamic Studies

Nazriati Nazriati, Istighfarin Meilidya Azhar, Irma Kartika Kusumaningrum — Sun, 21 Jun 2026 00:00:00 +0000

A silica aerogel/MgO composite synthesized from bagasse ash was investigated as a biomass-derived adsorbent for the removal of malachite green from aqueous solutions. The adsorption performance was systematically assessed through operational parameters, adsorption kinetics, equilibrium isotherms, and thermodynamic analyses. Comparative experiments demonstrated the superior adsorption capability of the silica aerogel/MgO composite relative to pristine silica aerogel, with adsorption capacities of 96.93 and 22.12 mg/g, respectively, recorded under the same experimental conditions, highlighting the beneficial interaction between the porous silica framework and MgO active sites. Equilibrium was attained after 80 min of contact time, and under optimum conditions, the composite achieved an adsorption capacity of 123.19 mg/g at 45°C with an initial dye concentration of 55 mg/L, while the highest removal efficiency (90.93%) was obtained at pH 9. Kinetic analysis revealed that the pseudo-second-order model most accurately represented the experimental data, yielding an R² value of 0.9923. Equilibrium studies further indicated that the Freundlich isotherm provided the best fit (R² = 0.9965–0.9973), suggesting adsorption on energetically heterogeneous surfaces with the possibility of multilayer uptake. Thermodynamic evaluation confirmed that the adsorption process occurred spontaneously and was favored at elevated temperatures, as evidenced by negative Gibbs free energy values (ΔG° = −4.68 to −6.29 kJ/mol), positive enthalpy changes (ΔH° = 12.46–15.29 kJ/mol), and positive entropy values (ΔS° = 58.76–67.10 J/mol·K). Overall, the results demonstrate the strong potential of the bagasse ash-derived silica aerogel/MgO composite as an efficient and sustainable adsorbent for the removal of cationic dyes from water.