Indonesian Journal of Chemical Analysis (IJCA)

Synthesis of Acrylonitrile Butadiene Styrene Membrane with Sulfonated Reduced Graphene Oxide and Cerium Filler

Firgi Siswantito — 2025-09-29

The study investigates the use of acrylonitrile butadiene styrene (ABS) polymer modified by sulfonated reduced graphene oxide (s-rGO) and cerium (Ce) as an alternative membrane to Nafion for Direct Methanol Fuel Cell (DMFC) applications. Pure ABS membranes and ABS membranes with s-rGO/Ce fillers were synthesized and characterized, with sulfonation at 60 °C using filler concentrations of 1%, 3%, and 5% v/v. The addition of fillers aimed to enhance ion exchange capacity (IEC), water absorption, and reduce methanol permeability. The membrane with 5% filler content showed optimal performance, with an IEC of 0.35 meq/g, a swelling degree of 1.5%, and controlled methanol permeability of 1.2670 × 10⁻⁷ cm²/s. FTIR analysis confirmed the presence of sulfonate groups (S=O) at 1054 cm⁻¹, indicating successful sulfonation. SEM analysis revealed that the filler was well-dispersed and formed more defined pores without compromising the structural integrity of the ABS matrix. This study demonstrates the potential of s-rGO/Ce-modified ABS membranes as a viable alternative to Nafion membranes in DMFC applications.

Optimization of Contact Time and Stirring Speed in The Adsorption of Cd(II) Using Acacia crassicarpa Bark Powder as Adsorbent

Mukhlis — 2025-09-29

Acacia crassicarpa bark powder showed potential as an adsorbent due to its high cellulose content of approximately 50%. This research aimed to determine the optimum contact time, stirring speed, and adsorption kinetic models of Acacia crassicarpa bark powder for Cd(II) removal. Adsorbent characterization was conducted using a Surface Area and Pore Size Analyzer, FTIR, and SEM-EDX, while batch adsorption experiments were conducted to evaluate performance. The adsorbent exhibited a specific surface area of 0.460 m²/g and pore diameters ranging from 32.707 to 45.426 Å, indicating mesoporous characteristics. FTIR analysis identified functional groups such as O–H, C=O, and O–Cd. SEM-EDX analysis before adsorption revealed a rough surface with open, irregular pores and dominant elements including C, N, and O. After adsorption, the surface appeared smoother, with pores filled by Cd(II), as confirmed by Cd peaks in the EDX spectrum. Optimum conditions were obtained at a contact time of 70 minutes and a stirring speed of 120 rpm, resulting in an adsorption efficiency of 96.93% and a 1.3613 mg/g capacity. The adsorption kinetics followed a pseudo-second-order model (R² = 0.9985), indicating that the adsorption mechanism occurred via chemisorption.

Preliminary Study on Fe(III) Detection Using Nitrogen-Doped Carbon Quantum Dots via HSV-Based Smartphone Fluorescence Analysis

Erika Agustina — 2025-09-29

This study successfully synthesized nitrogen-doped carbon quantum dots (N-CQDs) from banana peel waste via a hydrothermal method using urea as the nitrogen source. FTIR and optical characterization confirmed the presence of hydroxyl, carbonyl, and amine functional groups, along with distinct photophysical features, including an absorption peak at 304 nm, excitation at 392 nm, and blue fluorescence emission at 465 nm. Upon Fe(III) exposure, the N-CQDs exhibited selective fluorescence quenching and a measurable hue (H) value shift. A linear relationship was observed between hue and Fe(III) concentration in the 1-5 mM range (R² = 0.9822). The limit of detection (LOD) and limit of quantification (LOQ) were estimated at 0.948 mM and 2.875 mM, respectively. These findings demonstrate the potential of banana peel-derived N-CQDs as a low-cost, environmentally friendly, and smartphone-compatible fluorescence probe for Fe(III) detection in aqueous environments

Photocatalytic Activity of ZnO Nanoparticles Synthesized Using Persea sp. Leaf Extract Toward Methylene Blue Dye Degradation

Ryanna Nathania Simbolon — 2025-09-29

Methylene blue dye is widely used in various industries, but improper disposal can severely harm aquatic ecosystems. Zinc oxide (ZnO), a well-known semiconductor, is frequently employed to degrade dye pollutants in aqueous media. This study synthesized ZnO nanoparticles via a precipitation method incorporating a green synthesis approach, utilizing Persea sp (Persea sp.) leaf extract as an eco-friendly alternative to synthetic chemical reagents. Persea sp leaves contain diverse secondary metabolites, including saponins, alkaloids, tannins, flavonoids, and phenolics, which act as capping agents during water-based synthesis. Characterization was conducted using X-ray diffraction (XRD), UV–visible diffuse reflectance spectroscopy (UV-DRS), and scanning electron microscopy (SEM). The photocatalytic activity of the ZnO nanoparticles toward methylene blue degradation was evaluated under UV irradiation at time intervals of 10, 20, 30, 40, 50, and 60 minutes. UV-DRS results indicated a maximum absorption wavelength of 364 nm with a band gap energy of 3.26 eV. XRD analysis confirmed a hexagonal wurtzite structure (JCPDS no. 36-1451) with an average crystallite size of 21.24 nm. SEM imaging revealed a nanospherical morphology with an average particle size of 79.28 nm. The synthesized ZnO nanoparticles achieved 61.77% degradation efficiency for 5 ppm methylene blue. These findings demonstrate that green-synthesized ZnO nanoparticles from Persea sp. leaf have promising potential as sustainable photocatalysts for dye removal, contributing to the development of environmentally friendly wastewater treatment technologies

Heating Rate Behaviour Pyrolysis of Empty Fruit Bunches : Kissinger Kinetic Analysis

Amelia Sri Rezki — 2025-09-29

Biomass waste such as Empty Fruit Bunches (EFB), a byproduct of palm oil production in Indonesia, represents a promising renewable energy resource. Pyrolysis, a thermochemical conversion process, transforms this waste into valuable products and energy sources. This study uses the Kissinger kinetic model to investigate how a stepwise heating rate analysis, under both catalytic and non-catalytic conditions, influences the pyrolysis behaviour of EFB. Pyrolysis experiments were conducted in a batch reactor at 300 °C, 350 °C, and 400 °C, with and without adding a catalyst (aluminium white) at a 1:2 catalyst-to-feedstock ratio. Heating rates were calculated at 10 °C intervals, and the activation energy (Ea) was determined using the Kissinger kinetic model. The results indicate that, with the presence of a catalyst, the heating rate increases with temperature, while without a catalyst, the rate tends to decrease. Moreover, the catalyst substantially reduces the activation energy, from 12.046 kJ/mol (non-catalytic) to 10.957 kJ/mol (catalytic), indicating its effectiveness in enhancing thermal decomposition and facilitating pyrolysis with lower energy requirements.

Phytochemical Study of Ethanol Extract of Sengkubak Leaves (Pycnarrhena cauliflora (Miers) Diels) and Molecular Docking Analysis as a Potential Anti-Breast Cancer Agents

Yuneta — 2025-09-29

Reactive Oxygen Species (ROS) are a group of free radicals that play a major role in causing oxidative stress, which can trigger the development of degenerative diseases such as cancer. Sengkubak (Pycnarrhena cauliflora (Miers) Diels) contains antioxidant that may help protect the body from free radical exposure. This study aims to identify the metabolite compounds present in Sengkubak leaves through GC-MS analysis and to evaluate their anticancer potential of its major metabolites through in silico molecular docking analysis. The leaf simplicia was extracted using the maceration method with ethanol as the solvent. The analyses performed included GC-MS analysis and molecular docking analysis of the major compounds identified by GC-MS to evaluate their anticancer potential. GC-MS analysis identified a total of 84 compounds, with the five major ones being Phytol, Farnesol isomer a, L-Gala-L-ido-octose, E-11-HexadecenoicAacid ethyl ester, and Pentadecanoic acid ethyl ester. Furthermore, molecular docking analysis of the five major compounds demonstrated potential anticancer activity against breast cancer targets.

Synthesis of Biochar-Like Graphene Nanosheets (BLG) from Candlenut Shells with Integrated Conductive and Antibacterial Functionalities

Friscilla Romiduk Samosir — 2025-10-15

Graphene’s exceptional electrical, mechanical, and chemical properties have enabled breakthroughs in electronics, energy storage, and biomedicine, yet large-scale, low-cost, and sustainable production methods remain elusive. Here, we report a facile, scalable route to synthesize Biochar-Like Graphene Nanosheets (BLG) from candlenut shell biomass using activated carbon as a dual-function reducing agent and combustion inhibitor in a modified muffle furnace pyrolysis system. Structural analysis by X-ray diffraction and Fourier-transform infrared spectroscopy confirms the formation of defect-rich, low-oxygen sp² carbon networks, while scanning electron microscopy reveals wrinkled layered morphologies that promote electrolyte accessibility. Electrical measurements demonstrate a voltage-dependent conductivity, reaching 368.67 μS·cm⁻² at 1.5 V, alongside stable power density (6.72 W·kg⁻¹) and high energy density (403.2 Wh·kg⁻¹), indicative of excellent charge transport and storage capabilities. Remarkably, BLG exhibits potent antibacterial activity against Salmonella typhimurium with a 10.76 ± 0.23 mm inhibition zone and positive MIC and MBC responses, attributed to synergistic membrane disruption, reactive oxygen species generation, and electron transfer effects. This biomass-to-graphene strategy offers a sustainable, multifunctional nanomaterial platform for next-generation energy, environmental, and biomedical technologies