DOI: https://doi.org/10.31258/Jamt.7.1
Published: Jul 11, 2025
Articles
Self-doped porous carbon derived from acacia plantation residues for green-supercapacitor in sustainable energy applications
To improve bio-organic-carbon quality for supercapacitors, consider using dual or more heteroatom for more profitable carbon-chain doping. Developing suitable sources and preparation strategies is challenging but essential. Herein, we introduce a potential carbon source derived from acacia plantation residues, doped with boron, oxygen, and phosphorus. The pore structure of this carbon material can be precisely tuned to exhibit a well-defined hierarchical arrangement of micro-, meso-, and macropores through a low-ratio of phosphoric acid (H?PO?) impregnation method combined with dual-environment (N2 and CO2) vertical pyrolysis in one step integrated. The resulting material displays a confirmed hierarchical morphology with a hierarchical transformation into tunnel pores, in specific surface area of 521.70 m²/g which contributed to high charge storage and deliverability. Additionally, the material contains significant levels of boron (0.93%), oxygen (9.19%), and phosphorus (0.34%), facilitating a reversible Faradic reaction in the working electrode. Consequently, optimized-electrode achieves a specific capacitance of 198 F/g at 1 A/g in H?SO? electrolyte. In a two-electrode system, records energy density of 14 Wh/kg (1 A/g) at a maximum power density of 670 W/kg (10 A/g). These findings suggest that the natural incorporation of boron, oxygen, and phosphorus enhances both the activity and the hierarchical pore structure of carbon derived from acacia plantation residues.
Characterization and impact of graphene oxide on the curing and mechanical properties of epoxy resins
Graphene oxide (GO) has been widely studied as a nanofiller for epoxy resins due to its excellent mechanical, thermal, and interfacial properties. In this study, GO was synthesized via electrochemical exfoliation and characterized using FTIR, XRD, TGA, and SEM. GO was incorporated into an epoxy matrix (Litestone 3200 resin with 2131H hardener) at different weight percentages (0.10%, 0.13%, 0.20%, and 0.50%), and the curing behavior was analyzed through differential scanning calorimetry (DSC). The cure kinetics were evaluated using the Kissinger and Ozawa methods. The results indicated that the activation energy increased at 0.13% GO but decreased at higher concentrations. TGA analysis showed that the addition of GO improved thermal stability, particularly at 0.10% GO. FTIR confirmed the presence of oxygenated functional groups in GO, XRD indicated partial exfoliation and structural disorder, and SEM revealed sheet-like morphology. These results were consistent and complementary, supporting the successful incorporation of GO into the epoxy network. The addition of GO slightly improved the mechanical modulus without significantly altering the glass transition temperature (Tg).
From waste to value: Lapachol from teak wood waste as a green catalyst for sustainable soda cooking of Acacia and Eucalyptus
The development of a sustainable catalyst as an alternative to synthetic anthraquinone (AQ) is urgently needed for a more efficient pulping process. This study investigates the potency of lapachol, a natural naphthoquinone isolated from teak (Tectona grandis) wood waste, as a catalyst in soda cooking of three industrially important hardwoods: Acacia crassicarpa, Eucalyptus pellita, and Eucalyptus globulus. Approximately 97.7% purity of lapachol was isolated and applied at 0.09% (on oven-dry wood). For comparison, the commercial synthetic additive, 2-Methylanthraquinone (2-MAQ) was also used at the same dosage. Cooking experiments were conducted at 160°C under varying alkali dosages (23, 27, 31%) and times (4, 5, 6 h). The result revealed that the delignification performance was species-dependent: A. crassicarpa (S/V=0.74) was the hardest, while E. globulus (S/V=3.04) was the easiest to delignify. Notably, E. pellita (S/V=2.04) shows the greatest selectivity index. Lapachol shows the capability of enhancing delignification across the three wood species by decreasing the residual lignin by up to 5% in A. crassicarpa, 5% in E. Pellita, and 2% in E. globulus compared with soda cooking (control). Although the delignification is slightly lower than 2-MAQ, lapachol maintains pulp yields comparable to or higher than 2-MAQ. The selectivity index analysis confirmed that lapachol improved the balance between lignin removal and carbohydrate preservation, with the benefits most pronounced in E. globulus. These findings underscore lapachol as a promising sustainable pulping catalyst, offering the potential for impactful industry transformation through sustainable innovation.
Powder metallurgy synthesis of Pd-doped MoS2: A structural and morphological study
This study reports the synthesis and structural characterization of palladium (Pd)-doped molybdenum disulfide (MoS?) produced via the powder metallurgy route. The primary objective was to investigate how Pd incorporation influences the structural, morphological, and electrical properties of MoS?, thereby demonstrating the advantages of powder metallurgy compared to conventional synthesis techniques. The materials were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. XRD confirmed the retention of the hexagonal MoS? phase without the formation of secondary Pd-related phases, indicating successful substitutional doping. SEM–EDS analyses revealed a uniform Pd distribution and progressive morphological evolution with increasing Pd content, characterized by enhanced surface roughness and improved particle dispersion. FTIR and Raman spectra showed modifications in bonding environments and vibrational modes, evidencing the structural influence of Pd atoms on the MoS? lattice. Electrical measurements, performed using both I–V and four-point probe methods, demonstrated a conductivity increase from 9.6 × 10?? S·m?¹ for pure MoS? to 1.6 × 10?? S·m?¹ and 1.9 × 10?? S·m?¹ for the 1% and 2% Pd-doped samples, respectively. This enhancement is attributed to the higher charge carrier density and improved interlayer charge transport induced by Pd doping. These findings confirm that powder metallurgy provides an effective and scalable synthesis pathway for achieving homogeneous Pd incorporation in MoS?. The resulting materials exhibit excellent structural integrity and enhanced electrical performance, making them promising candidates for catalytic, sensing, and energy storage applications.
Fly ash adsorbent for ph improvement and manganese reduction in acid mine drainage
Metal solid waste from coal combustion (fly ash) is abundant in Indonesia, as an effective and economical adsorbent in neutralizing acid mine drainage (AMD). Given that the continuous utilization of coal produces environmental challenges in the form of AMD containing acid residues and heavy metals such as manganese (Mn), an appropriate treatment solution is required. The adsorption method was chosen due to its simplicity, cost effectiveness, and ability to remove heavy metal pollutants. The purpose of this research is to characterize fly ash before and after heating by SEM and XRD analysis, and evaluate the effect of fly ash physical activation temperature by heating at 100oC and 200oC for an interval of 60 minutes on the characteristics and adsorption ability of fly ash. In addition, this study also evaluated the effectiveness of the adsorbent mass (fly ash before heating and after heating) in increasing pH and reducing Mn concentration in AMD so that it meets the quality standards of Class 1 river water. The results obtained from this study show a fundamental difference in the properties of fly ash before and after heating. Based on BET analysis, the physical activation process resulted in pore enlargement (0.196 nm) and increased surface area of the adsorbent (0.847 m2/g), which significantly affected its binding capacity to solutes (adsorption capacity). The application of fly ash as an adsorbent showed the ability to increase the pH value of acid mine drainage towards neutral conditions. The process of reducing heavy metal ions Mn by using 50 g of fly ash heating at 100oC and 200oC, resulted in a removal percentage of 94.74% and 98.44%. It is hoped that this research can provide innovative and sustainable AMD treatment and increase the use value of fly ash waste.