Journal of Applied Materials and Technology

Preparation and characterization of MoS2 thin films for thermoelectric applications using the PVD technique

Joede dos Passos, Adhimar Flavio Oliveira, Rero Marques Rubinger — Thu, 18 Dec 2025 00:00:00 +0700

Molybdenum disulfide (MoS₂) is a two-dimensional material with electronic and thermal properties that make it promising for thermoelectric applications. This research presents the results of synthesizing and characterizing MoS₂ thin films obtained by Physical Vapor Deposition (PVD) on silicon dioxide (SiO₂) substrates. Three experimental approaches were explored to assess how changes in deposition conditions affect the material quality. In the first trial, films were formed from commercial MoS? powder in a sulfur-rich (S₂) atmosphere using a PVD tubular furnace. Next, water vapor (H₂O) was added to the process to observe possible improvements in material formation. Finally, silver doping was investigated, introduced during deposition to examine structural and vibrational changes in the MoS₂. The samples were characterized by Optical Microscopy (OM) and Scanning Electron Microscopy (SEM), as well as Energy Dispersive Spectroscopy (EDS), used to evaluate surface morphology and composition. X-ray Diffraction (XRD) was employed to identify the crystalline structure, while Raman Spectroscopy revealed the E₂g¹ and A₁g vibrational modes, associated with the crystallinity of the material. The results indicated that the presence of H2O during deposition favored the growth of more ordered films, with more intense peaks in XRD and Raman spectra. On the other hand, silver doping caused vibrational changes that suggest modifications in the electronic structure of MoS₂. These findings reinforce the material’s potential for use in thermoelectric devices and demonstrate that variations in synthesis conditions can significantly enhance its structural and functional properties.

Powder metallurgy synthesis of Pd-doped MoS2: A structural and morphological study

Tue, 11 Nov 2025 00:00:00 +0700

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

Nurlela, Tuty Emilia Agustina, Susila Arita, David Bahrin, Rianyza Gayatri — Sat, 22 Nov 2025 00:00:00 +0700

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 100^oC and 200^oC 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 100^oC and 200^oC, 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.

From waste to value: Lapachol from teak wood waste as a green catalyst for sustainable soda cooking of Acacia and Eucalyptus

Wed, 29 Oct 2025 00:00:00 +0700

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.

Photo-Fenton of Dyes Degradation Using Covalent Triazine Frameworks: Toward Industrial Wastewater Treatment Applications

Tue, 19 Aug 2025 00:00:00 +0700

A Covalent Triazine Framework (CTF-1) and carbon nanospheres (CS) were synthesized to develop a porous, thermally stable, and efficient photocatalyst for dye degradation in wastewater treatment applications. The synthesized composite material exhibited a high surface area exceeding 400 m²/g, a well-defined mesoporous structure, and excellent optical properties, including strong light absorption extending up to 550 nm and a moderate band gap of approximately 2.8 eV. These characteristics promote effective visible light-driven photocatalysis. The photocatalytic performance was assessed by degrading methylene blue (MB) as a model organic dye pollutant under photo-Fenton conditions. The system demonstrated high efficiency, with over 90% of the dye removed within 120 minutes of irradiation. The degradation followed pseudo-first-order kinetics, confirming the photocatalytic nature of the reaction. Parameter studies indicated that hydroxyl radicals (•OH) were the dominant reactive species responsible for dye degradation. Moreover, CTF-1 retained its photocatalytic activity and structural integrity over multiple reuse cycles, showcasing excellent reusability and stability. The integration of high surface area for dye adsorption, efficient photoactivation under visible light, and robust radical generation synergistically contributed to the enhanced degradation performance. The study highlights the promising role of CTF-1 and its composites as multifunctional materials for advanced oxidation processes. Given its effectiveness, durability, and environmental compatibility, CTF-1 presents a sustainable and scalable solution for the treatment of dye-laden industrial wastewater. This work contributes to the development of next-generation photocatalysts aimed at addressing global challenges in water pollution and environmental remediation.

Web-Based System for Statistical Analysis and Thesis Progress Monitoring

Ibadurrahman Al Hadi, Edi Susilo — Sun, 03 Aug 2025 00:00:00 +0700

Web-based monitoring systems serve as valuable tools in enhancing learning activities, particularly in the context of thesis supervision. Program heads and academic supervisors require timely, accurate information regarding students’ progress to guide academic outcomes effectively. This paper presents the development and implementation of an integrated web-based statistical and monitoring application tailored for thesis progress reporting. Built using the Laravel framework, the system incorporates statistical data visualization to enable students, supervisors, and administrators to interpret progress and communicate insights effectively. The system was developed using the prototype method, allowing iterative improvements based on user feedback. To ensure quality and functionality, the system was evaluated using the ISO/IEC 25010 quality model. A case study conducted in an electrical engineering department at a public university in Indonesia, involving students, academic supervisors, and administrative staff. The results demonstrate that the system not only improves oversight and coordination but also supports data-driven decision-making. By offering a clear, accessible overview of thesis progress, the application empowers all parties to take timely corrective actions, ultimately enhancing the overall educational experience.

Self-doped porous carbon derived from acacia plantation residues for green-supercapacitor in sustainable energy applications

Fri, 11 Jul 2025 00:00:00 +0700

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

Sat, 19 Jul 2025 00:00:00 +0700

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).

Treatment of oilseed industrial wastewater using corncob modified with NaOH as an adsorbent under a fixed bed column

Yushau Muhammad Salis, Aliyu Adamu Dandajeh — Mon, 30 Jun 2025 00:00:00 +0700

The treatment of industrial wastewater is a source of environmental concern due to the presence of various pollutants that could have detrimental effects on ecosystems and human health. This research aims to investigate the potential of using corncob treated with 1M NaOH as an adsorbent for the removal of pollutants from wastewater collected from Sunseed Nigeria Limited. Corncob, a byproduct of the agricultural waste, has shown capability as an adsorbent due to its high surface area and availability at low cost. The research involved the preparation of corncob adsorbent and its characterization using technique; Fourier-transform infrared spectroscopy (FTIR). Adsorption experiment was conducted using continuous study by a fixed bed column with a 5.0 cm internal diameter and a height of 45cm, to evaluate the efficiency of corncob in removing pollutants from oil seed industrial effluent. The initial concentrations of the pH, TSS, DO, BOD, COD, Lead and Cadmium were examined to be; 4.8, 360 mg/l, 110 mg/l, 40 mg/l, 7000 mg/l, 1.268 mg/l and 0.138 mg/l, respectively. The best removal efficiency for cadmium and lead were: 65.94% and 94.01%, respectively at pH of 6.5 and contact time of 6hrs. Furthermore, the removal efficiency for TSS, BOD, and COD were: 20%, 55% and 57.14%, correspondingly. It was therefore concluded that corncob has proven to be a potential material for the treatment of physico-chemical pollutants from industrial effluent. It is recommended that the corncob should be utilized in large amounts for the treatment of industrial effluents.

Properties of concrete containing crumb rubber and rice husk ash mixing with peat water

Thu, 10 Jul 2025 00:00:00 +0700

This study compares the effects of peat water and normal water as mixing and curing water on the properties of crumb rubber and rice husk ash concrete (CR-RHA). The number of crumb rubber and rice husk ash used on the concrete followed the optimum mixture from a previous study, which was 5% and 10%, respectively. The crumb rubber was treated to overcome the lack of adhesion by soaking it in water for 24 hours. Normal concrete (PCC) was also cast as a control. CR-RHA and PCC concrete were mixed and cured using normal and peat water. Compressive strength, tensile strength, and porosity were tested at 3, 7, 14, 28, and 56 days. In general, CR-RHA concrete and PCC concrete showed lower performance when mixed and cured with peat water compared to normal water. Peat water with high acidity decreased the calcium content and developed the amount of pores in concrete, resulting in strength reduction. However, due to the excess pozzolan from rice husk ash, CR-RHA concrete had better resistance as the strength loss was relatively smaller, respectively 11.4% at 28 days and 10.6% at 56 days. Furthermore, CR-RHA concrete showed lower porosity, higher compressive strength, and tensile strength than PCC concrete due to rice husk ash that improved concrete density by generating CSH and crumb rubber that prevented concrete from spalling in an acidic environment. It was also found that compared to the previous study, pre-treated crumb rubber exhibited better mechanical and durability of concrete.