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All Journal Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Science and Technology Indonesia Greensusmater
Januar Widakdo
National Taiwan University Of Science And Technology
Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Earth & Planetary Sciences Education Environmental Science Materials Science & Nanotechnology Physics

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Effect of Nanoparticle Ag on Wet Accumulator Performance Febri Rismaningsih; Januar Widakdo
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Vol. 11 No. 2 (2021)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v11n2.p138-147

Abstract

Energy is the most important and inevitable requirement for humankind. The increasing energy demand has been connected with technological advances and population growth. One of the world's most serious problems is providing sustainable energy. New alternative energy sources and renewable energy technologies have become notable research subjects due to the wide availability of renewable energy sources in the world. However, most renewable energy sources do not provide uninterrupted energy to consumers. This study aims to determine the resistance of the Ag nanoparticle using the UV-Vis spectrophotometer test. It determines the wavelength of Ag absorption, the output voltage characteristics, and the light intensity of the lamp produced from a wet accumulator with the addition of Ag nanoparticles. This research was started by making a solution of Ag nitrate (AgNO3) and a trisodium citrate (Na3C6H5O7) solution, then synthesizing Ag nanoparticles with a concentration of 3 mM, 4 mM, and 5 mM about 2 ml using the bottom-up method and chemical reduction. The results showed that Ag nanoparticles were suitable for use within three days and the Ag absorption wavelength was 328.1 nm. The output voltage on the wet accumulator without adding Ag nanoparticles lasts longer than the accumulator added by Ag nanoparticles. It can be seen clearly from the speed at which the voltage drops. For the light intensity produced by the pure wet accumulator, the H2SO4 solution was measured to be great and went out longer than the wet accumulator added with Ag nanoparticles. This research concluded that Ag nanoparticles with a concentration of 3 mM, 4 mM, and 5 mM in the H2SO4 solution reduce the performance of the wet accumulator.  
Analysis of Structure, Morphology, Magnetic Properties, and Microwave Absorption of Lanthanum Orthoferrite (LaFeO3) Naibaho, Marzuki; Widakdo, Januar; Kurniawan, Budhy; Nehan, Phahul Zhemas Zul; Vitayaya, Okvarahireka; Novita; Ramlan; Adi, Wisnu Ari; Ginting, Masno
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.851-856

Abstract

LaFeO3 has been prepared using the solid-state reaction method with High Energy Milling (HEM). The preparation of LaFeO3 was carried out using stoichiometric calculations. Based on the XRD measurement results, single-phase LaFeO3 with an orthorhombic crystal structure was obtained. From the SEM results, the morphology of LaFeO3 is uniform, and the EDS results show the weight percentage of La, Fe, and O elements are 49.74, 21.08, and 29.18 wt%, respectively. VSM LaFeO3 results show magnetic saturation, remanence, and coercivity are 0.24 emu/g, 0.02 emu/g, and 853.38 Oe, respectively, and the absorption of LaFeO3 is -7.40 dB at a frequency of 6.02 GHz with a LaFeO3 sample thickness of 1.5mm.
Precision Engineered Graphene Oxide Membranes Optimizing Thin Film Composite Layers for Solvent and Dye Separation Widakdo, Januar; Fadly Azril Priodani; Hannah Faye M. Austria; Tsung Han-Huang; Aditya Rianjanu; Canggih Setya Budi; Anawati Anawati; Wei-Song Hung
Science and Technology Indonesia Vol. 10 No. 4 (2025): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2025.10.4.1031-1048

Abstract

Organic solvent nanofiltration (OSN) is a promising separation technology with low energy consumption and environmental benefits. However, membrane stability in harsh organic solvents remains a challenge. Graphene oxide (GO) is widely explored due to its exceptional mechanical strength and selective permeability; however, further modifications are necessary to optimize its performance. This study investigates the enhancement of GO membranes by incorporating a thin-film composite (TFC) layer through interfacial polymerization using polyethyleneimine (PEI) and trimethyl chloride (TMC). The fabricated membranes were characterized for theirmorphology, chemical structure, and filtration performance using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and contact angle measurements. Filtration tests were conducted with ethanol and Congo red dye solutions. The optimized membrane, composed of 0.1 wt% PEI 800 Mw and 0.05 wt% TMC, exhibited superior performance, demonstrating a permeance of 8.06 ± 2.31 L L m-2 h-1 bar-1 and a rejection rate of 95.20 ± 1.54% for Congo red dye. Additionally, the membrane exhibited a charge-dependent separation mechanism, achieving a 98.64 ± 0.38% rejection of methyl green due to both affinity and Donnan effects. These findings provide insights into developing advanced OSN membranes for efficient solvent purification and dye separation.
Thermal annealing tailors crystallinity and magnetism in silica coated Ni-Zn ferrite (SiO2@NiZnFe2O4) nanoparticles Widakdo, Januar
Greensusmater Vol. 2 No. 2 (2025)
Publisher : Green and Sustainable Materials Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62755/greensusmater.2025.2.2.30-35

Abstract

Ni0.5Zn0.5Fe2O4 nanoparticles were synthesized using a co-precipitation method followed by annealing at different temperatures to investigate their structural, morphological, and magnetic properties. X-ray diffraction (XRD) confirmed the formation of a single-phase spinel structure, with increased crystallinity and grain growth observed at higher annealing temperatures. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) further revealed a transition from small, aggregated nanoparticles to well-defined crystalline grains. Magnetic hysteresis measurements demonstrated a significant enhancement in saturation magnetization (Ms) and coercivity (Hc) with increasing temperature, reaching up to 55.15 emu/g and 253.23 Oe, respectively, at 800 °C. These improvements are attributed to reduced surface spin disorder and increased magnetic domain alignment due to grain growth. The results underscore the importance of annealing temperature in tailoring the magnetic behavior and structural properties of Ni–Zn ferrite nanoparticles for potential applications in magnetic and electronic devices.
Development and materials characterization of hydrothermally grown niobium-doped BiVO4 for ciprofloxacin and methylene blue degradation Kurnia, Nadiya Rifqah; Amanda, Tia; Nurfitria, Rima; Aflaha, Rizky; Widakdo, Januar; Rianjanu, Aditya
Greensusmater Vol. 2 No. 2 (2025)
Publisher : Green and Sustainable Materials Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62755/greensusmater.2025.2.2.55-61

Abstract

This study reports the synthesis and characterization of niobium-doped BiVO4 (NbX-BiVO4, X = 0, 2, 4, 6 mol%) photocatalysts via a hydrothermal method, aimed at enhancing the degradation of organic pollutants under UV irradiation. X-ray diffraction (XRD) analysis confirmed the preservation of the monoclinic BiVO4 structure in all samples, although minor secondary features were detected in doped compositions. Field emission scanning electron microscope (FESEM) imaging revealed progressively rougher, nanostructured surfaces with increasing Nb content, while UV-Vis and photoluminescence (PL) spectroscopy indicated modified band structures and reduced recombination rates. Photocatalytic performance was evaluated using ciprofloxacin (CIP) and methylene blue (MB) as model pollutants. For CIP, the highest activity was achieved by Nb6-BiVO4 (k value of 0.09 min‒1 g–1), attributable to enhanced charge separation and increased surface texture. In contrast, MB degradation favored the undoped BiVO4 (k value of 0.29 min‒1 g–1) due to stronger dye adsorption, despite the optical improvements in doped samples. The findings demonstrate that Nb doping improves BiVO4 photocatalytic activity through synergistic structural and electronic effects, with pollutant-specific responses highlighting the importance of matching catalyst design to target contaminant properties.
Co-Authors Aflaha, Rizky Amanda, Tia Anawati Anawati Budhy Kurniawan Canggih Setya Budi Fadly Azril Priodani Febri Rismaningsih Hannah Faye M. Austria Kurnia, Nadiya Rifqah Masno Ginting Naibaho, Marzuki Nehan, Phahul Zhemas Zul Novita Nurfitria, Rima Ramlan Rianjanu, Aditya Tsung Han-Huang Vitayaya, Okvarahireka Wei-Song Hung Wisnu Ari Adi