Y. Fujii
Division of Engineering Applied Physics, Faculty of Engineering, University of Fukui 3-9-1 Bunkyo, Fukui-shi, Fukui 910-8507, Japan.

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Effect of pH and Stirring Speed on the γ-Fe2O3 Material Properties Synthesized from Iron Sand by Using Co-Precipitation Method L Agusu; Amiruddin; M. Nalis; S. Misudo; Y. Fujii; Y. Ishikawa; Alimin
International Journal of Acta Material Vol. 1 No. 1 (2024): August 2024
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v1i1.6

Abstract

Research has been conducted to investigate the impact of pH and stirring on the magnetic properties of γ-Fe2O3 nanoparticles derived from iron sand using the co-precipitation method. The objective of this study was to synthesize γ-Fe2O3 nanoparticles and examine how pH and stirring affect their size and properties. The co-precipitation method involved mixing iron sand with HCl as a solvent and NH4OH as a precipitator. The experimental setup included variations in pH, specifically pH 10 and pH 12, as well as stirring speeds of 600 rpm and 700 rpm. The synthesized maghemite nanoparticles were characterized using XRD (X-Ray Diffraction), SEM (Scanning Electron Microscope), and VSM (Vibrating Sample Magnetometer) techniques. XRD analysis revealed that the particle size at 600 rpm under pH 10 was 52.085 nm, whereas at 700 rpm under pH 12 it was 47.821 nm. The VSM characterization results demonstrated a remanent magnetization of 25.5 emu/gr, a coercivity field of -0.01 Tesla, and a saturation magnetization of 52.45 emu/gr. This study confirmed that the maghemite nanoparticles produced exhibited ferromagnetic properties.
Development of Eco-friendly Antimicrobial Bricks Using Nickel Slag Waste Enriched with TiO2 to Counteract E. coli Contamination L. Agusu; W. O. Nurtia; M. Z. Muzakkar; I W. Sutapa; Y. Ishikawa; Y. Fujii; T. Asano; S. Mitsudo; Y. Tatematsu
International Journal of Acta Material Vol. 2 No. 1 (2025): August 2025
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i1.20

Abstract

This study investigates the use of nickel slag waste, enriched with TiO2, as a sustainable material for producing antimicrobial bricks. The research focuses on evaluating the impact of variations in firing time and the addition of nickel slag on the mechanical properties of the bricks, as well as their antibacterial effectiveness against E. coli bacteria. The bricks were produced using an electric furnace with different composition ratios of clay, nickel slag, and TiO2. Results demonstrate that the optimal compressive strength of the bricks is 21.673 × 10⁵ N/m², achieved with a clay:slag:TiO2 ratio of 90:5:5 at a firing temperature of 1000°C for 12 hours. The water absorption rate for this composition was found to be 16.98%. Antimicrobial tests, using the scatter method, revealed that TiO2-enriched bricks significantly inhibited E. coli growth, with only two colonies present compared to 77 colonies on bricks without TiO2. X-ray diffraction (XRD) analysis confirmed the presence of key oxides such as SiO2, TiO2, and CaCO3. These findings suggest that nickel slag, when combined with TiO2, can be an effective additive in clay-based bricks to inhibit E. coli growth, offering potential for applications in water purification and environmental sustainability. Furthermore, the use of advanced heating techniques such as microwaves or gyrotrons may enhance the bricks’ structural integrity and antimicrobial performance in future applications.