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All Journal Indonesian Journal of Chemistry ASEAN Journal of Chemical Engineering
Siti Machmudah
Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Sepuluh Nopember, Surabaya 60111, Indonesia
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry

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Hydrothermal Synthesis: Low−Temperature Subcritical Water for Ceria−Zirconia Mixed Oxides Preparation Siti Machmudah; Widiyastuti Widiyastuti; Wahyudiono Wahyudiono; Sugeng Winardi; Hideki Kanda; Motonobu Goto
Indonesian Journal of Chemistry Vol 21, No 1 (2021)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.47357

Abstract

A low-temperature hydrothermal synthesis technique was employed as a medium to produce ceria−zirconia mixed oxides particles at temperatures of 200–300 °C and pressure of 10 MPa in a batch process. At these conditions, the average crystallite sizes of ceria−zirconia mixed oxides increased slightly with increasing reaction temperature when the feed solution containing ceria and zirconia with a ratio of 1:1 was fed. SEM images illustrated that the morphologies of the ceria−zirconia mixed oxides particles were spherical and spherical−like with a diameter of around 100 nm. The EDX spectrum indicated that the signal corresponding to the ceria and the zirconia elements at 5 and 2 keV, respectively, were strongly detected in the products. The XRD pattern revealed that the mixed metal oxides particle products that comprised of cerium and zirconium oxides particles with cubic and monoclinic structures, respectively, were affected by their molar content in the feed solution.
Microparticles Formation of Ganoderma lucidum Extract by Electrospraying Method Siti Machmudah; Dwi Setyorini; Sugeng Winardi; Wahyudiono Wahyudiono; Hideki Kanda
ASEAN Journal of Chemical Engineering Vol 19, No 2 (2019)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (913.918 KB) | DOI: 10.22146/ajche.52004

Abstract

In this work, Ganoderma lucidum (G. lucidum) extract was produced in microparticles form by electrospraying. G. lucidum was extracted hydrothermally at temperature of 160oC and pressure of 7 MPa. The extract solution was subsequently mixed with 6% of Polyvinyl pyrrolidone (PVP) and formed into microparticles by electrospraying process. The electrospraying was carried out at applied voltage of 12, 14, and 16 kV, and the distance between syringe tip and electrospun collector of 8, 10, and 12 cm. The microparticles formed was analyzed using scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectroscopy, and UV-Vis spectrofotometer. The antioxidant efficiency of particles was also analyzed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Based on the SEM analysis, the G. lucidum extract (GLE) – PVP spherical particles were formed by electrospraying. The finer fibres were clearly formed with the increasing applied voltage. The results showed that applied voltage and distance of tip to electrospun collector significantly influence the antioxidant efficiency and the diameter size of particles. The antioxidant efficiency increased with the rising applied voltage and gap of tip to electrospun collector, while the particle diameter decreased with the rising applied voltage and gap of tip to electrospun collector due to fast mass transfer and evaporation. The largest antioxidant efficiency of particles was 0.377/min obtained at 16 kV and 12 cm. It indicated that electrospraying is an effective process to produce pharmaceutical compounds in powder form.
Co-Authors Dwi Setyorini Hideki Kanda Hideki Kanda Motonobu Goto Wahyudiono Wahyudiono Wahyudiono Wahyudiono Widiyastuti Widiyastuti Winardi, Sugeng