The carbon-containing hydroxyapatite has been synthesized using the fish bone obtained from East Kalimantan, Indonesia. The synthesis was conducted at varying calcination temperature (300-700 °C) and duration time (1-5 h). The carbon-containing hydroxyapatite were characterized by using Nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Thermogravimetric analysis (TGA) and Differential thermal analysis (DTA). The carbon-containing hydroxyapatite nanoparticles consisted of the mesoporous structure with a specific surface area of 159 m2.g-1 and pore size of 44 Å. The carbon-containing hydroxyapatite nanoparticles were utilized as the adsorbent for the removal of methylene blue by varying the contact time, initial dye concentration, pH, adsorbent dosage and temperature. The maximum amount of adsorption capacity was 56.49 mg.g-1. The adsorption was well fitted with the Langmuir adsorption model (R2 ~ 0.998) and the pseudo-second-order model. This indicated that the dye molecules were adsorbed on the surface-active site of carbon-containing hydroxyapatite via chemical binding, forming an adsorbate monolayer. Hence, the adsorption capability corresponds to the physical properties such as the surface area and pore volume of hydroxyapatite because the larger surface area consists of higher binding sites for the adsorption. Thermodynamic parameters, including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS), indicated that the adsorption of methylene blue onto the carbon-containing hydroxyapatite nanoparticles was spontaneous. Thus, carbon-containing hydroxyapatite nanoparticles can be applied as a low-cost adsorbent for the treatment of industrial effluents that are contaminated with the methylene blue. Copyright © 2019 BCREC Group. All rights reserved

The catalytic performance of titania-supported carbon mesoporous-derived from fish bones (TiO2/CFB) has been investigated in styrene oxidation with aqueous H2O2. The preparation steps of (TiO2/CFB) catalyst involved the carbonization of fish bones powder at 500 °C for 2 h. followed by impregnation of titania using titanium(IV) isopropoxide (500 µmol) precursor, and calcined at 350 °C for 3 h. The physical properties of the adsorbents were characterized using Fourier transform infrared, X-ray diffraction (XRD), Scanning electron microscopy with energy dispersive X-ray (SEM-EDX), and nitrogen adsorption-desorption studies. The catalytic test was carried out using styrene oxidation with H2O2 as an oxidant at room temperature for 24 h. Its catalytic activity was compared with Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts. It is demonstrated that the catalytic activity of TiO2/CFB catalyst has the highest compared to Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts in the oxidation of styrene with styrene conversion ~23% and benzaldehyde selectivity ~90%. Kinetics of TiO2/CFB catalyzed oxidation of styrene has been investigated and mechanism for oxidation of styrene has been proposed. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA   License (https://creativecommons.org/licenses/by-sa/4.0).

No abstract

The kinetic evaluation of titania supported sulfonated fish bone-derived carbon (TiO2/SFBC) as a catalyst in styrene oxidation by aqueous hydrogen peroxide was carried out. The catalysts were prepared by carbonation of fishbone powder at varying temperatures 500, 600 and 700 °C, respectively for 2 h, followed by sulfonation with sulfuric acid (1M) for 24 h and impregnated by varied titania concentration 500, 1000 and 1500 µmol. The physical properties of catalysts were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX) and the nitrogen adsorption-desorption analysis. The catalytic activity result showed that TiO2/SFBC can be used as a potential catalyst in styrene oxidation. Worth noting that the sulfonation process has not only transformed the TiO2/FBC particulates (without sulfonation) to cuboid-shaped TiO2/SFBC (with sulfonation) but also contributed to the high selectivity of benzaldehyde. On the other hand, carbonization at different temperatures has an indistinct effect on catalytic performance due to their similar surface areas. The styrene conversion rate responded positively with the increasing amount of titania in the functionalized composites. The styrene oxidation by aqueous H2O2 unraveled the first-order reaction with the activation energy of ⁓63.5 kJ. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Pada penelitian ini dibahas mengenai sistem pendukung keputusan untuk menyeleksi saham prima. Masalah yang terjadi dalam penelitian adalah adanya kalangan umum maupun profesional yang masih melakukan analisis fundamental secara manual dalam pengambilan keputusan pembelian saham. Penggunaan sistem pendukung keputusan diharapkan dapat membantu dalam proses pengolahan data saham yang memiliki kategori prima menjadi lebih efektif. Metode Simple Additive Weighting (SAW) ini dipilih karena mampu menyeleksi alternatif terbaik dari sejumlah alternatif. Dalam hal ini alternatif yang dimaksudkan yaitu saham prima berdasarkan kriteria-kriteria yang ditentukan. Penelitian dilakukan dengan menentukan nilai bobot untuk setiap atribut, kemudian dilakukan proses perankingan yang akan menentukan alternatif yang optimal, yaitu saham terbaik. Hasil penelitian berupa aplikasi sistem pendukung keputusan penyeleksi saham prima yang dibangun dengan bahasa pemrograman Java dan basisdata MySQL. Aplikasi ini berguna untuk memilih alternatif yang terbaik untuk mendapatkan saham prima. Para investor yang akan berinvestasi di saham, tidak akan salah membeli saham karena sudah memiliki daftar nama-nama saham prima.

No abstract

The closure of schools due to the Covid-19 pandemic has forced all schools in Indonesia to be closed temporarily, therefore learning must be carried out online. Online learning is commonly carried out with teacher presentations and assignments therefore this makes learning monotonous and boring for students. So we need a medium that makes learning more interesting, namely with interactive powerpoints. The purpose of this study was to determine the effect of using interactive powerpoints in the online-based TGT model on thermochemistry material. This type of research is quasi-experimental research with a post-test only control group design. The data collection technique used the technique of daily test tests, documentation, and student perception questionnaires. The data were analyzed using the normality test, F test, and t test with a significance level of 5%. The results showed that before being given the treatment, the two classes were normally distributed, homogeneous variations and there was no difference in student absorption. After being given the treatment, the two classes had significant differences in absorption. Therefore it can be concluded that there is an effect of using interactive powerpoints in the online-based TGT model on thermochemistry material.

The research of negative effect of calcination to catalytic performance of coal char-loaded TiO2 catalyst in styrene oxidation with hydrogen peroxide as oxidant has successfully done. The effects of calcination step to catalyst properties were characterized with Fourier Transform Infra Red (FTIR), X-ray Difraction (XRD), nitrogen adsorption, Field Emission Scanning Electron Microscopy (FESEM), and Transmission electron microscopy (TEM). The catalytic performance of the catalysts has been investigated in styrene oxidation with hydrogen peroxide as oxidant. The catalytic study showed the calcination step influenced to catalytic properties and could decrease the catalytic performance of coal char-loaded TiO2 catalyst in styrene oxidation.