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Photochem ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 488-504
Author(s):  
Riska Dwiyanna ◽  
Roto Roto ◽  
Endang Tri Wahyuni

This study investigated the decolorization of Remazol Black (RBB) using a TiO2 photocatalyst modified by S and Co co-doped TiO2 (S-Co-TiO2) from a single precursor. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and UV–Vis specular reflectance spectroscopy were used to characterize the photocatalysts. The results revealed that the band-gap energy of the doped and co-doped TiO2 decreased, with the S-Co-TiO2 8% showing the greatest one, and was found to be 2.78 eV while undoped TiO2 was 3.20 eV. The presence of S and Co was also identified through SEM-EDX. An activity study on RBB removal revealed that the S-Co-TiO2 photocatalyst showed the best result compared to undoped TiO2, S-TiO2, and Co-TiO2. The S-Co-TiO2 8% photocatalyst reduced RBB concentration (20 mg L−1) up to 96% after 90 min of visible light irradiation, whereas S-TiO2, Co-TiO2, and undoped TiO2 reduced it to 89%, 56%, and 39%, respectively. A pH optimization study showed that the optimum pH of RBB decolorization by S-Co-TiO2 was 3.0, the optimum mass was 0.6 g L−1, and reuse studies show that S-Co-TiO2 8% has the potential to be used repeatedly to remove colored pollutants. The results obtained indicate that the modification of S, Co co-doped titania synthesized using a single precursor has been successfully carried out and showed excellent characteristics and activity compared to undoped or doped TiO2.


2021 ◽  
Vol 2 (1) ◽  
pp. 1-7
Author(s):  
Gustina Indriati ◽  
Ruth Rize Paas Megahati

Bioethanol is an alternative fuel to replace fossil fuels due to the reduction of fossil fuels. Bioethanol is produced from starch and converted to sugar by thermozyme amylase. Thermozyme amylase produced by thermophile bacteria can be obtained from Pariangan hot springs which have a temperature of  55 °C, pH of 9.2, and have a high level of bacterial diversity. The aim of this study was to obtained isolates of thermozyme amylase-producing bacteria that have the potential for bioethanol production. The research method were bacteria isolation, amylase stability test, temperature and pH optimization, and bioethanol production. The result showed that Enterobacter sp has been isolated from Pariangan hot springs is stable up to 5 hours of incubation, temperature and pH optimum was 85 °C, pH 8.5, and fructose as a carbon source. Thermozyme amylase converts starch into sugar under optimum conditions with a yield of 9.8% bioethanol


2021 ◽  
Vol 69 (1) ◽  
pp. 81-85
Author(s):  
Hironori Tanaka ◽  
Yuya Ochii ◽  
Yasushi Moroto ◽  
Tetsuharu Ibaraki ◽  
Ken-ichi Ogawara

2020 ◽  
Author(s):  
Thibaud Rossel

Incorporation of a copper catalyst within carbonic anhydrase affords artificial metalloenzyme for the oxidation of catechols in aqueous solution at physiological pH. Optimization of the performance can be achieved either by chemical or genetic means. In addition, a model of enzyme/inhibitor is proposed and discussed.


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