Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 616-623 |
| Journal | Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering |
| Volume | 52 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2017 |
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Photodecolorisation of melanoidins in vinasse with illuminated TiO2-ZnO/activated carbon composite. / Otieno, Benton; Apollo, Seth; Naidoo, Bobby E.; Ochieng, Aoyi.
In: Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering, Vol. 52, No. 7, 2017, p. 616-623.Research output: Contribution to journal › Article
TY - JOUR
T1 - Photodecolorisation of melanoidins in vinasse with illuminated TiO2-ZnO/activated carbon composite
AU - Otieno, Benton
AU - Apollo, Seth
AU - Naidoo, Bobby E.
AU - Ochieng, Aoyi
PY - 2017
Y1 - 2017
N2 - A hybrid photo-catalyst, TiO2-ZnO, was synthesized by immobilizing ZnO on commercial TiO2 (aeroxide P25). Activated carbon (AC) was subsequently used to support the hybrid, thus forming a TiO2-ZnO/AC composite catalyst. Fourier transform infrared (FTIR) analysis and scanning electron microscopy integrated with energy-dispersive X-ray spectroscopy (SEM-EDX) investigations revealed successful catalyst synthesis. Optical properties of the hybrid determined from photoluminescence (PL) and Ultraviolet-visible (UV-vis) spectroscopy confirmed a restrained recombination of electron-hole pairs and reduced energy band gap due to a successful heterojunction formation. The prepared catalysts were used to photodecolorise vinasse in a 12-W UVC batch photoreactor. TiO2-ZnO had improved photocatalytic activity compared with TiO2 and ZnO separately. On supporting the hybrid onto AC, both adsorption and photocatalytic activities were further enhanced with improved overall color removal of 86% from 68%. Photodecolorisation followed the pseudo-first-order reaction model with the rate constant () observed decreasing from 0.0701 to 0.0436 min−1 on increasing the initial concentration from 5,000 to 14,000 ppm. The UV process was found to be 33-fold less energy intensive for color reduction as compared to total organic carbon (TOC) reduction. Formation of nitrates during the photodecolorisation process was attributed to the mineralization of nitrogen heteroatoms in the color-causing melanoidin compounds.
AB - A hybrid photo-catalyst, TiO2-ZnO, was synthesized by immobilizing ZnO on commercial TiO2 (aeroxide P25). Activated carbon (AC) was subsequently used to support the hybrid, thus forming a TiO2-ZnO/AC composite catalyst. Fourier transform infrared (FTIR) analysis and scanning electron microscopy integrated with energy-dispersive X-ray spectroscopy (SEM-EDX) investigations revealed successful catalyst synthesis. Optical properties of the hybrid determined from photoluminescence (PL) and Ultraviolet-visible (UV-vis) spectroscopy confirmed a restrained recombination of electron-hole pairs and reduced energy band gap due to a successful heterojunction formation. The prepared catalysts were used to photodecolorise vinasse in a 12-W UVC batch photoreactor. TiO2-ZnO had improved photocatalytic activity compared with TiO2 and ZnO separately. On supporting the hybrid onto AC, both adsorption and photocatalytic activities were further enhanced with improved overall color removal of 86% from 68%. Photodecolorisation followed the pseudo-first-order reaction model with the rate constant () observed decreasing from 0.0701 to 0.0436 min−1 on increasing the initial concentration from 5,000 to 14,000 ppm. The UV process was found to be 33-fold less energy intensive for color reduction as compared to total organic carbon (TOC) reduction. Formation of nitrates during the photodecolorisation process was attributed to the mineralization of nitrogen heteroatoms in the color-causing melanoidin compounds.
U2 - 10.1080/10934529.2017.1294963
DO - 10.1080/10934529.2017.1294963
M3 - Article
VL - 52
SP - 616
EP - 623
JO - Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
JF - Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
SN - 1093-4529
IS - 7
ER -