Open AccessEnhanced photocatalytic degradation of N-doped TiO2-SiO2composite for degradation of phenol under simulated natural light assisted by S2O82-anions
Author(s) -
Huu-Tai Huynh,
MinhVien Le,
Luan Van Hoang
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/947/1/012020
Subject(s) - photocatalysis , degradation (telecommunications) , phenol , materials science , doping , visible spectrum , reaction rate constant , band gap , composite number , nuclear chemistry , analytical chemistry (journal) , catalysis , chemistry , kinetics , composite material , organic chemistry , optoelectronics , telecommunications , quantum mechanics , computer science , physics
In recent years, TiO 2 photocatalyst has been studied to increase the overall efficiency in the degradation of organic pollutants in water. Several solutions have been proposed such as non-metal doping to reduce a high band gap energy (3.2 eV) of TiO 2 to increase absorption in the visible region and synthesis of composite photocatalyst to improve the efficiency of electron-hole separation and the specific surface area. Herein, the N-doped TiO2-SiO2 photocatalysts were investigated. Powder samples with three molar ratios of TiO 2 /SiO 2 (95/5-TS5, 85/15-TS15, 75/25-TS25) were successfully synthesized, characterized, and estimated their photocatalytic activity toward the phenol degradation (initial concentration to be 10 ppm) under simulated natural light. N-doped TiO 2 -SiO 2 samples were prepared with molar ratios of N to designed TiO 2 to be 3%, 5%, 7%. The 3N-TS5 photocatalyst (3 mol % N doped TS5) shows the highest phenol efficiency degradation, to be 95% in 4 h, photocatalytic degradation rate constant of 1.02}10 −2 min −1 due to its narrower band gap energy (3.05 eV). Furthermore, the addition of S 2 O 8 2- anions at a concentration of 1 mM is enhanced degradation efficiency and degradation rate. And phenol is almost completely degraded within 60 min and achieved a degradation rate constant of 7.65*10 −2 min −1 , 7.5 times higher than that without the presence of S 2 O 8 2- anions. This attractive result is attributed to the generation of sulfate radical ( SO 4 *“) during photolysis. Finally, N-doped TiO 2 -SiO 2 photocatalyst assisted by S 2 O 8 2- anions shows potential to design and improve manufacturing processes to obtain photoreactors for organic degradation from waste-water under natural light degradation.