Enhanced photocatalytic degradation of humic acids using Al and Fe co-doped TiO_2 nanotubes under UV/ozonation for drinking water purification

摘要

O_3/UV/TiO_2 was used to effectively decompose humic acids (HAs) in drinking water. To obtain a large specific surface area and low band gap energy, Al and Fe co-doped TiO_2 nanotubes were successfully synthesized using the hydrothermal method. The effect of the optimal co-doped TiO_2 nanotubes catalyst on the HAs removal efficiency through O_3/UV/co-doped TiO_2 process was investigated. The highest HAs removal efficiency (79.4%) that exhibited a pseudo-first-order rate constant of 0.172 min~(-1) was achieved, in the presence of 550℃ calcined 1.0% co-doped TiO_2 nanotubes with an Al:Fe ratio of 0.25:0.75. The effects of calcination temperature and doping concentration on anatase phase weight fractions, average crystallite sizes, Brunauer-Emmett-Teller surface area, catalyst band gap energy, and catalyst photocatalytic activity were also discussed. The inorganic anions also affected the catalyst photocatalytic ability. In a neutral solution, SO_4~(2-) slightly promoted HAs removal. However, HCO_3~- was found to significantly inhibit the catalyst activity, whereas Cl~- had negligible effect on photocatalytic ability.