Pickering emulsions stabilized by salicylic acid and arginine modified titanium dioxide （TiO2-SA-Arg） nanopar- tides were prepared in this study for photocatalytic degradation of nitrobenzene in a rotating annular r...Pickering emulsions stabilized by salicylic acid and arginine modified titanium dioxide （TiO2-SA-Arg） nanopar- tides were prepared in this study for photocatalytic degradation of nitrobenzene in a rotating annular reactor, and the effects of various design parameters of the rotating annular reactor, initial nitrobenzene concentration, catalyst amount, and solution pH on the degradation rate of nitrobenzene were investigated. Meanwhile, the degradation mechanism of nitrobenzene was proposed. The results show that increasing the aeration rate, the rotational speed, and light intensity results in a higher photocatalytic degradation rate of nitrobenzene owing to the effective clearance of electrons and a high quantity of oxidative free radicals. The degradation of nitroben- zene in the rotating annular reactor follows the pseudo first-order kinetics, but it is not well described by the Langmuir-Hinshdwood equation. Aeration has a significant effect on the photocatalytic degradation pathway of nitrobenzene. Because nitrobenzene can undergo reduction reaction as electron acceptors and oxidative deg- radation initiated by hydroxyl free radicals, the photocatalytic degradation of nitrobenzene follows the reduction mechanism under no aeration, but the oxidation mechanism under aeration.展开更多
The photocatalytic kinetics of BPA （4, 4＇-isopropylidenediphenol）, a representative endocrine disruptor, was explored using immobilized ZnO nanoparticles as a photocatalyst in a laboratory scale photocatalytic reac...The photocatalytic kinetics of BPA （4, 4＇-isopropylidenediphenol）, a representative endocrine disruptor, was explored using immobilized ZnO nanoparticles as a photocatalyst in a laboratory scale photocatalytic reactor. The conditions of photocatalytic degradation were optimized. Direct photocatalytic degradation of BPA was undertaken in an aqueous solution containing ZnO nanoparticles under the optimized experimental conditions. The effects of various factors, such as initial BPA concentrations, initial pH values and various anions （CI, NO3, COa2, SO42-, HCO3＂） were investigated. In the case of the nanoparticles derived films, the photocatalytic efficiency was found not to be remarkably related with the calcination temperature employed in the coating process. Screen-printed ZnO nanoparticles films obtained in the optimal processing conditions showed that the photocatalytic activity is comparable to ZnO nanoparticles in aqueous suspensions. Over 90% degradation efficiency of BPA was achieved under the optimum conditions. The degradation rates in all photocatalytic experiments were linear with the degradation efficiencies of BPA by regression analysis （r ≥ 0.99）. The results showed that the degradation kinetics of BPA in the reactor with immobilized nano-ZnO film as photocatalyst was in agreement with a pseudo-first order rate law.展开更多
文摘Pickering emulsions stabilized by salicylic acid and arginine modified titanium dioxide （TiO2-SA-Arg） nanopar- tides were prepared in this study for photocatalytic degradation of nitrobenzene in a rotating annular reactor, and the effects of various design parameters of the rotating annular reactor, initial nitrobenzene concentration, catalyst amount, and solution pH on the degradation rate of nitrobenzene were investigated. Meanwhile, the degradation mechanism of nitrobenzene was proposed. The results show that increasing the aeration rate, the rotational speed, and light intensity results in a higher photocatalytic degradation rate of nitrobenzene owing to the effective clearance of electrons and a high quantity of oxidative free radicals. The degradation of nitroben- zene in the rotating annular reactor follows the pseudo first-order kinetics, but it is not well described by the Langmuir-Hinshdwood equation. Aeration has a significant effect on the photocatalytic degradation pathway of nitrobenzene. Because nitrobenzene can undergo reduction reaction as electron acceptors and oxidative deg- radation initiated by hydroxyl free radicals, the photocatalytic degradation of nitrobenzene follows the reduction mechanism under no aeration, but the oxidation mechanism under aeration.
文摘The photocatalytic kinetics of BPA （4, 4＇-isopropylidenediphenol）, a representative endocrine disruptor, was explored using immobilized ZnO nanoparticles as a photocatalyst in a laboratory scale photocatalytic reactor. The conditions of photocatalytic degradation were optimized. Direct photocatalytic degradation of BPA was undertaken in an aqueous solution containing ZnO nanoparticles under the optimized experimental conditions. The effects of various factors, such as initial BPA concentrations, initial pH values and various anions （CI, NO3, COa2, SO42-, HCO3＂） were investigated. In the case of the nanoparticles derived films, the photocatalytic efficiency was found not to be remarkably related with the calcination temperature employed in the coating process. Screen-printed ZnO nanoparticles films obtained in the optimal processing conditions showed that the photocatalytic activity is comparable to ZnO nanoparticles in aqueous suspensions. Over 90% degradation efficiency of BPA was achieved under the optimum conditions. The degradation rates in all photocatalytic experiments were linear with the degradation efficiencies of BPA by regression analysis （r ≥ 0.99）. The results showed that the degradation kinetics of BPA in the reactor with immobilized nano-ZnO film as photocatalyst was in agreement with a pseudo-first order rate law.
