Efficiency study on nitrobenzene removal by ozone/zeolite process

Degradation of nitrobenzene by ozone/zeolite process was investigated in a continuous flow reactor. The results showed that nitrobenzene was degraded by ozone/zeolite process efficiently in comparison to ozone alone. The removal of nitrobenzene was 100% in 7 minutes. The reaction followed pseudo-first-order kinetics. By investigating the effect of scavenger on nitrobenzene removal, it is concluded that nitrobenzene was mainly degraded by hydroxyl radicals in solution. Increasing zeolite dosage and ozone concentration also enhanced nitrobenzene removal. However, there was an optimum removal rate among zeolite dosages. The relationship between the ozone concentrations and the kinetic constants was linear. At the same time, nitrobenzene decomposition was independent of influent nitrobenzene concentration during ozone/zeolite process. Additionally, the degradation rate of ozone/zeolite process was inhibited significantly by increasing ionic strength. When the ionic strength concentration increased from 0 to 1 x 10^-3 mol/L, the removal of nitrobenzene by ozone/zeolite process decreased from 81.2% to 31.6% correspondingly. pH mainly affected the decomposition rate of ozone. As pH decreased, the degradation rate of nitrobenzene by ozone/zeolite process decreased too. Zeolite had a relatively longer lifetime.