Effects of Coexisting Substances on Nitrobenzene Degradation with O-3/H2O2 Process in High-Gravity Fields

This study used nitrobenzene as the simulated pollutant to study the effects of common inorganic sodium salts and organics on nitrobenzene degradation by O-3/H2O2 in high-gravity fields. The experiment results showed that the high-gravity technology could increase the nitrobenzene removal rate by improving the ozone transfer efficiency and ozone disso-lution. Coexisting substances had different effects on the degradation kinetics of nitrobenzene in high-gravity fields. Among such substances, Na2CO3, NaOH, Na3PO4, and NaNO3 accelerated the removal of nitrobenzene. The main action principle of nitrobenzene degradation by O-3/H2O2 is that the additives can increase the pH value of the solution, stimulate ozonoly-sis, generate hydroxyl radicals (-OH), and improve oxidation efficiency. By contrast, NaCl, NaHCO3, NaHSO4, ethanol (C2H5OH), acetic acid (CH3COOH), formic acid (HCOOH), and tert-butyl alcohol (TBA) inhibited nitrobenzene removal. When NaHCO3, CH3COOH, or HCOOH were added, the pH value of the solution decreased and free radical chain reactions were hindered. However, NaCl, NaHCO3, C2H5OH, and TBA consumed -OH radicals and inhibited nitrobenzene removal.