H Mozhdehvari - Faculty of Sciences, Department of Chemistry, University of Urmia, Urmia, Iran
S Motameni Tabatabaei - Faculty of chemical Engineering, Azad Islamic University, Ahar, Iran
N Noroozi Pesyan - Faculty of Sciences, Department of Chemistry, University of Urmia, Urmia, Iran
A Tajkhalili - Faculty of Sciences, Department of Chemistry, University of Urmia, Urmia, Iran

Nitrophenols (NPs) are a group of special interest due to their high toxicity and low biodegradability. The removal ofpara-Nitrophenol (pNP) from water has been studied by ozone and ozonation catalyzed with Titanium oxide (TiO۲). The effectiveness of catalytic degradation of pNP in several pHs was evaluated. Some of the main operating parameters like catalyst and basic pH exerted a positive influence in the ozonation rate. The results of HPLC and UV were used for study of pH and TiO۲ catalyst effects in the rate and percentage of degradation. The variation of TOC and COD removal with ozone has been observed. Effects of the pH and catalyst on TOC and COD degradation have been detected. In the presence of catalyst or absence of it, aqueous ozone (O۳) can be described by a two-stage behavior, first involving a short-term rapid decomposition followed by a second slow decomposition in various pHs. The present study validated that ozonation is a safe, economic and promising process for the removal of such nitroaromatics from aqueous solutions.

Catalyst, COD, Ozonation, Para-Nitrophenol, Titanium Oxide, TOC