The Kinetics of the ozonation of aromatic compounds in water solution

ABSTRACT Aromatic compounds are extensively used in various types of industry and can cause pollution in water sources. This work aims to examine the degradability by cleavage of aniline and phenol in water solutions using ozone, and to determine the kinetics of these cleavage reactions. Aniline and phenol have been used in 4 different concentrations (25 mg/L, 50 mg/L, 75 mg/L and 100 mg/L). The flow rate of ozone supplied for each solution has been selected as 2 g/h, 4g/h and 6 g/h 03. The medium temperature (T = 20 ± 1°C) and pH (pH = 9.00) have been kept constant using control devices. The reactions were batch reactions with respect to the organic compounds. Samples from the reaction medium were taken at definite time intervals (t = 0, 5, 10, 15, 20, 25, 30, 40, 50, 60, 90 and 120 min. for aniline and t = 0, 3, 5, 10, 15, 20, 25, 30, 45, 60, 75 and 90 min. for phenol), and the aniline and phenol concentrations were determined by UV/VIS spectrophotometry. The aniline concentrations were based on 230 nm. values, and the phenol concentrations were based on the 260 nm. values. The samples were also subjected to TOC analysis to determine the Total Organic Carbon values. To determine the kinetics of the reactions the concentration vs. time plots were used. The ln(Co/C) vs. time graphs were obtained to determine the k values. For each reaction the R^ values were also calculated. To determine the possible intermediate products, the samples were analyzed by GC/MS. The spectra have yielded nitrobenzene and azoxybenzene for the aniline reactions. In the phenol reaction samples no intermediate products have been found. Based on the experiments and determinations it can be concluded that. Aniline and phenol can be degraded by ring cleavage using ozone. The reactions take place only at sufficient ozone concentrations. The cleavage of both compounds proceed according to 1st order kinetics. Key Words : Ozonization, Aromatic pollutants, Aniline, Phenol, Kinetics vu