Humic acid degradation by the ozonation process: parameters effect and kinetic

Humic acid is one of the constituents that are easily found in the water. Interest of humic acid degradation has been escalating as water is one of the most important source in this world. Though these recent years, extensive research in ozonation has been rising as it a feasible and dynamic process. Thus, this study was aimed to investigate the efficiency of humic acid degradation by ozonation method under different operating conditions, such as initial concentration of humic acid, pH, temperature. The humic acid were characterised by Fourier Transform Infrared spectroscopy (FTIR) and Chemical Oxygen Demand (COD) before and after experiment. Different methods of ozonation were also applied in order to study the capability of each method for degradation of humic acid. The most efficient method for the degradation of humic acid was ozonation with hydrogen peroxide (H202), gave the higher degradation rates of 98.82 % in 120 min of reaction. Pseudo-first-order and pseudo-second-order model were used to simulate the degradation of humic acid as function of time. Overall, humic acid degradation data was found to fit well with the pseudo-second-order kinetic model. The maximum humic acid degradation of 95.29%, was achieved at pH 2, temperature 34 0C and 2.5 mg/L of initial humic acid concentration, respectively. The results of temperature effect showed that the activation energy Ea values -67.640 kJ/mol and -103.958 kJ/mol. The results lead to the conclusion that ozonation process is an efficient method for removing humic acid from aqueous solutions.