Effect of water temperature and pH on the concentration and time of ozone saturation

Efeito da temperatura e do pH da água na concentração e no tempo de saturação por ozônio

Abstract

Ozone has been used for many years to disinfect water due to its oxidizing potential. Since it decomposes quickly into molecular oxygen, leaving no residue, it has important advantages for use. The decomposition of ozone is affected by the temperature and pH of the medium, low pH values and temperatures increasing its half-life, which can result in more efficient disinfection. With the objective of increasing the effectiveness of ozonation, this study investigated the effect of temperature (8 ºC and 25 °C) and pH (3.0 and 6.0) of the water on the saturation time and gas concentration, employing two initial gas concentrations (13.3 and 22.3 mg L^-1). The concentration of ozone saturation increased as the temperature and pH of the medium decreased, as also with the higher initial gas concentration ( C₀). The highest saturation concentrations were obtained at pH 3.0 and 8 °C (4.50 and 8.03 mg L^-1 with C₀ of 13.3 and 22.3 mg L^-1, respectively). This higher ozone content could result in greater decontamination efficiency of the food products washed with this water.

Keywords:
Ozonation; Saturation concentration; Saturation time