Sankang Ozone Generator-Factors affecting ozone oxidation in sewage treatment

1. Effect of pH.

A crucial factor influencing ozone decomposition in aqueous solutions is pH. In systems involving O₃ and H₂O₂/O₃, pH must be properly controlled. A low pH can directly affect the ozone oxidation reaction, rendering it less selective and ineffective in removing organic matter. As the pH increases, the amount of OH⁻ in the solution increases, further enhancing the oxidative capacity and improving overall reaction efficiency. However, excessively high pH can lead to the presence of OH scavengers, which consume hydroxyl radicals and significantly impact the oxidation of organic pollutants.

In heterogeneous catalytic ozone oxidation  systems, the pH of the solution can directly affect the performance of certain catalysts, altering the OH generation pathway as follows:

When hydroxyl radicals are neutrally or negatively charged, they directly become active sites for ozone degradation, generating OH radicals. When the pH approaches the catalyst's equivalence point, the advantages of the catalytic oxidation system are fully realized. However, at this point, careful pH control is crucial. Excessively high pH can directly promote ozone decomposition, affecting the density of hydroxyl radicals on the catalyst surface and significantly reducing overall catalytic efficiency.

2. The impact of ozone dosage, method, and reactor.

As the reaction occurs, the amount of ozone increases continuously, significantly impacting the gas-liquid interface and, consequently, the air film resistance throughout the process, increasing ozone concentration. If the ozone concentration is too high, the gas-liquid mass transfer rate will be significantly reduced, reducing the overall ozone utilization rate and increasing application costs.

The ozone dosage method is also a crucial step in the entire reaction process, directly impacting the overall process. Xiao Chunjing et al. achieved good results in deep treatment of refinery and chemical wastewater using Ni-Cu-Mn-K/AC catalytic ozone oxidation. When adding ozone, it is best to use a staged dosing method. This method requires an effective control ratio of 6:3:1 during the dosing process. This method also improves COD removal efficiency.

Using microbubble ozone catalytic oxidation treatment can further improve COD removal efficiency in wastewater and fully utilize ozone. In general, when using this pretreatment method, it should be effectively combined with other methods, such as a biological aerated filter (Blackrock Municipal Income Filter), to further improve the removal efficiency of organic matter in wastewater while ensuring an effective post-treatment sequence.

3. Effect of Temperature.

Using the Arrhenius equation, the overall temperature can be further increased, further improving the reaction rate and ensuring the efficient progress of the ozone catalytic oxidation reaction. As the temperature continues to rise during this process, the solubility of ozone decreases, further reducing the driving force for gas-liquid mass transfer and slowing the rate. It can be seen that the increase in temperature and the reaction rate are inversely proportional to the gas-liquid mass transfer rate. In practical applications, it is necessary to effectively control the wastewater temperature, which will further increase the consumption rate. Therefore, each catalytic reaction system needs to be operated according to the actual situation.