How Do Ozone Decomposition Catalysts Overcome the Bottleneck in Wastewater Ozone Treatment?

The core value of ozone decomposition catalysts lies in catalyzing the generation of hydroxyl radicals (·OH) from ozone, transforming ozone's "selective oxidation" into "non-selective deep oxidation," while simultaneously improving ozone decomposition efficiency. Its mechanism is not simply accelerating ozone decomposition, but rather through electron transfer reactions between active components and ozone, directionally generating highly active free radicals. Compared to ozone alone, the oxidation potential of OH increases from 2.07V to 2.80V, which can completely mineralize ozone-resistant intermediates such as acetic acid and oxalic acid into CO₂ and H₂O. A case study of petrochemical wastewater treatment showed that after adding the catalyst, the ozone removal rate of COD increased from 28% to 62%, and the TOC removal rate also increased by 55%.

Currently, mainstream catalysts can be divided into two categories: one is supported metal oxide catalysts, using Al₂O₃ as a carrier to support active components such as Mn, Co, and Ni. They are suitable for medium and low-concentration organic wastewater and have the advantage of strong resistance to shock loads, and are widely used in dyeing wastewater treatment; the other is carbon-based catalysts, such as activated carbon loaded with nano-iron, which, with its high specific surface area, strengthens the adsorption-catalytic synergistic effect, and is more suitable for chemical wastewater containing chlorinated organic compounds and heterocyclic organic compounds. It is important to note that catalyst selection must match the wastewater pH – metal oxide catalysts exhibit optimal activity under neutral to weakly alkaline conditions, while carbon-based catalysts are more stable in acidic environments.

In practical applications, "catalyst lifespan management" is a core challenge. Sulfides and heavy metal ions in wastewater can lead to catalyst poisoning, while suspended particulate matter can block active sites. One pharmaceutical wastewater treatment plant removed over 90% of suspended solids through pre-treatment coagulation and sedimentation, and controlled the influent sulfide concentration to below 5 mg/L, extending the catalyst lifespan from 3 months to 8 months. Furthermore, the hydraulic retention time of the reaction system needs to be matched with the catalyst activity, typically controlled at 30-60 minutes; too short a time results in insufficient free radical generation, while too long a time leads to excessive ozone consumption.

In summary, ozone decomposition catalysts are not a "universal efficiency enhancer"; their effectiveness depends on their compatibility with the wastewater quality and the optimization of process parameters. Future advancements in improving catalyst activity for high-salt, high-toxicity wastewater, and breakthroughs in low-cost regeneration technologies, will be key to the further development of their applications.

Author: Hazel
Date: 2025-12-08