Technical challenges of catalytic oxidation method

Development of efficient, broad-spectrum, and inexpensive catalysts.

The wet oxidation method has advantages such as fast oxidation rate, high treatment efficiency, wide applicability, minimal secondary pollution, and the ability to recover energy and useful materials. However, there are certain limitations in its practical application and promotion, because the wet oxidation method generally requires operation under high temperature and high pressure conditions, which are quite stringent ； The intermediate product is an organic acid, which places high demands on the materials used for the equipment; these materials must be able to withstand high temperatures and pressures as well as resist corrosion. As a result, the cost of the equipment is high, and the initial investment is significant ； Even under high temperature and pressure conditions, wet oxidation cannot oxidize all organic compounds (for example, the removal of polychlorinated biphenyls and small molecular carboxylic acids is not effective, and complete oxidation is even more difficult to achieve). As mentioned on the second floor, the development of catalysts is also a challenge and a key focus! Currently, research on advanced oxidation processes is receiving considerable attention, but there is still a distance to go before they can be put into practical use! Last edited by Fightinghard on 2009-4-14 09:11]

This post was last edited by shanyee on 2009-5-4 21:44. The operating costs are too high, as the key technologies are monopolized by foreign companies (although such technologies are also available in China, they require extensive testing over a long period of time). The price of the process packages is high, making it difficult for ordinary companies to afford them.

The reasons why catalytic oxidation is not widely used at present are as follows: first, a catalyst is required; second, high conditions such as high temperature and pressure are needed; third, the operation is inconvenient and requires extensive knowledge; fourth, the treatment cost is high. These factors limit its dissemination. If catalytic oxidation can be developed to work at normal temperature and pressure, and its treatment cost is only slightly higher than that of conventional methods, then it will surely be more widely adopted. This requires **significant financial investment to address it, rather than the company developing a solution on its own.

Wet catalytic oxidation is an advanced environmental protection technology developed internationally in the mid-1980s for treating high-concentration organic wastewater. The main principle of this technology is to pass the wastewater through a reactor equipped with catalysts with high oxidation capabilities, under certain pressures (2–8 Mpa) and temperatures (200–280°C). This process enables the catalytic oxidation of organic substances as well as toxic compounds containing nitrogen and sulfur into harmless substances such as CO2, H2O, N2, and SO42-. It has advantages such as high purification efficiency, no secondary pollution, a simple process, and low space requirements. ； Its disadvantages are high equipment investment and large reagent consumption. With few exceptions of two-component catalysts consisting of precious metals and rare earth elements, most catalysts are made of precious metals or other metals; they are expensive, require large quantities, and are prone to poisoning and contamination, which can lead to catalyst deactivation and poor oxidation efficiency of organic substances ； Treating wastewater requires high temperature and pressure, and the reactors are expensive, resulting in high investment costs and elevated wastewater treatment expenses, which hinders the application of this technology. To this end, research and development in the following areas should be strengthened: 1) Development of highly stable catalysts with excellent performance and broad-spectrum catalytic activity, including single or combined catalysts with sufficient oxidation activity under mild conditions, at moderate prices. 2) Develop efficient reactors that enable thorough contact between gas, solid, and liquid phases, provide good oxidation separation effects, and are resistant to acid and alkali corrosion, including improved fluidized bed reaction systems. Improve the catalytic efficiency of the catalyst as well as the oxidation and decomposition efficiency of organic substances, and further reduce catalyst loss. 3) Reduce conditions such as temperature and pressure required in the wastewater treatment process. This also facilitates the selection of high-performance catalysts and the development of efficient reactors, as well as reducing the costs associated with using wet catalyst oxidation methods for treating industrial organic wastewater. 4) Strengthen research on combined processes of wet catalytic oxidation with other wastewater treatment methods to expand their application scope. In summary, the wet catalytic oxidation method for treating high-concentration, refractory organic wastewater is highly efficient and fast; it enables the rapid oxidation and decomposition of many toxic organic substances that are difficult to treat using conventional oxidation or biochemical methods. As a result, this method has become an innovative and effective wastewater treatment technique that has attracted widespread attention both domestically and internationally. This post was last edited by lyhh9024 on 2009-4-19 09:03.]

Catalytic oxidation relies mainly on efficient catalysts; issues include 1) the problem of domestic production, and 2) the need to reduce operating conditions. Catalytic oxidation is not used only in wastewater treatment. It is also used quite often in other areas.

I look forward to the day when wet catalytic oxidation can play a significant role!