In the field of water treatment, catalysts have application potential in the emission reduction of refractory polymers, which has attracted the attention of commercial and academic research. Effective and efficient water purification methods, including Fenton's reagent, ozonation, electrochemical and photocatalytic methods, have been widely explored.
Alfa Chemistry Catalysts is committed to providing customers with a wide range of catalysts to deal with the challenges in water treatment.
Mechanism of Heterogeneous Catalytic Oxidation and Degradation of Pollutants
- Heterogeneous Fenton Catalysis
The Fenton catalytic oxidation reaction chain system is as follows:
Figure 1. The schematic of the heterogeneous Fenton catalytic process.
- Heterogeneous photocatalysis
- Heterogeneous electrocatalysis
Electrocatalysis is a kind of catalysis that accelerates the charge transfer reaction between the electrode and the electrolyte. Electrocatalysis is mainly used for the treatment of organic wastewater, the degradation of chromium-containing wastewater, the desulfurization of flue gas and raw coal, the simultaneous removal of NOx and SO2, and the reduction of carbon dioxide and nitrogen.
- Common catalysts for pollutants
The comparison of the degradation of different pollutants by some catalysts is shown below.
Figure 2. Comparison of catalysts for pollutant degradation. 
Catalyst for Heterogeneous Catalytic Ozonation
- Heterogeneous catalytic ozonation has potentially higher efficiency in the degradation and mineralization of refractory organic pollutants, and has less negative impact on water quality. Cobalt-based catalysts (such as Co/SiO2, CoOx/Al2O3, CoMgAl and CoNiAl, etc.) have been used in ozonolysis studies, but their stability is insufficient, and a large amount of Ni2+ will remain in the solution. Recent studies have shown that MnOx, CoOx or CuOx can be anchored on the surface of mesoporous ZrO2 or γ-Al2O3 by interacting with the surface hydroxyl groups of the carrier, which improves the catalytic efficiency and stability, and can be used for difficult-to-degrade organic compounds in mineralized water.
Figure 3. The removal of TOC during the degradation of 2,4-D in aqueous dispersions of various catalysts with ozone. 
Catalyst for Ultrasonic-Assisted Water Treatment
- Ultrasonic combined catalyst is used in water treatment, which can effectively improve the removal rate of organic pollutants and reduce energy consumption. Among all types of catalysts, iron-based catalysts have the greatest potential due to their low cost, high safety and wide distribution. Zero-valent iron (ZVI), Fe2(SO4)3, FeSO4, FeCl3, and FeOOH have long been used in water treatment.
Figure 4. Schematic diagram of the mechanism of sonocatalytic degradation. 
- Ting Zhang. (2019). "Heterogeneous Catalytic Process for Wastewater Treatment." Advanced Oxidation Processes - Applications, Trends, and Prospects.
- Dapeng LI. (2009). "The progress of catalytic technologies in water purification: A review." Journal of Environmental Sciences 21(6): 713-719.
- Nan Zhang. (2018). "Iron Based Catalysts Used in Water Treatment Assisted by Ultrasound: A Mini Review." Frontiers in Chemistry 6: 12.
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