Experimental study on integrated desulfurization and denitrification of low-temperature flue gas by oxidation method

In this paper, TiO₂ catalysts doped with different Fe contents (Fe-TiO₂ catalysts) were prepared by coprecipitation method and the Fe loading capacity was optimized, and then the integrated pollutant removal experiment was conducted, in which TiO₂ doped with Fe as catalyst and H₂O₂ as oxidant. The results show that under the condition of constant H₂O₂/(SO₂ + NO) molar ratio, low concentration of SO₂ can promote the oxidation and removal efficiency of NO, while high concentration of SO₂ can inhibit the removal of NO_x. The pollutant removal efficiency is proportional to the amount of catalyst, liquid-gas ratio and pH value of the absorbing solution. The optimal experimental conditions are H₂O₂/(SO₂ + NO) molar ratio 1.5, space velocity ratio 10,000 h^-1, H₂O₂ mass fraction 10 wt%, liquid gas ratio 10, pH 10. Correspondingly, NO oxidation efficiency reaches 88%, NO_x removal efficiency 85.6%, and SO₂ is almost completely removed. The microstructure of the catalyst before and after the reaction was characterized, and the crystal structure did not change obviously. However, with the deepening of the reaction, the specific surface area of the catalyst decreases, and the catalytic effect decreases slightly.