Application Prospect of K Used for Catalytic Removal of NOx, COx, and VOCs from Industrial Flue Gas: A Review

Abstract

NOx, COx, and volatile organic compounds (VOCs) widely exist in motor vehicle exhaust, coke oven flue gas, sintering flue gas, and pelletizing flue gas. Potassium species have an excellent promotion effect on various catalytic reactions for the treatment of these pollutants. This work reviews the promotion effects of potassium species on the reaction processes, including adsorption, desorption, the pathway and selectivity of reaction, recovery of active center, and effects on the properties of catalysts, including basicity, electron donor characteristics, redox property, active center, stability, and strong metal-to support interaction. The suggestions about how to improve the promotion effects of potassium species in various catalytic reactions are put forward, which involve controlling carriers, content, preparation methods and reaction conditions. The promotion effects of different alkali metals are also compared. The article number about commonly used active metals and promotion ways are also analyzed by bibliometric on NOx, COx, and VOCs. The promotion mechanism of potassium species on various reactions is similar; therefore, the application prospect of potassium species for the coupling control of multi-pollutants in industrial flue gas at low-temperature is described.

Enhanced activity and sulfur resistance of Cu- and Fe-modified activated carbon for the reduction of NO by CO from regeneration gas

“…1 There are many ways to remove NO x , including selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and the dissociation of NO. 2,3 Among them, SCR is one of the most commonly used methods in the treatment of industrial flue gas, especially NH 3 -SCR. 4 However, there are some problems with NH 3 -SCR, such as NH 3 escape, corrosion of pipelines and air preheater blockages.…”

The mechanism of alkali promoting water splitting on g-C3N4

“…18 In addition to promoting the hydrogenation of CO 2 , 19 it also controls the adsorption, desorption and reaction pathway selectivity of pollutants NO x and CO x with similar mechanisms. 20 When alkali acts as a dopant, it changes the band structure and electronic properties of g-C 3 N 4 . 21 As for the alkali ions in solution, they are able to accelerate the water dissociation and H 2 production from water dissociation on a TiO 2 surface, 22,23 where the interaction between the alkali and OH groups is supposed to play a key role.…”

Activity of Ag/CeZrO2, Ag+K/CeZrO2, and Ag-Au+K/CeZrO2 Systems for Lean Burn Exhaust Clean-Up

“…A recently published review [18] presents a thorough literature compilation about the positive influence of potassium ions on the activity of different types of catalyst in a variety of reactions, such as N 2 O and NO decomposition, NH 3 -and HC-SCR, NO oxidation, and soot combustion. Although the modification of gold catalysts with alkali metals has not been widely studied, the beneficial effect of the presence of potassium ions on the activity of silver catalysts in several reactions has been shown in the presence of potassium ions [19][20][21].…”