Catalytic effect of Mn2+, Fe3+ and Mg2+ ions on desulfurization using phosphate rock slurry as absorbent

Mutual promotion effect of SO2 and NOx during yellow phosphorus and phosphate rock slurry adsorption process

“…It can be observed from Figure S5A that the CaMg(CO 3 ) 2 gradually disappears as the reaction time increases due to its better reactivity 22 . The SO 2 was absorbed to form CaSO 4 •2H 2 O that was detected in the spent phosphate rock, which is consistent with our previous results 21‐23 . The NO is oxidized to high valence nitrogen oxides (NO 2 and N 2 O 5 ) with ozone induced by yellow phosphorus, and then dissolved in the slurry to form nitrite and nitrate.…”

“…And then a free radical chain reaction initiated by O 2 is involved via reactions () (The sign “T” stands for triplet state.) 23 . The SO 3 •− radicals become the key substance to promote the free radical chain reaction.…”

“…Despite these radicals can be detected in S(IV) solution in the absence of NO 2 − , the signal of free radicals is extremely weak. Because the formation of SO 3 •− via the reaction of S(IV) with O 2 needs to consume up to 111 kJ/mol energy, which limits the production of SO 4 •− and OH• in subsequent chain reactions 23 . when NO 2 − is added to S(IV) solution, the signals of SO 3 •− become significantly stronger, showing that NO 2 − can promote the yields of SO 3 •− .…”

“…More importantly, the NO 2 become the continual driving force for generation of SO 3 •− . Consequently, The S(VI) can be quickly obtained through the free radical oxidation chain reactions () induced by SO 3 •− , leading to a continuous increase in De‐SO 2 efficiency 23 . At the same time, the sulfur species produced in the chain reaction can effectively oxidize NO and NO 2 toward HNO 3 by reactions ().…”

Experimental Investigation of SO2 Removal from Flue Gases by Cleaning with Solution of Lime Suspension and Formic Acid

“…In this regard, a number of researchers [12][13][14][15][16][17][18][19][20][21][22] explored and developed a series of procedures for SO 2 reduction, in order to find the optimal and economic procedure. Having this in mind, the authors of this paper explored the possibility of the application of a solution of lime suspension and formic acid for the removal of SO 2 from flue gas since formic acid enhances the absorption process.…”