Homogeneous catalytic activation of peroxymonosulfate and heterogeneous reductive regeneration of Co2+ by MoS2: The pivotal role of pH

A porous graphitic biochar wrapped Co9S8 core–shell composite enables pH-universal activation of peroxymonosulfate for highly efficient and rapid antibiotics degradation

“…The relatively strong EPR signal of DMPO–OH adducts was detected in the Co 9 S 8 @N–O–BC*/PMS system, while a weakly visible DMPO–SO 4 adduct was observed due to SO 4 ˙ − being rapidly converted to ˙OH under reaction conditions. 53 In addition, the characteristic peaks of DMPO–O 2 could be clearly seen. However, these results were inconsistent with the results of free radical quenching that it almost had no influence on the degradation system.…”

“…Additionally, the specific oxidant efficiency (SOE, calculated by dividing the TOC with the PMS concentration used) in this work (3.08) was higher than that of MoS 2 –Co 2+ /PMS (1.12). 53…”

“…Additionally, the specific oxidant efficiency (SOE, calculated by dividing the TOC with the PMS concentration used) in this work (3.08) was higher than that of MoS 2 -Co 2+ /PMS (1.12). 53 A minor amount of chloride in the solution resulted in a decline in TOC removal owing to the reaction of Cl − with SO 4 ˙− and ˙OH, producing fewer reactive radicals, thus leading to a decreased degradation efficiency. 54 However, with the chloride concentration increased, the inhibition effect on TOC removal gradually decreased, because large 7)-( 10)).…”

Revisiting the Heterogeneous Peroxymonosulfate Activation by MoS2: a Surface Mo–Peroxymonosulfate Complex as the Major Reactive Species

“…20,21 In particular, MoS 2 has also been studied as co-catalysts or catalysts in various AOPs. 22,23 In these processes, MoS 2 could either facilitate the redox cycle of other catalysts, for example, Fe(III)/Fe(II), 24 Cu(II)/Cu(I), 25 and Co(III)/Co(II), 26 or directly activate the oxidants including PMS. 27,28 Previous studies have reached the agreement that the reactivity of MoS 2 in these reactions, regardless of its role as a co-catalyst or catalyst, highly relies on the unsaturated active Mo sites on the edge.…”

“…Molybdenum disulfide (MoS 2 ), a representative transition-metal sulfide with a unique two-dimensional layered structure, has been extensively investigated in many areas such as sensing, energy storage and conversion, electro-/photocatalysis, and environmental remediation. , In particular, MoS 2 has also been studied as co-catalysts or catalysts in various AOPs. , In these processes, MoS 2 could either facilitate the redox cycle of other catalysts, for example, Fe­(III)/Fe­(II), Cu­(II)/Cu­(I), and Co­(III)/Co­(II), or directly activate the oxidants including PMS. , Previous studies have reached the agreement that the reactivity of MoS 2 in these reactions, regardless of its role as a co-catalyst or catalyst, highly relies on the unsaturated active Mo sites on the edge . More importantly, the mechanism for the activation of PMS using MoS 2 as a catalyst has been reckoned to be free radicals exclusively.…”