Insight into the catalytic performance of silver oxides towards peroxymonosulfate activation for pollutants degradation: Efficiency, mechanism and stability

Sulfur vacancies on MoS2 enhanced the activation of peroxymonosulfate through the co-existence of radical and non-radical pathways to degrade organic pollutants in wastewater

“…These vacancies had a good affinity for PMS in water and then could react with each other to generate reactive oxygen species. 33 At the liquid-solid interface, the intermediates were nally evolved into O 2 c À , as shown in formulas (3)(4)(5)(6)(7)(8) and (3-9):…”

“…In a word, the reaction system included free radical species such as SO 4 c À , cOH and O 2 c À , and non-radical species like 1 O 2 . Among them, O 2 c À and 1 O 2 were the main reactive oxygen species, as demonstrated in formula (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). In order to verify the source of these species, the variation in the PMS concentration before and aer the reaction was investigated, and the results are shown in Fig.…”

“…With the development of industries, a large number of organic pollutants are discharged into the water environment, causing a serious problem of water pollution. Many useful technologies including adsorption, 1 membranes, 2 and advanced oxidation reactions (AORs) [3][4][5] have been developed to dispel organic pollutants. In these ways, the AOR involving peroxymonosulfate (denoted as PMS) as an oxidant is an ideal choice.…”

“…Accordingly, it has to introduce external activation factors including heat, 6 alkaline conditions, 7 and homogeneous 8,9 and heterogeneous catalysts. [3][4][5][10][11][12][13][14][15] Among them, a heterogeneous catalyst for the activation of PMS is a good strategy for repeated use, realization of radical and non-radical routes, etc. The activation of PMS by heterogeneous catalysts containing defect sites has attracted much attention in the past few years.…”

“…as shown in formulas(3)(4)(5)(6)(7)(8)(9)(10) and(3)(4)(5)(6)(7)(8)(9)(10)(11); (ii) the vacancies interacted with PMS; 43 and (iii) O 2 c À reduced Mo(VI),44 as shown in formulas(3)(4)(5)(6)(7)(8)(9)(10)(11)(12):2O 2 c À + H 2 O / H 2 O 2 + OH À + 1 O 2 (3-10) O 2 c À +cOH + 2H + / OH À + 1 O 2 (3-11)Mo(VI) + O 2 c À + 2H + / Mo(IV) + 1 O 2(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) …”