Comparison of the Catalytic Performances of Different Commercial Cobalt Oxides for Peroxymonosulfate Activation During Dye Degradation

• Published in: Chemical research in Chinese universities Vol. 33; no. 5; pp. 822 - 827
• Main Authors: Zhang, Botao, Zhang, Yang, Xiang, Weixu, Teng, Yanguo, Wang, Ying
• Format: Journal Article
• Language: English
• Published: Changchun Jilin University and The Editorial Department of Chemical Research in Chinese Universities 01.10.2017; Springer Nature B.V
• Subjects: Activation; Analytical Chemistry; Catalysis; Catalytic oxidation; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Cobalt oxides; Degradation; Dyes; Free radicals; Hydroxyl radicals; Inorganic Chemistry; Methylene blue; Organic Chemistry; Oxidation; Physical Chemistry; System effectiveness; 催化性能; 商业; 四氧化三钴; 性能比较; 染料降解; 氧活化; 硫酸根自由基; 钴氧化物; Cobalt oxide; Degradation; Dye; Heterogeneous catalysis; Peroxymonosulfate
• ISSN: 1005-9040; 2210-3171
• DOI: 10.1007/s40242-017-6413-6

The catalytic performances of different commercial cobalt oxides（CoxOy, i.e., Co2O3, Co3O4, and CoO） for peroxymonosulfate（PMS） activation in dye degradation were compared in this study. The CoO/PMS system exhibited the highest catalytic oxidation performances with more than 96% methylene bhie（MB） removal at 90 rain. The concentration of dissolved cobalt ions from CoO was 1.474 mg/L at neutral pH and 5.231 mg/L at acidic pH at 90 rain which accounted for the high MB removal and CoO activated PMS homogeneously compared to the associated CoSO4/PMS. Co304 and Co203 exhibited similar catalytic performances and characteristics. The MB removal in Co3OffPMS and Co203/PMS system were more than 88% at neutral pH and over 64% at acidic pH, respectively, in 90 rain. The concentration of dissolved cobalt ions from Co3O4 and Co2O3 was less than 0.018 mg/L at neutral pH and 0.036 mg/L at acidic pH at 90 rain. The MB removal achieved by Co3O4/PMS and Co2O3/PMS were approximately three time higher than that achieved by their associated CoSO4/PMS systems and the heterogeneous cataly played a principal role in the processes. According to scavenger experiments, the contributions of the hydroxyl radicals in the MB degradation were negligible compared to sulfate radicals in the CoO/PMS system, Hydroxyl radicals contributed one-third or more and sulfate radicals were the dominant oxidizing species in the Co3O4/PMS and Co20]PMS systems. COxOy could also effectively activate PMS to generate free radicals for degradation of other dyes. The dyedegradation processes in Co3O4/PMS, Co2O3/PMS and Co3O4/PMS systems followed pseudo-first-order kinetic model and dye degradation rates in different systems were also compared.