Activated carbon enhanced ozonation of oxalate attributed to HO·oxidation in bulk solution and surface oxidation: Effect of activated carbon dosage and pH  

作　　者：Linlin Xing Yongbing Xie Daisuke Minakata Hongbin Cao Jiadong Xiao Yi Zhang John C. Crittenden 

机构地区：[1]National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology [2]Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences [3]Beijing Engineering Research Center of Process Pollution Control [4]University of Chinese Academy of Sciences [5]Department of Civil and Environmental Engineering, Michigan Technological University,Houghton, MI 49931, United States [6]School of Civil and Environmental Engineering, Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology,Atlanta,GA 30332, United States

出　　处：《Journal of Environmental Sciences》2014年第10期2095-2105,共11页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 21177130);the National Key Technology R&D Program (No. 2011BAC06B09);the Chinese Academy of Sciences Visiting Professorships for Senior International Scientists (No. 2009G2-28)

摘　　要：Ozonation of oxalate in aqueous phase was performed with a commercial activated carbon（AC）in this work. The effect of AC dosage and solution pH on the contribution of hydroxyl radicals（HOU） in bulk solution and oxidation on the AC surface to the removal of oxalate was studied. We found that the removal of oxalate was reduced by tert-butyl alcohol（tBA） with low dosages of AC,while it was hardly affected by tBA when the AC dosage was greater than 0.3 g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05 g/L, but it did not work when the AC dosage was no less than 0.1 g/L. These observations indicate that HOUin bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HOU oxidation in bulk solution is significant when the dosage of AC is low, whereas surface oxidation is dominant when the dosage of AC is high. The oxalate removal decreased with increasing pH of the solution with an AC dosage of 0.5 g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HOUoxidation in basic bulk solution. A mechanism involving both HOUoxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.Ozonation of oxalate in aqueous phase was performed with a commercial activated carbon（AC）in this work. The effect of AC dosage and solution pH on the contribution of hydroxyl radicals（HOU） in bulk solution and oxidation on the AC surface to the removal of oxalate was studied. We found that the removal of oxalate was reduced by tert-butyl alcohol（tBA） with low dosages of AC,while it was hardly affected by tBA when the AC dosage was greater than 0.3 g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05 g/L, but it did not work when the AC dosage was no less than 0.1 g/L. These observations indicate that HOUin bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HOU oxidation in bulk solution is significant when the dosage of AC is low, whereas surface oxidation is dominant when the dosage of AC is high. The oxalate removal decreased with increasing pH of the solution with an AC dosage of 0.5 g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HOUoxidation in basic bulk solution. A mechanism involving both HOUoxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.

关 键 词：Activated carbon Oxalate Ozonation Hydroxyl radicals Surface oxidation Catalytic ozonation 

分 类 号：X703[环境科学与工程—环境工程]