The characteristics of wet air oxidation of phenol over CuOx/Al2O3 catalysts : Effect of copper loading

• Published in: Chemosphere (Oxford) 2007-06, Vol.68 (2), p.287-292
• Main Authors: KIM, Sang-Kyung, KIM, Kyoung-Hun, IHM, Son-Ki
• Format: Article
• Language: English
• Subjects: Air; Aluminum Oxide - chemistry; Applied sciences; Catalysis; Copper - chemistry; Exact sciences and technology; General purification processes; Oxidation-Reduction; Phenol - chemistry; Pollution; Wastewaters; Water treatment and pollution
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2006.12.080

The nature of active copper species is well-known to vary with copper loading, i.e., isolated Cu(2+) to bulk CuO. In this work, however, the effect of copper loading on the activity and the selectivity was investigated for the wet oxidation of phenol over CuO(x)/Al(2)O(3) catalysts. The activity and the mineralization selectivity of the catalysts increased with copper loading up to 7wt% and remained almost the same at a higher loading. The optimum copper loading was about 7wt% for the wet oxidation of phenol over CuO(x)/Al(2)O(3) catalysts in this work. The nature of copper species with different loading was characterized with TPR, XRD, and XANES. The chemical states of copper in the CuO(x)/Al(2)O(3) catalysts were confirmed as varying with copper loading: isolated Cu(2+) ions for 1wt%; highly dispersed Cu(2+) cluster for 5wt% and 7wt%, and bulk CuO for 10-25wt%. The stability of the CuO(x)/Al(2)O(3) catalysts with different copper loading was also studied with respect to carbonaceous deposits and copper leaching.