Catalytic ozonation not relying on hydroxyl radical oxidation: A selective and competitive reaction process related to metal-carboxylate complexes
Type
ArticleAuthors
Zhang, TaoCroue, Jean-Philippe
KAUST Department
Biological and Environmental Sciences and Engineering (BESE) DivisionEnvironmental Science and Engineering Program
Water Desalination and Reuse Research Center (WDRC)
Date
2014-01Permanent link to this record
http://hdl.handle.net/10754/563279
Metadata
Show full item recordAbstract
Catalytic ozonation following non-hydroxyl radical pathway is an important technique not only to degrade refractory carboxylic-containing organic compounds/matter but also to avoid catalyst deactivation caused by metal-carboxylate complexation. It is unknown whether this process is effective for all carboxylates or selective to special molecule structures. In this work, the selectivity was confirmed using O3/(CuO/CeO2) and six distinct ozone-resistant probe carboxylates (i.e., acetate, citrate, malonate, oxalate, pyruvate and succinate). Among these probe compounds, pyruvate, oxalate, and citrate were readily degraded following the rate order of oxalate>citrate>pyruvate, while the degradation of acetate, malonate, and succinate was not promoted. The selectivity was independent on carboxylate group number of the probe compounds and solution pH. Competitive degradation was observed for carboxylate mixtures following the preference order of citrate, oxalate, and finally pyruvate. The competitive degradation was ascribed to competitive adsorption on the catalyst surface. It was revealed that the catalytically degradable compounds formed bidentate chelating or bridging complexes with surface copper sites of the catalyst, i.e., the active sites. The catalytically undegradable carboxylates formed monodentate complexes with surface copper sites or just electrostatically adsorbed on the catalyst surface. The selectivity, relying on the structure of surface metal-carboxylate complex, should be considered in the design of catalytic ozonation process. © 2013 Elsevier B.V.Citation
Zhang, T., & Croué, J.-P. (2014). Catalytic ozonation not relying on hydroxyl radical oxidation: A selective and competitive reaction process related to metal–carboxylate complexes. Applied Catalysis B: Environmental, 144, 831–839. doi:10.1016/j.apcatb.2013.08.023Publisher
Elsevier BVae974a485f413a2113503eed53cd6c53
10.1016/j.apcatb.2013.08.023