Promotion of true catalytic activity via acid oxidation in carbon supported mixed metal oxide catalysts Bence Solymosi School of Chemistry, Institute of Process Research and Development, University of Leeds, UK Globally 1 in 3 people don’t have access to safe drinking water due to the presence of micropollutants [1] . These persistent pollutants include pharmaceuticals, industrial chemicals, and pesticides, and can have significant adverse health effects, like increased risk of cancer, reproductive impairment, or cognitive deficits [2][3][4] . The only ways current water treatment methods can remove micropollutants is through adsorption and biological breakdown during primary and secondary treatment, respectively. Both of these are low-capacity and are incapable of fully detoxifying water. Most emerging tertiary treatment methods are similarly based on adsorption or degradation; the former does remove pollutants from effluents but saturated adsorbents are still problematic. Even current degradation-based water treatment methods come with significant drawbacks: most importantly high installation and operating costs, and the potential production of secondary pollution [5][9]. An alternative is to use catalytic oxidation over heterogeneous catalysts, however, such systems are currently far from optimal. The use of high surface area supports can significantly enhance catalytic activity by increasing catalyst dispersion, which necessarily reduces environmental impact, as well. Carbon materials have become a popular choice as catalyst supports due to their low cost, high abundance and specific emergent interactions with the supported catalysts. This emergent synergism has been documented in other contexts, but it remains underexplored for AOPs that don’t require external activation [7-9, 12]. An often overlooked aspect of such composites is that the apparent catalytic activity is a combination of adsorption and true catalytic degradation. The ratio of these is generally unknown, and the structure-performance relationship governing these processes is not usually studied. This can lead to an overestimation of catalytic activity, which in real-world applications would significantly drop off after the catalyst becomes saturated with organics. This study utilises a model dye degradation process facilitated by a novel metal oxide catalyst supported on a macroscale carbon material. Acid oxidation of the carbon support was used to maximise the contribution of true catalytic degradation in the overall dye removal. As a result, adsorption on the catalyst is decoupled from catalytic degradation facilitated by industrially relevant carbon-supported transition metal oxides providing a deeper understanding of how relatively adsorptionless, high- activity composite catalysts can be produced for more environmentally benign tertiary water treatment methods. References 1. Progress on drinking water, sanitation and hygiene: 2000-2017., UN Joint Monitoring Programme report, 2017 Y. Luo et al., Sci. Total Environ., 473–474, 2014 , 619-641M. 2. A. La Merrill et al., Nat. Rev. Endocrinol. , 16, 2020 , 45–57E. Diamanti-Kandarakis et al., Endocr. Rev. , 30(4):293-342, 2009 3. D. Bokare et al., J. Hazard. Mater. , 275, 2014 , 121-135Y. 4. Liang et al., Nature Mater. , 10, 2011 , 780–786L. Dai et al., Nano Energy , 27, 2016 , 185-195 X. Li et al., J. Hazard. Mater. , 383, 2020 , 121211, M. A. Oturan et al., Crit. Rev. Environ. , 44, 2014 , 2577–2641S. Natarajan et al., J. Environ. Sci. , 65, 2018 , 201-222
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