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Title: Using hydrogen peroxide derived in-situ for oxidation reactions : applications in greywater sterilisation and the development of new Pd-SnO2 catalysts
Author: Harrhy, Jonathan
ISNI:       0000 0004 6425 6339
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2017
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This thesis explores a new use for the direct synthesis of hydrogen peroxide (H2O2), water sterilisation. The first part of this work seeks to identify if in-situ derived H2O2 can be used to sterilise household greywater (GW). It was found that H2O2 synthesised via the direct synthesis reaction in a continuous flow reactor can remove concentrations of up to 109 CFU ml-1 of Escherichia Coli after only a single pass through the reactor. The effectiveness of in-situ generated H2O2 was then compared with various ex-situ H2O2 sources and it was found that: In-situ ≥ pre-synthesised > commercial unstabilised > commercial stabilised. The next part of this thesis builds on the findings of the initial work, investigating whether insitu generated H2O2 is effective as an antimicrobial agent against recognised standard strains of Staphylococcus Aureus, Escherichia Coli and Pseudomonas Aeruginosa. It was found that a 2-log reduction of Staphylococcus Aureus is possible after a single pass through the flow reactor and this can be increased to a maximum of a 3-log reduction by optimising the reaction conditions and using a 1 wt.% AuPd/TiO2 catalyst. The same result was found for Escherichia Coli but only a 1-log reduction was possible in the case of Pseudomonas Aeruginosa. Incorporating iron (Fe2+ and Fe3+) into the catalyst led to greater antimicrobial activity but catalyst instability was an issue. In the final part of this thesis, the use of a novel palladium catalyst supported on tin oxide (PdSnO2) for the direct synthesis of H2O2 was investigated. It was found that catalysts prepared by impregnation are active for the direct synthesis but in using a novel sol-gel preparation, the catalyst activity is greatly increased. Selectivity towards H2O2 was found to be less than PdSn bimetallic catalysts and an ORO heat treatment led to some morphological changes in the solgel catalysts but only small changes in the activity and selectivity were observed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry