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Investigation of photocatalytic generation of reactive oxygen species for the degradation of phthalates in water Xinzhu Pang (14503853) PUREID: 382761759 Photocatalysis Cavitation Hydrogen Peroxide kinetics Phthalates With the process of industrialization, the introduction and accumulation of Phthalate Esters (PAEs) into water streams can result in harm to aquatic and human life with adverse effects such as endocrine-disrupting effects. These compounds are frequently being detected in the environment and people realize that there are several exposure pathways, so more efforts to research the elimination of such material in water has been undertaken. This thesis provides a mini review of the occurrence of PAEs and effects on humans following exposure to them. Semiconductor photocatalysis has been demonstrated to be an efficient and promising solution towards eliminating PAEs from the environment. This work reviewed the range of photocatalyst materials previously reported for PAEs removal including the initial work using single metal oxides such as TiO2 along with doped materials such as Fe, Ag co-doped ZnO. Composite materials were also reviewed including Layered double hydroxide-TiO2 which could enhance the removal of PAEs through both adsorption and photocatalytic degradation.In photocatalysis, many Reactive Oxygen Species (ROS) generated and among them, H2O2 is a special one as it is the only stable ROS and it can act as an efficient additive to accelerate photocatalytic reaction. The investigation of mechanism of photocatalytic generation of H2O2 was conducted with controlled periodic illumination (CPI).  This work proved that CPI is a vital evaluation tool to further explore the crucial relationship between catalyst loading, formation rate and light, highlighting the potential CPI has for probing photocatalysis further to understand the key parameters. To further investigate the photocatalytic generation of H2O2, Au/ZnO, Ag/ZnO and Au-Ag/ZnO catalysts were prepared by simultaneous impregnation of HAuCl4 and AgNO3, and they were used to generate H2O2 from a methanol/O2 system. The ability of different catalysts to generate H2O2 and their photonic efficiency was investigated. That would provide some insight for catalysts-making for H2O2 photocatalytic generation. Di-isobutyl phthalate (DiBP) was chosen as a model of PAEs in this research. For the first time, the decomposition of the DiBP by semiconductor photocatalysis was investigated in water, together with a modified kinetic model which accounted for the influence of intermediates on the process has been reported. Both TiO2 and ZnO were found to be effective materials for the photocatalytic degradation of DiBP, and for both materials •OH and •O2− were confirmed to play an importance role in the photocatalytic decomposition of DiBP. The generation and subsequent degradation of one of the primary degradation products, PA, was examined and it was also demonstrated that this compound was degraded quickly in parallel with DiBP. Photocatalytic degradation of DiBP coupled with acoustic cavitation was investigated and a synergistic effect was observed for this hybrid system. Additionally, the synergistic effect was greater for the ZnO photocatalyst compared to that observed with TiO2.The effect of pH on the photocatalytic degradation of DiBP on both ZnO and TiO2 materials was also studied. It was established that the degradation of DiBP was favoured when pH was higher than its point of zero charge (PZC). For Acoustic Cavitation (AC) - Photocatalysis (PC) hybrid system, degradation rate was higher in basic environment, suggesting that photocatalysis plays a more important role in AC-PC system. On illuminated TiO2, low concentration of H2O2 (50 μM) was proven enhance for DiBP degradation, and with higher concentration of H2O2 (100 μM) this enhancement disappears. On illuminated ZnO, when the addition of H2O2 change from 0 μM to 100 μM, no enhancement was observed. These results demonstrated the effectiveness of photocatalytic technology for the removal of this phthalate compound, which has known potential mutagenic effects, which has been increasingly detected in the environment.<br><br> 2026-10-01T17:01:45Z Text Thesis 10.17034/32633604.v1 https://figshare.com/articles/thesis/Investigation_of_photocatalytic_generation_of_reactive_oxygen_species_for_the_degradation_of_phthalates_in_water/32633604 All Rights Reserved