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High‐efficiency photocatalysts that are synthesized for hydrogen production via photocatalytic water splitting and glycerol conversion without the generation of additional pollutants are presented. Photocatalytic hydrogen production is particular promising because it utilizes glycerol, which is an inexpensive waste from biodiesel production. The main goal of the investigation was the proper selection of photocatalysts based on finding the optimal conditions of the photocatalytic production of hydrogen in the glycerol–water system. TiO2 as well as TiO2 doped with platinum, palladium or gold (0.1, 0.5, 1 wt%), prepared by the photodeposition and sol–gel method, were applied as photocatalysts. The photocatalysts were characterized by X‐ray powder diffraction analysis (XRD). The influences of the preparation methodology, the addition of the doped metal and amount of the doping, radiation intensity, solvent additives, and the amount of photocatalysts on process efficiency were investigated. The efficiency of hydrogen production is high compared to that reported in the literature. It was found that a high yield is impossible without the addition of glycerol or other organic compounds. The hydrogen production exceeded 141 × 103 μmol H2/h·gcat when 0.5 wt% Pt doped TiO2 was used. The novelty of this study is the highest hydrogen productivity obtained at a laboratory scale. The production rate of hydrogen depended on the catalyst concentration, the amount of the noble metal in the catalysts and the glycerol concentration. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 680–687, 2019

Abstract:The conventional wastewater treatments are inadequate for emerging contaminants detoxification. Photocatalytic ozonation with suitable catalyst can be considered as a suitable solution on the removal of these compounds. The aim of this study was to verify the effect of Ag, Pd and Pt with different loadings (0.1, 0.5 and 1% wt %) onto TiO 2 surface for the degradation of a mixture of parabens (methyl, ethyl, propyl, butyl and benzyl) through photocatalytic ozonation. Chemical oxygen demand (COD) and total organic carbon (TOC) was also analyzed after treatments, as well as the effect of the treatment on the samples toxicity over different species, including bacteria, clams and plants. The effect of metal loading on the parabens degradation; COD and TOC removal is very dependent upon the type of noble metal used. This can be related with the different pathways influenced by the metal load. On the one hand, it can be related with the reduction of electron-hole recombination phenomenon, and, on the other hand, the trapping of electrons by the metals reduces the amount of ozonide and hydroxyl radicals produced. In terms of toxicity, apparently the best results were achieved with the intermediate noble metal load. However, the effect of noble metal load must be analyzed case to case.