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The synthesis and characterization of a hydrochar/CeO2 composite along with its evaluation in methylene blue degradation under visible light are presented. The methodology consisted of a single-pass hydrothermal method, having as synthesis conditions 9 h of reaction time, 210 °C, autogenous pressure, and a biomass/CeO2 ratio of 100:1. The composite characterization revealed good dispersion of CeO2 in the carbonaceous matrix and significant synergy in the composite activation using visible irradiation. The photodegradation experiments showed an efficiency of 98% for white LED light, 91% for UV light, 96% for solar irradiation, and 85% for blue LED light using as conditions pH 7.0, 50 mg of composite, 50 mL of solution, 10 mg/L of dye initial concentration, and 120 min of contact time. Meanwhile, the reusability experiments evidenced a reuse capacity of up to five times with a constant photodegradation efficiency (99%); moreover, it was determined that the presence of electrolytes at pH below 7.0 during degradation negatively affected methylene blue degradation. Finally, the results of this work demonstrate that the hydrochar/CeO2 composite can be synthesized by a green method and used for the efficient treatment of water contaminated with methylene blue. [ABSTRACT FROM AUTHOR]

Titanium silicalites (TS) are well‐known materials for their use in industrial oxidation reactions, and although they are used as photocatalysts, their activity is limited. Therefore, numerous synthetic strategies are investigated to improve their photocatalytic activity. Herein, three series of modified titanium silicalites are synthesized using three different organotriethoxysilanes at different molar percentages with the aim of modifying the structure of the zeolite, both at a porous and chemical level, to obtain materials with high photocatalytic activity. The study of their morphological, textural, chemical, and UV–vis light absorption properties through various characterization techniques has allowed the selection of the best candidates to test their photoactivity in the degradation of venlafaxine, an antidepressant drug that persists as a contaminant in wastewater and has serious neurotoxic effects. Materials synthesized using a 5% molar percentage of RTEOS and 10% of PhTEOS (Ph = phenyl) are able to degrade venlafaxine, whereas the reference material does not show any photocatalytic activity. These results lead the way to use this synthetic strategy to develop titanium silicates and optimize their photocatalytic activity in degradation reactions of different pollutants. [ABSTRACT FROM AUTHOR]

10.3390/catal11091130 2 Hernández R., Hernández-Reséndiz J.R., Cruz-Ramírez M., Velázquez-Castillo R., Escobar-Alarcón L., Ortiz-Frade L., Esquivel K. Au-TiO2 synthesized by a microwave- and sonochemistry-assisted sol-gel method: Characterization and application as photocatalyst. 10.3390/catal10050574 6 Fernández-Perales M., Rozalen M., Sánchez-Polo M., Rivera-Utrilla J., López-Ramón M.V., Álvarez M.A. Solar degradation of sulfamethazine using rGO/Bi composite photocatalysts. The sonochemistry-synthesized photocatalysts displayed the most promising results, with improved PC removal, and a catalyst gold content of 0.7 wt.% was found to be optimal for this process. Over recent years, public concerns have arisen about environmental pollution by so-called emerging organic pollutants (EOPs) in water sources and factory effluents, because of their potentially adverse effects on human health and aquatic ecosystems. [Extracted from the article]

[Display omitted] • Carbon nitride (gCN) was synthesised with different barbituric acid (BA) contents. • gCN photocatalytic response was improved by merging copolymerisation and exfoliation. • More N-vacancies and surface defects increased charge transfer and light absorption. • Positive-shifted VB potential in gCNex-1.6BA material allows a direct RhB oxidation. • BA reduced the bandgap and created mid-gap states for enhanced production of ROS. Graphitic carbon nitride (gCN) photocatalysts were synthesised by copolymerisation of dicyandiamide precursor and different barbituric acid (BA) shares, followed by thermal exfoliation. The morphological, textural, structural, photo- and electrochemical properties of the obtained materials were studied to identify the effect of BA on the material exfoliation. Moreover, its influence on photocatalytic efficiency was investigated by the degradation of a model contaminant (rhodamine B – RhB) under simulated solar irradiation. The results indicated that incorporating carbonyl-based networks of BA into the aromatic moieties of the gCN structure contributed to a higher degree of exfoliation. Furthermore, this endowed the copolymerised materials with a larger surface area since there was a more disordered nanosheet formation and increased porosity. The best-performing catalyst was the 1.6 wt% BA-modified material, owing to the higher density of nitrogen vacancies detected in the exfoliated gCN material. This density of vacancies yielded a larger quantity of active sites at gCN sheet edges, a more rapid electronic transfer and inhibited photo-induced electron/hole pairs recombination. The newly integrated electronic properties, induced by the copolymerisation synthesis with 1.6 wt% of BA, improved the photocatalytic degradation of the RhB by direct oxidation with photogenerated positive holes and more abundant oxy-radicals. The presence of the BA copolymer during gCN synthesis also permitted, after thermal exfoliation, exceptionally lower energy mid-gap positions to occur, which is highly beneficial for an accelerated oxidation mechanism. [ABSTRACT FROM AUTHOR]