Addition of NaCl and LiCl salts to glycerol–urea synthesis leads to the formation of rods and small spheres of ZnO-NPs.

Ibuprofen (IBU) is one of the most-sold anti-inflammatory drugs in the world, and its residues can reach aquatic systems, causing serious health and environmental problems. Strategies are used to improve the photocatalytic activity of zinc oxide (ZnO), and thosethat involvethe inclusion of metalhave received special attention. The aim of this work was to investigate the influence of the parameters and toxicity of a photoproduct using zinc oxide that contains cerium (ZnO-Ce) for the photodegradation of ibuprofen. The parameters include the influence of the photocatalyst concentration (0.5, 0.5, and 1.5 g L−1) as well as the effects of pH (3, 7, and 10), the effect of H2O2, and radical scavengers. The photocatalyst was characterized by Scanning Electron Microscopy-Energy Dispersive Spectroscopy, Transmission electron microscopy, Raman, X-Ray Diffraction, surface area, and diffuse reflectance. The photocatalytic activity of ibuprofen was evaluated in an aqueous solution under UV light for 120 min. The structural characterization by XRD and SEM elucidated the fact that the nanoparticle ZnO contained cerium. The band gap value was 3.31 eV. The best experimental conditions for the photodegradation of IBU were 60% obtained in an acidic condition using 0.50 g L−1 of ZnO-Ce in a solution of 20 ppm of IBU. The presence of hydrogen peroxide favored the photocatalysis process. ZnO-Ce exhibited good IBU degradation activity even after three photocatalytic cycles under UV light. The hole plays akey role in the degradation process of ibuprofen. The toxicity of photolyzed products was monitored against Artemia salina (bioindicator) and did not generate toxic metabolites. Therefore, this work provides a strategic design to improve ZnO-Ce photocatalysts for environmental remediation.

Nanotechnology has a wide and interesting scientific and industrial potential in technological applications. In general terms, nanoparticle (NP) synthesis demands high temperatures, long reaction time and, expensive/toxic precursors. The main goal of this work is to optimize and expand NP synthesis from a glycerol-urea (GU) route. The GU route utilizes glycerol as a basic solvent and allows the use of additives (such as urea and other derivatives) in order to control the size and shape of the NPs. So as to produce metal oxide NPs (ZnO, CuO, and Fe3O4), different reaction parameters were modified during synthesis. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF) and transmission/scanning electron microscopy (TEM/SEM) were utilized as means of NPs characterization. The GU route promoted fast ZnO NPs formation (<1 hour) with high purity, with average purity of 99.8%. The ZnO NPs maintained their expected average size of 15 to 25 nm, with up to 10:1 glycerol:urea molar ratio. Higher proportion than 10:1 showed NPs without uniform particle size. The ratio of Zn 2+ /-OH above 1:4 lead to micrometric ZnO particles. Synthesis utilizing glycerol-water or, only glycerol, resulted in micrometric ZnO particles. The substitution of urea for acetone, thetramethylurea, and formamide yielded ZnO NPs with high crystallinity and uniform spherical morphology. The dimethylurea or water substitution leads to non-uniform micrometric particles, revealing the structural influence of the organic additive in nucleation process of NPs formation. Experiments for CuO and Fe3O4 showed no formation of metal oxide NPs, but nitrates or thiol complexes resulting from the urea reaction with copper and iron. CuO NPs were obtained only after calcination in a muffle oven, resulting in single monoclinic structure and nanometric crystallite size.

MgO nanoribbons were prepared by an innovative route from Mg(OH)2 hydrogels. Such hydrogels were prepared without using any polymers or organic ligands as structuring agents which is an advantage compared...