International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Laser ablation in liquid is an eco-friendly and efficient method to produce nanomaterials with interesting properties in a laboratory scale. Previously reported ZnO nanoparticles, obtained by nanosecond and millisecond pulsed laser under various laser parameters, demonstrated photocatalytic, gas-sensing, and antibacterial activity. Here we explore the possibility for laser ablation of Zn metal plate in natural zeolite suspension and isolation of a composite ZnO-Zeo. It was characterized by UV-vis, XPS and SEM methods. The characteristic UV-vis peak for ZnO nanoparticles was observed at 340 nm, which is associated with small particles size, proven by SEM images to be 30-50 nm. The spherical ZnO particles are located on the zeolite surface. It was found that the attraction forces between both phases cause a shift in Zn 2p XPS peak positions which were determined at 1022.0 eV and 1045.1 eV for 2p3/2 and 2p1/2 levels, respectively. The approach for laser ablation in suspension could open avenue for simultaneous formation and incorporation of various nanoparticles into different supports.

The time being, one of the greatest concerns is the environmental pollution. Nowadays, various dangerous compounds reach to the air, soil and water. Pharmaceuticals, such as 17α-ethinylestradiol (EE2), are one of the most emerging pollutants in water ecosystems. Hence, powerful but green approaches should be developed in order to completely remove the pollutants. Heterogeneous photocatalysis is a sustainable and efficient process in the removal of organic pollutants, such as pharmaceuticals. ZnO is one of the most commonly used semiconductors but also possess some drawbacks. In this study novel synthesis pathway of ZnO nanoparticles from banana peel extract was
obtained. Besides, the photocatalytic efficiency of the newly synthesized ZnO was examined in the degradation of EE2. Both the eco-friendly ZnO nanoparticles, as well as pure banana peel extract showed a promising photocatalytic activity in the degradation of EE2 under simulated solar irradiation (SSI). Namely, EE2 was completely degraded after 60 min of SSI.

ZnO nanosized materials are well known for their photocatalytic and antibacterial properties. Their implication in water treatment and environmental protection, especially as a part of composite materials, has been an object of study of a great number of researchers working in the field. Zeolites are excellent candidates for support of composites preparation with semiconductor oxides since they are nonhazardous, non-expensive and naturally abundant materials. In order to synthesize nanosized ZnO with well-developed surface area and uniform size distribution in pristine form and supported on zeolite, we applied the method of precipitation assisted by sonicatio n. As prepared ZnO nanoparticles and the composite ZnO-zeolite were characterized by XRD, SEM and UV-Vis spectroscopy. The ZnO crystalized in wurtzite structure in both materials. The morphology of ZnO nanoparticles was affected by the zeolite framework, as in the composite the ZnO was formed in-situ at the presence of zeolite. The ultrasonic irradiation during the precipitation of Zn(OH)2 and aging of the reaction mixture causes activation of the zeolite surface and prevents the aggregation of ZnO particles. In result evenly distributed ZnO nanoparticles were obtained in the composite.