Synthesis and characterization of CuO/rGO composite nanoparticles for photocatalytic removal of organic pollutants from wastewater

Interest in nanomaterials continues to increase day by day due to the extraordinary properties of these materials. Today, nanomaterials can be more visible in our daily life only if they can be produced in more quantities and at lower costs. For this, there is still a need to develop new environmentally friendly, low-cost, fast, and highly efficient processes. This study aims to develop a method that will allow the commercial-scale production of CuO nanoparticles, which is a crucial semiconductor and CuO@rGO composite nanoparticles. Moreover, synthesized nanomaterials were used as a photocatalyst for the removal of organic pollutants in wastewater. In order to improve the photocatalytic activities of the produced CuO nanoparticles, CuO@rGO composite nanoparticles were produced by assembling with reduced graphene oxide (rGO) to the structure, and the effect of reduced graphene oxide added to the structure on the photocatalytic activities of CuO nanoparticles was investigated. For this purpose, in the first stage, the synthesis of CuO nanoparticles and CuO@rGO composite nanoparticles with microwave-assisted combustion technique, which is a low-cost, easy-to-apply and environmentally friendly method, was investigated. In synthesis studies, two basic approaches were adopted for the production of CuO nanoparticles and CuO@rGO composite nanoparticles. In the first method, the conventional microwave-assisted combustion method was applied, while the microwave-assisted solution-combustion technique was applied in the second method. Both CuO nanoparticles and CuO@rGO composite nanoparticles were produced by both methods. For this purpose, reduced graphene oxide (rGO) produced in the laboratory by the modified hummers method was used. In the production of the composite material, CuO and rGO were synthesized separately and then assembled (self-assembly). The data obtained from the synthesis studies showed that CuO nanoparticles and CuO@rGO composite nanoparticles could be successfully synthesized by both methods. In these studies, nanomaterials with a size distribution in the size range of about 10-20 nm were obtained. Later, these materials were used as photocatalysts in the photocatalytic oxidation removal of a dyestuff from wastewater, known as Tartrazine, which is used extensively in the food industry. In these trials, the initial pollutant concentration was 50 mg/L. In photocatalysis experiments, an immersion lamp with a light intensity of 4400µW/cm2 was used to provide the required radiation. It has been observed that the pollutant in the environment can be removed entirely in the experiments carried out with the natural pH value of the solution and in the experiments with almost all synthesized catalysts. In addition, in the kinetic analysis, it was determined that all the processes examined fit the pseudo-first-order kinetic model.