$ NANOMATERIALS} Excessive plastic use in domestic, industrial, and agricultural sectors provides new environmental challenges. In particular, polyethylene (PE) is one of the most widely used plastics in the world, with more than 100 million tons produced annually [1]. According to the reports, more than 80% of agricultural films is made from low-density polyethylene (LDPE) [2]. Once microplastics enter the environment, they can accumulate or be transferred through different ecosystems and eventually reach human body. Thus, attention has been focused on advanced technologies for the degradation of microplastics, such as photocatalytic, chemical, and biological methods. Among these methods, photocatalytic degradation stands out as the most promising approach for the degradation of microplastics. TiO\(_{2}\) nanoparticles are widely applicable for degrading organic pollutants due to their high photoactivity and stability. However, TiO\(_{2}\) initiated degradation of LDPE is often limited by the rapid recombination of electron-hole pairs. Therefore, in this study, Ag-TiO\(_{2}\) nanomaterials were proposed as more photoactive alternatives for the degradation of LDPE films. Moreover, since the effectiveness of microplastic degradation is dependent on the properties of the particles, the influence of microplastic size on its degradation was also evaluated.
Ag-TiO\(_{2}\) nanomaterials with different amount of Ag were synthesized using the photoreduction method. Black LDPE microplastic films with a size of 1×1 mm and 3×3 mm were used. The reaction was carried out in a closed UV chamber under UV-A irradiation in an aqueous medium. A higher Ag concentration in Ag-TiO\(_{2}\) nanocomposites enhanced the degradation efficiency of LDPE films by up to 35%. LDPE films with a size of 1×1 mm exhibited a higher degradation efficiency (9.4%) after 960 minutes compared to 3×3 mm films (6.18%). A carbonyl group peak at 1725 cm\(^{-1}\) was observed after 120 minutes of UV irradiation for the 1×1 mm film, while it appeared only after 360 minutes for the 3×3 mm film. The obtained results suggested that size of microplastics is a crucial parameter, with photocatalytic performance being more efficient for smaller size LDPE microplastic films.