Exploring the photocatalytic degradation mechanism for low-density polyethylene utilizing Bi4Ti3O12 nanoflower catalyst

Abstract

The escalating presence of microplastics (MPs), specifically low-density polyethylene (LDPE), in various ecosystems has sparked considerable environmental and health concerns. These persistent pollutants, due to their small size and resistance to degradation, pose a serious threat to both ecosystems and human health. This study explores the efficacy of Bi4Ti3O12 nanoflower as a photocatalyst in the photocatalytic degradation of LDPE MPs under the influence of a 300 W xenon lamp. Bi4Ti3O12, synthesized via a hydrothermal method, showcases a unique layered perovskite structure that enhances photocatalytic activity by promoting the separation of photogenerated electrons and holes. The degradation efficacy was significantly superior, with LDPE MPs experiencing a weight loss of 38.27 % in 6 hours, outperforming the reported photocatalysts within a shorter timeframe. Through comprehensive analytical techniques, including SEM, XRD, FTIR, XPS, and GC-MS, the study delineates the structural, morphological, and chemical changes of LDPE MPs, highlighting the critical role of reactive oxygen species such as •OH, •O2−, and 1O2 in the degradation process through active species detection and capture experiments. The identification of various degradation by-products suggests the conversion of LDPE MPs into small molecular substances such as esters and aromatic compounds, which are then further oxidized to CO2 and H2O by •OH, •O2−, and 1O2, significantly increasing the degradability and availability of LDPE MPs. Ultimately, the present work not only sheds light on the photocatalytic degradation mechanisms but also highlights the innovative potential of Bi4Ti3O12 nanoflowers as a catalyst for reducing microplastic pollution, setting a foundation for future advancements in environmental cleanup technologies.