Degradation of Microplastics by a Thermal Fenton Reaction

Abstract

Microplastics (MPs) are ubiquitous in the environment and are infiltrating the food chain, causing potential risks to living beings. However, current methods of MP removal from an aqueous environment are limited by low efficiency. Advanced oxidation processes (AOPs) are emerging techniques for MP purification. Herein, a hydrothermal coupled Fenton system is developed for decomposition of ultrahigh-molecular-weight polyethylene, achieving 95.9% weight loss in 16 h and 75.6% mineralization efficiency in 12 h. The high effectiveness is attributed to the synergy of hydrothermal hydrolysis, proton-rich environment, and massive production of hydroxyl radicals. The system is also efficient to remediate different petroleum-based plastics and maintains high efficiency in practical water bodies. Characterizations revealed a two-stage degradation process: chain unfolding/stretching and oxidation, giving rise to the formation of carbonyl groups and decreased crystallinity of MPs during the hydrothermal treatment. The chain stretching stage is pivotal to the whole treatment because it remarkably facilitates subsequent chain cleavage and Fenton oxidation. This study provides a new approach to removing MPs in water bodies and new insights into MP degradation by the AOP technology.

Sustainable chemical upcycling of waste polyolefins by heterogeneous catalysis

“…In addition, when UV light was introduced to the reaction system, the degradation rate of PE in the Bio-Photo-Fenton system was significantly enhanced, and the product concentrations of acetic acid and butyric acid were much higher than those of the Bio-Fenton system. Furthermore, Hu et al 82 developed a strategy that couples Fenton reaction with hydrothermal reaction to mineralize the microplastics (MPs, including UHMWPE, HDPE, LDPE, PVC, PS, PP, PET). This process solves the problem of the slow degradation rate of Fenton reaction in aqueous solution (Figure 7D).…”

Effects and Impacts of Different Oxidative Digestion Treatments on Virgin and Aged Microplastic Particles

“…These pores, favoured by an increase in temperature, may generate a release of tiny fragments of PVC such as those found in the soil. The presence of larger cavities has been reported in [ 52 ] for some polymers after the Fenton oxidation process.…”

Manipulating Excitonic Effects in Layered Bismuth Oxyhalides for Photocatalysis

“…The expansion of the world’s population and unrestrained industrial growth in the past few decades have escalated the consumption of fossil fuels (coal, petroleum, natural gas), as well as the unabated release of greenhouse gas (CO 2 ). − According to a report from Earth System Research Laboratories, the CO 2 content in the atmosphere in 2019 was much beyond preindustrial levels, which has intensified global warming and caused anomalous climate change. Meanwhile, a vast number of environmentally harmful pollutants and toxins (NO x , SO x , organic pollutants) arising from fossil fuel combustion are discharged into the air and water bodies, posing a danger to the ecosystem and contributing to pollution-related diseases. − To ensure global sustainability, developing environmentally benign and energy-efficient technologies to decrease the CO 2 concentration and eliminate environmental pollutants should therefore be our goal.…”