We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Understanding microplastic aging driven by photosensitization of algal extracellular polymeric substances
Summary
Researchers found that substances released by algae significantly speed up the breakdown of polystyrene microplastics under sunlight. The algal compounds generate reactive molecules that attack the plastic surface, creating smaller fragments and releasing dissolved organic matter. The findings are particularly relevant for understanding how microplastics degrade in waterways affected by algal blooms.
The aging of microplastics (MPs) is extremely influenced by photochemically-produced reactive intermediates (PPRIs), which are mediated by natural photosensitive substances. Algal extracellular polymeric substances (EPS) can produce PPRIs when exposed to sunlight. Nonetheless, the specific role of EPS in the aging process of MPs remains unclear. This work systematically explored the aging process of polystyrene (PS) MPs in the EPS secreted by Chlorella vulgaris under simulated sunlight irradiation. The results revealed that the existence of EPS accelerated the degradation of PS MPs into particles with sizes less than 1 µm, while also facilitating the formation of hydroxy groups on the surface. The release rate of dissolved organic matter (DOM) from PS MPs was elevated from 0.120 mg·L·day to 0.577 mg·L·day. The primary factor contributing to the elevated levels of DOM was humic acid-like compounds generated through the breakdown of PS. EPS accelerated the aging process of PS MPs by primarily mediating the formation of triplet excited states (EPS*), singlet oxygen (O), and superoxide radicals (O), resulting in indirect degradation. EPS* was found to have the most substantial impact. This study makes a significant contribution to advance understanding of the environmental fate of MPs in aquatic environments impacted by algal blooms.
Sign in to start a discussion.
More Papers Like This
Polystyrene microplastics enhanced the photo-degradation and -ammonification of algae-derived dissolved organic matters
Researchers studied how polystyrene microplastics affect the breakdown of organic matter released by algae when exposed to UV light. They found that the presence of microplastics accelerated the degradation of amino acid-like compounds and increased ammonia production compared to UV exposure alone. The study suggests that microplastics can act as environmental photosensitizers, potentially altering nutrient cycling in natural water bodies.
Molecular-level insights into the heterogeneous variations and dynamic formation mechanism of leached dissolved organic matter during the photoaging of polystyrene microplastics
Researchers investigated the molecular-level changes that occur when polystyrene microplastics break down under light exposure and release dissolved organic matter into water. They found that the released molecules were highly diverse and changed dynamically over the course of aging, with different chemical classes appearing at different stages. The study provides new insight into how degrading microplastics introduce complex mixtures of organic chemicals into aquatic environments.
Photochemistry of microplastics-derived dissolved organic matter: Reactive species generation and organic pollutant degradation
Researchers investigated how dissolved organic matter released from degrading polystyrene and PVC microplastics behaves when exposed to sunlight in water. They found that sunlight breaks down the aromatic compounds in this plastic-derived material and generates reactive chemical species, though at lower rates than natural organic matter. Despite this, these reactive species significantly accelerated the breakdown of co-existing pollutants, suggesting that degrading microplastics may act as unexpected natural catalysts in aquatic environments.
Enhancing aggregation of microalgae on polystyrene microplastics by high light: Processes, drivers, and environmental risk assessment
Researchers found that bright light conditions caused algae to clump together with polystyrene microplastics much more readily than dim light, by secreting sticky protein-rich substances. This aggregation process changes how microplastics behave in water, potentially causing them to sink and concentrate in certain zones. Since algae are at the base of aquatic food chains, these interactions could affect how microplastics move through ecosystems and eventually reach organisms consumed by humans.
Polystyrene microplastics accelerated photodegradation of co-existed polypropylene via photosensitization of polymer itself and released organic compounds
Researchers discovered that polystyrene microplastics can accelerate the breakdown of polypropylene microplastics when both are present together in water exposed to sunlight. The polystyrene acts as a photosensitizer, generating reactive oxygen species that speed up the oxidation and fragmentation of polypropylene. The finding reveals that different types of microplastics can interact with each other in unexpected ways, potentially accelerating the generation of even smaller plastic particles in the environment.