0
Article Tier 2 Remediation Sign in to save

[Effects of Aging on the Cd Adsorption by Microplastics and the Relevant Mechanisms].

PubMed 2022 5 citations

AI summary Read the abstract

This study examined how aging affects the ability of microplastics — including polyethylene and polystyrene — to adsorb the heavy metal cadmium. Weathered microplastics showed different adsorption behavior than virgin particles, which has implications for how microplastics transport toxic metals through aquatic environments.

It has been verified that, as an emerging contaminant, microplastics are capable of adsorbing certain traditional contaminants like the heavy metal Cd. However, the majority of previous studies only focused on certain types of virgin microplastics, especially for PE and PS. In addition, this adsorption process might be affected by microplastics inevitably undergoing aging and consequent changes in the natural environment. Unfortunately, the relevant reports on aging effects were mainly about organic pollutants, rather than heavy metals. By far, there have been few comprehensive and mechanistic studies on the key aging effects on the Cd adsorption by various types of microplastics. In this study, five representative types of microplastics (i.e., PS, ABS, PP, PVC, and PET) were selected for aging by ultraviolet radiation, and the physicochemical properties of virgin and aged microplastics were thoroughly compared, including specific surface area, crystallinity, surface functional groups, and surface elements. Accordingly, the changes in adsorption isotherms of Cd by microplastics were discussed. The results showed that:① aging induced non-significant changes in specific surface area but a significant decrease in crystallinity. Surface functional groups also changed, including the emergence of a C=O functional group on PS and ABS, the decrease in C=C absorption peak intensity on ABS, and the increase in absorption peak intensities of C=O, C-O, and polar ester groups on PET. Regarding surface C content, C=C/C-C decreased, whereas C-O and O-C=O increased. The total O content and O/C significantly increased as well. ② The Langmuir model well-fitted the adsorption isotherms of Cd by virgin and aged microplastics. Aging significantly expanded the adsorption capacity of Cd by microplastics, as the order of saturated adsorption capacity before aging was ABS (0.2284 mg·g-1)>PVC (0.1360 mg·g-1)>PS (0.1286 mg·g-1)>PP (0.1005 mg·g-1)>PET (0.0462 mg·g-1) and then became PS (0.2768 mg·g-1)>ABS (0.2586 mg·g-1)>PVC (0.1776 mg·g-1)>PP (0.1721 mg·g-1)>PET (0.0951 mg·g-1) after aging. ③ Both crystallinity and surface functional groups played key roles in the adsorption of Cd by microplastics. As for virgin microplastics, crystallinity was negatively correlated with the saturated adsorption capacity of Cd, because the amorphous regions contributed most to Cd adsorption. Aging brought about the decrease in crystallinity and the increase in amorphous regions, which further promoted the oxidation reaction on microplastics. Consequently, oxygen-containing functional groups increased on the surface and eventually expanded the adsorption capacity of Cd by microplastics. Note that certain specific functional groups of various microplastics also had impacts on the adsorption process. These results provide valuable information about the environmental behaviors and interactions of microplastics and heavy metals in nature.

More Papers Like This

Article Tier 2

Study on the Adsorption Behavior and Mechanism of Heavy Metals in Aquatic Environment before and after the Aging of Typical Microplastics

AI summary Read the abstract

Researchers investigated the adsorption behavior and mechanisms of heavy metals by typical microplastics before and after environmental aging, finding that aging significantly alters microplastics' surface properties and capacity to bind metals such as cadmium and lead in aquatic systems.

Article Tier 2

Sorption properties of cadmium on microplastics: The common practice experiment and A two-dimensional correlation spectroscopic study

AI summary Read the abstract

Laboratory experiments examined how cadmium adsorbs onto microplastics of different polymer types and aging states, finding that surface chemistry and weathering significantly affect how much heavy metal the plastics can carry. This matters because microplastics contaminated with heavy metals represent a dual pollution risk when ingested by aquatic organisms.

Article Tier 2

Aging microplastics in wastewater pipeline networks and treatment processes: Physicochemical characteristics and Cd adsorption

AI summary Read the abstract

Researchers found that microplastics passing through wastewater pipeline networks and treatment processes develop altered physicochemical properties compared to virgin particles, with aged polyamide, polyethylene, and polystyrene showing enhanced cadmium adsorption capacity.

Article Tier 2

Adsorption Performance and Mechanism of Naturally Aged Polyethylene(PE) Microplastics on Cadmium Ions (Cd2+) in Water

AI summary Read the abstract

River-aged polyethylene microplastics showed increased surface roughness, altered functional groups, and enhanced adsorption capacity for cadmium ions compared to pristine particles, with aging duration influencing both the kinetics and isotherms of metal binding. These results confirm that environmental weathering transforms microplastics into more effective heavy metal carriers, increasing the risk of combined plastic-metal toxicity in aquatic ecosystems and food chains.

Article Tier 2

Aging properties of polyethylene and polylactic acid microplastics and their adsorption behavior of Cd(II) and Cr(VI) in aquatic environments

AI summary Read the abstract

Researchers compared how polyethylene and polylactic acid (PLA) microplastics age in the environment and how that aging affects their ability to absorb heavy metals like cadmium and chromium from water. They found that aging changed the surface chemistry of both plastic types, increasing their capacity to pick up these toxic metals. The findings matter because aged microplastics in the environment may concentrate and transport more pollutants than fresh plastic particles.

Research digests by email

When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.

Email me about

Share this paper