Revivable self-assembled supramolecular biomass fibrous framework for efficient microplastic removal

Global distribution characteristics and ecological risk assessment of microplastics in aquatic organisms based on meta-analysis

As microplastic pollution in the natural environment intensifies, the risk of microplastic contamination faced by aquatic organisms has garnered increasing widespread attention. Most studies have primarily focused on the impacts of microplastics within specific regions and on particular species. However, with the global migration of microplastics, it is necessary to conduct comprehensive research on the distribution characteristics, ingestion mechanisms, and ecological impacts of microplastics across various aquatic organisms. To address this research gap, the present study systematically evaluates the distribution status of microplastics in global aquatic organisms and assesses their potential ecological risks. Firstly, a review of the sources and impacts of microplastics within aquatic organisms is provided. Secondly, a bibliometric analysis is employed to examine the current research landscape and trends, coupled with a quantitative analysis of how the biological characteristics of aquatic organisms influence microplastic ingestion and the distribution patterns of microplastics within these organisms. Thirdly, the study investigates the mechanisms by which microplastics affect aquatic food chains by examining their impact on organisms at different trophic levels. Finally, strategies to reduce microplastic input into water bodies and future research directions are proposed. The findings offer scientific foundations and decision-making support for global microplastic pollution control, aiming to protect the health and sustainable development of aquatic ecosystems.

Distribution and diversity of microplastics along the aquatic food web in the largest mangrove reserve of China

Knowledge of microplastics (MPs) in consumers at different trophic levels and with different feeding strategies in mangroves is essential to evaluate pathways and ecological effects from exposure to MPs. We conducted a comprehensive study on the distribution of MPs along the food web in the largest natural mangrove reserve in China, and applied diversity index of MPs, D'(MP), in terms of color, size, shape and type, to investigate complexity of MPs through the trophic cascades. The highest abundance of total MPs occurred at 5.7 ± 2.6 items/individual in fish, followed by 4.8 ± 1.9, 3.2 ± 0.5, 2.2 ± 0.9 items/individual in crabs, bivalves and shrimps, respectively. There was a correlation between the abundance of MPs in the gastrointestinal tracts (GITs) or soft tissues of organisms and trophic levels (r = 0.47, p < 0.01), while microplastic abundance were also correlated with body wet weights. The abundance and diversity of MPs in mangrove organisms were influenced by their feeding behaviors and living habitats, as consumers through indirect ingestion had significantly higher abundance of MPs than discriminate feeders. For MPs in their GITs, crabs had the highest shape D'(MP), but the lowest size D'(MP) and color D'(MP), while fish had highest color D'(MP), but significantly lower shape D'(MP). Our application of diversity index of MPs to mangrove ecosystem for the first time reveals a rather complicated distribution of MPs along the aquatic food web, demonstrating an urgent need for measures to reduce the discharge of MPs into mangrove and develop a remediation strategy.

C─S Bonds Modulated Nanointerface Tension to Create Stable Magnetic Hollow Nanocarbons for Efficient Microplastics Capture

Microplastic pollution poses significant threats to aquatic ecosystems and human health. Hollow nanomaterials are promising adsorbents for microplastics remediation due to their tailorable architectures, functions, and large contact area. Nevertheless, the structural stability of well-defined nanostructures has always been a critical factor, and understanding the stability principle is desired. Herein, we fabricated magnetic hollow nanocarbons as "nano-analytical tool", revealing that the stability is related to additional pressure caused by nanointerface tension at curved carbon shell surface. To mitigate this, we introduced C─S bonds by sulfurizing carbon matrix, suppressing the condensation of oxygen-containing groups and thereby reducing interface tension. As a showcase, the stable hollow Fe3O4@C/S enabled rapid and efficient microplastics capture (100% within 10 s, 53 600 mg g-1 capacity) under an alternating magnetic field, owing to the magnetically accelerated mass transfer and increased contact area. Additionally, sulfur modification broadens applicability range where carbon surface is oppositely charged to microplastics, expanding the universality in capturing multiple types of microplastics, even under challenging conditions including different pH and salinities. This work offers guidance into the precise synthesis of hollow nanomaterials from nanointerface perspective. The design principles involving sulfur modification and high-contact area may open prospects for high-capacity microplastics capture in complex aquatic environments.

High-performance amino-crosslinked phosphorylated microcrystalline cellulose/MoS2 hybrid aerogel for polystyrene nanoplastics removal from aqueous environments

Currently, the development of high-performance adsorbents for the removal of nanoplastics in complex aquatic environments is challenging. In this study, a functionalized polyethyleneimine-phosphorylated microcrystalline cellulose/MoS2 (PEI-PMCC/MoS2) hybrid aerogel was prepared and applied to remove carboxyl-modified polystyrene (PS-COOH) nanoplastics from the aqueous solution. Benefiting from the introduced functional groups and the expanded lamellar structure in MoS2 nanosheets as well as the highly porous 3D structure of the aerogel, PEI-PMCC/MoS2 demonstrated high efficiency in PS-COOH nanoplastics removal, achieving a 402.4 ± 7.5 mg/g maximum adsorption capacity at the optimal adsorption pH of 7.0 (C0 = 300 mg/L). The adsorption isotherm and kinetics data fitted well with the Langmuir and pseudo-second-order models, respectively, suggesting that the removal of PS-COOH nanoplastics was dominated by the monolayer chemisorption process, and the thermodynamic studies revealed the exothermic nature of the spontaneous adsorption process. Furthermore, the adsorption performance of PEI-PMCC/MoS2 in different complex aqueous environments, as well as its reusability, was evaluated, and the interactions between PEI-PMCC/MoS2 and PS-COOH nanoplastics were analyzed to elaborate the adsorption mechanism. These results confirmed the high nanoplastics removal efficiency and favorable reusability in PEI-PMCC/MoS2, laying a solid foundation for developing high-performance adsorbents for nanoplastics removal.

Microplastic removal, identification and characterization in Chennai sewage treatment plants

Sewage treatment plants (STPs) act as either sinks or sources of microplastic (MP) contamination in the environment. This study examined and assessed the occurrence, removal efficiencies, abundance and characteristics of MPs in two STPs in Chennai, India. Large volumes of influent and effluent water were collected and filtered on site via a filter in a series system. The samples were later treated in the laboratory to isolate the MPs from other organic and inorganic particles. The MPs were analysed via Fourier Transform Infra-Red (FTIR) spectroscopy and Raman spectroscopy to analyse the chemical composition of the isolated microplastics. Pollution load index (PLI) and EU classification, labelling and packaging (CLP) standard was incorporated to assess the pollution risk of MPs in STP. According to the results obtained from this research work, the MP concentrations in the influent waters were high for both STPs (5443 MPs/L and 4800 MPs/L). Although the MP removal efficiency of the STPs were quite high (~96 % and ~93 %), the pollution load indices at Kodungaiyur and Koyambedu STPs were observed to be 0.272 and 0.208 respectively, which were moderately contaminated. PORI scores revealed that Kodungaiyur Plant is in danger level I with the hazard score of 9.25 and Koyambedu plant is in danger level II with the hazard score of 12.78. The estimated quantity of the MPs discharged from the monitored STPs was approximately 28.4 & 28.2 billion MPs/day.

Biophysics-guided uncertainty-aware deep learning uncovers high-affinity plastic-binding peptides

Plastic pollution, particularly microplastics (MPs), poses a significant global threat to ecosystems and human health, necessitating innovative remediation strategies. Biocompatible and biodegradable plastic-binding peptides (PBPs) offer a potential solution through targeted adsorption and subsequent MP detection or removal from the environment. A challenge in discovering plastic-binding peptides is the vast combinatorial space of possible peptides (i.e., over 1015 for 12-mer peptides), which far exceeds the sample sizes typically reachable by experiments or biophysics-based computational methods. One step towards addressing this issue is to train deep learning models on experimental or biophysical datasets, permitting faster and cheaper evaluations of peptides. However, deep learning predictions are not always accurate, which could waste time and money due to synthesizing and evaluating false positives. Here, we resolve this issue by combining biophysical modeling data from Peptide Binder Design (PepBD) algorithm, the predictive power and uncertainty quantification of evidential deep learning, and metaheuristic search methods to identify high-affinity PBPs for several common plastics. Molecular dynamics simulations show that the discovered PBPs have greater median adsorption free energies for polyethylene (5%), polypropylene (18%), and polystyrene (34%) relative to PBPs previously designed by PepBD. The impact of including uncertainty quantification in peptide design is demonstrated by the increasing improvement in the median adsorption free energy with decreasing uncertainty. This robust framework accelerates peptide discovery, paving the way for effective, bio-inspired solutions to MP remediation.