Advances in magnetic materials for microplastic separation and degradation

Organic matter and microplastics nexus: A comprehensive understanding of the synergistic impact on soil health

The interactional nexus of microplastics (MPs) and organic matter (OM) can subtly disrupt the delicate balance of soil ecosystems, influencing nutrient dynamics, biodiversity, and overall soil health. To explore this complex interplay between MPs and OM concerning several perspectives, a comprehensive keyword search was conducted across key scientific databases, and the retrieved data was curated according to the PRISMA guidelines to reflect the objectives. Several studies have highlighted that organic-based inputs, such as manures, composts, and sewage sludge, widely used for soil amendment, are potential sources of MPs to soil contamination. These coinciding sources of MPs and OM raise potential concerns about their impact on overall soil health. MPs and OM have parallel characteristics and play a critical role in the soil organic carbon (SOC) and dissolved organic matter (DOM), critical for biogeochemical transformations and nutrient cycling. In light of this, the present review explores the multifaceted nexus between MPs and OM, explaining their interaction mechanisms and their effects on the biological and physicochemical properties of the soil. Despite significant implications on soil ecosystem, challenges remain in accurately quantifying the effects of MPs due to the complexities introduced by DOM. The intricate interaction between MPs and DOM can obscure analytical results, complicating efforts to separate and identify these pollutants effectively. Given these challenges, this review underscores the urgent need for innovative methods to characterize and quantify MPs in complex environmental matrices. Finally, we discuss emerging research directions aimed at advancing the detection and management of MPs in soil ecosystems.

Microplastic types dominate the effects of bismuth oxide semi-conductor nanoparticles on their transport in saturated quartz sand

The transport of microplastics (MPs) is of great significance due to its potential threat to subsurface systems. The copresence of MPs and semi-conductor nanoparticles is quite common in practical environments (i. e. in electronic/electrical waste disposal sites). To date, the influence of bismuth oxide (Bi2O3) semi-conductor nanoparticles on MPs transport in porous media has still been rarely and explicitly explored. Therefore, the effect of Bi2O3 on the transport of distinct types of MPs were investigated using column experiments. The MPs included 0.51 μm and 1.1 μm polystyrene (PS), 1 μm polyethylene terephthalate (PET) and 1 μm polyethylene (PE) MPs. Mechanisms for the differently altered transport of various MPs with Bi2O3 were further elucidated. It was verified that the deposited Bi2O3 on sand surfaces could contribute to the decreased transport of PET and PE MPs by column experiments with pre-treatment. Moreover, scanning electron microscopy (SEM), dynamic light scattering (DLS) measurements, and electrochemical Nyquist curves demonstrated that the interaction of PE and PET MPs with Bi2O3 was more pronounced than that of PS MPs, especially for PE MPs. In addition, density functional theory (DFT) calculations combined with adsorption experiments further confirmed that the adsorption between PE MPs and Bi2O3 was the strongest, which then contributed to the highest decrease of PE MPs transport. This study highlighted that the MPs types might be the major factor controlling its interaction with copresent substances, thereby affecting its fate and transport in soil systems.

Microplastic pollution in marine environments: An in-depth analysis of advanced monitoring techniques, removal technologies, and future challenges

Microplastics, recognized as toxic contaminants, have pervaded terrestrial, atmospheric, and marine environments, transitioning from emerging pollutants to pervasive threats. About 10 % of the plastic produced worldwide enters into the ocean which constitutes 85 % of marine litter. Microplastic distribution holds the highest concentration in the Atlantic Ocean whereas the Southern Ocean holds the lowest. Concerning microplastics, reports state that each year about 1.3 million metric tons of microplastics enter the ocean. The microparticles account for about 90 % of the floating ocean debris and over 75 % of these particles originate from land-based sources which include urban runoff, and mismanaged wastes. This review offers a thorough examination of the sources of microplastics and their environmental consequences and ecological impacts. The ubiquity of microplastics necessitates robust control measures, starting with their monitoring and detection in aquatic ecosystems to assess the effectiveness of mitigation strategies. Current removal methods, including physical, chemical, and bio-based techniques, are detailed, alongside advances in filtration, separation, and integrated hybrid approaches for microplastic control. The review concludes with perspectives on the limitations of existing methods and directions for future research in microplastic monitoring, detection, and removal.

Assessment and treatment of microplastics in different environmental compartments of Kallar Kahar Lake-a case study

Microplastic pollution has garnered global attention in recent decades due to its recognized ecological concerns through previous studies. However, in Pakistan, scarce information has been reported on MP pollution concerning the freshwater ecosystem. The current study was conducted on Kallar Kahar Lake, Punjab, Pakistan for (1) quantification, characterization, and distribution of MPs in surface water, sediments, and fish samples and (2) two treatment processes (magnetization and coagulation + flocculation) for the removal of MPs from the water. Samples were collected from each point by grab sampling method to investigate the MPs according to their type, shape, and color. The MP quantification and analysis were accomplished via the counting method by a stereomicroscope and Fourier transform infrared spectroscopy for their polymer type and composition. Results indicated the average MP abundance as 49.6 ± 11.14 MP/500 mL, 143 ± 48.18 MP/100 g, and 79 ± 12.2 items for water, sediments, and fish correspondingly. The dominant MP colors were blue, transparent, and green in all three environmental compartments. The ATR-FTIR identified the polymer types in lake water, sediment, and fish were PPS, PIB, and PLF; PET, PE, PP, and Natural Latex Rubber; and PET, respectively. The MP removal rate was observed high in both treatments. The average % removal rate of iron ore magnetization treatment was observed to be 80% at 1300 mg/L dosage of Fe2O3. Similarly in chemical coagulation processes, the highest MP removal efficiency was 85% (PET), 83% (PPS) and 80% (PIB) at the different concentration dosages of 150 + 15 mg/L, 111 + 15 mg/L, and 150 + 111 + 15 mg/L for Combination 1, Combination 2, and Combination 3, respectively. Overall, this study provided an integrative and novel approach for the removal of MP from surface water, which also holds an explicit commercial utilization prospect to overpower the MP pollution in water bodies. Also, the current findings serve as baseline data for the study of local freshwater systems.

Potential health, environmental implication of microplastics: A review on its detection

Microplastic contamination of terrestrial and aquatic environment has gained immense research attention due to their potential ecotoxicity and biomagnification property when enterer into food chain. Heterogenous nature of microplastics coupled with their ability to combine with other emerging pollutants have increased the severity of this crisis. Existing detection methods often fails to accurately quantify the amount of microplastic components present in environmental and biological samples. Thus, a great deal of research gap always exists in our current understanding about microplastics including the limitations in screening, detection and mitigation. This review work presents a comprehensive out look on the impact of microplastics on both terrestrial and aquatic environment. Furthermore, an in-depth discussion on various microplastic detection techniques recently used for microplastic quantification along with their significance and limitations is summarised in this review. The review also elaborates various physical, chemical and biological methods used for the mitigation of microplastics from environmental samples.

Global microplastics pollution: a bibliometric analysis and review on research trends and hotspots in agroecosystems

The prevalence of microplastics (MPs) in agricultural ecosystems poses a notable threat to dynamics of soil ecosystems, crop productivity, and global food security. MPs enter agricultural ecosystems from various sources and have considerable impacts on the physiochemical properties soil, soil organisms and microbial communities, and plants. However, the intensity of these impacts can vary with the size, shape, types, and the concentrations of MPs in the soil. Besides, MPs can enter food chain through consummation of crops grown on MPs polluted soils. In this study, we conducted a bibliometric analysis of 1636 publications on the effects of MPs on agricultural ecosystems from 2012 to May 2024. The results revealed a substantial increase in publications over the years, and China, the USA, Germany, and India have emerged as leading countries in this field of research. Social network analysis identified emerging trends and research hotspots. The latest burst keywords were contaminants, biochar, polyethylene microplastics, biodegradable microplastics, antibiotic resistance genes, and quantification. Furthermore, we have summarized the effects of MPs on various components of agricultural ecosystems. By integrating findings from diverse disciplinary perspectives, this study provides a valuable insight into the current knowledge landscape, identifies research gaps, and proposes future research directions to effectively tackle the intricate challenges associated with MPs pollution in agricultural environments.

Harnessing Magnetic Nanoparticles for the Effective Removal of Micro- and Nanoplastics: A Critical Review

The spread of micro- (MPs) and nanoplastics (NPs) in the environment has become a significant environmental concern, necessitating effective removal strategies. In this comprehensive scientific review, we examine the use of magnetic nanoparticles (MNPs) as a promising technology for the removal of MPs and NPs from water. We first describe the issues of MPs and NPs and their impact on the environment and human health. Then, the fundamental principles of using MNPs for the removal of these pollutants will be presented, emphasizing that MNPs enable the selective binding and separation of MPs and NPs from water sources. Furthermore, we provide a short summary of various types of MNPs that have proven effective in the removal of MPs and NPs. These include ferromagnetic nanoparticles and MNPs coated with organic polymers, as well as nanocomposites and magnetic nanostructures. We also review their properties, such as magnetic saturation, size, shape, surface functionalization, and stability, and their influence on removal efficiency. Next, we describe different methods of utilizing MNPs for the removal of MPs and NPs. We discuss their advantages, limitations, and potential for further development in detail. In the final part of the review, we provide an overview of the existing studies and results demonstrating the effectiveness of using MNPs for the removal of MPs and NPs from water. We also address the challenges that need to be overcome, such as nanoparticle optimization, process scalability, and the removal and recycling of nanoparticles after the completion of the process. This comprehensive scientific review offers extensive insights into the use of MNPs for the removal of MPs and NPs from water. With improved understanding and the development of advanced materials and methods, this technology can play a crucial role in addressing the issues of MPs and NPs and preserving a clean and healthy environment. The novelty of this review article is the emphasis on MNPs for the removal of MPs and NPs from water and a detailed review of the advantages and disadvantages of various MNPs for the mentioned application. Additionally, a review of a large number of publications in this field is provided.

Highly Efficient Separation of Ethanol Amines and Cyanides via Ionic Magnetic Mesoporous Nanomaterials

Simple and efficient sample pretreatment methods are important for analysis and detection of chemical warfare agents (CWAs) in environmental and biological samples. Despite many commercial materials or reagents that have been already applied in sample preparation, such as SPE columns, few materials with specificity have been utilized for purification or enrichment. In this study, ionic magnetic mesoporous nanomaterials such as poly(4-VB)@M-MSNs (magnetic mesoporous silicon nanoparticles modified by 4-vinyl benzene sulfonic acid) and Co2+@M-MSNs (magnetic mesoporous silicon nanoparticles modified by cobalt ions) with high absorptivity for ethanol amines (EAs, nitrogen mustard degradation products) and cyanide were successfully synthesized. The special nanomaterials were obtained by modification of magnetic mesoporous particles prepared based on co-precipitation using -SO3H and Co2+. The materials were fully characterized in terms of their composition and structure. The results indicated that poly(4-VB)@M-MSNs or Co2+@M-MSNs had an unambiguous core-shell structure with a BET of 341.7 m2·g-1 and a saturation magnetization intensity of 60.66 emu·g-1 which indicated the good thermal stability. Poly(4-VB)@M-MSNs showed selective adsorption for EAs while the Co2+@M-MSNs were for cyanide, respectively. The adsorption capacity quickly reached the adsorption equilibrium within the 90 s. The saturated adsorption amounts were MDEA = 35.83 mg·g-1, EDEA = 35.00 mg·g-1, TEA = 17.90 mg·g-1 and CN-= 31.48 mg·g-1, respectively. Meanwhile, the adsorption capacities could be maintained at 50-70% after three adsorption-desorption cycles. The adsorption isotherms were confirmed as the Langmuir equation and the Freundlich equation, respectively, and the adsorption mechanism was determined by DFT calculation. The adsorbents were applied for enrichment of targets in actual samples, which showed great potential for the verification of chemical weapons and the destruction of toxic chemicals.

Robinia pseudoacacia L. (Black Locust) Leaflets as Biomonitors of Airborne Microplastics

Here we investigate the suitability of Robinia pseudoacacia L. (black locust) leaflets as a novel biomonitor of airborne microplastics (MPs) including tyre wear particles (TWPs). Leaflets were collected from rural roadside locations (ROs, n = 5) and urban parks (UPs, n = 5) in Siena, Italy. MPs were removed by washing, identified by stereomicroscope, and analysed for polymer type by Fourier transform infrared spectroscopy. Daily MP deposition was estimated from leaf area. The mass magnetic susceptibility and the bioaccumulation of traffic-related potentially toxic elements (PTEs) were also analysed. The total number of MPs at ROs was significantly higher at 2962, dominated by TWPs, compared with 193 in UPs, where TWPs were not found. In contrast, total microfibres were significantly higher in UPs compared with ROs (185 vs. 86). Daily MP deposition was estimated to range from 4.2 to 5.1 MPs/m2/d across UPs and 29.9-457.6 MPs/m2/d across ROs. The polymer types at ROs were dominated by rubber (80%) from TWPs, followed by 15% polyamide (PA) and 5% polysulfone (PES), while in UPs the proportion of PES (44%) was higher than PA (22%) and polyacrylonitrile (11%). The mean mass magnetic susceptibility, a proxy of the bioaccumulation of traffic-related metallic particles, was higher at ROs (0.62 ± 0.01 10-8 m3/kg) than at UPs (-0.50 ± 0.03 10-8 m3/kg). The content of PTEs was similar across sites, except for significantly higher concentrations of Sb, a tracer of vehicle brake wear, at ROs (0.308 ± 0.008 µg/g) compared with UPs (0.054 ± 0.006 µg/g). Our results suggest that the waxy leaflets and easy determination of surface area make Robinia an effective biomonitor for airborne MPs including TWPs.

Recent Study of Separation and Identification of Micro- and Nanoplastics for Aquatic Products

Micro- and nanoplastics (MNPs) are polymeric compounds widely used in industry and daily life. Although contamination of aquatic products with MNPs exists, most current research on MNPs focuses on environmental, ecological, and toxicological studies, with less on food safety. Currently, the extent to which aquatic products are affected depends primarily on the physical and chemical properties of the consumed MNPs and the content of MNPs. This review presents new findings on the occurrence of MNPs in aquatic products in light of their properties, carrier effects, chemical effects, seasonality, spatiality, and differences in their location within organisms. The latest studies have been summarized for separation and identification of MNPs for aquatic products as well as their physical and chemical properties in aquatic products using fish, bivalves, and crustaceans as models from a food safety perspective. Also, the shortcomings of safety studies are reviewed, and guidance is provided for future research directions. Finally, gaps in current knowledge on MNPs are also emphasized.