Microplastics (MPs) are emerging as a class of pollutants that are a potential threat to biological and human health. Aggregation and settling are crucial to controlling MPs transport and environmental fate. However, the influence of clay minerals in the aqueous environment on the aggregation-settling processes of larger size MPs and its mechanisms remain unclear. In this study, homoaggregation of pristine and aged polyethylene microplastics (PEs) and heteroaggregation-settling of PEs with typical clay minerals (chlorite, illite, kaolinite, montmorillonite) under different hydrochemical conditions (NaCl, CaCl, MgCl) were systematically investigated. The results showed that the cation type has a greater influence on the homoaggregation system. In detail, the aged PEs is more stable than pristine PEs in monovalent electrolyte solutions, but not in divalent electrolytes. In heteroaggregation systems, electrostatic repulsion dominates the interaction of PEs (pristine, aged) with clay minerals. However, the settling ratio of PEs (pristine, aged) contributed by clay minerals is not very dependent on the clay mineral type. Conversely, high NaCl concentrations are more conducive to the heteroaggregation-settling of PEs, which can be explained by the DLVO theory. The findings of this study provide new insights into the environmental fate and distribution of MPs in natural waters.
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http://dx.doi.org/10.1016/j.envpol.2022.120649 | DOI Listing |
Exposure to ambient particulate matter (PM) with an aerodynamic diameter of <10 μm (PM) is a well-established health hazard. There is increasing evidence that geogenic (Earth-derived) particles can induce adverse biological effects upon inhalation, though there is high variability in particle bioreactivity that is associated with particle source and physicochemical properties. In this study, we investigated physicochemical properties and biological reactivity of volcanic ash from the April 2021 eruption of La Soufrière volcano, St.
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January 2025
School of Civil Engineering, Southwest Jiaotong University, Chengdu, Sichuan Province 610031, China.
Chemical weathering of lithologies with high geochemical backgrounds such as black shale has been proposed to be a critical source for toxic elements in soil and water systems. However, mechanisms controlling the release, migration and enrichment of toxic elements during black shale weathering are poorly understood. This study utilized a suite of micro analytical techniques such as TESCAN integrated mineral analyzer (TIMA), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and electron micro-probe analysis (EMPA) to elucidate the intimate relationship between mineralogical transformations and elemental behaviors from profile scale to mineral scale.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou, Henan 450001, PR China; School of Chemical Engineering, Zhengzhou University, Zhengzhou, Henan 450001, PR China; Luoyang Industrial Technology Institute, Luoyang, Henan 471132, PR China; The Key Lab of Critical Metals Minerals Supernormal Enrichment and Extraction, Ministry of Education, Zhengzhou, Henan 450001, PR China.
An efficient adsorbent for Ga(III) recovery was developed by applying the geochemical principles of Ga mineralization, using Al-rich clay minerals with a natural affinity for Ga as the raw material. Sodium alginate (SA) facilitated the cross-linked assembly of montmorillonite nanosheets (MMTNS), forming a three-dimensional structured hydrogel. This was achieved through electrostatic interactions between -OH groups on the edges of MMTNS and -COO groups in SA, as well as the complexation of Ca and -COO groups.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA; High Meadows Environmental Institute, Princeton University, Princeton, NJ 08544, USA. Electronic address:
Knowledge Gap: The aggregation of clay minerals in liquid water exemplifies colloidal self-assembly in nature. These negatively charged aluminosilicate platelets interact through multiple mechanisms with different sensitivities to particle shape, surface charge, aqueous chemistry, and interparticle distance and exhibit complex aggregation structures. Experiments have difficulty resolving the associated colloidal assemblages at the scale of individual particles.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Key Laboratory for Enhanced Oil & Gas Recovery of the Ministry of Education, Northeast Petroleum University, Daqing 163318, China.
In the process of oilfield development, the surfactant-polymer (SP) composite system has shown significant effects in enhancing oil recovery (EOR) due to its excellent interfacial activity and viscoelastic properties. However, with the continuous increase in the volume of composite flooding injection, a decline in injection-production capacity (I/P capacity) has been observed. Through the observation of frozen core slices, it was found that during the secondary composite flooding (SCF) process, a large amount of residual oil in the form of intergranular adsorption remained in the core pores.
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