The heteroaggregation and deposition behavior of nanoplastics on Al2O3 in aquatic environments

Mineral Morphology-Mediated Interaction of Boehmite with Polystyrene Nanoplastics (PSNPs) and Validation in an Aqueous Environment

“…Oriekhova et al indicated that heteroaggregates were formed between Fe 2 O 3 and PSNPs because of the charge neutralization mechanism . Our previous studies also proved that electrostatic interaction promotes aggregation between PSNPs and many kinds of minerals (kaolinite, LDH, Al 2 O 3 , and ferrihydrite), thus influencing the transportation and sedimentation behaviors of PSNPs in aqueous environments − (more details are shown in Table S1). The fact that the increase of ionic strength contributes to the heteroaggregation between PSNPs and minerals has been widely proven in laboratory experiments; ,, however, these results may not be reliably extrapolated to more complex natural environments.…”

“…Our previous studies also proved that electrostatic interaction promotes aggregation between PSNPs and many kinds of minerals (kaolinite, LDH, Al 2 O 3 , and ferrihydrite), thus influencing the transportation and sedimentation behaviors of PSNPs in aqueous environments − (more details are shown in Table S1). The fact that the increase of ionic strength contributes to the heteroaggregation between PSNPs and minerals has been widely proven in laboratory experiments; ,, however, these results may not be reliably extrapolated to more complex natural environments. The heteroaggregation between PSNPs and minerals might show different laws if the electrolyte concentration was not the dominant factor in natural environments.…”

“…After that, the individual and mixed suspensions (3 mL) were moved to a quartz cuvette for absorbance measurements at 215 nm by a UV–vis spectrophotometer (Agilent-2600) (an analytical device that measures analyte absorbances of light at certain wavelengths) for the quantification of PSNPs. , The concentration of PSNPs in the supernatant did not change, indicating that unabsorbed PSNPs could not precipitate under centrifugation. In the wavelength of 215 nm, the absorbance of boehmite after centrifugation is close to zero, which could not affect the concentration detection of PSNPs (Figure S1).…”

Colloidal Interactions of Microplastic Particles with Anionic Clays in Electrolyte Solutions

“…These phenomena, as well as the stability of the occurring particles, are further influenced by solution properties (e.g., pH, ionic strength, and natural organic matter content), as well as the features of the plastics (e.g., particle size, shape, and chemical composition) and other colloidal particles (e.g., composition, size distribution). ,,,, Furthermore, the mass ratio and the surface charge of the interacting particles are also important, while the electrostatic forces have been proven to play a key role in the formation of heteroaggregates. – Numerous studies have explored the impact of ionic strength on heteroaggregation, with emphasis on specific particle ratios. , The critical coagulation concentration (CCC) for heteroaggregation (at a given particle mass ratio) has been identified as being highly sensitive to boundary conditions, especially when one of the particles approaches the charge reversal point. This sensitivity can be attributed to the interplay of double-layer forces between charged and neutral particles, which is highly influenced by the charge regulation characteristics of the weaker charged surface.…”

“…18 In addition, heteroaggregation between MPs and other colloids was shown to alter the buoyancy of MPs and increase their sedimentation rate, which is a key process in efficient water treatment or during the migration of MPs in the environment. 25−28 These phenomena, as well as the stability of the occurring particles, are further influenced by solution properties (e.g., pH, ionic strength, and natural organic matter content), 29 as well as the features of the plastics (e.g., particle size, shape, and chemical composition) and other colloidal particles (e.g., composition, size distribution). 17,21,24,30,31 Furthermore, the mass ratio and the surface charge of the interacting particles are also important, while the electrostatic forces have been proven to play a key role in the formation of heteroaggregates.…”