Impact of Nanoparticle Surface Properties on the Attachment of Cerium Oxide Nanoparticles to Sand and Kaolin

Abstract

Soil texture has been found to be a critical factor in regulating the fate and transport of cerium oxide nanoparticles (CeONPs) in the terrestrial environment. However, the underlying mechanisms for the interactions between CeONPs and different components of soil are still poorly understood. The attachment of CeONPs onto two typical components of soil (sand and kaolin) in batch experiments were investigated to provide insights into the retention and bioavailability of CeONPs in soil. Surface properties of CeONPs, including surface charge and surface coating condition, had strong impacts on the interactions between CeONPs and soil particles. Positively charged CeONPs [CeONPs(+)] displayed the greatest attachment onto kaolin, whereas the negatively charged CeONPs [CeONPs(-)] showed poorest attachment onto sand. The attachment of CeONPs onto kaolin was significantly greater than onto sand, irrespective of surface charge. Homoaggregation of CeONPs increased the size of CeONPs on the surface of sand and kaolin. Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) calculations agreed with the experimental observations that surface charge and coating condition of CeONPs played a vital role in the homoaggregation and adsorption of CeONPs. For CeONPs(-) coated with polyvinylpyrrolidone (PVP), the steric repulsion between soil particles and CeONPs increases rapidly with the increase of maximum surface concentration of PVP. Adsorption isothermal fittings indicated that the adsorption of CeONPs onto sand and kaolin can be properly described by the Dubinin-Radushkevich isotherm. The results obtained in this study are crucial for the understanding of the fate and transport of engineered nanomaterials in the environment.

Surface coating determines the response of soybean plants to cadmium sulfide quantum dots

“…Wang et al showed that the transport of CdSe/ZnS or CdSe/CdZnS QDs in sand is primarily governed by the surface charge of the particle rather than the molecular weight of the ligand or the overall particle size (Wang et al, 2013). Surface modified ENMs with negative zeta (ζ) potential have been shown to be more mobile in sand compared to positively charged or neutral particles (Wang et al, 2013;Zhang et al, 2018), thereby increasing bioavailability and in planta translocation to aerial tissues (Judy et al, 2012;Zhu et al, 2012;Spielman-Sun et al, 2017;Ashfaq et al, 2017;Al-Salim et al, 2011;Koo et al, 2015). It is important to understand the mechanisms controlling ENM bioavailability, localization, and accumulation, as well as associated impacts on plant and soil health, as influenced by surface coating.…”

“…It is important to understand the mechanisms controlling ENM bioavailability, localization, and accumulation, as well as associated impacts on plant and soil health, as influenced by surface coating. Several researchers have investigated the uptake of differentially coated QDs (Koo et al, 2015;Li et al, 2018), metal-based (Zhang et al, 2018;Judy et al, 2012;Zhu et al, 2012;Spielman-Sun et al, 2017;Li et al, 2016), and carbon-based (Ashfaq et al, 2017) nanomaterials by plants. Among ENMs, QDs are the least studied in agricultural crops, thus demanding immediate attention.…”

Nano zero valent iron (nZVI) particles for the removal of heavy metals (Cd2+, Cu2+ and Pb2+) from aqueous solutions

“… 64 nZVI has small particle size and high surface energy, which can adsorb heavy metals or cationic pollutants easily, but it is very difficult to separate it from either sludge or effluent. 65 Coating Pd on nZVI surfaces has improved the interstitial characteristics of nZVI; 66 the co-existing organic and inorganic substances impact each of the modified/immobilized nZVI–composites via various mechanisms and reduce the targetted heavy metals removal action from the solution. Hence, modifying the nZVI via additional support material to improve the effect of co-existing interfering substances is helpful.…”

The fate of cerium oxide nanoparticles in sediments and their routes of uptake in a freshwater worm

“…Binding of positively charged uncoated CeO 2 nanoparticles to these negative charged sites, which will be abundant in the clayey loam LUFA Speyer 2.4 (Supporting Information SI 7), could prevent dissociation of CeO 2 within the worms upon ingestion. Indeed, investigation into the adsorption of CeO 2 nanoparticles of similar size to those studied in this article (<25 nm) in model saturated soils, demonstrated greater attachment of the nanomaterials to kaolin clay than sand particles in batch experiments (Zhang et al 2018). Positively charged CeO 2 also had greater attachment to kaolin clays than negatively charged forms, attributed to physical adsorption processes through electrostatic interactions.…”