Effects of the silica nanoparticles (NPSiO2) on the stabilization and transport of hazardous nanoparticle suspensions into landfill soil columns

Abstract

This study evaluates the stability and transport behaviors of hazardous nanoparticles into soil landfills using experimental procedures to simulate the effects of natural silica nanoparticle suspensions during their percolation into the soil layers of municipal waste landfills. For this, we prepared stabilized suspensions of nanoparticle oxides containing silicon (NPSiO 2 ), titanium (NPTiO 2 ), copper (NPCuO) and zinc (NPZnO), which are recognized as hazardous to the environment, and we conducted leaching experiments within the soil column by simulating landfills layers and simulating the capture and attenuation of nanomaterials into municipal waste landfills. The results demonstrated that the presence of NPSiO 2 in suspensions increases the stable concentrations of copper, zinc and titanium oxides and strongly decreases soil layer effectiveness. In contrast, NPZnO improves effectiveness due to its ability to promote agglomeration and setting conditions, allowing further complexation.

Effects of addition of engineered ZnO nanoparticles on the stability of colloidal suspensions containing TiO2 interacting with sandy soil

“…The soil samples were collected and the parameters measured for the characterization of the soil indicating the physical and chemical characteristics as presented in Table 1. The soil characterization was carried out in a previous study and reproduced for the present analysis (Oliveira et al 2014(Oliveira et al , 2017(Oliveira et al , 2019.…”

“…The column experiment setup was prepared in PVC tubes of 20 cm high and 5 cm in diameter (Tassi et al, 2011, Oliveira et al, 2017, Yang et al, 2018. The lower portion of the tube was equipped with a paper disc (filter) and supported Table 1 -Physical characterization of the sandy soil.…”

“…Figure 2 illustrates a schematic view of the column experiment setup. The suspensions of NPTiO 2 were prepared following the procedure previously reported by the authors (Oliveira et al, 2016;Oliveira et al, 2017). The colloidal suspensions were produced by vigorous mixing of the nanoparticles of TiO 2 and ZnO in three combinatory mixing procedures of nanoparticles, 250 mL and milli-Q water.…”

“…The supernatant from the beakers which contained unsettled ZnO and TiO 2 nanoparticle suspensions (ZnO and TiO 2 nanoparticles colloids) were collected after 10 days and used for the leaching experiments. The protocol of these preparations has been applied for a wider number of nanoparticles colloids preparations and analysed using different techniques (Oliveira et al, 2014, 2017, Fang et al, 2009. Hamaker constant: A 3 x 10 -21 -4 x 10 -20 J Table 2 -Specifications of the nanoparticles and characteristics of the colloidal suspensions.…”

“…The zetaSizer nano was used for both measurements of the zeta potential and average size of the nanoparticles colloidal suspensions (Oliveira et al, 2014, 2017, Komendová et al, 2019, Mahanty et al, 2019.…”