Breakthrough Curves of SDS Stabilized Magnetite Nanoparticles in Two Coarse Textured Soils

Due to the increasing usage of nanoparticles and its entry into the environment, it is necessary to study the transport of nanoparticles in soil. The purpose of this research was quantitative study of transport of SDS modified magnetite nanoparticles in two soil types (sand and loamy sand) columns under saturation conditions. For this, transport, experiments were done in glass columns for measurement of breakthrough curves of nanoparticles and chloride in saturated conditions, and effect of nanoparticles concentration (0.1 and 0.5 g L-1) and pore velocity (2 and 10 cm pressure head) was investigated on nanoparticles transport. The results showed that 100% of nanoparticles remained in 0.5 cm layer of loamy sand soil indicating nanoparticles attachment to soil clays and modified magnetite nanoparticles straining. However, nanoparticles breakthrough curve in sandy soil compared with loamy sand soil indicated that increasing soil particle diameter caused greater mobility of nanoparticles in soil, because of reduction of porous medium particles specific surface area and increase in pores diameter. By changing the pressure head on the sandy soil column, the maximum relative concentration of nanoparticles in the outflow remained unchanged. Transport of modified magnetite nanoparticles increased with decreasing concentration of nanoparticles in inflow suspension to the sandy soil column. Because of concentration increase, nanoparticles aggregation increased and, consequently, larger particles were formed and transport was reduced due to the attachment, detachment, and possibly straining.