Evaluating the effect of using iron nanoparticles on geotechnical parameters of soils contaminated with cadmium

Today, soil and groundwater contamination by toxic and dangerous pollutants has been raised as a global environmental problem. Soil contamination by heavy metals, especially cadmium (Cd), is a big problem with harmful effects on human health and the earth's ecology. This heavy metal also affects the geotechnical properties of the soil, leading to irreparable effects on the soil beneath structures. One of the efficient and economical methods to rehabilitate soil contaminated with Cd is the stabilization of this toxic metal in the soil by zero-valent iron nanoparticles. The present study is conducted on the effect of heavy metal cadmium contamination on some geotechnical characteristics of soil using Etterberg limit tests (liquid limit and plastic limit), uniaxial compressive strength (UCS), and compaction. Next, this contamination is stabilized in soil by using zero-valent iron nanoparticles, and the characteristics of the modified soil are examined. For this purpose, these nanoparticles were prepared by reducing Ferric Chloride (FeCl3) with sodium borohydride (NaBH4) in a vacuum environment. The laboratory results illustrate the high efficiency of these synthesized nanoparticles in removing ionic cadmium in the sample so that the amount of absorbable Cd in the samples was significantly reduced by using them in optimal conditions. The results show a very high effect in changing the amount of kaolinite and cadmium and the presence of nanoparticles on the soil’s geotechnical parameters. Also, the results of the unconfined compression tests showed that the uniaxial stress of samples with iron nanoparticles increased by 45.6, 63, 67.1, and 67.7%, respectively,