Remediation of heavy metal contamination of sediments and soils using ligand-coated dense nanoparticles

Abstract

Sediment and soil contamination with toxic heavy metals, including cadmium (Cd 2+) and lead (Pb 2+), represents a major long-term remediation challenge. Resuspension of contaminated sediments into the water column, or the uptake of toxic metals from top soil, can lead to exposure of aquatic or terrestrial organisms, followed by bioconcentration, bioaccumulation and biomagnification, which may pose a threat to public health. We have developed a novel nanoscale engineered material, namely ligand-coated dense nanoparticles (Ligand DNPs), which contain a dense WO 3 nanoparticle core and a shell functionalized with a metal-binding organic ligand (EDTA), to effectively sequester heavy metal ions deeper into the soil and sediments. We demonstrate that one application of Ligand DNPs can remove from 60% to almost 80% of the Cd and Pb in two different soil matrices, driving these metal ions deeper into the sediment or soil column via gravity, and making them less bioavailable. Ligand DNPs can provide a relatively fast, convenient, and efficient in-situ approach for the remediation of sediments and soils contaminated with heavy metals.

Metal pollution in the topsoil of lands adjacent to Sahiwal Coal Fired Power Plant (SCFPP) in Sahiwal, Pakistan

“…Millions of hectares of land contaminated with trace metals need remediation to get rid of metals like Cu, Ni, Zn, As, Se, Cd, Co, Hg, and Pb [13,14]. Various remediation techniques are applied ex-situ and in-situ to remove metal contamination from soils [15][16][17]. These include landfilling [18,19], soil washing [20], soil sealing or encapsulation [21], surface capping [22] solidification [23], electro-kinetic extraction [24], verification [18], stabilization [23], bioremediation [18], and phytoremediation [25].…”

The impact of chromium ion stress on plant growth, developmental physiology, and molecular regulation

“…The earlier remediation methods were mainly based on excavation and landfill, but their sustainability was not viable, especially with the advancement of science and technology. Further, the treatment of heavy metal soil pollution has now evolved into the use of chemical soil stabilization (Hamon et al, 2002 ), soil leaching (Huang and Keller, 2020 ), electrodynamic restoration (Zhang M. et al, 2019 ), and the use of plant ecological restoration (Lian et al, 2018 ). The earlier methods were relatively expensive and labor intensive; however, the chemical released can cause secondary pollution of the soil environment.…”