Heavy metal pollution and the role of inorganic nanomaterials in environmental remediation

Abstract

Contamination of water and soil with toxic heavy metals is a major threat to human health. Although extensive work has been performed on reporting heavy metal pollutions globally, there are limited review articles on addressing this pernicious phenomenon. This paper reviews inorganic nanoparticles and provides a framework for their qualities required as good nanoadsorbents for efficient removal of heavy metals from water. Different inorganic nanoparticles including metals, metal oxides and metal sulfides nanoparticles have been applied as nanoadsorbents to successfully treat water with high contaminations of heavy metals at concentrations greater than 100 mg l −1 , achieving high adsorption capacities up to 3449 mg g −1 . It has been identified that the synthesis method, selectivity, stability, regeneration and reusability, and adsorbent separation from solution are critical parameters in deciding on the quality of inorganic nanoadsorbents. Surface functionalized nanoadsorbents were found to possess high selectivity and capacity for heavy metals removal from water even at a very low adsorbent dosage of less than 2 g l −1 , which makes them better than conventional adsorbents in environmental remediation.

The Performance of Functionalized Multi-Walled Carbon Nanotube-Based Filters for Water Treatment Applications

“…2. Specificity and selectivity: It might be difficult to extract a particular heavy metal ion from a complicated mixture because of the great attraction of carbon nanotubes toward a variety of heavy metals [57].…”

Application of Nanoparticles in Soil and Water Treatment

“…The chemical makeup of the substances is employed to functionalize the surface NPs and increase selectivity for heavy metal ions in solution as shown in Figure 4. The selectivity of Pd 2+ , Pb 2+ , Cd 2+ , Zn 2+ , Cu 2+ , Co 2+ , and Mn 2+ was assessed by the covalent attachment of a dendrimer, L-cysteine methyl ester onto the surface of NPs [100], in order to improve the preferential adsorption of Hg 2+ onto SiO2-Al2O3-mixed oxide [62].…”

Transition Metal Catalysts for Atmospheric Heavy Metal Removal: A Review of Current Innovations and Advances

“…Zinc nanoparticles present abundant Lewis acidic sites that selectively bind soft heavy metals like Hg(II) [23]. Porous ZnO supported Zn NPs prepared using a zincethanolamine complex showed excellent capture of elemental mercury from flue gas [24].…”