Nanoadsorbants for the Removal of Heavy Metals from Contaminated Water: Current Scenario and Future Directions

Abstract

Heavy metal pollution of aquatic media has grown significantly over the past few decades. Therefore, a number of physical, chemical, biological, and electrochemical technologies are being employed to tackle this problem. However, they possess various inescapable shortcomings curbing their utilization at a commercial scale. In this regard, nanotechnology has provided efficient and cost-effective solutions for the extraction of heavy metals from water. This review will provide a detailed overview on the efficiency and applicability of various adsorbents, i.e., carbon nanotubes, graphene, silica, zero-valent iron, and magnetic nanoparticles for scavenging metallic ions. These nanoparticles exhibit potential to be used in extracting a variety of toxic metals. Recently, nanomaterial-assisted bioelectrochemical removal of heavy metals has also emerged. To that end, various nanoparticle-based electrodes are being developed, offering more efficient, cost-effective, ecofriendly, and sustainable options. In addition, the promising perspectives of nanomaterials in environmental applications are also discussed in this paper and potential directions for future works are suggested.

Cosmetic wastewater treatment technologies: a review

“…During the last two decades, micro- and nano-scaled magnetic particles have attracted attention as adsorbents for eliminating the biological molecules, organic pollutants, and heavy metal ions from water and wastewater. The major advantage with magnetic nanomaterials lies in their easy recovery after exhaustion from the treated solution by for an external magnetic field, as presented in one of the studies performed using magnetic mesoporous silica nanospheres for the removal of Pb 2+ , Hg 2+ , and Pd 2+ (Kumar et al 2021 ).…”

Valorization of Fibrous Plant-Based Food Waste as Biosorbents for Remediation of Heavy Metals from Wastewater—A Review

“…Several technologies have been employed for eliminating heavy metals from wastewater, contaminated aquatic media, and industrial effluents over the last three decades, including chemical precipitation [ 26 ], solvent extraction [ 27 ], coagulation–flocculation [ 28 ], advanced oxidation [ 29 ], membrane filtration [ 30 ], reverse osmosis [ 31 ], ion exchange [ 26 ], ozonation [ 32 ], photocatalysis [ 33 ], adsorption [ 34 , 35 ], biosorption/bioaccumulation [ 36 ], bioleaching [ 37 ], phytoextraction using hydroponic systems coupled with bioremediation [ 38 ], phytofiltration [ 39 ], electroremediation [ 34 ], etc. However, there is no single best method to provide adequate treatment, as each treatment has its own distinct benefits and shortcomings, not only in terms of cost but also in terms of consistency, efficacy, practicability, viability, and operational difficulties ( Table 2 ) as well as environmental impact [ 40 ].…”

Adsorption isotherms and kinetics for Pb(ii) ion removal from aqueous solutions with biogenic metal oxide nanoparticles

“…Recently, there has been considerable interest in exploring the potential of biogenic nanomaterials as effective sorbents for the removal of heavy metal ions. 23,24 Various plant sources, including extracts from leaves, flowers, seeds, fruits, peels, and roots, have not only been extensively utilized for the synthesis of NPs but also hold promise as supporting materials for biogenic composites. 25…”