Review of Advances in Engineering Nanomaterial Adsorbents for Metal Removal and Recovery from Water: Synthesis and Microstructure Impacts

Abstract

Adsorption is widely applied in both potable and municipal or industrial wastewater treatments process. Nanomaterial adsorbents (NAs) have emerged as efficient candidates to remove toxic metals from water. However, scalable application of NAs beyond bench-scale material discovery and translation to full scale deployment has been limited but essential to realize the potential NAs offer for environmental remediation. In this critical review, we summarize, discuss, and compare various NA synthesis methods and assess their scalability to supply materials for full-scale applications. Moreover, as the importance of the microstructure of nanomaterial itself has been recognized in recent years, we also scrutinize the effect of NAs structures including crystal facets, phases, and tunability of active sites (e.g., functional groups) on metal adsorption. The review concludes with prioritizing research needs that balance large-scale production costs and feasibility to produce desired properties of NAs at commercial scale quantities. Meanwhile, an NAs evaluation protocol (e.g., life cycle costing (LCC) and life cycle assessment (LCA)) should be established to test NAs at the material discovery stage that considers both adsorption capacity and mass transfer kinetics and perform long-term testing (e.g., recovery) of NA real applications.

Enhanced Photocatalytic Activity of Cu2O Cabbage/RGO Nanocomposites under Visible Light Irradiation

“…Membrane treatment [ 11 ], adsorption [ 12 ], fenton oxidation [ 13 ], electrochemical [ 14 ], biological [ 15 ], photocatalysis [ 16 ], and other methods and technologies are actively attempted for efficient remediation of dyes in the effluents. Polymers and polymer inorganic nanocomposite are also an excellent recent material to remove contamination of industrials waste because of the high surface area of the polymer and its composite with inorganic metal oxides.…”

Advanced Oxidation Processes Coupled with Nanomaterials for Water Treatment

“…The removal of metal ions soluble in water can be achieved by adsorption to the solid phase of the nanomaterial [71][72][73][74]. Additionally, some water remediation can be foreseen by the transformation, oxidation or reduction, of a metal ion into a less toxic species.…”

“…Additionally, some water remediation can be foreseen by the transformation, oxidation or reduction, of a metal ion into a less toxic species. A huge number of nanomaterials have been developed as metal ion adsorbents and the most important classes are [71][72][73][74] (iii). Magnetic nanoparticles functionalized with; biomolecules (for example, alginate and cellulose), organic molecules, carbonaceous materials, inorganic molecules (for example, EDTA); (iv).…”

Chitosan/Zeolite Composite Aerogels for a Fast and Effective Removal of Both Anionic and Cationic Dyes from Water

“…Polymer-based foams or aerogels based on cellulose [ 10 , 11 ], alginate [ 12 ], and chitosan (CS) [ 13 , 14 , 15 , 16 ] have been extensively explored for water remediation purposes. High surface area nanoparticles [ 17 , 18 ] and micro/meso-porous particles, such as zeolites and metal–organic frameworks [ 4 , 19 , 20 , 21 , 22 , 23 ] have also been widely investigated as effective adsorbents. However, their reuse is hindered by the difficult recovery from polluted solutions, that can often lead to secondary pollution.…”