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Review
. 2019 Apr 17;9(4):625.
doi: 10.3390/nano9040625.

The Roles of Nanomaterials in Conventional and Emerging Technologies for Heavy Metal Removal: A State-of-the-Art Review

Mahesan Naidu Subramaniam  1 , Pei Sean Goh  2 , Woei Jye Lau  3 , Ahmad Fauzi Ismail  4
Affiliations
Review

The Roles of Nanomaterials in Conventional and Emerging Technologies for Heavy Metal Removal: A State-of-the-Art Review

Mahesan Naidu Subramaniam et al. Nanomaterials (Basel). .

Abstract

Heavy metal (HM) pollution in waterways is a serious threat towards global water security, as high dosages of HM poisoning can significantly harm all living organisms. Researchers have developed promising methods to isolate, separate, or reduce these HMs from water bodies to overcome this. This includes techniques, such as adsorption, photocatalysis, and membrane removal. Nanomaterials play an integral role in all of these remediation techniques. Nanomaterials of different shapes have been atomically designed via various synthesis techniques, such as hydrothermal, wet chemical synthesis, and so on to develop unique nanomaterials with exceptional properties, including high surface area and porosity, modified surface charge, increment in active sites, enhanced photocatalytic efficiency, and improved HM removal selectivity. In this work, a comprehensive review on the role that nanomaterials play in removing HM from waterways. The unique characteristics of the nanomaterials, synthesis technique, and removal principles are presented. A detailed visualisation of HM removal performances and the mechanisms behind this improvement is also detailed. Finally, the future directions for the development of nanomaterials are highlighted.

Keywords: adsorption; heavy metal removal; membrane; nanomaterials; photocatalysis.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Common route of absorption, distribution, and excretion related to the exposure of HMs and inorganic pesticides. Adapted from [29], with permission from Frontiers, 2017.
Figure 2
Figure 2
Schematic illustration of the adsorption of HM via the surface of (a) hybrid polyaniline/TiO2 nanocomposite adsorbents. Adapted from [45], with permission from Elsevier, 2018. (b) cation exchange by hierarchically porous zeolite for improved adsorption of cationic HMs. Adapted from [46], with permission from Elsevier, 2019. and (c) selective HM ion adsorption by biochar in a single and binary metal system. Adapted from [47], with permission from Elsevier, 2019.
Figure 3
Figure 3
Excitation of an electron in a structure of photocatalyst and subsequent creation of ROS. Adapted from [48], with permission from Elsevier, 2018.
Figure 4
Figure 4
HM removal via (a) adsorptive membrane technique. Adapted from [56], with permission from Elsevier, 2017. (b) surface-charged modified membrane repellent. Adapted from [57], with permission from Elsevier, 2019. and (c) size exclusion of HM ions. Adapted from [58], with permission from Elsevier, 2019.
Figure 5
Figure 5
Examples of nanomaterial structures (a) nanoflowers. Adapted from [85]. (b) nanotubes. Adapted from [86]. (c) nanosheets. Adapted from [87], and (d) nanorods. Adapted from [88].
Figure 6
Figure 6
Nanomaterial synthesis route of nanomaterials following top-down, or bottom-up. Adapted from [107], with permission from CHEMIK, 2014.
Figure 7
Figure 7
(a) Photoreduction of Cr (VI) in the presence and absence of Rhodamine B (RhB) and (b) removal rate of both Cr (VI) and RhB at different individual cycles. Adapted from [155], with permission from Elsevier, 2019.
See this image and copyright information in PMC

References

    1. Carolin C.F., Kumar P.S., Saravanan A., Joshiba G.J., Naushad M. Efficient techniques for the removal of toxic heavy metals from aquatic environment: A review. J. Environ. Chem. Eng. 2017;5:2782–2799. doi: 10.1016/j.jece.2017.05.029. - DOI
    1. Duncan A.E., de Vries N., Nyarko K.B. Assessment of heavy metal pollution in the sediments of the River Pra and its tributaries. Water Air Soil Pollut. 2018;229:272. doi: 10.1007/s11270-018-3899-6. - DOI - PMC - PubMed
    1. Thakur L.S. Heavy metal Cu, Ni and Zn: Toxicity, health hazards and their removal techniques by low cost adsorbents: A short overview. Int. J. Plant Sci. 2015;3:143–157.
    1. Akpor O.B., Ohiobor G.O., Olaolu T.D. Heavy metal pollutants in wastewater effluents: Sources, effects and remediation. Adv. Biosci. Bioeng. 2014;2:37–43. doi: 10.11648/j.abb.20140204.11. - DOI
    1. Yi Y., Tang C., Yi T., Yang Z., Zhang S. Ecotoxicology and environmental safety health risk assessment of heavy metals in fi sh and accumulation patterns in food web in the upper Yangtze River, China. Ecotoxicol. Environ. Saf. 2017;145:295–302. doi: 10.1016/j.ecoenv.2017.07.022. - DOI - PubMed

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