Removal of contaminants in wastewater, such as heavy metals, has become a severe problem in the world. Numerous technologies have been developed to deal with this problem. As an emerging technology, nanotechnology has been gaining increasing interest and many nanomaterials have been developed to remove heavy metals from polluted water, due to their excellent features resulting from the nanometer effect. In this work, novel nanomaterials, including carbon-based nanomaterials, zero-valent metal, metal-oxide based nanomaterials, and nanocomposites, and their applications for the removal of heavy metal ions from wastewater were systematically reviewed. Their efficiency, limitations, and advantages were compared and discussed. Furthermore, the promising perspective of nanomaterials in environmental applications was also discussed and potential directions for future work were suggested.

https://www.mdpi.com/2079-4991/9/3/424/pdf

Nanomaterials for the Removal of Heavy Metals from Wastewater

Nanotechnology has great potential to improve water purification and decontamination efficiency. Nanomaterials are efficient at removing organic and inorganic pollutants and heavy metals from wastewater and killing microorganisms. The distinctive characteristics of metal oxides make them the most varied class of materials, and they have properties that cover almost all aspects of solid-state physics and material science. Only a few review articles in the literature specifically address metal oxide nanoparticles and their application in the treatment of wastewater. This review article aims to fill this gap and present a thorough review of the various types of metal oxide nanoparticles in contaminating water impurities. Metal oxide nanoparticles have great potential for treating contaminated water due to their unique properties, such as their large surface areas and low concentration. This paper discussed in detail five metal oxide nanoparticles and their applications for antibacterial and wastewater applications. Highlights •In literature, only a few review articles addresses applications of metal oxide nanoparticlesin the treatment of wastewater.•We present a thorough review of the various types of metal oxide nanoparticles in contaminating water impurities.•Metal oxide nanoparticles have great potential for treating contaminated water.•This paper discussed five metal oxide nanoparticles and their applications for antibacterial and wastewater applications.

The role of some important metal oxide nanoparticles for wastewater and antibacterial applications: A review

To restore the natural nitrogen cycle (N-cycle), artificial N-cycle electrocatalysis with flexibility, sustainability, and compatibility can convert intermittent renewable energy (e.g., wind) to harmful or value-added chemicals with minimal carbon emissions. The background of such N-cycles, such as nitrogen fixation, ammonia oxidation, and nitrate reduction, is briefly introduced here. The discussion of emerging nanostructures in various conversion reactions is focused on the architecture/compositional design, electrochemical performances, reaction mechanisms, and instructive tests. Energy device advancements for achieving more functions as well as <i>in situ</i>/<i>operando</i> characterizations toward understanding key steps are also highlighted. Furthermore, some recently proposed reactions as well as less discussed C–N coupling reactions are also summarized. We classify inorganic nitrogen sources that convert to each other under an applied voltage into three types, namely, abundant nitrogen, toxic nitrate (nitrite), and nitrogen oxides, and useful compounds such as ammonia, hydrazine, and hydroxylamine, with the goal of providing more critical insights into strategies to facilitate the development of our circular nitrogen economy. 

https://www.sciopen.com/article_pdf/1531201054523838466.pdf

Recent advances in nanostructured heterogeneous catalysts for N-cycle electrocatalysis

Nanoadsorbents for water and wastewater remediation.

NiCo2 O4 nanowire array on carbon cloth (NiCo2 O4 /CC) is proposed as a highly active electrocatalyst for ambient nitrate (NO3 - ) reduction to ammonia (NH3 ). In 0.1 m NaOH solution with 0.1 m NaNO3 , such NiCo2 O4 /CC achieves a high Faradic efficiency of 99.0% and a large NH3 yield up to 973.2 µmol h-1  cm-2 . The superior catalytic activity of NiCo2 O4 comes from its half-metal feature and optimized adsorption energy due to the existence of Ni in the crystal structure. A Zn-NO3 - battery with NiCo2 O4 /CC cathode also shows a record-high battery performance.

Jingtao Bi

Papers

Nanomaterials for the Removal of Heavy Metals from Wastewater

Design and synthesis of core-shell Fe3O4@PTMT composite magnetic microspheres for adsorption of heavy metals from high salinity wastewater.

Oil-phase cyclic magnetic adsorption to synthesize Fe3O4@C@TiO2-nanotube composites for simultaneous removal of Pb(II) and Rhodamine B

Fe-doped ilmenite CoTiO3 for antibiotic removal: Electronic modulation and enhanced activation of peroxymonosulfate

Fabrication, application, optimization and working mechanism of Fe2O3 and its composites for contaminants elimination from wastewater.