Keywords : nano zerovalent iron
Benefits and risks of nanozerovalent iron, titanium dioxide nanoparticles and carbon nanotubes for water treatment technologies
Advanced Materials Letters,
2017, Volume 8, Issue 12, Pages 1132-1144
An overview is presented of potential improvements in performance that can be achieved by using three different types of nanomaterials in water treatment applications: (i) zerovalent iron for reducing concentrations of chlorinated hydrocarbons and heavy metals in groundwater; (ii) titanium dioxide for photocatalytic drinking water purification, enabling reduced consumption of chemicals for disinfection; (iii) carbon nanotube membrane filters that transport water molecules at elevated fluxes, while rejecting other molecules and ions. The distinctive characteristics of the nanomaterials, such as high specific surface area, enhanced reactivity and adsorption capacity, have already led to significant increases in efficiency. Future developments are expected based on surface modification of zerovalent iron to improve its reactivity and transport characteristics, advanced chemical synthesis methods to increase the area of photoreactive facets and doping to inhibit electron-hole recombination or to allow visible light photocatalysis in titanium dioxide, and functionalization of carbon nanotubes to increase ion rejection rates. Implementation of these innovative methods for removal of contaminants from water will be contingent on reduction of the present high cost of the nanomaterials and assessment of the possible risks associated with their, as yet only partly understood, toxic and ecotoxic properties.