Zero valent iron nanoparticles for water treatment and purification - Water and Wastewater - Water Treatment
All described properties of Fe(0) nanoparticles can be even used for decomposition of pollutants contained in the waste water, mainly for treatment of industrial sewage and hutch water. The usage of nanoiron can represent a significant qualitative step in the classical technologies of water treatment including drinking water. The extremely reactive iron nanoparticles thus offer a possibility to solve long-lasting problems with a high content of uranium and arsenic in a variety of localities in the Central Europe. They can be also used for a reduction of the content of heavy metals, nitrates and phosphates in the drinking water. Just these inorganic pollutants, which are hardly or expensively removed by standard technologies, are effectively removed by Fe(0) nanoparticles.
Although this field of usage of zero-valent iron is in its early stage for the present, in forthcoming years, we can expect a boom of their application in the area of waste water. Beside significant decontamination effect, their advantage relies on the formation of non-toxic product of oxidation of nanoparticles (very often Fe3O4), which is either deposited in the given locality and almost negligibly increases the natural occurrence of iron oxides or comes to filtration devices of cleaning units. In order to utilize these Fe(0) nanoparticles in the treatment of waste water, NANO IRON, s.r.o. company developed NANOFER 25 product which exhibits a large surface area along with an extraordinary reactivity in contact with pollutants. Thus, this product simultaneously acts as a solid sorbent, which may bind colloidal and solid impurities contained in the water.
In the present work, a holistic approach was applied towards processes which simultaneously occur after the treatment of real effluent water from a small biological wastewater treatment plant (SBWTP) with different nanoscale zero-valent iron (nZVI) particles. Three different types of nZVI particles were tested: in-house nZVI, commercially available Nanofer STAR and Nanofer25 slurry, which differ in reactivity and their methods of synthesis. In order to optimise the conditions for the efficient removal of selected elements, nitrogen species, and pathogenic bacteria (Coliform bacteria, Escherichia coli, Intestinal Enterococci and Clostridium perfringens), effluent water samples were treated with different iron loads from each of the investigated nZVI at various mixing and settling times.