A Proof-of-Concept Portable Water Purification Device Obtained from PET Bottles and a Magnetite-Carbon Nanocomposite

Abstract

Widespread access to potable water is still far from being granted to populations of developing countries, especially in rural zones. For this reason, the development of easy-to-make, easy-to-use water purification devices is a topic of great social and economic importance. Poly(ethylene terephthalate) (PET) bottles are available worldwide, even in the remotest and poorest countries, as testified by the increasingly common practice of re-using bottles for solar water disinfection (SODIS). Here, we demonstrate how PET bottles could be re-used as a proof-of-concept water purification system. In this way, virtually the same bottle could be used first for SODIS and then for removing chemical contaminants. In the proposed approach, the bottles are treated with ethylenediamine to introduce amine groups, which are subsequently protonated with dilute acid. These functional groups allow the stable adsorption of a magnetite-activated carbon nanocomposite, which is prepared by a simple coprecipitation protocol. The efficiency of the nanocomposite and of the resulting prototype to remove model inorganic and organic pollutants (hexavalent chromium, industrial dyes) from water has been demonstrated. The proposed purification device is easy, cheap, and effective, all factors which could promote its use in developing and rural countries.