Utilization of graphene and its derivatives for air & water filtration: A review

Abstract

Graphene is novel & invigorating nanocarbon material that has drawn in both scholastic and industrial interest in last 10–15 years. It is by and large widely investigated as a result of its extraordinary properties including, superior mechanical and non-corrosive property, amazingly high surface area, great optical translucency, outstanding electrical and heat carrying properties and so forth. More importantly, these properties can be tailored to some extent by developing different grades of derivatives of Graphene. In this report, a various routes used to produce Graphene & Graphene-based materials are reviewed, detailed review of recent progress in application of these materials for desalination of water and purification of air is presented. Various attributes of Graphene & its derivatives which can revolutionise the air filtration & water desalination processes are underlined. Graphene Aerogels and doped sheets prove to be efficient alternates for air filtration & pollutant removal applications with relatively high specific surface area of around 1300 m2/g [24]. These doped derivatives show improved adsorption efficiency around 55–65% [25], which is studied to be rising with energy inputs like potential difference. Graphene and its derivatives-based water filtration is proving to be extremely efficient than the conventional water filtration & desalination mechanisms. Reverse Osmosis (RO), one of the widely used conventional methods of desalination comes with a large expense of money and energy but yields low volumes of filtered water. About 85–95% of input water gets wasted in the RO mechanism, yielding only 5–15% of usable water. The conventional Solar desalination is more efficient as compared to RO, but even that can be improved by 70–90% [45-47] by incorporating Graphene and its derivatives as part of a volumetric system, light absorbing layer and filtration layer in Solar Desalination process. The graphene-based membranes because of their high permeability and excellent ion repellency can be used for desalination applications with a removal efficiency of 33–100% [61] depending on the pore size and the applied pressure. Capacitive Deionization method of desalination can also be a very efficient alternative to the RO due to its minimal energy requirement of only 0.1–2.03 kWh/m3 [52].