Advanced Floating Materials For Wastewater Remediation By Solar Light

In the recent years, an increased attention to environmental issues and the growing legislative constraints have addressed the efforts of the scientific community towards the engineering of innovative, efficient and inexpensive materials able to solve new needs in different fields. Among them, the scarcity of fresh water, caused by leaking landfills, industrial waste, and sewage, has become imperative global issues to be solved. Advanced oxidation processes offer important perspectives in this regards. Among these approaches, photocatalytic degradation has a special place, operating at ambient conditions, being able to degrade many pollutants without the addition of chemical oxidants. TiO2 is still the most used heterogeneous photocatalyst due to its chemical and physical stability, good photoactivity and low cost. However, because of its wide band gap (3.2 eV) its efficiency under solar light is dramatically limited. Hence, if on the one hand much effort has been devoted to extend the photoresponse of TiO2 to the visible region, on the other hand new materials more active under sunlight have also been developed. Moreover, to overcome problems related to the use of slurry systems for water purification, floating substrates were employed to immobilize the photocatalyst. These buoyant materials are emerging as promising alternative to traditional photocatalysts for water decontamination, thanks to their characteristics in terms of efficiency due to the high oxygenation of the photocatalyst surface, full sunlight irradiation, easy recovery and reuse. In the present study different floating materials were fabricated by inexpensive, ease and innovative environmentally friendly approaches and tested for the degradation of organic (rodhamine) and inorganic (CrVI) pollutants under solar light. The best materials were subjected to recycle tests in order to demonstrate their stability under the reaction conditions.