Phenol and its derivatives are important materials in many industries, but are also hazardous and potentially mutagenic and/or carcinogenic. For such reason, destroying organic pollutants in aquatic environment has been one of the major foci in the field of wastewater treatment. To date, oxidative destruction of phenolic compounds has been carried out mostly through the advanced oxidation processes (AOPs), which exploit generated secondary radicals as the powerful oxidants in aqueous conditions.
For example, ferrous ion-based catalysts have been widely employed to oxidatively destruct major industrial pollutants such as phenolic compounds through the advanced oxidation processes (AOPs). These agents, however, inevitably show several drawbacks including steps to remove residual salts and optimization under relatively harsh conditions such as low pH. In addition, other candidates without ferrous ions predominantly demand external energies including UV light and electricity, which complicates their universal applications.
Here we report the use of chemical vapour deposition (CVD) graphene film as a novel metal-free catalyst for the AOP-based degradation of phenols in aqueous solution, which does not require additional steps for salt removal nor external energy to activate the process. We have also verified that the catalytic activity is strongly dependent on the surface area of graphene film and degradation efficiency can be markedly improved by exploiting an array of multiple graphene films. Finally, the recyclability of graphene film has been validated by performing repetitive degradation tests to ensure the practical use.