A new green approach to Fenton’s chemistry using tea dregs and coffee grounds as raw material

Abstract

Abstract Fenton’s chemistry has long been useful in industry because of the power of hydrogen peroxide (HP), in the presence of ferrous iron (Fe2+), to produce a highly reactive free radical species capable of oxidizing aqueous materials. However, its application has been limited due to the rapid oxidation of ferrous iron. The rapid oxidation of ferrous iron limits the production of free radicals necessary for a powerful reaction. We developed two ‘green’ iron catalysts using used tea leaves (tea dregs) or coffee grounds as raw material. The new ‘green’ iron catalysts contained iron in a reductive stable status for a Fenton catalyst. The study showed that the developed ‘green’ iron catalysts can be used as iron fertilizer and for the Fenton’s reaction on the degradation of methylene blue (MB), and in the disinfection of Escherichia coli. The tea and coffee polyphenols were estimated to be responsible for the reductive stable state of the iron in the developed catalysts, due to their reducing power and chelating iron ability. The developed new ‘green’ iron catalysts are expected to diffuse in wide fields such as food, medicine, public health, agriculture, the environment, etc.