POTENTIAL OF RED MUD IN FENTON PROCESSES FOR THE DEGRADATION OF ORGANIC POLLUTANTS IN WATER - A MINI REVIEW

Abstract

Fenton processes, in which hydrogen peroxide in the presence of divalent iron ions generates hydroxyl radicals (•OH), are widely used for the degradation of organic pollutants (phenols, antibiotics, dyes). In this review, red mud is analysed as a cheap source of iron ions in Fenton processes. Raw red mud can be used without additional modifications, but to increase the catalytic efficiency, its modification is required, which includes chemical reduction, carbothermal treatment or doping with metals. Particular attention is given to photo-Fenton and electro-Fenton processes, where red mud doped Cо, Sn or Cе, or in combination with reduced graphene oxide and biochar, allow the generation of not only hydroxyl radicals (•OH) but also singlet oxygen (1O2) and superoxide radicals (•O2–), achieving ≥99% pollutant removal. At the same time, the synthesised catalysts showed high stability and reusability. Based on a comparative analysis of more than 30 studies, it is concluded that red mud represents a cheap source of iron ions for heterogeneous Fenton processes, with significant potential for industrial application.
Keywords: Fenton process, hydroxyl radicals, organic pollutants, red mud.