The differences in heterogeneous Fenton catalytic performance and mechanism of various iron minerals and their influencing factors: A review

Abstract

Since the reaction between iron-based catalysts and H2O2 can produce extremely reactive hydroxyl radicals, heterogeneous Fenton reactions have drawn great concerns in degradating stubborn organic pollutants. Iron minerals are the most commonly studied heterogeneous Fenton catalysts as they are omnipresent on the near-surface of earth and inexpensively available precursors/components with high reactivity. Therefore, Numerous studies have been conducted on discovering the heterogeneous Fenton reactivity of various iron minerals, and several reviews on the use of iron minerals in the heterogeneous Fenton process have been reported, indicating the great potential of iron minerals in the area of wastewater treatment and soil remediation. However, as far as we are aware, there has not been a comprehensive review of this topic published. This review, for the first time, systematically compares the heterogeneous Fenton reactivities of different iron minerals and clarifies the influencing factors that dominate these differences, such as the crystallinity, specific surface areas, and oxygen vacancies of iron minerals, as well as the redox potential of iron minerals/Fe2+. This review also summarizes the performance of several typical iron minerals in the heterogeneous Fenton processes and clarifies the internal relations between reactivities and mechanisms from mineral structure, physical and chemical properties, and surface active site. The practical application potential of different iron minerals in the area of wastewater treatment and soil remediation is also evaluated. We believe this review can elucidate the structure-activity relationship of various iron minerals in the heterogeneous Fenton processes and inspire the development of novel iron minerals-based heterogeneous Fenton catalysts.