title: Natural Magnetite: an efficient catalyst for the degradation of organic contaminant.
abstract: Iron (hydr)oxides are ubiquitous earth materials that have high adsorption capacities for toxic elements and degradation ability towards organic contaminants. Many studies have investigated the reactivity of synthetic magnetite, while little is known about natural magnetite. Here, we first report the reactivity of natural magnetites with a variety of elemental impurities for catalyzing the decomposition of H2O2 to produce hydroxyl free radicals (•OH) and the consequent degradation of p-nitrophenol (p-NP). We observed that these natural magnetites show higher catalytic performance than that of the synthetic pure magnetite. The catalytic ability of natural magnetite with high phase purity depends on the surface site density while that for the magnetites with exsolutions relies on the mineralogical nature of the exsolved phases. The pleonaste exsolution can promote the generation of •OH and the consequent degradation of p-NP; the ilmenite exsolution has little effect on the decomposition of H2O2, but can increase the adsorption of p-NP on magnetite. Our results imply that natural magnetite is an efficient catalyst for the degradation of organic contaminants in nature.
authors.affiliation: 1] CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2] Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China.
authors.forename: Hongping
authors.initials: H
authors.lastname: He
authors.affiliation: 1] CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2] University of Chinese Academy of Sciences, Beijing 100049, China [3] Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China.
authors.forename: Yuanhong
authors.initials: Y
authors.lastname: Zhong
authors.affiliation: 1] CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2] Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Liang
authors.affiliation: 1] CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2] University of Chinese Academy of Sciences, Beijing 100049, China [3] Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tan
authors.affiliation: 1] CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2] Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China.
authors.forename: Jianxi
authors.initials: J
authors.lastname: Zhu
authors.affiliation: 1] CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2] Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China.
authors.forename: Christina Yan
authors.initials: CY
authors.lastname: Wang