Identifying Iron-Bearing Nanoparticle Precursor for Thermal Transformation into the Highly Active Hematite Photo-Fenton Catalyst

Abstract

The hematite photo-Fenton catalysis has attracted increasing attention because it offers strong oxidation of organic pollutants under visible light at neutral pH. In the present work, aqueous synthesis of hematite photo-Fenton catalysts with high activity is demonstrated. We compare photo-Fenton activity for hematite obtained by hydrolyzation at 60 °C or by a thermally induced transformation from iron-bearing nanoparticles, such as amorphous iron oxyhydroxide or goethite. A link between their structure and visible light photo-Fenton reactivity is established. The highest activity was observed for hematite obtained from goethite nanowires due to oblong platelet-like structure, high surface area and the presence of nanopores.

Antibacterial Activity of Positively and Negatively Charged Hematite (α-Fe2O3) Nanoparticles to Escherichia coli, Staphylococcus aureus and Vibrio fischeri

“…Moreover, as mentioned above, iron oxides are abundant in nature [ 30 ]. Hematite ( α -Fe 2 O 3 ) is the most stable among iron oxides, as it is thermodynamically stable at ambient conditions, chemically stable at various pH [ 3 , 27 , 28 , 29 ], and can be synthesized by simple aqueous (green) approaches [ 31 , 32 ] in various shapes and with a broad size range [ 25 ]. Hematite NPs have gained a lot of attention due to their diverse applications, e.g., photoelectrochemical water splitting [ 33 ], as ingredients in sunscreens and cosmetics to optimize the present UV filter efficiency [ 34 , 35 ], and as anticancer [ 20 , 21 , 22 , 23 ] and water disinfection agents [ 36 ].…”

Visible-Light Active Flexible and Durable Photocatalytic Antibacterial Ethylene-co-vinyl Acetate—Ag/AgCl/α-Fe2O3 Composite Coating

“…α-Fe 2 O 3 was prepared by co-precipitation method followed by calcination, as described in our previous works [14,21]. Briefly, 0.1 M iron(III) nitrate solution was prepared, after adding a 0.4 M NaOH solution.…”

“…Wang et al (2008) [10] first synthesized Ag/AgCl particles with efficient and stable plasmonic visible-light activated photocatalytic properties, due to the combination of the plasmon resonance of noble-metal nanoparticles with a semiconductor catalyst and efficient electron-hole separation [11,12]. Hematite (α-Fe 2 O 3 ), the most stable state of iron oxide due to its relatively narrow band gap of 2.0-2.2 eV, is one of the most extensively investigated materials in photocatalytic degradation of numerous organic contaminants [13,14]. However, there are also some disadvantages such as poor charge transfer properties and fast recombination of charged species, i.e., the high electron-hole recombination efficiency [13,15], but these disadvantages can be amended by synthesis of heterostructures, composites, and/or doping with other materials [13,16].…”

Green Synthesis of Iron Oxide Nanoparticles Using Hibiscus rosa sinensis Flowers and Their Antibacterial Activity

“…Various types of iron/iron oxide (Fe/ FeO-NPs) have been synthesized using extracts from plants and their parts, such as roots, leaves, fruits, flowers, bark, stems, and seeds. [11][12][13], and they have been investigated for their use in photocatalysis and the elimination of various organic dyes in wastewater [14]. However, a few studies are available with the hematite iron oxide phase compared to other iron oxide phases.…”