Facile Chemical Solution Transportation for Direct Recycling of Iron Oxide Rust Waste to Hematite Films

Abstract

Convenient and economic recycling of the environmental solid waste is one of the most essential and challenging issues for the sustainable development of modern society. In this work, for the first time, a chemical solution transportation method has been developed to convert iron oxides and related rust into (photo)­electroactive hematite films on a conductive F-doped SnO2 substrate in a hydrothermal system. We found that the zeta potential of the substrate and the precursor particles could be modulated by controlling the NaNO3 electrolyte concentration. The decrease of the positive surface charge densities caused less adsorption of Fe­(C2O4)3 3– intermediates on the iron oxide precursors, while the intermediate adsorption at the F-SnO2 substrate increased relatively. As a result, the small hematite nanocrystals were deposited on the substrate through an island nucleation mechanism, which transferred into a continuous dense hematite film with transportation time increase. These hematite films exhibited high photoelectrochemical and electrochemical activities in water oxidation for hydrogen generation. This direct chemical transportation method could be a promising solution for sustainable recycling of metal rust waste.

Rational Electrochemical Recycling of Spent LiFePO4 and LiCoO2 Batteries to Fe2O3/CoPi Photoanodes for Water Oxidation

“…To further confirm the hematite phase, we also checked the sample with the Raman spectrum (Figure c). The vibration peaks at 225, 245, 293, 410, 500, and 611 cm –1 were attributed to the unique hematite . The UV–vis spectra of the different thicknesses of hematite, which were prepared from various charges for the reduction, exhibited the main absorption in the range of 300–450 nm and a band edge absorption at about 590–600 nm (∼2.1 eV).…”

“…The vibration peaks at 225, 245, 293, 410, 500, and 611 cm −1 were attributed to the unique hematite. 50 The UV−vis spectra of the different thicknesses of hematite, which were prepared from various charges for the reduction, exhibited the main absorption in the range of 300−450 nm and a band edge absorption at about 590−600 nm (∼2.1 eV). Moreover, the absorption at 400 nm demonstrated a linear relationship between the accumulated charge density (0.3−0.6 C/cm 2 ) in the electrochemical deposition process (the inset in Figure 5d), which coincided with the AFM results (Figure 4).…”

Sustainable Recycling of Insoluble Rust Waste for the Synthesis of Iron-Containing Perovskite-Type Catalysts

“…Recently, rusted iron coil and stainless steel wires have also been used for preparing hematite film with water oxidation and oxygen evolution activity. 10 Apparently, only in the works by Pullar et al 11 and Dufour et al 12 a perovskite-type barium hexaferrite magnetic material has been produced from dried steel wiredrawing sludge waste as iron source. Waste iron, which is produced from the scraping of rusted iron-containing materials, can also be used as an iron source for the synthesis of nanomaterials with high catalytic activity and selectivity 13−15 and represents a cheap, eco-friendly, and inexhaustible source of iron.…”

“…For example, waste ferrous sulfate from titanium dioxide industry, heavy tonnage iron-removal sludge waste, oily cold rolling mill sludge, and ashes of scum from anaerobic treatment of municipal sewage have been used as inorganic precursors for preparing iron-based pigments or hematite nanoparticles. Recently, rusted iron coil and stainless steel wires have also been used for preparing hematite film with water oxidation and oxygen evolution activity . Apparently, only in the works by Pullar et al and Dufour et al a perovskite-type barium hexaferrite magnetic material has been produced from dried steel wiredrawing sludge waste as iron source.…”

Dendritic silver hierarchical structures for anode materials in Li ion batteries

“…The conversion and storage of energy is very critical to the development of the society [1][2][3][4][5][6]. Among various electrical energy storage devices, Li ion batteries (LIBs) have drawn tremendous research for widely used in various electronic devices, such as video cameras, computers and mobile phones, due to their high energy density, good cycle life and high capacity [7,8].…”