<p>There are abundant sources of metal-oxide-based wastes from industries such as electronics and metal production, which generally have a detrimental effect on the environment when not recycled. In this concise review, we aim to provide a brief overview of the state-of-the-art research on how these metal-oxide wastes are being used by the scientific community in the applications of energy storage, catalysis, and sensing. We focus on three important waste streams: E-waste, waste from the production of metals, such as red mud and slag, and waste from metal recovery, for example, rusted wires and discarded capacitors. We review some promising routes for obtaining high-quality metal-oxide nanoparticles and nanowires and critically review potential pitfalls that hinder the wide-scale application of these waste-streams. © 2020 John Wiley &amp; Sons Ltd</p>

Susanta Sinha Roy

Physics

(SoNS) School of Natural Sciences

Bhattacharya G.

Fishlock S.J.

McLaughlin J.A.

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Shiv Nadar University

International Journal of Energy Research

This work demonstrates the applicability of red-mud-reduced graphene oxide (RM-rGO) nanocomposites (NCs) for the reliable and selective electrochemical (EC) detection of arsenic. The new NC material shows excellent anti-interference activity toward arsenic (As3+) ions with the cooccurrence of other common cations (Cd2+, Cr2+, Zn2+, Pb2+, and Hg2+). Especially, the NC is exceptionally selective for As3+ ions in the presence of Cu2+ ions, which is stated to be the main interfering agent in the EC detection of As3+. Under optimal experimental conditions, the new NC displays a high sensitivity (2.49 μA ppb-1) as well as a very low detection limit (0.07 ppb) toward As3+ detection. This excellent EC performance of the composite is accounted for by the high adsorption proficiency of hematite (Fe2O3)-phase-rich red mud nanoparticles and enhanced electron-transfer kinetics due to the presence of rGO. © 2020 American Chemical Society.

Fulltext

ACS Applied Nano Materials

Red Mud-Reduced Graphene Oxide Nanocomposites for the Electrochemical Sensing of Arsenic

Flexible micro-supercapacitors, with high energy and power density, and using materials with a low environmental impact are attractive for next-generation energy storage devices. Carbon-based materials are widely used for supercapacitors but can be increased in energy density via combination with metal oxides. Red mud is an iron-oxide-rich by-product of aluminum production, which needs to be more widely utilized to reduce its environmental damage. To achieve a flexible micro-supercapacitor device with increased energy density, a laser-induced graphene (LIG) supercapacitor is realized from a polyimide substrate, decorated with red-mud nanoparticles (LIG-RM), employing a solid-state ionic liquid electrolyte with a mixture of poly(vinylidene fluoride) (PVDF), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]), and 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]). The fabricated two-electrode flexible device, in an interdigitated planar design, with inkjet-printed silver current collectors, has a high energy of 0.018 mWh cm−2 at a power of 0.66 mW cm−2, with 81\% of capacitance retained after 4000 cycles and good resistance to bending and flexing. The high energy storage performance, brought about through the combination of graphene and red-mud nanoparticles, which would—if not utilized—be an environmental liability, shows a promise as a material for future energy storage with low environmental impact. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Advanced Sustainable Systems

Recycled Red Mud–Decorated Porous 3D Graphene for High-Energy Flexible Micro-Supercapacitor

Pinecone biomass‐derived activated carbon: the potential electrode material for the development of symmetric and asymmetric supercapacitors

Application of artificial intelligence to maximize methane production from waste paper

Frontiers in Chemistry

Three-Dimensional Core-Branch α-Fe2O3@NiO/Carbon Cloth Heterostructured Electrodes for Flexible Supercapacitors

Metal-oxide nanomaterials recycled from E-waste and metal industries: A concise review of applications in energy storage, catalysis, and sensing