Green Route for Beneficiation of Metallic Materials from Electronic Waste for Selective Reduction of CO₂

Abstract

The effective disposal of ever-increasing electronic waste (e-waste) is one of the grand challenges for the scientific and technological community today. As e-waste has exponentially been increasing the burden on our environment with long-term effects on the ecosystem, the need for finding sustainable means to recover, reuse, and recycle the materials available in the e-waste is much sought after in the present time. In this background, we demonstrate an easily scalable green route for the beneficiation and effective usage of metallic materials from the e-waste using cryo-temperature grinding with the primary objective of retrieving the near-full metallic residue from e-waste by an energy-efficient and eco-friendly approach. The metallic nanoparticles thus obtained are subsequently utilized for the selective reduction of CO 2 into different gaseous products via the electrochemical route, leading to the evolution of CH 4 , H 2 , and CO as major gaseous products at neutral pH and CO as the major product at basic pH. In a nutshell, the current approach can provide useful means for achieving major metallic residue from the e-waste, which can further be utilized for green energy production in an eco-friendly manner, making the process sustainable.

Conducting Graphene Synthesis from Electronic Waste

“…The average compositional distribution of the various elements present in the powder has been summarized in Table T1 (see the Supporting Information). The values indicate that the present route has the potency to provide a high yield of physical separation of components present in e-waste . Moreover, it is imperative to mention here that trace amounts of catalytically active metallic elements such as Cu, Ni, and Fe are reported to enhance the propensity to transform amorphous carbon into crystalline graphene sheets .…”

“…The values indicate that the present route has the potency to provide a high yield of physical separation of components present in e-waste. 8 Moreover, it is imperative to mention here that trace amounts of catalytically active metallic elements such as Cu, Ni, and Fe are reported to enhance the propensity to transform amorphous carbon into crystalline graphene sheets. 20 These metallic particles in the ewaste powder can act as nucleation sites for graphene nuclei, resulting in the formation of graphene domains of varying thicknesses.…”

“…Moreover, these approaches involve discarding or improper processing of the other constituents (ceramics and polymers). In this direction, recent investigations by Tiwary et al 7 and Sharma et al 8 have established zero waste disposal of PCBs via cryogenic grinding. The method proposed in these studies has piqued the scientific community's interest due to its near-net recovery of valuable metals for their use in modern applications.…”

Melanins as Sustainable Resources for Advanced Biotechnological Applications

“…[ 617,689,690 ] There is consequently potential for greener manufacture processes which produce less toxic materials and by‐products that have promise in medical and technical applications (e.g., biosensors, [ 691 ] printing [ 692–697 ] ), especially given that OEs are comparatively lightweight and flexible. [ 617,620,690 ] Further research into OEs has the potential to reduce environmental impacts by adoption of renewable resources and green processes, thereby effectively managing the amount of e‐waste generated annually (currently ≈50 million tonnes); [ 640,698–703 ] and health impacts by use of the technologies for medical applications. OE development is not without challenges [ 704–706 ] and requires a market demand to be articulated [ 707,708 ] to create scalability and realize the potential economic and environmental benefits.…”

Recent Advances in Bio‐Templated Metallic Nanomaterial Synthesis and Electrocatalytic Applications

“…Metals like Ag, [236,237] Au [238,239] and Cu [240,241] have been found to be promising electrocatalysts for reducing CO 2 with high activity under appropriate conditions. Ag and Au NMs are of particular interest as they showed higher selectivtiy towards CO products compared to other metal catalysts [242‐244] . High selectivty is important to avoid product separation processes and thus save cost in industrial applications.…”