Veena Sahajwalla

The rapid increase in electronic waste, especially from flexible printed circuit boards (FPCB), presents a growing environmental challenge, demanding urgent and sustainable resource recovery solutions. This study presents a robust two‐step thermal upcycling process, leveraging low‐temperature polymer degradation (700°C) followed by high‐temperature arc discharge (2600°C), to extract and transform copper from waste FPCBs into high‐purity copper nanoparticles (CuNPs). The synthesized CuNPs exhibit a predominantly spherical morphology under 100 nm, with an agglomerated structure featuring interstitial voids and a surface area of 7.31 m ² g ⁻¹ . Elemental and phase analyses verified a purity of 96% copper with detectable cuprous oxide (Cu ₂ O), with high‐resolution TEM indicating a lattice spacing of 0.203 nm assigned to the Cu(111) plane. The nitrogen adsorption‐desorption behavior at high relative pressure was successfully determined to reflect interparticle voids created by nanoparticle agglomeration rather than intrinsic mesoporosity. This process exemplifies a circular economy model by converting hazardous e‐waste into functional nanomaterials without a wet‐chemical synthesis step. Ultimately, our findings highlight how advanced resource recovery strategies can address critical electronic waste recycling challenges and contribute to sustainable metal recovery.

Tyre and road wear particles (TRWPs) represent one of the most significant yet under-recognised sources of global microplastic pollution, contributing up to 28% of total emissions. Generated from the complex interaction between vehicle tyres and road surfaces, TRWPs are chemically diverse, morphologically heterogeneous, and environmentally persistent, making their detection and management particularly challenging. This review provides a critical synthesis of current knowledge on TRWP generation mechanisms, influenced by tyre composition, road types, and vehicle operation, and their environmental dispersion through air, stormwater runoff, snow removal, and roadside deposition. The chemical and physical complexity of TRWPs—often composed of rubber, bitumen, road paint, and heavy metals—necessitates multifaceted analytical approaches. We synthesise current advancements in TRWP identification techniques, including microscopy, micro-spectroscopy, and thermal desorption methods, while benchmarking their applicability using ISO standards. Furthermore, we develop an integrated framework synthesising current classification schemes, detection strategies, and regional policy responses for TRWP assessment. By identifying analytical and regulatory gaps, this review highlights the need for harmonised methodologies, improved analytical comparability, and coordinated policy interventions to address the environmental and health implications of TRWPs.

Understanding the hybrid structural characteristics of carbon remains a significant challenge, hindering the development of clear design principles for optimizing electrode materials in energy storage systems—particularly in lithium‐ion (Li‐ion) and sodium‐ion (Na‐ion) batteries. Traditionally, the localized structural disorder and intrinsic porosity of carbon have been regarded as the primary contributors to its high storage capacity in Na‐ion batteries. However, our investigation reveals that the hybrid structural features of carbon play a more dominant role in enhancing energy storage performance in Li‐ion systems compared to Na‐ion counterparts. Through comprehensive materials characterization and electrochemical analysis, we establish a direct correlation between the local microstructural attributes of carbon and its ion storage kinetics which elucidate the distinct ion‐storage mechanisms that differentiate Li‐ion from Na‐ion systems. This study reinforces our findings that configurational defects are crucial for achieving high initial storage capacity in carbon crafted with mixed‐phase structures, but the in‐plane size of nano‐layered microdomains plays a key role in ensuring long‐term stable storage capacity in rechargeable batteries.

The ever-increasing market demand and the rapid uptake of the technologies of electronics create an unavoidable generation of high-volume electronic waste (e-waste). E-waste is embedded with valuable metals, alloys, precious metals and rare earth elements. A substantial portion of e-waste ends up in landfills and is incinerated due to its complex multi-material structure, creating loss of resources and often leading to environmental contamination from the release of landfill leachates and combustion gases. Conversely, due to the ongoing demand for valuable metals, global industrial and manufacturing supply chains are experiencing enormous pressure. To address this issue, researchers have put multifaceted efforts into developing viable technologies and emphasized right-scaling for e-waste reclamation. Several conventional and emerging recycling technologies have been recognized to be efficient in recovering metal alloys, precious and rare earth metals from e-waste. The recovery of valuable metals from e-waste will create an alternative source of value-added raw materials, which could become part of supply chains for manufacturing. This review discusses the urgency of metal recycling from e-waste for sustainability and economic benefit, up-to-date recycling technologies with an emphasis on their potential role in creating a circular economy in e-waste management. This article is part of the discussion meeting issue ‘Sustainable metals: science and systems’.

The development of efficient recovery methods for waste printed circuit boards (WPCBs) not only tackles the environmental risks of disposal but also promotes the conservation of resources within the electronics industry. This study proposes a two-step leaching approach for recovering metals from WPCBs. Initially, transition metals are leached using nitric acid, followed by the recovery of precious metals with thiourea in the second stage. In the first stage, dissolution rates exceeding 90 wt% were achieved for transition metals, including Cu, Fe, Ni, Pb, and Sn. In this stage, the dissolution of precious metals (i.e., Au and Pd) was insignificant. In the second stage, the effect of four parameters was investigated, including the impact of temperature, concentrations of ferric ions, sulfuric media, and thiourea on the recovery of Au and Pd. Precise control over sulfate concentration played a vital role in achieving maximum Au recovery. The optimal acid concentration was 0.2 M, resulting in a recovery rate of ~50 wt%. Ferric ion concentration positively affects Au recovery, whereas, in extracting Pd, optimal conditions imposed the absence of ferric ions. Thiourea concentration positively impacted Au and Pd recovery rates, peaking at 49 wt% for Au at 1 M and 44 wt% for Pd at 1.5 M. Prolonged leaching resulted in declining Au recovery rates, indicating a decrease in reagent concentration. Temperature variation yielded similar outcomes, with 50 °C resulting in peak recovery rates of 53 wt% for Au and 54 wt% for Pd. Metal dissolution kinetics during leaching were analyzed using pseudo-first-order and pseudo-second-order models. The second-order model proved suitable for transition metals in the first stage, while only for Au and Pd in the second stage (with R² = 0.99).

Carbon anode‐based Li‐ion batteries (LIBs) have been widely used ranging from portable electronics to electric vehicles (EVs). Here a novel carbon material called microzonal carbon is introduced, synthesized from waste hard rubber (WHR), as an anode material for next‐generation LIBs. This material consists of a hybrid carbon structure embedded with short range ordered carbon zones, including expanded graphene sheets and nanopores. Two types of microzonal carbons (M‐5H and M‐10H) are tested in LIBs to unveil their electrochemical performance. The anode fabricated with M‐10H provides a high initial coulombic efficiency (60%), reversible capacity (377 mA h g⁻¹ at 0.13 C), rate capability (275 mA h g⁻¹ at 2.6 C) and cyclic stability (capacity retention of 99% at 0.13 C after 100 cycles). The electrochemical properties of microzonal carbon can be attributed to its unique hybrid carbon structure, facilitating fast ion diffusion, high electronic conductivity, and the ability to form stable interphase. Therefore, this work presents new insights into the electrochemical behavior of microzonal carbon as an anode material in next‐generation LIBs.

Post-consumer soft plastics often face inadequate management practices, posing threats to both human life and the environment while also leading to the loss of valuable recyclable materials when not recycled. Traditional mechanical recycling methods are unsuitable for waste soft plastics due to their thin and flimsy nature. This study presents an effective, user-friendly process for converting waste soft plastics into new products, generating value, and expediting their collection and recycling without the need for pelletization. The outcome of this process was compared with products derived from traditional recycling and commercially available alternatives through various analytical techniques including tensile testing, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The findings suggest that waste soft plastics can be transformed into flexible sheets without significant alterations to their properties. In particular, the ultimate tensile strength of samples recycled using the developed process in this study and traditional recycling were found to be 25.9 ± 0.4 and 25.2 ± 0.8 MPa, respectively, surpassing commercially available products by nearly 15 MPa. Additionally, a life cycle assessment revealed that producing flexible sheets from waste soft plastics using this innovative approach, rather than virgin polymer, could reduce fossil fuel depletion and global warming by 99.4% and 94.6%, respectively. This signifies the potential of the process to mitigate environmental pollution and produce high-quality products exclusively from 100% waste plastics.

Packaging in India comprises around 59% of total plastic consumption, with most of the waste originating from single‐use and short shelf‐life products. The plastic recycling industry is primarily made up of informal processing units which have predominantly been recycling Polyethylene terephthalate (PET) waste due to ease of availability, sorting, and higher upscale values than most other single‐use packaging. Other packaging, such as Polyethylene (PE) shopping bags, thin film and multi‐material packaging waste is either directed to downcycling, incineration or landfill. About 94% of total recycling in India is carried out through mechanical recycling, which comes through informal and fragmented recycling units. Most of the recycling units in India rely on rudimentary technologies. One example is a visual sorting system that involves manual handling to recycle plastic waste, which is resource and time intensive. There has been some advancement towards chemical and energy recovery techniques, but mostly been limited to pilot‐scale deployment. This article explores the existing and emerging technological options suitable for recycling post‐consumer flexible plastic packaging waste in India. It also discusses the status of multi‐material packaging waste, and the advancement being made for its recycling. The paper also explores India's increased momentum in the use of innovative recycling techniques, such as distributed recycling and manufacturing techniques and plastic waste in steel manufacturing.This article is categorized under: Climate and Environment > Ecosystem Services Climate and Environment > Circular Economy Emerging Technologies > Materials

Generally, fossil carbon materials (coal, coke/char, and petroleum coke), biological carbon materials (charcoal, woodchips), and quartz from the earth’s crust are sources of carbon and silica to synthesise silicon carbide (SiC) at temperatures between 2000 and 2200 °C. The study investigated the isothermal and non-isothermal kinetics of synthesising SiC from automotive shredder residues (ASR) and windshield glass of end-of-life-vehicle (ELVs) at 1300 °C, 1400 °C, and 1500 °C for 30 min. The kinetics of ASR and waste glass degradation were studied by relating the thermogravimetric data via the Coats–Redfern model. The reaction mechanism includes the rapid formation of a gaseous SiO intermediate, and carbon reduction of the SiO to SiC is reaction-rate-controlling. The understanding of kinetics inferred that the optimisation of SiC formation is entirely associated with the conversion of SiO₂ to SiO vapour and their reaction with CO and carbon particles. The kinetic parameters of the degradation of mixed ASR and waste glass were determined, and the activation energy of mixed ASR and glass for non-isothermal conditions are 22.48 kJ mol⁻¹, 2.97 kJ mol⁻¹, and 6.5 kJ mol⁻¹, and for the isothermal study to produce SiC is 225.9 kJ mol⁻¹, respectively. The results confirmed that this facile way of synthesising SiC would conserve about 50% of chemical energy compared to the traditional way of producing SiC. A beneficial route of transforming the heterogenous ASR and glass wastes into SiC with economic and environmental benefits is recognised.