Highlights COVID-19 presents unprecedented challenge to all facets of human endeavour. A critical review of the negative and positive impacts of the pandemic is presented. The danger of relying on pandemic-driven benefits to achieving SDGs is highlighted. The pandemic and its interplay with circular economy (CE) approaches is examined. Sector-specific CE recommendations in a resilient post-COVID-19 world are outlined.

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The increasing awareness of the environmental and health threats of lead as well as environmental legislation, both in the EU and around the world targeted at decreasing the use of hazardous substances in electrical appliances and products has reinvigorated the race to develop lead-free alternatives to lead zirconate titanate (PZT), which presently dominates the market for piezoelectric materials. Emphasis has been placed on one of the most likely piezoelectric materials, potassium sodium niobate (KNN), as a lead-free replacement for PZT. KNN has been speculated to have better environmental credentials and is considered as a "greener" replacement to PZT. However, a comparative environmental impact assessment of the life cycle phases of KNN versus PZT piezoelectric materials has not been carried out. Such a life cycle assessment is crucial before any valid claims of "greenness" or environmental viability of one material over the other can be made and is the focus of this paper. Against this backdrop, a methodologically robust life cycle supply chain assessment based on integrated hybrid life cycle framework is undertaken within the context of the two piezoelectric materials. Results show that the presence of niobium in KNN constitutes far greater impact across all the 16 categories considered in comparison with PZT. The increased environmental impact of KNN occurs in the early stages of the LCA due to raw material extraction and processing. As a result, the environmental damage has already occurred before its use in piezoelectric applications during which it doesn't constitute any threat. As such, the use of the term "environmentally friendly" for the description of KNN should be avoided. Cost-benefit analysis of substituting PZT with KNN also indicates that the initial cost of conversion to KNN is greater, especially for energy usage during production. This environmental assessment has allowed us to define and address environmental health and safety as well as sustainability issues that are essential for future development of these materials. Overall, this work demonstrates insightful findings that can be garnered through the application of life cycle assessment and supply chain management to a strategic engineering question which allows industries and policy makers to make informed decisions regarding the environmental consequences of substitute materials, designs, fabrication processes and usage. IntroductionIn recent times, there has been a drive to develop new piezoelectric materials for a wide range of applications with properties comparable with lead zirconate titanate (Pb (Zr, Ti) O 3 , PZT). One main driver has been the growing awareness of the environmental impact and health concerns due to the toxicity of lead [1][2][3][4][5][6] which has led to existing environmental legislations and restrictions both in the EU and across the globe under the auspices of Waste Electrical and Electronic Equipment (WEEE) and Restriction of Hazardous Substances (RoHS) directives which concern the reduction of the...

Life cycle assessment within a techno-economic framework is carried out for triboelectric nanogenerators in the context of other technologies.

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High volumetric efficiency capacitors are found in all smart electronic devices, providing important applications within circuits, including flexible filter options, power storage and sensing, decoupling and circuit smoothing functions. Multilayer ceramic capacitors (MLCCs) hold the major market share but tantalum electrolytic capacitors (TECs) provide a viable alternative if higher breakdown strengths are required. The reduced costs, smaller dimensions suitable for spaceconstrained electronic circuits, exceptional high-frequency characteristics, higher reliability, ripple control and longevity, however, are driving the market to replace TECs with MLCCs wherever possible. To date, no current research regarding the transition from TECS to MLCCs has been conducted from an entirely environmental viewpoint. This article identifies, quantifies, ranks and compares the environmental impacts of the MLCC and TEC supply chains using an integrated hybrid life cycle assessment framework. Three recovery methods: incineration; hydrometallurgy and pyrometallurgy are considered in the overall impact assessment. Electrical energy consumption during fabrication alongside the use of nickel paste are the major environmental hotspot for MLCCs. The high proportion of tantalum in TECs results in an overall greater environmental impact in comparison with MLCCs, due to intensive extraction, processing and purification requirements of tantalum. Of the three recovery methods, the hydrometallurgy process offers the least environmental impact for both MLCCs and TECs. Overall, the current work shows that while the industry led transition from TECs to MLCCs offers both an operational and functional edge, it is also an environmentally intelligent move. Intervention options that can further drive down the environmental impacts of MLCCs are also proposed such as a reduction in the reliance of MLCCs on rare earth elements and Cu external electrodes in some designs and material recovery.

Considered as a less hazardous piezoelectric material, potassium sodium niobate (KNN) has been in the fore of the search for replacement of lead (Pb) zirconate titanate for piezoelectrics applications. Here, we challenge the environmental credentials of KNN due to the presence of ∼60 wt% Nb 2 O 5 , a substance much less toxic to humans than Pb oxide, but whose mining and extraction cause significant environmental damage.Piezoelectric materials based on lead zirconate titanate, PbZr x Ti 1−x O 3 , (PZT) have held sway in numerous applications (automobiles, microphones, sonar, resonators, medical imaging/diagnostics, printers, ultrasonic motors, wearable devices, smart structures, medical implants, etc.) for over 50 years. The dominance of PZT-based ceramics is due to their superior piezoelectric response, which ultimately ensures an unmatched efficiency in the direct interconversion of electrical and mechanical energy. Beyond this superior piezoelectric response, lies a level of toxicity that threatens the position of PZT as the leading piezoelectric ceramic, and has sparked urgent global efforts to identify environmentally benign substitutes. PZT accrues its toxicity from >60 wt% lead oxide (PbO). Pb is a toxic heavy metal that has been the subject of calls for elimination from all consumer electronics and products, [1][2][3][4][5][6] based on worldwide initiatives for electronic equipment reuse and recycling such as the EU directives on waste electrical and electronic equipment (WEEE) and restriction of hazardous substances (RoHS). [3,7,8]