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Perspective

13 September 2023

Estimate of Economic Impact of EVs Li-ion Batteries Recovery

Nowadays, increasing attention is directed towards the sustainable use of raw materials. For a circular economy, recovery from spent devices represents a fundamental practice. With the transition to electric mobility, an increasing number of devices powered by lithium batteries are produced. Indeed, this is the fastest growing sector producing spent batteries, which are an important secondary source of critical raw materials, such as lithium, cobalt, graphite, and nickel. Therefore, this work aims to quantify the economic impact of recovering raw materials from lithium batteries used in the electric vehicles sector. Based on the chemical composition of the various lithium batteries and their market diffusion, the intrinsic economic value of this waste has been estimated to be around 6500 €/ton. Starting from the literature data on the global energy demand from lithium batteries and deriving the trend of their specific energy over time, the mass of material introduced into the market annually is estimated to reach 60 Mton/year by 2040. The annual amount of end-of-life lithium batteries was calculated by applying the Weibull distribution to describe the probability of failure, yielding 10 Mton/year by 2040. Finally, based on these results, the economic impact of the recovery market was assessed for two different scenarios.

Keywords: Li-ion battery; Recovery; Lithium; Graphite; Cobalt; CRMs; Economic impact; End-of-life

Article

08 September 2023

Synthesis and Characterization of Cyclic Carbonate End-Functional Linear and Star Polyesters via Ring-Opening Polymerization

Well-defined α-(cyclic carbonate), ω-hydroxyl heterotelechelic poly (D,L-lactide)s (PDLLAs) were prepared with good end-group fidelity by ring-opening polymerization (ROP) of D,L-lactide catalyzed by organo catalyst namely, N,N′ dimethyl amino pyridine (DMAP) in conjunction with a renewable, functional bio-based initiator namely glycerol 1,2-carbonate (GC) in bulk at 135 °C with 82% yield. In the case of GC/DMAP catalyzed polymerizations, the HO-PDLLA-COOH series was not observed in MALDI TOF mass analysis unlike as obtained due to transesterification reactions when catalyzed by GC/Sn(Oct)2. Also, cyclic carbonate end-functional 4-arm star poly(ε-caprolactone) (PCL) was prepared via coupling of GC with (PCL-COOH)4 at room temperature in the presence of N,N′-dicyclohexylcarbodiimide (DCC) and DMAP. Quantitative conversion of hydroxyl functionality in (PCL-OH)4 to carboxylic acid and then to cyclic carbonate functionality was achieved with 90% yield for low molecular weight 4-arm star PCL confirmed by NMR, FT-IR, and MALDI TOF mass spectroscopy.

Keywords: Telechelics; Functional initiator; Organo catalyst; Reactive and functional polymers; Ring-opening polymerization (ROP); Poly(d,l-lactide); Poly(ε-caprolactone); Star polyesters

Review

01 September 2023

In Vitro BioTransformation (ivBT): Definitions, Opportunities, and Challenges

Great needs always motivate the birth and development of new disciplines and tools. Here we propose in vitro BioTransformation (ivBT) as a new biomanufacturing platform, between the two dominant platforms—microbial fermentation and enzymatic biocatalysis. ivBT mediated by in vitro synthetic enzymatic biosystems (ivSEBs) is an emerging biomanufacturing platform for the production of biocommodities (i.e., low-value and bulk biochemicals). ivSEB is the in vitro reconstruction of artificial (non-natural) enzymatic pathways with numerous natural enzymes, artificial enzymes, and/or (biomimetic or natural) coenzymes without living cell’s constraints, such as cell duplication, basic metabolisms, complicated regulation, bioenergetics, and so on. The two great needs (i.e., food security and the carbon-neutral renewable energy system) have motivated the birth and development of ivBT. Food security could be addressed by making artificial food from nonfood lignocellulose and artificial photosynthesis for starch synthesis from CO2. The carbon-neutral renewable energy system could be addressed by the construction of the electricity-hydrogen-carbohydrate cycle, where starch could be a high density of hydrogen carrier (up to 14.8% H2 wt/wt) and an electricity storage compound (greater than 3000 Wh/kg). Also, ivBT can make a number of biocommodities, such as inositol, healthy sweeteners (e.g., D-allulose, D-tagatose, D-mannose), advanced biofuels, polymer precursors, organic acids, and so on. The industrial biomanufacturing of the first several biocommodities (e.g., myo-inositol, D-tagatose, D-mannose, and cellulosic starch) would wipe off any prejudice and doubt on ivBT. Huge potential markets of biocommodities with more than tens of trillions of Chinese Yuan would motivate scientists and engineers to address the remaining technical challenges and develop new tools within the next decade.

Keywords: Biocommodity; Biomanufacturing; In vitro biotransformation; In vitro synthetic enzymatic biosystem; Food security; Carbon-neutral energy system

Article

01 September 2023

The Priority of Nature-based over Engineered Negative Emission Technologies: Locating BECCS and DACCS within the Hierarchy of International Climate Law

Drastically reducing emissions is essential to achieve the Paris Agreement’s (PA) goal of keeping global temperature well below 2 °C, ideally at 1.5 °C. With regard to residual emissions, however, a demand for negative emission technologies (NETs), also known as carbon dioxide removal (CDR), remains. NETs are particularly necessary to reach net-zero goals by offsetting emissions in hard-to-abate sectors. This article examines the distinction between “engineered” and “nature-based” removals from the perspective of international climate change law. To that end, the relevant legal norms in the United Nations Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol (KP), and the PA are interpreted—with a particular emphasis on two engineered removals: bioenergy with carbon capture and storage (BECCS) and direct air carbon capture and storage (DACCS). We posit that the three treaties establish a normative hierarchy that is more favorable towards so-called nature-based removals and less favorable to engineered removals (and even more favorable towards emission reductions).

Keywords: Climate law; Environmental law; Negative emission technologies; BECCS; DACCS; Paris Agreement; UNFCCC; Climate change

Article

31 August 2023

Potential Role of Exciton in Photocatalysis

This article commemorates the outstanding Russian scientists E.F. Gross and A.N. Terenin. It revisits their successors’ efforts to develop Terenin’s idea of using excitons, discovered by Gross, for photocatalytic redox reactions on wide-gap semiconductors. Terenin proposed ZnO as the subject of study. To explore the possibility of replacing photogenerated electrons and holes in a redox reaction by an exciton being a quasi-neutral particle, the test reaction of the photoactivated oxygen isotope exchange (POIE) was studied. It was found that many years of initial unsuccessful attempts were due to the fact that the exciton energy is spent on luminescence. In our experiments, the excitons decayed non-radiatively, and the long-lived electron-donor F-type and hole V-type active centers were formed by creating the 2D surface nanostructure ZnO/ZnO1−x/O. These centers allowed to obtain the reaction efficiency 5–8 times higher than with the interband transitions. Thus, the developed 2D surface nanostructure ZnO/ZnO1−x/O resolved the problem of using an exciton in photocatalysis and demonstrated the perspective of this nanostructure as an efficient photocatalyst.

Keywords: Photocatalysis; ZnO; Exciton; Photoactivated oxygen isotope exchange (POIE); Redox reactions

Review

28 August 2023

Dynamic Metabolic Control: From the Perspective of Regulation Logic

Establishing microbial cell factories has become a sustainable and increasingly promising approach for the synthesis of valuable chemicals. However, introducing heterologous pathways into these cell factories can disrupt the endogenous cellular metabolism, leading to suboptimal production performance. To address this challenge, dynamic pathway regulation has been developed and proven effective in improving microbial biosynthesis. In this review, we summarized typical dynamic regulation strategies based on their control logic. The applicable scenarios for each control logic were highlighted and perspectives for future research direction in this area were discussed.

Keywords: Dynamic regulation; Control logic; Feedback control; Oscillation

Editorial

25 August 2023

Article

21 August 2023

Role of Youth in Implementing SDGs Future City in Tosacho, Kochi, Japan

The “SDG Future Cities” established by the SDG (Sustainable Development Goals) Promotion Headquarters of Cabinet Office of Government of Japan, are being expanded to all municipalities in Japan through government support for the efforts of leading municipalities. Tosa town is a small town with less than 4000 people with high aging population and surrounded by mountains in Kochi Prefecture. The town was selected as one of the SDG Future City in 2020. In this paper, through a literature review, interviews with the Tosa Town Office, and a questionnaire survey and interview with residents of Tosa town, we considered what young people need to do to achieve SDG-11. Although Tosa Town has a variety of local government initiatives, the definition of a town where young people can continue to live, as revealed in the literature review, was found to be insufficient in terms of “economic resources,” “decision-making,” “data,” and “knowledge”. However, it was found that “community leaders,” “nature/topography,” and “community/people” are the most important factors for creating a town where people can continue to live. As for future issues, it is necessary to take measures for “decision-making,” “data,” and “knowledge,” as well as to solve issues specific to Tosa town.

Keywords: Sustainable Development Goal 11; SDG future cities; Tosa Town, Kochi Prefecture; Youth

Review

15 August 2023

Green Composites Using Naturally Occurring Fibers: A Comprehensive Review

Depletion of non-renewable resources and health hazards of petroleum-based polymers and plastics has enforced the development of eco-friendly materials. The use of conventional plastics has to be minimized and can be replaced with environmentally friendly and sustainable bio-based polymers or biopolymers due to extensive environmental impact. A major share of petroleum-based polymers is used for polymeric composites with research focus on green composites and biocomposites containing renewable/bioderived matrix polymer and fillers from naturally occurring fibers. Biocomposites hold great promise to replace petroleum-based polymer composites owing to their lower cost, non-toxicity, abundance of raw material, renewability, and high specific strength. All these merits of biocomposites have led to an increment in the development of new biocomposites with enhanced properties, wide applicability and ever demanding criteria. The recently published review studies detailed the raw materials used, fabrication techniques, characterization, and applications including biodegradation and rheological studies performed in recent years. This review covers all the important properties of biocomposites along with detailed description of synthesis, properties, characterizations and applicability of these green composites in several areas. The review also focuses on their raw materials, types, recent biocomposites, processing techniques, characterizations, applications, and current challenges with future aspects.

Keywords: Biopolymers; Natural fibers; Biocomposites; Biodegradation; Sustainability

Article

15 August 2023

Thermal and Economic Evaluations of a Drain Water Heat Recovery Device under Transient Conditions

This study explores the transient characteristics of a drain water heat recovery (DWHR) device employed for heat recovery from warm grey water in buildings. Experimental measurements were conducted to investigate the response time of the DWHR device under various flow conditions. The thermal performance of the system was assessed using both transient and steady-state effectiveness analyses. The findings reveal that the response time is influenced by the water volume within the system, with an increase observed, and by the water flow rate, which leads to a decrease in response time. Additionally, a decrease in effectiveness is noted when hot water is used in short and frequent intervals. Furthermore, an economic analysis demonstrates that considering the transient behavior of the device results in a significant overall decrease of 37% in annual savings. Specifically, the usage of sinks exhibits a reduction in annual savings by 56%, while showers show a decrease of 13% in annual savings.

Keywords: Drain water heat recovery; Heat exchanger; Experimental investigation; Transient
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