Efficient Recycling Research Articles

Thermostable nanofiltration membranes enabling superior hot wastewater purification

Emerging nanofiltration (NF) separation technology for precision ionic/molecular separation at the nanoscale, which has the advantages of energy conservation, excellent separation and a small footprint, is promising for obtaining sustainable water resources via efficient water treatment and recycling. However, traditional NF membranes are restricted to applications at approximately room temperature because of the sharp deterioration in stability induced by the fragility of the nanopore structure at higher temperatures. Herein, we synthesized an unparalleled nanofiltration (NF) membrane with superior thermal stability up to 90 °C and finely tailored nanopores with 0.3–1.1 nm, via de novo carbon skeleton-mediated polymerization (CSMP). Molecular thermodynamics simulations and experiments demonstrated that C–C skeletons can manipulate the stability of the intrinsic structure and intermolecular gap size, contributing to exceptionally thermostable and well-tailored nanopores. The synthesized membrane exhibited excellent long-term water permeance and high rejection of (sub)nanoscale contaminant molecules at high temperatures, which is far superior to the performance of currently available NF membranes.

Green strategy for recovering cathode materials from end-of-life lithium-ion batteries using grape pomace

The extraction of critical metals from End-of-life lithium-ion batteries (EOL LIBs) have garnered particular attention for efficient resource recycling. This study provides a method for recycling EOL LIBs using grape pomace (GP) as a reducing agent. The efficacy of this method is demonstrated using LiNixCoyMnzO2 (NCM) cathode material. Kinetic studies suggest that the leaching process of the cathode material in H2SO4 + GP is governed by internal diffusion. The leachate efficiencies of lithium, cobalt, manganese and nickel, surpassed 98 % through manipulation of the thermodynamic conditions. The NCM523 cathode materials are successfully regenerated from the leachate by removing impurities, evaporating and crystallizing, dry ball milling at room temperature and oxidative calcination. Electrochemical data of the regenerated layered oxide phase also showed that the leachate could be upgraded to next-generation materials. This study presents a sustainable with industrial applicability for the large-scale recycling of EOL LIBs.

A Study on the Construction and Evaluation of the Water Resource Reutilization System for Farmland Diversion and Drainage

Water is an essential resource for both rural and agricultural areas; it can be wisely distributed and used in the field to protect daily life, production, the natural environment, and the safety and stability of regional drainage and flood control systems. Our research selected a typical plains rural river network area with agriculture as the main industry to investigate the most effective method of farmland diversion and drainage. We comprehensively planned and transformed the water system flow, water conservation engineering, and the ecological environment in the irrigation area through the reutilization system. The reutilization system’s operation and scheduling design is implemented for four specific periods: the water replenishment cycle, agricultural irrigation, agricultural drainage and the rainy period of the flood season. The research period ranges from 2020 to 2023 after the completion of the system. We used monitoring, the recording of hydraulic equipment parameters and data collection to evaluate the balance of water supply and demand in the study area. At the same time, we have tracked and evaluated the four aspects of water quality enhancement, water conservation and flood control, and agricultural irrigation. The results show that the total agricultural water consumption decreased by 2.9%, and the amount of water saved increased by 9.6%. The current segment creates the rivers’ embankment standards. With a 92% irrigation guarantee rate, the current section forms and the embankment standards of the rivers satisfy the design storage volume and the flood level of one in twenty years. The water quality of all the rivers in the area has decreased by 5~10% compared to the average concentration prior to establishment. This study verifies the comprehensive effect and the suitability of the system by comparing the before and after effects, and provides a scientific basis for the method of efficient recycling and utilization of water resources in the rural plains river network area; we also propose the guidance of increasing the digital twin control and long-term operation mechanism to ensure the long-term stable operation of the technology.

Battery Deactivation for Safe and Efficient Recycling

With the substantial increase in the demand for lithium-ion batteries (LIBs) for the adoption of electrification to reduce CO2 emission, safe and efficient recycling of spent LIBs is essential to utilize LIBs sustainably1. In hydrometallurgy-based or direct LIB recycling systems, which are expected to become mainstream in the future because of their low environmental impacts, deactivation is a crucial pretreatment step to safely handle LIBs during the processes2, 3. However, a common deactivation method, in which an external short circuit is induced using electronic loads or conductive liquid, cannot deactivate LIBs with disconnected electrical circuits or metallic Li plating on the negative electrode surface, despite their high safety risks.We propose the advanced deactivation method, injecting a redox mediator (RM) solution inside the LIBs. The RM delivers electrons from the negative electrode to the positive electrode by cycling the reduction and oxidation on the negative and positive electrodes, respectively (redox shuttle reaction), resulting in discharging LIBs. In other words, the RM causes a short circuit inside the LIB. Therefore, it is possible to discharge a LIB that cannot be discharged externally, for example, a LIB with disconnected electrical circuits due to a safety device operation. Furthermore, the RM can strip Li metal plated on the negative electrode even though it is “dead lithium.” This unique characteristic contributes to the improvement in the safety and the Li collection rate in the recycling processes. Additionally, in this presentation, the deactivation mechanism of LIBs and its relationship with the electrochemical properties of the RMs will be discussed. The present findings will be beneficial and helpful for designing RMs for deactivation of more and more diversified spent LIBs. References J. Neumann, et al.: "Recycling of Lithium‐Ion Batteries—Current State of the Art, Circular Economy, and Next Generation Recycling" Adv. Energy Mater. 12, (2022). A. Kwade, et al.: "Recycling of lithium-ion batteries" The LithoRec Way, Switzerland: Springler International Publishing AG (2018). H. Rouhi, et al.: "Voltage behavior in lithium-ion batteries after electrochemical discharge and its implications on the safety of recycling processes" Journal of Energy Storage 35, (2021).

Efficient Direct Recycling of Spent Cathode Materials in Lithium-Ion Batteries

The demand for lithium-ion batteries (LIBs) has surged in recent years, driven by the rapid growth of electric vehicles (EVs) and emerging energy storage technologies. Yet, this surge in demand has also resulted from a significant increase in the number of spent batteries. Given the potential for environment pollution wastage, it is absolutely crucial to prioritize the recovery and recycling of these used lithium-ion batteries.The common techniques employed in large-scale industrial settings for battery recycling are pyrometallurgy and hydrometallurgy. These are pivotal multi-step processes, particularly suitable for materials containing Cobalt (Co) and Nickel (Ni), such as NMC (LiNixMnyCozO2). Aside from NMC, there has been a surge in the adoption of LFP (LiFePO4) as a cathode material target for lithium-ion batteries in electric vehicles worldwide over the past few decades. However, these established industrial recycling methods are not applicable to LFP due to the comparatively lower value of iron. This necessitates the pursuit of direct recycling approaches.In order to accomplish this goal, direct recycling stands out as the most suitable technique for regenerating spent batteries1. Unlike processes involving solution-based or high-temperature steps that entail potentially wasteful steps, thisapproach aims to reduce energy consumption and costs, all while maintaining environmental integrity through a judicious utilization of resources, materials, and energy. Consequently, our attention is directed towards this specific LFP material, prompting us to detail a direct recycling procedure for spent LFP cathodes via a chemical lithiation process at room temperature in a solution containing lithium iodide (LiI) and various solvents2 (Fig. 1).

A TEM Study of Structural Degradation in LiFePO4 Batteries after Hybrid Vehicle Use

Establishing a robust, efficient circular economy for batteries hinges on understanding how they decay over time under various conditions. This understanding is crucial to maximize material use before recycling or disposal. A key aspect of this endeavor is the study of lithium iron phosphate (LiFePO4), a pivotal battery technology whose structural integrity over time remains a subject of inquiry.1 Known aging mechanisms in LiFePO4 (LFP) batteries include electrode degradation, SEI growth, and electrolyte decomposition.1 These processes extend to the cathode, where degradation can manifest as Fe dissolution, Li inventory loss, Fe/Li anti-site defects, and LFP amorphization.1–3 However, these mechanisms are typically studied in lab-aged cells under controlled conditions, leaving a gap in our understanding of their behavior in real-life, commercialized applications.Our research aims to bridge this gap by characterizing the degradation mechanisms of LFP cathode material in various states of health (SOH) after use in a hybrid vehicle. We sourced our cathode samples from 26650 cells extracted from a BAE ESS-A123 hybrid bus battery pack. After selecting cells with drastically different SOHs based on previous analyses,4 we employed transmission electron microscopy (TEM) for detailed characterization.In this talk, we will share insights gained from high-resolution TEM characterization, alongside chemical analysis using energy-filtered TEM and electron energy loss spectroscopy (EELS). Our focus will be on changes in the olivine structure, including lattice parameter alterations, Li and Fe migration, and Fe oxidation. By combining cell-level SOH analyses with TEM characterization, we will highlight how electrochemical test results correlate with material degradation mechanisms, enhancing our understanding of battery health, longevity, and diagnostics. Wang, L. et al. Insights for understanding multiscale degradation of LiFePO4 cathodes. eScience 2, 125–137 (2022). Li, X. et al. First Atomic-Scale Insight into Degradation in Lithium Iron Phosphate Cathodes by Transmission Electron Microscopy. J. Phys. Chem. Lett. 11, 4608–4617 (2020). Xu, P. et al. Efficient Direct Recycling of Lithium-Ion Battery Cathodes by Targeted Healing. Joule 4, 2609–2626 (2020). Ramirez-Meyers, K., Rawn, B. & Whitacre, J. F. A statistical assessment of the state-of-health of LiFePO4 cells harvested from a hybrid-electric vehicle battery pack. J. Energy Storage 59, 106472 (2023).

Selective Recovery of Rare Earth Elements from Waste Magnets by Molten Salt Electrochemical Process

Neodymium magnets are the strongest permanent magnets with Nd2Fe14B as the main phase. In applications where high temperature operation is expected, such as motors for electric vehicles (EVs) and hybrid electric vehicles (HEVs), Dy is added to prevent degradation of magnetic properties. Currently, the demand for EVs and HEVs is growing rapidly, and Dy-doped NdFeB magnets are used in these vehicles. Thus, a large amount of waste magnets will be generated in the future. Moreover, for heavy rare earths such as Dy, high-quality resources are extremely unevenly distributed in the world, and there are already concerns about their stable supply. Given the above background, there is a need to develop an efficient recycling process that can replace the conventional wet recycling process, which has a large environmental impact and energy consumption.Our research group has proposed a process for the separation and recovery of rare earth elements (REEs) from the waste of neodymium magnet using molten salt electrolysis and alloy diaphragms [1,2]. The principle of this process is shown in Fig. 1. First, the Nd and Dy ions in the waste magnet used as the anode are dissolved into the molten salt by anodic dissolution. Next, the dissolved Nd or Dy ions are reduced on the surface of the diaphragm, which functions as a bipolar electrode, and only one of the ions is reduced to form an alloy. Furthermore, Nd or Dy diffuses through the alloy diaphragm and is dissolved into the molten salt by anodic dissolution on the cathode chamber side surface of the diaphragm. Finally, Nd and Dy are separated and recovered on the cathode.So far, we have reported that selective permeation of Dy [2] and Nd [3] is possible using LiCl-KCl as the molten salt and a solid Ni-RE alloy as the diaphragm. In the present study, we selected LiF-CaF2 as a more practical fluoride-based molten salt and Hastelloy as a more durable diaphragm, and investigated the electrochemical permeation of RE. We also considered that liquid Fe-RE alloy is expected to be a more desirable diaphragm with higher durability and faster permeation. As a fundamental study, the formation behavior of liquid Fe-Nd and Fe-Dy alloys was investigated, and the results will also be reported.[1] T. Oishi, H. Konishi, T. Nohira, M. Tanaka, and T. Usui, Kagaku Kogaku Ronbunshu, 36, 299 (2010). [in Japanese][2] T. Oishi, M. Yaguchi, Y. Katasho, H. Konishi, and T. Nohira, J. Electrochem. Soc., 167, 163505 (2020).[3] T. Oishi, M. Yaguchi, Y. Katasho, and T. Nohira, J. Electrochem. Soc., 168, 103504 (2021). Figure 1

(Invited) Efficient Recycling of Dilute Nitrate to Ammonia Using Cu-Based Electrocatalyst

The use of nitrogen fertilizers has contributed significantly to the growth of agricultural production, but the nitrogen use efficiency is typically lower than 40%, so most of the nitrogen readily leaches into ground water, rivers, and lakes, causing an increase of nitrate (NO3 −) concentration and severe environmental problems. Electrochemical reduction of nitrate has emerged as a promising route for the recycling of nitrate from wastewater and sustainable production of ammonia when powered by renewable electricity. Here I present our recent studies of the intrinsic activity and selectivity of Cu for nitrate electroreduction, as well as a rational design of Cu-based catalysts for single-pass conversion of nitrate to ammonia. Using polycrystalline Cu foils for benchmarking, we elucidated the impact of often overlooked factors on nitrate reduction, including Cu facet exposure, nitrate concentration, and electrode surface area. We find that an electropolished Cu foil exhibits a higher activity and selectivity for nitrate reduction to ammonia than a wet-etched Cu foil, benefiting from a greater exposure of Cu(100) facets that are more favorable for the reaction. The NH3 selectivity shows no apparent dependence on the nitrate concentration, but it increases monotonically with Cu electrode area, which is attributed to a promoted conversion of intermediately produced NO2 − to NH3 on a larger electrode. Based on the understandings, we further developed a Cu/Co-based tandem electrocatalyst, which achieved nearly 100% single-pass conversion of dilute nitrate (5−50 mM) to NH3 at a low overpotential using a flow cell.

Reprocessable carbon fiber vitrimer composites: Reclamation and reformatting of carbon fibers for second generation composite materials

AbstractCarbon fibers (CFs) are experiencing a growing demand owing to their low specific weight, exceptional mechanical properties, superior temperature, and corrosion resistance, however, their sustainability and energy consumption during manufacturing is still a challenge. Therefore, reclamation of waste CFs and their reformatting has gained significant attention. Herein, we synthesized a chemically degradable vitrimer matrix by curing bisphenol‐A diglycidyl ether (BADGE) with 2‐aminophenyl disulfide (2‐AFD) and further utilized the matrix for the development of CF reinforced composites (CFRCs) through vacuum‐assisted resin infusion molding (VARIM) process. The obtained vitrimeric system and its composites show excellent mechanical, self‐adhering, shape‐memory, and reprocessing properties. Meanwhile, the developed CFRP vitrimer composites can be rapidly dissolved in thiol solvent (1‐octanethiol), resulting in the efficient recycling of CFs. X‐ray diffraction, scanning electron microscopy, and Raman spectroscopy validate that the chemical structure of the recycled fibers closely resembles the structure of the original CFs. The recycled CFs were further used to prepare second generation composite materials with excellent thermal, dynamic, and mechanical properties for nonstructural applications (e.g., sports, automotive, etc.). Thus, with an effective CF recycling method, this study can assist in preparing reliable, long‐term functional, recyclable, and high‐performance composites.

Efficient Regeneration of Graphite from Spent Lithium-Ion Batteries through Combination of Thermal and Wet Metallurgical Approaches.

With the large-scale application of lithium-ion batteries (LIBs) in various fields, spent LIBs are considered one of the most important secondary resources. Few studies have focused on recycling anode materials despite their high value. Herein, a new efficient recycling and regeneration method of spent anode materials through the combination of thermal and wet metallurgical approaches and restored graphite performance is presented. Using this method, the lithium recycling ratio from spent anode materials reaches 87%, with no metal impurities detected in the leaching solution. The initial Coulombic efficiency of the recycled graphite (RG) materials is 90.5%, with a reversible capacity of 350.2 mAh/g. Moreover, RG shows better rate performance than commercial graphite. The proposed method is simple and efficient and does not involve toxic substances. Thus, it has high economic value and application potential in graphite recycling from spent LIBs.

Techno-economic assessment of electro-synthetic fuel based on solid oxide electrolysis cell coupled with Fischer–Tropsch strategy

Electro-synthetic fuel is proposed as an approach to achieve net-zero carbon emissions for heavy-duty internal combustion engines and meet carbon neutrality targets. This method is based on high temperature co-electrolysis using a solid oxide electrolysis cell (SOEC) coupled with Fisher-Tropsch (FT) synthesis due to its high efficiency and carbon recycling capacity. To access the techno-economic viability of this pathway and identify the key elements impacting the cost of electro-synthetic fuels, a comprehensive techno-economic model is constructed. This model aims to offer cost cutting guidance and includes SOEC, FT, and techno-economic sub-models, with SOEC and FT validated using literature data. The cost breakdown and sensitivity analysis indicate that heating costs, electricity prices, and stack lifetime are critical factors in reducing the cost of electro-synthetic fuel. Three alternative system layouts that fully utilize thermal and chemical energy are proposed to address the significant heating expense issue. Among these, the optimal system design lowers costs by approximately 5.3 %. Furthermore, this work introduces the contradiction between high performance, high stability, and low-cost accounting for the SOEC lifetime, which is bounded by operating current density. When considering the degradation and replacement of SOEC stacks, the long-term profitability of operating SOEC at a current density of 500 mA/cm2 is superior to that of 850 mA/cm2. Despite the most effective layout being currently unprofitable, it is anticipated that in the future, carbon trade, renewable electricity and technological advancements will drive the cost of electro-synthetic fuel to become competitive with that of diesel.

Influence of Carboxylic Acid Structure on the Kinetics of Polyurethane Foam Acidolysis to Recycled Polyol.

Closed-loop recycling of plastics is needed to bridge the gap between the material demands imposed by a growing global population and the depletion of nonrenewable petroleum feedstocks. Here, we examine chemical recycling of polyurethane foams (PUFs), the sixth most produced polymer in the world, through PUF acidolysis via dicarboxylic acids (DCAs) to release recyclable polyols. Acidolysis enables recycling of the polyol component of PUFs to high-quality materials, and while the influence of DCA structure on recycled PUF quality has been reported, there are no reports that examine the influence of DCA structure on the kinetics of polyol release. Here, we develop quantitative relationships between DCA structure and PUF acidolysis function for ∼10 different DCA reagents. PUF acidolysis kinetics were quantified with ∼1 s time resolution using the rate of carbon dioxide (CO2) gas generation, which is shown to occur concomitantly with polyol release. Pseudo-zeroth-order rate constants were measured as a function of DCA composition, reaction temperature, and DCA concentration, and apparent activation barriers were extracted. Our findings demonstrate that DCA carboxyl group proximity and phase of transport are descriptors of PUF acidolysis rates, rather than expected descriptors like pK a. DCAs with closer proximity acid groups exhibited faster PUF acidolysis rate constants. Furthermore, a shrinking core mechanism effectively describes the kinetic functional form of the kinetics of PUF acidolysis by DCAs. Measurements of acidolysis kinetics for model PUF (M-PUF) and end-of-life PUF (EOL PUF) confirm the applicability of our analysis to postconsumer materials. This work provides insights into the physical and chemical mechanisms controlling acidolysis, which can facilitate the development of efficient closed-loop PUF chemical recycling schemes.

Development of water vapor recovery membrane for efficient recycling system

Abstract In wastewater treatment at semiconductor plants separation operations are currently conducted mainly by distillation. Membrane distillation using ceramic surface-treated membranes is expected to provide more efficient separation. In this study, we investigated the improvement of acid resistance of surface-treated ceramic membranes by using four silicon alkoxides, Hexamethyldisiloxane(HMDS), Dimethyldimethoxysilane(DMDMOS), 3,3,3-Trifluoropropyltrimethoxysilane (TFPrTMOS), Tetramethoxysilane(TMOS) were used as surface treatment and it was performed in the gas phase. The water vapor permeance of the TFPrTMOS surface treated membrane was 2.35✕10−6 [mol m−2 s−1 Pa−1], and it maintained its functionality after immersion in a 10 wt% sulfuric acid solution under 60°C for 170 h. The membrane with multiple surface treatments with TFPrTMOS showed an increase in acid resistance to 491h, indicating that unreacted alkoxide affected the degradation. The water vapor permeance of the TFPrTMOS-DMDMOS treated membrane combined silicon alkoxides was 2.85✕10−6[mol m−2 s−1 Pa−1] and the acid resistance was 687 h. It is possible that DMDMOS acted as a cross-linker in modifying the unreacted alkoxide portion of the membrane, leading to improved resistance.

A Review of the Thermal Recycling Methods of Carbon Fibers from Carbon Fiber Reinforced Thermosetting Resin Composites

Carbon fiber reinforced thermosetting resin composites (CFRTRC) have drawn great attention in automotive, aerospace, wind turbine blades and other important industry sectors, due to their characteristics of high specific strength and good corrosion resistance. With the extensive use of CFRTRC, the waste composite generated and accumulated is a problem that must be tackled. Thus, the efficient recycling of carbon fibers from CFRTRC is essential. There are many recycling methods; among them the thermal recycling methods have attracted great interest for the CFRTRC in general. The thermal recycling methods of CFRTRC are reviewed in this paper, listed in the order of publication, and are classified into pyrolysis method, fluidized bed method, microwave pyrolysis method and superheated steam method. The advantages and disadvantages of the thermal recycling methods are described in detail. This paper describes in detail the thermal recycling methods of CFRTRC, which, we suggest, will contribute to the sustainable development of the composite industry.

Deriving material composition of products using life cycle inventory databases

AbstractUnderstanding the detailed material composition of the various industrial and consumer products is essential for implementing efficient recycling practices and policies, conducting material flow analyses, and facilitating a transition toward a circular economy. However, existing data sources are limited in their product and material coverage. Currently, no source or methodology allows such data to be obtained in a relatively uniform, updated, and accessible manner across a diverse range of products. This work presents an approach that allows estimating the material composition of thousands of products using available life cycle inventory (LCI) databases. Methodologically, this is implemented by splitting the physical flows that describe supply chains in LCI databases into “incorporated” and “not incorporated” fractions using an incorporation parameter. Building primarily on existing matrix‐based life cycle assessment calculations, this approach can be used to calculate the material content of products. A generally applicable mathematical model, as well as a ready‐to‐use software, is presented for future practitioners. To demonstrate the robustness of the proposed method, a case study involving three metals and plastic in three consumer goods has been conducted based on the ecoinvent database. Our method delivered accurate material content estimates (i.e., weight fractions of materials in products) with an average relative error of 26% and an absolute error of 1.1% (between our estimates and existing values).

Highly Efficient Recycling Waste Plastic into Hydrogen and Carbon Nanotubes through a Double Layer Microwave-Assisted Pyrolysis Method.

Microwave-assisted pyrolysis of PE to hydrogen and carbon material has great potential to solve the problem of waste PE induced white pollution and provide a promising way to produce hydrogen energy. To increase the hydrogen yield, a new microwave-assisted pyrolysis procedure should be developed. In the present study, a facile double-layer microwave-assisted pyrolysis (DLMP) method is developed to pyrolyze PE. Within this method, PE can be converted to hydrogen, multiwalled carbon nanotubes with extremely high efficiency compared with the traditional methods. A high hydrogen yield of 66.4 mmolg-1 PE is achieved, which is ≈93% of the upper limit of the theoretical hydrogen yield generated from the PE pyrolysis process. The mechanism of high hydrogen yield during the microwave-assisted pyrolysis of PE using the DLMP method is also clarified in detail. The DLMP method paved the potential way for recycling plastic waste into high-value-added products.

Blockchain Based Reverse Logistics Data Tracking: An Innovative Approach to Enhance E - Waste Recycling Efficiency

Blockchain Based Reverse Logistics Data Tracking: An Innovative Approach to Enhance E - Waste Recycling Efficiency

Brominated Flame Retardants (BFRs) in China Over the Past Half-Century: Stocks, Flows, Fates, and Ecological Risks.

China is a significant producer and consumer of various brominated flame retardants (BFRs), raising environmental concerns due to their widespread presence and potential threats to ecosystems and organisms. This study adopts a life cycle perspective, combining material flow analysis, multimedia environmental modeling, and ecological risk assessment to systematically analyze the substance metabolism and ecological risks of six BFR types in China from 1970 to 2021. The findings reveal that China's cumulative BFR consumption reached 3.3 Mt, with the electronics sector being the predominant contributor at 52.1%. Consequently, 1.5 kt of BFRs were released into the environment, with 24.9%, 31.5%, and 43.6% being discharged into the air, water, and soil, respectively. Notably, the proportion of novel BFRs in emissions has steadily increased over the years, exemplified by the increase in decabromodiphenyl ethane (DBDPE) from 21.3% in 2010 to 30.1% in 2021. Geographically, BFR concentrations are higher in the eastern and southwestern regions compared to those in the northwest. Presently, certain BFRs like tetrabromobisphenol A (TBBPA) and DBDPE exhibit moderate to high ecological risks, primarily concentrated in the Shandong and Sichuan provinces. A combination of efficient recycling, emission control, and substitution with novel flame-retardant can minimize the exposure of BFRs to the environment and organisms.

Decisions on blockchain adoption and echelon utilization in the closed-loop supply chain for electric vehicles under carbon trading policy

The rapid increase in ownership of new energy vehicles has resulted in a surge in retired power batteries, necessitating the development of an efficient recycling system. Given the application of blockchain in recycling, we analyze the blockchain adoption and echelon utilization decisions for the manufacturer in a closed-loop supply chain under the carbon trading policy and offer four distinct models: 1) without echelon utilization and without blockchain, 2) without echelon utilization but with blockchain, 3) echelon utilization without blockchain, and 4) echelon utilization with blockchain. Equilibrium decisions and profits are derived across these models. The results show: adopting blockchain technology is consistently the optimal choice for the manufacturer irrespective of echelon utilization business, and can enhance the recycling quantity. The manufacturer’s decision regarding echelon utilization depends on the recycling competition coefficient between the manufacturer and the echelon utilizer. If the competition coefficient falls below a threshold, the manufacturer engages in echelon utilization business; Otherwise, the manufacturer refrains from engaging in echelon utilization activities. The carbon emission reduction level is independent of the manufacturer’s involvement in echelon utilization but is improved by the adoption of blockchain. Additionally, conducting Nash negotiation on profit allocation is beneficial for both members.

Hydrogel Applications in Nitrogen and Phosphorus Compounds Recovery from Water and Wastewater: An Overview

This article provides an overview of the diverse applications of hydrogels in nutrient recovery from water and wastewater. Due to their unique properties, such as high water-retention capacity, nutrient rerelease, and tunable porosity, hydrogels have emerged as promising materials for efficient nutrient capture and recycling. It has been suggested that hydrogels, depending on their composition, can be reused in agriculture, especially in drought-prone areas. Further research paths have been identified that could expand their application in these regions. However, the main focus of the article is to highlight the current gaps in understanding how hydrogels bind nitrogen and phosphorus compounds. The study underscores the need for research that specifically examines how different components of hydrogel matrices interact with each other and with recovered nutrients. Furthermore, it is essential to assess how various nutrient-recovery parameters, such as temperature, pH, and heavy metal content, interact with each other and with specific matrix compositions. This type of research is crucial for enhancing both the recovery efficiency and selectivity of these hydrogels, which are critical for advancing nutrient-recovery technologies and agricultural applications. A comprehensive research approach involves using structured research methodologies and optimization techniques to streamline studies and identify crucial relationships.