Cyclic Economy Research Articles

Valorization of recycled fine powder glass (RFPG) in additive manufacturing: Optimization of the RFPG content in polyethylene terephthalate glycol (PETG) and multi-response analysis

A cyclic economy and sustainability-driven production are key aspects of the industry. Recycled feedstocks are steadily replacing virgin materials to produce parts and as sustainable additives to develop eco-friendly composites. The reinforcing potential of recycled fine powder glass (FPG) on terephthalate glycol (PETG) is investigated. The performances of six different compounds (with FPG loadings of 2.0, 4.0, 6.0, 8.0, 10.0, and 12.0 wt%) in filament and three-dimensional (3D) specimens form (manufactured with the material extrusion – MEX method) were compared with PETG pure. This research included thermal and rheological analyses, mechanical tests, and morphological and structural investigations. According to these findings, the PETG/RFPG 8.0 wt% composite presented remarkable results in the tensile and flexural (16.3 % and 16.9 % strength increase, respectively) tests, while PETG/RFPG 10.0 wt% had the greatest performance concerning microhardness. Both the dimensional deviation and porosity results show excellent performance in the case of PETG/RFPG 6.0 wt%, by being 67.3 % and 87.1 % improved vs. the PETG pure. These results indicate that RFPG is a promising reinforcement additive for MEX 3D printing that can replace the commonly used inorganic fillers and promote the sustainability of 3D printing.

Assessment of Agricultural Sustainability: Case Study of Baltic States

The agri-food sector is the world’s largest economic sector having the biggest impact on environment. According to the Food and Agriculture Organization of the United Nations (FAO), sustainable agriculture must meet the needs of present and future generations while ensuring profitability, environmental health and social and economic equity. Therefore, agricultural systems need transition to become more sustainable. The use of renewables in agriculture allows to reduce energy costs and GHG emissions and implement cyclic economy principles. Sustainability assessment of agriculture can be done by applying various sets of indicators. The sustainability assessment of agriculture can be performed on country and micro level. The paper presents assessment of agricultural sustainability of Baltic States based on indicators framework and applies MCDA tool for ranking of Baltic States in terms of agriculture sustainability.

Law and Ecology: Interdependence of Scientific Fields in Teaching a Jurist

Introduction . The global environmental crisis unfolding nowadays requires changes not only in the policies of the single states, but also in the public worldview, because the laws, even most perfect, are not able to change the situation if citizens reject laws’ basic postulates. If the society is convinced that nature exists exclusively for satisfying the economic demands in natural resources and its only function is to serve people’s needs, the attempts to stop poaching or reduce the number of unauthorised waste dumps will never achieve the goal. The aim of the study is to determine the disputable aspects in legal regulation of the environmental education, its organisational and methodological problems, the issues of ecological worldview formation in law ecologists through extending the interdisciplinary relations and some other issues. Materials and Methods . Legal, organisational, worldview, methodological and other aspects of the environmental and law education development in the Russian Federation are considered using the scientific knowledge methods generally accepted in Russia: general scientific (dialectical method) and specific scientific methods (analysis, synthesis, concrete- historical, logical methods, etc.). Results . The systematisation of the modern problems of the environmental and law education in Russia has been carried out, the recommendations on improvement of its efficiency have been outlined. In the course of the research, the authors have paid special attention to the review of concepts of nature and society interaction, enabling to form students’ worldview adequate to the modern environmental threats. In the article the concepts of sustainable development, “green” economy, the theory of climate change and the concept of cyclic economy are analysed. Discussion and Conclusions. To increase the efficiency of the Russian environmental and law education, the complex of multidirectional measures of legal, organisational, methodological and other scope is required, which would bring modern law education closer to solving the environmental problems of the XXI century. The conducted research has theoretical and practical significance and is targeted at persons engaged in professional training of future jurists.

BIOENERGY PRODUCTION FROM SUNFLOWER HUSK IN UKRAINE: POTENTIAL AND NECESSARY INVESTMENTS

Sunflower is a strategic crop in the agriculture of Ukraine as it is important for food and energy production. Recently the processing of secondary products, solving the issues of waste disposal and improving the environment have been paid much attention. This is an example of a cyclic economy, as during the production of oil from sunflowers, their husk can be used for energy production. The ash obtained by burning husk is a valuable complex mineral fertilizer and can be further applied as ecological fertilizer. The aim of this article is to assess the energy and investment potential for sunflowers as an internal reserve for increasing production efficiency and reducing carbon dioxide emissions. In particular, the equivalents of energy substitution of sunflower husks for energy costs at fat-and-oil enterprises, the reduction of carbon dioxide emissions are estimated. A generalized scheme for the production of electricity from sunflower husks is considered. In particular, the use of ash from sunflower husks as a fertilizer is described. The research has shown that the sunflower husks available in Ukraine can be used more efficiently to produce electricity. Therefore policy recommendations were developed based on a study conducted.

People and Talent-Based Circular Economy

Future organizations will need help addressing the shortage of skilled resources. While a progressive education system would bridge the gap for some of these resource challenges, other challenges that we could encounter would be associated with the liberalization of workforces in the Gig Economy. The overall objective is not for the race towards being the biggest or best but for working in a cohesive ecosystem that would meet the growing business needs. The circular economy is receiving worldwide increased attention to accelerate economic growth from the optimal consumption of resources. Cities and urban regions are a growing source of resource consumption and are increasingly recognized by national and regional governments as an arena to mitigate resource problems associated with urbanization. This research paper aims to prescribe the approaches that will help organizations adopt a Cyclic Economy to address the growing demand for skilled resources in the years ahead, thus capturing more value from resources.

Investment in Cyclic Economy and Investment Growth

Is it possible, by combining several cyclical theories, to obtain clear information about the financial performance of the company and its possible development in the ever-changing macroeconomic environment? Due to the constantly changing conditions of the business environment, more and more timely, fast, and adapted answers are needed. It is necessary to understand and study the external environment and its elements, as well as internal processes. Using observation and analysis of two cyclical theories and putting, on the one hand, the development of the business cycle, and, on the other hand, the development of the company life cycle and their connection with investments, we will present recommended investment strategies leading to growth.

The use of activated bio-carbon derived from “Posidonia oceanica” sea-waste for Lithium-Sulfur batteries development

Lithium-Sulfur Batteries is promising energy storage systems due to their superior capacity and energy density. A promising solution for drawbacks such as low sulfur utilization and cycling stability is the use of porous carbon as sulfur carrier. On the other hand, cyclic economy and green ideas is of great importance nowadays. Carbon-sulfur cathodes from waste valorization, abundant, and low-cost precursors is an attractive approach. Herein, an activated carbon (AC-Poc) derived from “Posidonia oceanica” sea-waste, was studied as a matrix for the development of a novel carbon–sulfur composite cathode (AC-Poc/S) for the first time. AC-Poc can be used as an effective sulfur host, due to its high specific BET surface area (1264 m2∙g−1) hierarchical porous structure, and total pore volume 0.81 cm3∙g−1. AC-Poc/S reveals an outstanding initial capacity of 1539 mAh∙g−1 as cathode material, combined with high reversible capacity at 0.2 C. Furthermore, the discharge capacity of 390 mAh/g at 2 C reveals good rate capability, even at increased C-rate. AC-Poc/S composite exhibits excellent sulfur utilization (92 %) alongside with sufficiently well electrochemical performance. These results combined with the easy synthesis method of the activated carbon from an abundant and low-cost precursor make AC-Poc/S a very promising material for LSBs applications.

Potential uses of phosphogypsum: A review

Phosphogypsum (PG) is a by-product of the phosphate fertilizer industry that is produced during the phosphoric acid production process. Annual global PG production ranges between 100 to 300 Mt, with only 15% of that utilized while the rest is usually placed on large dumps with potential serious human and environmental impacts. The aim of this study is to give an overview and to evaluate the existing and potential uses of PG that extend from soil stabilization to cement and chemical industry and for agricultural to geotechnical, human impacts, and environmental applications. More specifically, PG can be used as a substitute in the cement industry, in building materials and in road construction, as a fertilizer for soil improvement, as a raw material for the production of some chemicals, and as a backfilling material for the rehabilitation of abandoned mines and quarries, while the recovery of gypsum and the extraction of rare earth elements signifies the potential importance of PG to cyclic economy. The paper offers an extensive overview of existing and potential uses of PG, discusses their adequacy, and reveals that PG can be widely used under certain conditions, rather than disposed as waste in stockpiles.

Performance of Thyme Oil@Na-Montmorillonite and Thyme Oil@Organo-Modified Montmorillonite Nanostructures on the Development of Melt-Extruded Poly-L-lactic Acid Antioxidant Active Packaging Films.

Today, the use of natural biodegradable materials in the production processes is more and more adopted by industry to achieve cyclic economy targets and to improve environmental and human health indexes. Active packaging is the latest trend for food preservation. In this work, nanostructures were prepared by incorporation of thyme oil with natural natrium-montmorillonite and organo-montmorillonite with two different techniques, direct impregnation and the green evaporation–adsorption process. Such nanostructures were mixed with poly-L-lactic-acid for the first time via an extrusion molding process to develop a new packaging film. Comparisons of morphological, mechanical, and other basic properties for food packaging were carried out via XRD, FTIR, TG, SEM/EDS, oxygen and water vapor permeation, and antimicrobial and antioxidant activity for the first time. Results showed that poly-L-lactic-acid could be modified with clays and essential oils to produce improved active packaging films. The final product exhibits food odor prevention characteristics and shelf-life extension capabilities, and it could be used for active packaging. The films based on OrgMt clay seems to be more promising, while the thyme oil addition improves their behavior as active packaging. The PLLA/3%TO@OrgMt and PLLA/5%TO@OrgMt films were qualified between the tested samples as the most promising materials for this purpose.

Ways of improving tariff regulation efficiency

The system of tariff regulation in the Russian Federation has been experiencing improvements since the beginning of the transition period and up until today. The issues of tariff regulation are given particular attention to both in the Russian Federation and abroad. At the time, tariffs do not form subsequent to certain economic waves, but are in most cases described by an annual regulation cycle and a quite limited range of regulation with regard to the long-term horizon. The authors have analyzed average consumer prices (tariffs) for particular services along with producer price indices by types of economic activities and average annual producer prices for main energy resources in Russia over the last 20 years based upon the official statistical data. The authors conclude that it is necessary to introduce new ways of improving tariff regulation efficiency. Among the priority ways are the following: formation of an investment-worthy tariff and justification of the supporting tariff for crucial social projects; digital tariff modeling and etc. All these changes require methodological justification and further development of the variable supporting tariff theory in order to test new cyclic models of regulation matching the cyclic economy of the country.

Nanoclay and Polystyrene Type Efficiency on the Development of Polystyrene/Montmorillonite/Oregano Oil Antioxidant Active Packaging Nanocomposite Films

Over the years, there has been an effort to extend food shelf life so as to reduce global food waste. The use of natural biodegradable materials in production procedures is more and more adopted nowadays in order to achieve cyclic economy targets and improve environmental and human health indexes. Active packaging is the latest trend for food preservation. In this work, polystyrene was mixed with natural NaMt, OrgNaMt montmorillonite, and oregano essential oil to develop a new packaging film. Strength, oxygen and water-vapour permeation, blending and homogeneity, and antimicrobial and antioxidant activity were measured as basic parameters for food packaging films characterization. Instruments such as a tensile measurement instrument, XRD, FTIR, DMA, OPA (Oxygen Permeation Analyzer), and other handmade devices were used. Results showed that polystyrene could be modified, improved, and exhibits food odour prevention characteristics in order to be used for applications on food active packaging. The material with the code name PS5OO@OrgMt qualified between the tested samples as the most promising material for food active packaging applications.

Sustainable lubrication: low molecular weight PTFE micro-particles as extreme pressure additives for heavy duty grease applications

Purpose The purpose of this paper is to formulate heavy-duty lithium complex grease using low molecular weight poly tetra fluoro ethylene (PTFE) micro-particles as extreme pressure (EP) additive manufactured by E-beam scissoring and ultra-high speed grinding process of pre-sintered PTFE scrap. Design/methodology/approach Lithium complex grease is formulated with PTFE micro-particles, and optimum treat rate was studied by standard bench tests by ASTM D 2266 and IP-239 for tribological properties and compared with commercially available Molybdenum Di sulphide (Moly)-based lithium complex grease. The performance of the grease was further evaluated by a cyclic load test at varying speeds and loads to simulate the operational field conditions. Findings The lithium complex PTFE grease was manufactured using PTFE micro-particles as EP additive. The PTFE micro-particles dispersed in the lithium complex grease significantly improve the anti-wear performance and load bearing properties. Further, when the product was tested under a cyclic load conditions on standard tribological bench test against commercially available Moly lithium complex grease, shows stable anti-wear properties and reduced coefficient of friction. Originality/value The low molecular weight PTFE micro-particles, manufactured in the in-house electron beam (E-beam) and ultra-high speed micronizer facility from a pre-sintered PTFE scrap has been used as EP additive for grease applications for the first time. The results on the cyclic load tests indicate significant performance improvement in retaining the anti-wear and friction properties. Thus, value addition is done in formulating superior performance grease and evaluating under cyclic load conditions similar to field operating conditions and also in creating value added additives by converting the pre-sintered PTFE scarp which is environmental hazard due to poor biodegradability, creating a cyclic economy and a sustainable concept.

A review on sustainable recycling technologies for lithium-ion batteries

Due to increasing environmental awareness, tightening regulations and the need to meet the climate obligations under the Paris Agreement, the production and use of electric vehicles has grown greatly. This growth has two significant impacts on the environment, with the increased depletion of natural resources used for the production of the lithium-ion batteries for these electric vehicles and disposal of end-of-life lithium-ion batteries. In particular, when end-of-life lithium-ion batteries are incorrectly landfilled, pollution to groundwater and soil occurs. Therefore, sustainable recycling technologies must be implemented to construct a cyclic economy for the lithium-ion battery market and help alleviate the severity of these environmental consequences. The majority of current recycling methods involve energy-intensive pyrometallurgy, whereas hydrometallurgy techniques pose a viable alternative with promising advances at lab scale that can adapt with the evolution of new mixed cathode chemistries. As reviewed in this work, a combination of pre-treatment and hydrometallurgical processes was identified as a potential mechanism that could meet this criterion, which focuses on the recovered economic value and cumulative environmental benefits. Furthermore, automation of the pre-treatment process and mechanisms for electrolyte recovery were identified as potential opportunities for future works. Here, we evaluate the opportunities for sustainable recycling technologies for lithium-ion batteries.

Recyclable and Light-Adaptive Vitrimer-Based Nacre-Mimetic Nanocomposites.

Nacre's natural design consists of a perfect hierarchical assembly that resembles a brick-and-mortar structure with synergistic stiffness and toughness. The field of bioinspired materials often provides attractive architecture and engineering pathways which allow to explore outstanding property areas. However, the study of nacre-mimetic materials should not be limited to the design of its architecture but ought to include the understanding, operation, and improvement of internal interactions between their components. Here, we introduce a vitrimer prepolymer system that, once integrated into the nacre-mimetic nanocomposites, cures and cross-links with the presence of Lewis acid catalyst and further manifests associative dynamic exchange reactions. Bond exchanges are controllable by molecular composition and catalyst content and characterized by creep, shear-lag, and shape-locking tests. We exploit the vitrimer properties by laminating ca. 70 films into thick bulk materials, and characterize the flexural resistance and crack propagation. More importantly, we introduce recycling by grinding and hot-pressing. The recycling for highly reinforced nacre-mimetic nanocomposites is critically enabled by the vitrimer chemistry and improves the sustainability of bioinspired nanocomposites in cyclic economy. Finally, we integrate photothermal converters into the structures and use laser irradiation as external trigger to activate the vitrimer exchange reactions.

Development of Poly(L-Lactic Acid)/Chitosan/Basil Oil Active Packaging Films via a Melt-Extrusion Process Using Novel Chitosan/Basil Oil Blends

Following the global trend toward a cyclic economy, the development of a fully biodegradable active packaging film is the target of this work. An innovative process to improve the mechanical, antioxidant, and barrier properties of Poly(L-Lactic Acid)/Chitosan films is presented using essential basil oil extract. A Chitosan/Basil oil blend was prepared via a green evaporation/adsorption method as a precursor for the development of the Poly(L-Lactic Acid)/Chitosan/Basil Oil active packaging film. This Chitosan/Basil Oil blend was incorporated directly in the Poly(L-Lactic Acid) matrix with various concentrations. Modification of the chitosan with the Basil Oil improves the blending with the Poly(L-Lactic Acid) matrix via a melt-extrusion process. The obtained Poly(L-Lactic Acid)/Chitosan/Basil Oil composite films exhibited advanced food packaging properties compared to those of the Poly(L-Lactic Acid)/Chitosan films without Basil Oil addition. The films with 5%wt and 10%wt Chitosan/Basil Oil loadings exhibited better thermal, mechanical, and barrier behavior and significant antioxidant activity. Thus, PLLA/CS/BO5 and PLLA/CS/BO10 are the most promising films to potentially be used for active packaging applications.

Nanoporous Activated Carbon Derived via Pyrolysis Process of Spent Coffee: Structural Characterization. Investigation of Its Use for Hexavalent Chromium Removal

Hexavalent chromium (Cr(VI)) is a heavy metal that is highly soluble and exhibits toxic effects on biological systems. Nevertheless, it is used in many industrial applications. The adsorption process of Cr(VI), using activated carbon (AC), is under investigation globally. On the other hand, around six million tons of spent coffee is sent to landfill annually. In the spirit of cyclic economy, this research investigated the production of AC from spent coffee for the removal of Cr(VI) from wastewater. The AC was produced via pyrolysis process under a nitrogen atmosphere. Chemical activation using potassium hydroxide (KOH) occurred simultaneously with the pyrolysis process. The produced AC was tested as an absorber of Cr(VI). The best fitted kinetic model was the diffusion–chemisorption model. A 24-h adsorption experiment was carried out using a solution with a pH of 3 and an initial Cr(VI) concentration of 54.14 ppm. This resulted in an experimental maximum capacity of 109 mg/g, while the theoretical prediction was 137 mg/g. It also resulted in an initial adsorption rate (ri) of 110 (mg/(g h)). The Brunauer–Emmett–Teller surface area (SgBET) was 1372 m2/g, the Langmuir surface area (SgLang.) was 1875 m2/g, and the corrugated pore structure model surface area (SgCPSM) was 1869 m2/g. The micropore volume was 84.6%, exhibiting micropores at Dmicro1 = 1.28 and Dmicro2 = 1.6 nm. The tortuosity factor (τ) was 4.65.

The Role of Nanofluids and Renewable Energy in the Development of Sustainable Desalination Systems: A Review

Desalination accounts for 1% of the total global water consumption and is an energy-intensive process, with the majority of operational expenses attributed to energy consumption. Moreover, at present, a significant portion of the power comes from traditional fossil-fuel-fired power plants and the greenhouse gas emissions associated with power production along with concentrated brine discharge from the process, pose a severe threat to the environment. Due to the dramatic impact of climate change, there is a major opportunity to develop sustainable desalination processes to combat the issues of brine discharge, greenhouse gas emissions along with a reduction in energy consumption per unit of freshwater produced. Nanotechnology can play a vital role to achieve specific energy consumption reduction as nanofluids application increases the overall heat transfer coefficient enabling the production of more water for the same size desalination plant. Furthermore, concentrated brine discharge harms the marine ecosystems, and hence, this problem must also be solved to support the objective of sustainable desalination. Several studies have been carried out in the past several years in the field of nanotechnology applications for desalination, brine treatment and the role of renewable energy in desalination. This paper aims to review the major advances in this field of nanotechnology for desalination. Furthermore, a hypothesis for developing an integrated solar thermal and nanofluid sustainable desalination system, based on the cyclic economy model, is proposed.

Use of biochar for the sorption of volatile organic compounds (VOCs) emitted from cattle manure.

The ability of biochar to be used as filter or as additive for the adsorption of volatile organic compounds (VOCs) emitted from cattle manure is investigated. The employed biochar was produced from cattle manure after slow pyrolysis at 550 °C (under nitrogen). Towards this, in-house-made glass emission reactors were filled with fresh cattle manure samples and a thin layer of biochar (10% w/w) was placed on the top of the manure layer. The mixture was left for 24 h to equilibrate and air samples were collected from the headspace air. The samples were then analyzed using the headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method. Cattle manure emissions are considered unpleasant and odoriferous. The respective changes in the emitted cattle manure VOCs were reported; these included mainly reduction in sulfur- (thiols and sulfides) and oxygen-containing VOCs (alcohols, ketones, phenolics), showing a promising application of biochar for the removal of such compounds from manure wastes. Also, five VOCs were selected as sorbents for further laboratory studies: hexane, dimethyl trisulfide, phenol, p-cresol, and 2-methyl-3-pentanone. The results of cattle manure-derived biochar, revealed a reduction in their emitted concentrations (low ppbv). The present application highlights a straightforward example of cyclic economy, where a waste product is reused after being processed; its re-usage as odor adsorbent serves again the agriculture sector.

Cycles and Etagers in New System of Municipal Solid Waste Management in Russian Federation

Analysis of the first results of adoption in RF since January 2019 of the new system of management of municipal solid waste (MSW) and comparison of them with the world experience has been performed, and it has been shown that the principal results supposed to be obtained in the next years, but, the authors believe, that the trends have been chosen correctly and it is possible to hope that the raised problems will be solved successfully. It has been shown that the proposed concept of the life cycles and etageres (whatnots) in the new system of management of MSW in RF does allow to optimize the practical steps, directed to realization of the zero landfilling "No landfills – no waste" principle. By this, due to the separate collecting of MSW, their additional sorting and using the modern technologies complex one can secure environmental safety of population and realize the principles of sustainable cyclic (circular) economy.

Cyclic Economy in a Globalized World

The article is devoted to solving the problems of the development of a cyclical economy in the conditions of globalization, since the further development of society while maintaining the current growth rates of production and consumption with increasing population can lead to a global catastrophe. The traditional development model is based on intensive industrial growth and resource-intensive infrastructure. In a global cyclical economy, it is necessary to separate economic growth from resource consumption, focusing on preserving value in order to protect ecosystems and natural capital. The aim of the work is to develop tools for the transition to a cyclical economy in the context of globalization. The research methodology is based on an analysis of international and national legislation, scientific publications and ongoing projects for building elements of a cyclical economy. To model the development of cyclical development in the context of globalization, economic opportunities are identified based on specific indicators and identified barriers for which solutions and policy options are developed. For the practical implementation of the ideas of a cyclical economy, government measures are needed to overcome institutional, economic and political barriers. The transition to a cyclical economy leads to an increase in transaction costs, uncertainty, opportunistic behavior. The concept of a cyclical economy is global in nature and represents a systemic shift that shapes long-term sustainability, creates economic opportunities and provides environmental and social benefits.