RecyclingPub Date : 2023-10-24DOI: 10.3390/recycling8060082
Shiva MohammadKarimi, Benedikt Neitzel, Maximilian Lang, Florian Puch
{"title":"Investigation of the Fiber Length and the Mechanical Properties of Waste Recycled from Continuous Glass Fiber-Reinforced Polypropylene","authors":"Shiva MohammadKarimi, Benedikt Neitzel, Maximilian Lang, Florian Puch","doi":"10.3390/recycling8060082","DOIUrl":"https://doi.org/10.3390/recycling8060082","url":null,"abstract":"This paper explores the mechanical recycling of continuous fiber-reinforced thermoplastics (CFRTPs) waste into injection molded products, focusing on the influence of recycling parameters on fiber length and mechanical properties. CFRTPs are gaining attention for their promising attributes, including weight-specific mechanical properties, short cycle times, storability, and recyclability, making them suitable for diverse applications. However, as CFRTP production rates rise, recycling strategies become crucial for sustainability. This study investigates the processability of CFRTP waste, defines size reduction conditions, and evaluates the impact of various compounding parameters such as temperature, screw speed, and fiber volume content during extrusion. The research findings indicate that higher screw speeds lead to fiber length reduction, whereas elevated temperatures result in longer fibers. Increased fiber volume intensifies interactions, resulting in shorter lengths. Additionally, the study examines the influence of injection molding parameters such as back pressure, screw speed, and initial fiber length on the resulting fiber length and mechanical properties of injection molded specimens, emphasizing the need for precise parameter control to optimize performance in recycled CFRTPs. Key findings are that increasing the initial fiber length from 260 μm to 455 μm results in an average fiber length after injection molding of 225 μm and 341 μm, respectively. This implies that longer initial fibers are more prone to breakage. Regarding the mechanical properties, increasing back pressure from 20 bar to 60 bar results in a reduction in Young’s modulus of approximately 40 MPa. Higher screw speed also reduces modulus by approximately 70 MPa due to intensified fiber–screw interactions. However, back pressure and screw speed have neutral effects on the tensile strength and the elongation at break.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"49 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135315879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Avocado Waste Biorefinery: Towards Sustainable Development","authors":"Teresa Sandoval-Contreras, Fernando González Chávez, Amrita Poonia, Maricarmen Iñiguez-Moreno, Lizet Aguirre-Güitrón","doi":"10.3390/recycling8050081","DOIUrl":"https://doi.org/10.3390/recycling8050081","url":null,"abstract":"The increasing demand for avocado consumption has led to a vast generation of waste products. Despite the high nutritional value of avocados, the waste generated from their processing poses a significant environmental challenge. Therefore, the development of a sustainable approach to avocado waste management is a major concern. Biorefinery presents a promising approach to the valorization of avocado waste components, including the seed, peel, and pulp residues. This paper explores the potential of avocado waste biorefinery as a sustainable solution to produce bio-based products. Several approaches, including extraction, hydrolysis, fermentation, and biodegradation, to obtain valuable products such as starch, oil, fiber, and bioactive compounds for food or feed goods have been proposed. The review also highlights the approaches towards addressing challenges of energy security and climate change by utilizing avocado waste as a source to produce biofuels such as biogas, biodiesel, and bioethanol. In conclusion, the development of avocado waste biorefinery presents a promising avenue for sustainable development. This process can efficiently convert the avocado waste components into valuable bio-based products and clean energy sources, contributing to the attainment of a circular economy and a more sustainable future.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-10-16DOI: 10.3390/recycling8050080
Eunmi Park, Minji Kim, Min-Wook Pin, Hyunsik Park, Yong-Hwan Kim
{"title":"Precious Metal Recovery from Waste Electrical and Electronic Equipment through Oxidative Refining","authors":"Eunmi Park, Minji Kim, Min-Wook Pin, Hyunsik Park, Yong-Hwan Kim","doi":"10.3390/recycling8050080","DOIUrl":"https://doi.org/10.3390/recycling8050080","url":null,"abstract":"This study delves into the application of oxidative refining for the recovery and concentration of precious metals, namely palladium (Pd) and gold (Au), from waste electrical and electronic equipment by WEEE recycling, leveraging pyrometallurgical techniques. The primary objective is to optimize refining parameters, encompassing variations in gas pressure, temperature, and gas composition, to maximize the extraction and purification of precious metals from recycled materials. Through an array of comprehensive characterization techniques, encompassing microstructural analysis, elemental composition assessment, and metal concentration measurement, this study scrutinizes the potential of oxidative refining. The conclusive findings underscore the remarkable potential of oxidative refining in augmenting the efficiency and effectiveness of metal recovery from waste printed circuit boards (PCBs), with a pronounced emphasis on the concentration of Pd and Au. This research not only highlights the promise of oxidative refining but also concludes that optimizing process parameters, such as a N2/O2 mixed gas pressure of 4 L/min, a process time of 40 min, and a temperature of 1400 °C, is imperative for achieving the highest efficiency in metal recovery from electronic waste, especially precious metals like Pd and Au. It further contributes to the sustainable management of electronic waste and the strategic extraction of valuable precious metals.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"11230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136112415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-10-08DOI: 10.3390/recycling8050079
Charlotte Badenhorst, Iwona Kuzniarska-Biernacka, Alexandra Guedes, Elsayed Mousa, Violeta Ramos, Gavin Rollinson, Guozhu Ye, Bruno Valentim
{"title":"Recovery of Graphite from Spent Lithium-Ion Batteries","authors":"Charlotte Badenhorst, Iwona Kuzniarska-Biernacka, Alexandra Guedes, Elsayed Mousa, Violeta Ramos, Gavin Rollinson, Guozhu Ye, Bruno Valentim","doi":"10.3390/recycling8050079","DOIUrl":"https://doi.org/10.3390/recycling8050079","url":null,"abstract":"Critical raw materials, such as graphite and lithium metal oxides (LMOs), with a high supply risk and high economic importance are present in spent lithium-ion batteries (LIBs). The recovery and recycling of these critical raw materials from LIBs will contribute to the circular economy model, reduce the environmental footprint associated with the mining of these materials, and lower their high supply risk. The main aim of this paper is to present a separation process to recover graphite from black mass (BM) from spent LIB. Simultaneously, LMO and copper (Cu) and aluminum (Al) foils were also recovered as by-products from the process. The process used a combination of simple and/or low environmental footprint technologies, such as sieving, sink-float, citric acid leaching, and milling through ultrasound and soft attrition, to allow separation of the LIB valuable components. Three graphite-rich products (with purities ranging between 74 and 88 wt.% total carbon and a combined yield of 14 wt.%) with three different sizes (<25 µm, <45 µm, and <75 µm), Cu and Al foil fragments, and an LMO-rich precipitate product are delivered. The developed process is simple, using low temperatures and weak acids, and using affordable and scalable equipment available in the market. Its advantage over other LIB recycling processes is that it can be implemented, so to speak, “in your backyard”.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135251442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-10-07DOI: 10.3390/recycling8050078
Gavin E. Collis, Qiang Dai, Joanne S. C. Loh, Albert Lipson, Linda Gaines, Yanyan Zhao, Jeffrey Spangenberger
{"title":"Closing the Loop on LIB Waste: A Comparison of the Current Challenges and Opportunities for the U.S. and Australia towards a Sustainable Energy Future","authors":"Gavin E. Collis, Qiang Dai, Joanne S. C. Loh, Albert Lipson, Linda Gaines, Yanyan Zhao, Jeffrey Spangenberger","doi":"10.3390/recycling8050078","DOIUrl":"https://doi.org/10.3390/recycling8050078","url":null,"abstract":"Many countries have started their transition to a net-zero economy. Lithium-ion batteries (LIBs) play an ever-increasing role towards this transition as a rechargeable energy storage medium. Initially, LIBs were developed for consumer electronics and portable devices but have seen dramatic growth in their use in electric vehicles (EVs) and via the gradual uptake in battery energy storage systems (BESSs) over the last decade. As such, critical metals (Li, Co, Ni, and Mn) and chemicals (polymers, electrolytes, Cu, Al, PVDF, LiPF6, LiBF4, and graphite) needed for LIBs are currently in great demand and are susceptible to global supply shortages. Dramatic increases in raw material prices, coupled with predicted exponential growth in global demand (e.g., United States graphite demand from 2022 7000 t to ~145,000 t), means that LIBs will not be sustainable if only sourced from raw materials. LIBs degrade over time. When their performance can no longer meet the requirement of their intended application (e.g., EVs in the 8–12 year range), opportunities exist to extract and recover battery materials for re-use in new batteries or to supply other industrial chemical sectors. This paper compares the challenges, barriers, opportunities, and successes of the United States of America and Australia as they transition to renewable energy storage and develop a battery supply chain to support a circular economy around LIBs.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135301591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-10-06DOI: 10.3390/recycling8050077
Laura Leinad Lobo-Ramos, Yulibeth Carolina Osorio-Oyola, Alvaro Espeleta-Maya, Francisco Narvaez-Montaño, Shirley Patricia García-Navarro, Luis Alfonso Moreno-Pacheco, Ricardo Andrés García-León
{"title":"Experimental Study on the Thermal Conductivity of Three Natural Insulators for Industrial Fishing Applications","authors":"Laura Leinad Lobo-Ramos, Yulibeth Carolina Osorio-Oyola, Alvaro Espeleta-Maya, Francisco Narvaez-Montaño, Shirley Patricia García-Navarro, Luis Alfonso Moreno-Pacheco, Ricardo Andrés García-León","doi":"10.3390/recycling8050077","DOIUrl":"https://doi.org/10.3390/recycling8050077","url":null,"abstract":"Ecological materials have been implemented in different industrial sectors due to their good performance as thermal insulators and the fact that they are 100% natural, recyclable, and biodegradable, contributing to environmental sustainability. The main objective of this article is to compare the thermal conductivity coefficients of three natural insulators with that of expanded polystyrene (a non-biodegradable material). Expanded polystyrene is one of the materials which is most often used to maintain cold temperatures in containers built for this purpose in the fishing industry; it is used for this purpose because of its properties, including a light weight and a high thermal insulation capacity and resistance. Almost all insulators have the ecological disadvantage of being environmentally unfriendly materials because they are made up of oil particles, which are not recyclable and are harmful to ecosystems. The natural insulator materials were evaluated and subjected to a drying process to reduce the humidity coefficient; then, the containers were built with an adequate insulation thickness of 25 mm. Three filling tests were carried out (at 100, 70, and 50%) to evaluate the thermal conductivity, using the Mann–Whitney U statistical analysis process to determine insulator differences. The results show that the expanded polystyrene had the lowest thermal conductivity of 0.032 W/m K, followed by the rice husk, which had a value of 0.036 W/m K. Finally, a comparative study of conservation costs was carried out in the different containers built with the natural insulators; the lowest value found was for the expanded polystyrene (COP 159.57 around USD 0.040). This allowed to conclude that rice husk is the material that comes closest to the insulating characteristics of expanded polystyrene.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135352415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-10-03DOI: 10.3390/recycling8050076
Wisam Abu Jadayil, Eman Aqil
{"title":"Building a Deposit–Refund System (DRS) for Closed-Loop Recycling of Water Bottles in the United Arab Emirates","authors":"Wisam Abu Jadayil, Eman Aqil","doi":"10.3390/recycling8050076","DOIUrl":"https://doi.org/10.3390/recycling8050076","url":null,"abstract":"Water bottles are widely used in the Gulf countries. One estimate indicates that the water bottle usage in the United Arab Emirates (UAE) may reach up to 250 L of water per person annually. Generally, the water bottles are made of polyethylene terephthalate (PET), a recyclable material. Because of the non-availability of a powerful incentive system, these recyclable water bottles are often disposed of in landfills. This paper proposes a feasibility study of building a Deposit–Refund System (DRS) to encourage the closed-loop recycling of 0.5 L PET water bottles in the UAE waste disposal system. Water bottles are collected by a reverse vending machine (RVM) and recycled to produce PET bottles, and the proposed system will reward consumers with 0.04 United Arab Emirates Dirham (AED) per deposited water bottle. Additionally, this study calculates the cost of 100% virgin polyethylene terephthalate (vPET) and 60% recycled polyethylene terephthalate (rPET) bottles based on the UAE population, data obtained from local water bottle companies, and existing research. Adopting this DRS will cut down on waste, protect the environment, improve the manufacturing process of water bottles, and boost the local economy.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135696494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-09-29DOI: 10.3390/recycling8050075
Mirko Hänel, Ganbaatar Khurelbaatar, Emil Jespersen, Aryan Upadhyay, Andrés Acosta, Nadeem Khalil, Hans Brix, Carlos A. Arias
{"title":"Application Potential of Wastewater Fertigated Short Rotation Coppice Systems in a Selected Region (Aligarh, UP, India)","authors":"Mirko Hänel, Ganbaatar Khurelbaatar, Emil Jespersen, Aryan Upadhyay, Andrés Acosta, Nadeem Khalil, Hans Brix, Carlos A. Arias","doi":"10.3390/recycling8050075","DOIUrl":"https://doi.org/10.3390/recycling8050075","url":null,"abstract":"In many Indian regions, increased wastewater is both a threat to public health and the environment, but it also presents an opportunity as a source of water and nutrients. With less than one-third of India’s wastewater treated and an alarming water scarcity situation, efficient wastewater treatment and reuse schemes are needed to face impending water and fertiliser shortages. This study explores the application potential of wastewater fertigated Short Rotation Coppice systems (wfSRC) as a cost-efficient and promising solution for treating and reusing wastewater in a specific region (400 km2, 184 settlements) of Aligarh (UP), India. Based on real data from a local wfSRC pilot site using bamboo, willow, and poplar, we analysed the system’s treatment performance, nutrient recovery, carbon sequestration potential, land requirements, biomass production potential, and cost–benefit, under various scenarios. The results show that the pilot wfSRC system is efficiently treating 250 m3/day of domestic wastewater on 6864 m2 of land, and serving 2500 people. The land requirements for wfSRC systems vary depending on local conditions (e.g., climate, soil type, wastewater composition) and user demands (e.g., water reuse efficiency, type, and amount of biomass). The calculated areas ranged from 2.75 to 25.7 m2/PE, which equates to a required land area in the whole study region of between 108 and 1006 ha in 2036. This would produce up to 100 DM t/ha/year of valuable biomass. Early local stakeholder involvement and the monitoring of pollutants are recommended as priorities during the planning process for the large-scale implementation of wfSRC systems in India.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-09-27DOI: 10.3390/recycling8050074
Hadid Sukmana, Etelka Tombácz, Gergő Ballai, Gábor Kozma, Zoltán Kónya, Cecilia Hodúr
{"title":"Comparative Study of Adsorption of Methylene Blue and Basic Red 9 Using Rice Husks of Different Origins","authors":"Hadid Sukmana, Etelka Tombácz, Gergő Ballai, Gábor Kozma, Zoltán Kónya, Cecilia Hodúr","doi":"10.3390/recycling8050074","DOIUrl":"https://doi.org/10.3390/recycling8050074","url":null,"abstract":"Methylene blue (MB) and basic red 9 (BR9) are cationic dyes that are commonly used in the dye industry and negatively affect humans and other living organisms. This study compares the performance of Indonesian rice husk (IRH) and Hungarian rice husk (HRH) as bio-adsorbents for removing MB and BR9 from aqueous solutions. Chemical content, zeta potential, and Fourier-transform infrared spectroscopy analyses were used to characterize the rice husks (RHs). Adsorption studies were performed through batch experiments involving several parameters, namely, pH, adsorbent dose, initial dye concentration, contact time, and temperature to observe the self-association (aggregation) of MB and BR9. Adsorption kinetic studies showed that maximum dye removal was achieved at a contact time of 120 min. MB and BR9 adsorption followed a pseudo-second order kinetic model, and the BET multilayer isotherm model provided a better fit to the experimental data of MB and BR9 adsorption. The IRH adsorption capacities were 15.0 mg/g for MB and 7.2 mg/g for BR9, whereas those of HRH were 24.4 mg/g for MB and 8.3 mg/g for BR9. Therefore, these RHs are potential bio-adsorbents for removing MB and BR9 from aqueous solutions.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135579952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RecyclingPub Date : 2023-09-22DOI: 10.3390/recycling8050073
Rimena Canuto Oliveira, Irenilza de Alencar Nääs, Solimar Garcia
{"title":"Combining SWOT with AHP for Analyzing the Adoption of a Circular Economy in the Apparel Industry in Brazil","authors":"Rimena Canuto Oliveira, Irenilza de Alencar Nääs, Solimar Garcia","doi":"10.3390/recycling8050073","DOIUrl":"https://doi.org/10.3390/recycling8050073","url":null,"abstract":"The Brazilian fashion industry is the country’s second-largest generator of direct and indirect jobs. Despite Brazilian design being a world reference mainly for prints and summer-related collections, it is also the second most polluting industry in the country. We investigated the factors that impact adopting a circular economy in the textile industry using an association of a SWOT analysis and the AHP approach. We analyzed the adoption of a circular economy in the apparel industry. The opportunities, strengths, weaknesses, and threats were associated using the evaluators’ comparison of the selected SWOT items related to the application of a circular economy in the conventional apparel industry were used as criteria for the AHP approach. The case study used managers from two intimate apparel industries in northeastern Brazil and four academics in Production Engineering. By applying the concepts to the case study, we found that expanding products, upcycling, and increasing sustainability were the three vital criteria for reaching a circular economy in the studied apparel industry.","PeriodicalId":36729,"journal":{"name":"Recycling","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136060031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}