Circular Economy最新文献

{"title":"Status and development trends of phosphogypsum utilization in China","authors":"Xiong Shi ,&nbsp;Ao Zeng ,&nbsp;Huabo Duan ,&nbsp;Hui Zhang ,&nbsp;Jiakuan Yang","doi":"10.1016/j.cec.2024.100116","DOIUrl":"10.1016/j.cec.2024.100116","url":null,"abstract":"<div><div>Phosphogypsum (PG) is a byproduct generated in large quantities by the phosphate industry, and it serves as a significant source of total phosphorus (TP) pollution along the Yangtze River. Environmentally sound management of PG has, therefore, become a critical challenge. This review outlines the generation processes and environmental risks associated with PG in China. It further examines the technical characteristics of various PG utilization methods and explores the relevant technical standards and policy frameworks. Enhanced utilization of PG in building materials, road construction, soil remediation, and other high-value products is essential. Additionally, the urgent need to promote ecological restoration of PG tailings ponds is emphasized. This study provides a valuable reference for developing effective technological systems for managing PG and preventing TP pollution in China.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 4","pages":"Article 100116"},"PeriodicalIF":0.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Progress on the adsorption characteristics of nZVI and other iron-modified biochar for phosphate adsorption in water bodies","authors":"Ruiqing Huang ,&nbsp;Xuebin Lu ,&nbsp;Wei Li ,&nbsp;Jian Xiong ,&nbsp;Jueyuan Yang","doi":"10.1016/j.cec.2024.100112","DOIUrl":"10.1016/j.cec.2024.100112","url":null,"abstract":"<div><div>The issue of water body eutrophication induced by phosphorus is escalating, and there is an urgent need for materials that can control phosphate in water bodies. Biochar is often used as an adsorption material for phosphate removal from water bodies because of its high efficiency, strong stability, and low cost. However, the phosphate adsorption capacity of pristine biochar is limited, and iron and its compounds are often loaded to overcome this limitation and improve the adsorption effect. The current status of the use of nanoscale zero-valent iron (nZVI) and other iron-modified biochar in the treatment of eutrophic water is summarized. The preparation process of nanoscale zero-valent iron-modified biochar was introduced. The adsorption mechanism of nZVI and other iron-modified biochar in phosphorus removal from water was explained (mainly related to the roles of electrostatic, precipitation, complexation, ion exchange, etc.); the effects of factors such as dosage, pH value, and initial phosphate concentration on the adsorption of phosphate by iron-modified biochar were analyzed; and the possibility of reusing iron-modified biochar after adsorbing phosphate was pointed out. Based on the above research, the problems and future development directions of nZVI and other iron-modified biochars were proposed. This study provides a theoretical basis for the treatment of eutrophication in water bodies and the utilization of solid waste resources.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 4","pages":"Article 100112"},"PeriodicalIF":0.0,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using solid waste from the leather tanning industry to produce a mixed calcium/zinc thermal stabilizer for polyvinyl chloride","authors":"I Dewa Gede Arsa Putrawan,&nbsp;Shifa Mardiani,&nbsp;Vita Wonoputri","doi":"10.1016/j.cec.2024.100115","DOIUrl":"10.1016/j.cec.2024.100115","url":null,"abstract":"<div><div>The leather tanning industry has historically posed considerable environmental challenges owing to the substantial solid waste it produces. This study examines innovative uses for the solid waste generated by this sector, focusing on the waste from the fleshing process. Our research involved extracting fat from fleshing waste, synthesizing Ca and Zn carboxylates from the extracted fat, and assessing their effectiveness as a combined Ca/Zn thermal stabilizer for polyvinyl chloride (PVC). The synthesized Ca and Zn carboxylates contained 6.4% Ca and 11.4% Zn, respectively, while the total fatty matter was determined to be 86.2% and 88.5%, respectively. Thermal analysis indicated that both carboxylates remained stable up to 200 °C. Tests on dehydrochlorination and roll milling revealed that the mixed Ca/Zn thermal stabilizer effectively improved the thermal stability of PVC resin. It also showed a synergistic effect when combined with pentaerythritol, enhancing its overall efficacy. The synthesized mixed Ca/Zn thermal stabilizer exhibited thermal stabilizing properties and flowability comparable to those of mixed Ca/Zn stearate, a widely used thermal stabilizer for PVC. These results suggest that fleshing fat could serve as a valuable raw material in the production of mixed Ca/Zn-based PVC thermal stabilizers.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 4","pages":"Article 100115"},"PeriodicalIF":0.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbon footprint impact of waste sorting on the municipal household waste treatment system: A community case study of Hangzhou","authors":"Jun Yin ,&nbsp;Min Wang ,&nbsp;Xiaoqin Yu ,&nbsp;Meizhen Wang ,&nbsp;Yanfeng Zhang ,&nbsp;Ting Chen ,&nbsp;Jianguo Liu","doi":"10.1016/j.cec.2024.100114","DOIUrl":"10.1016/j.cec.2024.100114","url":null,"abstract":"<div><div>Considering the pressing need to reduce carbon emissions, the environmental impacts of waste sorting and its influencing factors remain unverified across many practical scenarios. This study focused on separating perishable and residual waste in a community in Hangzhou, China, examining how waste sorting behavior affects the carbon footprint of subsequent waste treatment systems through a randomized tracking survey and life cycle assessment (LCA) method. The results indicated that the sorted waste treatment system could achieve net carbon emissions ranging from −139.92 to −254.03 kg CO₂ eq per day by integrating the anaerobic digestion of sorted perishable waste with the incineration of residual waste. In comparison to the conventional mixed incineration system, which had net carbon emissions between −56.37 and −115.46 kg CO₂ eq per day and generated 383 kWh/t of power, the carbon reduction benefits of the sorted system were considerably greater, by a factor of 2.2–2.5. Additionally, the average amount of recovered electrical energy (993 kWh/t) was also higher by a factor of 2.6. Therefore, source separation of waste significantly enhances energy recovery and carbon reduction in household waste treatment systems. In this research system, incineration power generation and oil recovery serve as the primary units for reducing carbon emissions, and the proportion of residual waste generated greatly influences the total carbon emissions of the sorted waste treatment system (p &lt; 0.05). Consequently, increasing the percentage of classified residual waste and optimizing machine efficiency will increase the carbon reduction benefits of waste sorting and treatment systems. These findings provide crucial references and guidance for advancing carbon reduction and waste classification in municipal solid waste (MSW) management systems.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 4","pages":"Article 100114"},"PeriodicalIF":0.0,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Process optimization and economic estimation of nitric acid dissolution for recycling waste wind blades","authors":"Muqian Guo,&nbsp;Zhe Yuan,&nbsp;Xingnan Zhang,&nbsp;Ying Li","doi":"10.1016/j.cec.2024.100113","DOIUrl":"10.1016/j.cec.2024.100113","url":null,"abstract":"<div><div>With the widespread retirement of wind turbines, many discarded waste wind blades have been generated, and how to handle them efficiently has become a critical issue. This study investigated the dissolution of discarded waste wind blades with nitric acid (HNO₃) by varying acid concentration, reaction time, temperature, and HNO₃ volume. Based on a series of single-factor experiments, the optimal conditions for low energy and acid consumption were determined, and the separation rate of resin reached 95%. As the cost-benefit analysis results suggested, an economic method to recycle a variety of high-value products was achieved. Furthermore, the implementation of a continuous chemical decomposition strategy for multi-batch processing significantly minimized acid consumption, resulting in a further reduction in recycling costs. This work provided an economically and technologically feasible way for recycling materials from decommissioned wind turbines, in order to answer the challenge of emerging solid waste management.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 4","pages":"Article 100113"},"PeriodicalIF":0.0,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formulating efficient P-rich biobased starter fertilizers: Effects of acidification and pelletizing on fertilizer properties","authors":"Pietro Sica ,&nbsp;Dorette Müller-Stöver ,&nbsp;Jakob Magid","doi":"10.1016/j.cec.2024.100111","DOIUrl":"10.1016/j.cec.2024.100111","url":null,"abstract":"<div><div>Animal-derived biowastes can be alternatives to mineral phosphorus fertilizers. However, they typically have lower efficiency and higher transport costs because of their low bulk density. Pelleting can reduce their volume and facilitate their use as placement fertilizers but may also decrease phosphorus availability. This study examined how acidification and pelletizing affect phosphorus availability in biowastes. Digestate solid fraction and meat and bone meal were treated in four ways: (1) untreated (U), (2) acidified (A), (3) untreated pelletized (UP), and (4) acidified pelletized (AP). These treatments were tested in soil incubation and pea growth experiments, with fertilizers placed 5 cm beneath the seeds to evaluate their effectiveness as placement fertilizers. Acidification significantly enhanced the phosphorus solubility of DSF and MBM by approximately 5 and 7 times respectively, while pelletizing acidified materials reduced it. In the incubation experiment, acidified materials in the powdery form showed the highest soil water-extractable phosphorus, with no significant differences among U, UP, and AP ways. In the rhizobox experiment, pelletizing untreated digestate significantly reduced plant dry matter compared to the untreated fibrous form (from 2.0 g to 1.35 g). Acidified and acidified pelletized digestate treatments resulted in the highest shoot dry matter (2.8 g and 2.95 g, respectively), surpassing even triple the amount of superphosphate (2.53 g). For meat and bone meal, the acidified powder led to the highest plant growth (2.0 g), while untreated powder resulted in the lowest amount of plant growth (0.4 g), which was lower than that of the negative control (0.6 g). No significant differences were noted between untreated and acidified pellets. These findings indicate that acidification enhances phosphorus availability in biowastes, while pelletizing reduces it. The acidified pelletized digestate solid fraction has lower volume and higher P use efficiency than its untreated material, showing higher plant growth when compared to mineral P fertilizer.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 4","pages":"Article 100111"},"PeriodicalIF":0.0,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isothermal pyrolysis of discarded bakelite: Kinetics analysis and batch pyrolysis studies","authors":"Pabitra Mohan Mahapatra ,&nbsp;Dipransu Pradhan ,&nbsp;Sachin Kumar ,&nbsp;Achyut Kumar Panda","doi":"10.1016/j.cec.2024.100102","DOIUrl":"10.1016/j.cec.2024.100102","url":null,"abstract":"<div><p>Plastic is widely used, leading to an increase in plastic waste in the environment and resulting in pollution. Plastic waste can currently be managed differently and reduced by converting it into useful products via different methods. The extensive use of thermosetting polymers such as bakelite, which are nonrecyclable, has led to an increase in bakelite scrap and pollution. Therefore, minimizing pollution due to such waste requires sustainable, modern, eco-friendly, and economical recycling technology and the upgrading of existing recycling technology. This work reports the recycling of discarded bakelite through pyrolysis and a kinetic study of the isothermal pyrolysis of bakelite via model fitting methods as well as product analyses. Therefore, isothermal degradation experiments for discarded bakelite were carried out at different temperatures (300, 350, 400, 450, and 500 °C) for 2 h. The isothermal degradation of bakelite follows the D₁-diffusion model fitting method, with an activation energy (<em>E</em>_a) of 17.178 kJ/mol and an Arrhenius constant (<em>A</em>) of 0.095 min⁻¹. The kinetic information provided throughout the research will aid in the development of an appropriate reactor for the valorization of discarded bakelite. Batch pyrolysis of bakelite gives the highest yield of 39.12% pyrolytic waxy oil at 450 °C. The presence of components such as alkanes, cycloalkenes, alkenes, alcohols, ethers, and aromatic compounds in the pyrolytic waxy oil and residue was confirmed by FTIR and GC‒MS analysis.</p></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 3","pages":"Article 100102"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277316772400030X/pdfft?md5=d009b6c8867e002fea12c2bcaff8942c&pid=1-s2.0-S277316772400030X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizing the packaging waste generation patterns and carbon emissions of university delivery service","authors":"Huabo Duan ,&nbsp;Guanghan Song ,&nbsp;Qiuxia Zou ,&nbsp;Ruichang Mao ,&nbsp;Xiao Liu","doi":"10.1016/j.cec.2024.100103","DOIUrl":"10.1016/j.cec.2024.100103","url":null,"abstract":"<div><p>As the main consumer group for online shopping and ordering fast food, young people—particularly university students—have contributed to a substantial amount of packaging waste. In the present study, the material flow method was employed to quantify the generation and end-of-life flows of packaging waste from both the express delivery and food delivery sectors at universities in China. Moreover, this study takes reusable packaging materials for food delivery services as a case study to evaluate their environmental benefits through a simplified life cycle assessment approach. The results show that approximately 1.7 (±0.3) million metric tons and 123 (±1.0) kilo metric tons of packaging waste were generated from express delivery and food delivery services, respectively, for university students in 2021. Although reusable food packaging is more complex and costly than regular disposable food packaging is, our modeling results show that reusable food packaging has significant emission reduction benefits under the current practice of 63 cycles per year of actual operation at a specific university. The reusable packaging mode in universities is feasible from an environmental perspective; however, it faces significant challenges due to a few concerns among stakeholders, such as high costs and inadequate recycling supply systems.</p></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 3","pages":"Article 100103"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773167724000311/pdfft?md5=3f09542abe9827a809c321dd12300f3b&pid=1-s2.0-S2773167724000311-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D printing of alkali-activated geopolymers for sustainable and circular economy advancements","authors":"Arslan Yousaf,&nbsp;Ans Al Rashid,&nbsp;Muammer Koç","doi":"10.1016/j.cec.2024.100101","DOIUrl":"10.1016/j.cec.2024.100101","url":null,"abstract":"<div><p>The urgent global challenges of climate change and resource overconsumption highlight the need for sustainable innovations in the construction industry. Ordinary Portland cement, a vital construction material, significantly contributes to carbon emissions. Alkali-activated materials have emerged as promising alternatives. Three-dimensional printing (3DP) has gained attention in construction, because it offers efficiency and sustainability benefits. This study addresses the integration of alkali-activated materials and 3DP, focusing on circular economy implications. This study examines 1200 research articles from the Scopus database and comprehensively reviews 47 articles on 3DP of geopolymer structures. This study identifies critical research gaps, including a lack of focus on 3DP for alkali-activated materials, circular economy models, optimal mixtures, anisotropy mitigation, reinforcement strategies, and scalability. These insights highlight the transformative potential of 3DP with alkali-activated materials in sustainable construction, fostering a circular economy.</p></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 3","pages":"Article 100101"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773167724000293/pdfft?md5=9d3b343e2bfd0cdd2cc1fec51d483f3f&pid=1-s2.0-S2773167724000293-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Malachite green dye removal with aluminosilicate nanopowder from aluminum dross and silicomanganese slag","authors":"Mostafa Mahinroosta ,&nbsp;Rozita M Moattari ,&nbsp;Ali Allahverdi ,&nbsp;Pooria Ghadir","doi":"10.1016/j.cec.2024.100100","DOIUrl":"10.1016/j.cec.2024.100100","url":null,"abstract":"<div><p>Malachite green is a persistent, bioaccumulative, mutagenic, carcinogenic, and teratogenic dye that poses significant risks in water sources, making its removal from water a critical necessity. This study aims to fabricate a sorbent comprising amorphous aluminosilicate nanopowder utilizing silicomanganese slag (SMS) and secondary aluminum dross (SAD) waste materials to remediate dye-contaminated water. The silica and alumina components of the SMS and SAD were extracted as sodium silicate and sodium aluminate leachates, respectively, through an effective hydrometallurgical conversion process. An empirical formula of Al₂O₃·2.3SiO₂ was deduced from the X-ray fluorescence analysis of the synthesized material. The X-ray diffraction (XRD) pattern indicated the amorphous nature of the synthesized aluminosilicate, with no evidence of nanocrystals or ordered clusters observed via high-resolution transmission electron microscopy (TEM). Based on TEM micrographs, the aluminosilicate particles ranged in size from 20 to 80 nm. The synthesized aluminosilicate nanopowder was utilized to treat wastewater containing malachite green dye, demonstrating a remarkable dye removal efficiency of 97% after a 15-min contact time using 30 mg of adsorbent in a 30 mL dye solution at 200 rpm. The methodology proposed in this study could facilitate the production of amorphous aluminosilicate powder as a high-value product from industrial waste. Studies on its reusability demonstrated that it could remove over 90% of the dye after three cycles of use.</p></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 3","pages":"Article 100100"},"PeriodicalIF":0.0,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773167724000281/pdfft?md5=8d7c68ca5080d1a4a6f37f07c3eba6f3&pid=1-s2.0-S2773167724000281-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142087131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}