Circular Economy最新文献

{"title":"Unlocking the potential of rice straw: Sustainable utilization strategies for Bangladesh","authors":"Bidhan Nath ,&nbsp;Md Moudud Ahmmed ,&nbsp;Subrata Paul ,&nbsp;Md Durrul Huda ,&nbsp;Mohammad Afzal Hossain ,&nbsp;Sharmin Islam","doi":"10.1016/j.cec.2025.100126","DOIUrl":"10.1016/j.cec.2025.100126","url":null,"abstract":"<div><div>Bangladesh annually produces vast amounts of rice straw. However, they have low utilization efficiency, with a significant portion being wasted, and are usually openly burned (cooking food/heating) by farmers, lost during collection, and discarded or directly burned in the field. Straw holds immense potential for conversion into valuable products beyond its raw form. In the 2021–2022 season alone, Bangladesh produced 52.25 million tons of rice straw, with an energy potential of 189.52 × 10⁹ MJ. This study provided tangible information on various aspects of rice straw, including its availability, distribution, energy potential, common uses, and causes and impact as waste. Moreover, it is a comparative analysis of traditional uses alongside recent innovation utilization of straw. Suggested management options incorporating multifaceted conversion strategies are explored to encourage alternative utilization, which requires policies and diverse initiatives with financial support. Innovative approaches, such as the conversion of straw to renewable energy, along with alternative application strategies, are highlighted as promising technologies that can enhance flexibility and efficiency in utilization. Moreover, a comparative analysis has been carried out on traditional straw uses alongside recent innovations in its utilization, such as biogas production, biofuel generation, biochar creation, and composting, alongside value-added applications such as papermaking and industrial materials. A strategic approach to overcoming challenges and leveraging opportunities in rice straw utilization through technological advancements is proposed, aiming for sustainable and environmentally friendly practices. The current study emphasizes the importance of further research, particularly in the exploration of industrial and commercial applications of rice straw, to maximize its potential as a valuable agricultural residue.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"4 1","pages":"Article 100126"},"PeriodicalIF":0.0,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349605","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":"Hybrid kinetic analysis of FR-2 and FR-4 type printed circuit boards: A thermogravimetric analysis","authors":"Anuj Thukral ,&nbsp;Adhithiya Venkatachalapati Thulasiraman ,&nbsp;Arun K. Vuppaladadiyam ,&nbsp;Savan Kumar Patel ,&nbsp;Manoj Kumar Jena ,&nbsp;Kalpit Shah ,&nbsp;Neha Gupta ,&nbsp;Rahul Saha ,&nbsp;Anuushka Pal ,&nbsp;Parveen Saini","doi":"10.1016/j.cec.2024.100125","DOIUrl":"10.1016/j.cec.2024.100125","url":null,"abstract":"<div><div>This study investigated the non-isothermal (5, 10, and 20 °C/min) pyrolysis of non-metallic fractions (NMFs) of the FR-2 (phenolic resin reinforced with laminated paper) and FR-4 (epoxy resin reinforced with glass fiber) type waste printed circuit boards (WPCBs), under an inert atmosphere of flowing nitrogen gas. Three iso-conversional kinetic models (Friedman, Flyn-Wall–Ozawa (FWO), and Kissinger–Akahira–Sunose (KAS) approaches) were employed to understand the kinetics of the pyrolysis process. Thermogravimetric-differential thermogravimetric (TG-DTG) analysis revealed that FR-4 NMFs displayed a shift in mass loss above 287 °C at a heating rate of 10 °C/min and reached 95% conversion at 515 °C. In the case of the FR-2 NMFs, two distinct devolatilization zones were observed between 250–330 °C and 330–530 °C. The kinetic investigation revealed mean activation energy values of 264.38 kJ/mol for FR-2 and 221.99 kJ/mol for FR-4. The pyrolysis reaction mechanism for FR-2 NMFs displayed a decreasing trend for conversion (<em>α</em>), which was indicative of the simplified third-order model (F3) until <em>α</em> = 0.5 and shifted to second-order diffusion (D2) in the later part of the conversion. For FR-4 NMFs, the reaction function <em>f</em>(<em>α</em>) is between random nucleation with three nuclei on the individual particle (F3) and random nucleation with one nucleus on the individual particle (F1) over the selected range of conversion. For the FR-2 and FR-4 NMFs, the average Δ<em>H</em> values were 259.30 and 217.00 kJ/mol<em>,</em> and Δ<em>G</em> values were 161.03 and 176.92 kJ/mol, respectively.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"4 1","pages":"Article 100125"},"PeriodicalIF":0.0,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139078","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":"Microalgae as potential agents for biochar production: Future of industrial wastewater treatment","authors":"Sayantani Ghosh ,&nbsp;Sulagna Das ,&nbsp;Avirup Panja ,&nbsp;Alexei Solovchenko ,&nbsp;Priyanka Jha","doi":"10.1016/j.cec.2024.100117","DOIUrl":"10.1016/j.cec.2024.100117","url":null,"abstract":"<div><div>Diverse industries like breweries, textiles, paper &amp; pulp, mining, chemical &amp; nuclear, and food processing generate huge amounts of wastewater which can be toxic. This wastewater, rich in both organic compounds and inorganic salts, suspended solids, heavy metal ions and other pollutants should be properly treated before discharging into the environment. Recent studies demonstrated the efficiency of microalgae-based treatment. Microalgae are efficient in this regard since they produce photogenerated oxygen oxidizing the pollutants and toxin degrading enzymes, readily consume organics, and uptake/adsorb other pollutants. The current bottlenecks for microalgal bioremediation are high costs and low energy efficiency. The resulting biomass can be utilized for producing various forms of bioenergy via assorted traditional as well as modern techniques such as hydrothermal carbonization, pyrolysis, and torrefaction. One of the valuable outputs of these processes is biochar which is rich in nutrients and is capable of ion exchange. Therefore, it finds potential application in agriculture e.g., for revamping soil fertility and in wastewater treatment as adsorbent removing organic and inorganic pollutants. Here, we review novel processes designed for microalgae-based wastewater treatment with an emphasis on biochar production and utilization. Special attention is paid to the characterization of the physicochemical properties of biochar to maximize its targeted applications.</div></div>","PeriodicalId":100245,"journal":{"name":"Circular Economy","volume":"3 4","pages":"Article 100117"},"PeriodicalIF":0.0,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706100","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":"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}