Pub Date : 2025-02-07DOI: 10.1016/j.wasman.2025.02.002
Jun Ma , Ming Ma , Jiangshan Li , Qirui Yang , Yong Wan , Kai Zhao , Yi Zhang , Lei Liu , Xunchang Fei
Microplastics (MPs), an emerging pollutant, have garnered global attention as significant environmental concerns. Landfills are the major sources of MPs. However, research on the distribution and characteristics of MPs in leachate and underneath soil of informal landfills remains limited. This study investigated the abundance, polymer type, size, and morphology of MPs in 6 leachate samples and 18 underneath soil samples at different depths from two informal landfills. The ranges of MPs abundance in leachate and underneath soil from landfills were 4,010–33,213 items/Land 592–870 to 47,819 items/kg, related to the landfilled waste composition. MPs size between 20 and 100 µm accounted for the highest proportion (70 %). The fragmentation coefficient α in the underneath soil was higher than that in the leachate, indicating smaller MPs were more likely to migrate into underneath soil after filtration. The fibrous MPs proportion was below 22 %, while the fragmented MPs was more than 78 %. Large fibrous MPs were detected in the underneath soil in landfill A. Polyethylene Terephthalate (PET), Polyurethane (PU) and Polystyrene (PS) were the predominant MPs polymers types in leachate and underneath soil. Polypropylene (PP) was primarily concentrated in the upper and middle underneath soil layers, and Polyurethane (PU) was predominantly in the middle and lower layers. Principal component analysis (PCA) results indicated that geographical factors significantly influenced the distribution and characteristics of MPs. This study revealed the distribution of MPs in leachate and underneath soil at different depths, providing a valuable reference for the risk assessment of MPs pollution.
{"title":"Distribution and characteristics of Microplastics in leachate and underneath soil of two informal landfills","authors":"Jun Ma , Ming Ma , Jiangshan Li , Qirui Yang , Yong Wan , Kai Zhao , Yi Zhang , Lei Liu , Xunchang Fei","doi":"10.1016/j.wasman.2025.02.002","DOIUrl":"10.1016/j.wasman.2025.02.002","url":null,"abstract":"<div><div>Microplastics (MPs), an emerging pollutant, have garnered global attention as significant environmental concerns. Landfills are the major sources of MPs. However, research on the distribution and characteristics of MPs in leachate and underneath soil of informal landfills remains limited. This study investigated the abundance, polymer type, size, and morphology of MPs in 6 leachate samples and 18 underneath soil samples at different depths from two informal landfills. The ranges of MPs abundance in leachate and underneath soil from landfills were 4,010–33,213 items/Land 592–870 to 47,819 items/kg, related to the landfilled waste composition. MPs size between 20 and 100 µm accounted for the highest proportion (70 %). The fragmentation coefficient α in the underneath soil was higher than that in the leachate, indicating smaller MPs were more likely to migrate into underneath soil after filtration. The fibrous MPs proportion was below 22 %, while the fragmented MPs was more than 78 %. Large fibrous MPs were detected in the underneath soil in landfill A. Polyethylene Terephthalate (PET), Polyurethane (PU) and Polystyrene (PS) were the predominant MPs polymers types in leachate and underneath soil. Polypropylene (PP) was primarily concentrated in the upper and middle underneath soil layers, and Polyurethane (PU) was predominantly in the middle and lower layers. Principal component analysis (PCA) results indicated that geographical factors significantly influenced the distribution and characteristics of MPs. This study revealed the distribution of MPs in leachate and underneath soil at different depths, providing a valuable reference for the risk assessment of MPs pollution.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"195 ","pages":"Pages 155-166"},"PeriodicalIF":7.1,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143337955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.wasman.2025.02.001
Shanshan E. , Boyang Xu , Bo Niu , Zhenming Xu
Spent disposable Zn-Mn and Zn-C batteries are important resources for recycling. Acid leaching is the crucial step in the hydrometallurgy process for recycling Zn and Mn from these spent Zn-based batteries. However, to obtain the optimal leaching efficiency, the uncontrollable components in waste feed and various leaching parameters cause numerous replicated optimal experiments, increasing the recovery cost and environmental risks. To solve the issues, we employed machine learning (ML) techniques to construct models to predict Zn and Mn leaching from spent disposable batteries without optimizing experiments. Among four ML algorithms tested, the extreme gradient boosting demonstrated superior predictive performance, achieving an R2 of 0.85–0.98 across the training, test, and verification datasets. An analysis of feature importance indicated that the particle size, waste composition, acid concentration, temperature, and time affected the metal leaching most. This study also revealed the interaction effects of the waste properties and leaching process on the metal leaching. Furthermore, we created a user-friendly graphical user interface (GUI) that enables quick acquisition of metal leaching results, requiring only the measurement of waste particle size and component. Finally, experimental verification confirmed the practicability of the GUI. This study achieves intelligent metal leaching from spent batteries and overcomes the high recovery cost and environmental risks associated with traditional experimental optimizing methods.
{"title":"Intelligent leaching of Zn and Mn from spent disposable batteries to avoid traditional optimizing experiments","authors":"Shanshan E. , Boyang Xu , Bo Niu , Zhenming Xu","doi":"10.1016/j.wasman.2025.02.001","DOIUrl":"10.1016/j.wasman.2025.02.001","url":null,"abstract":"<div><div>Spent disposable Zn-Mn and Zn-C batteries are important resources for recycling. Acid leaching is the crucial step in the hydrometallurgy process for recycling Zn and Mn from these spent Zn-based batteries. However, to obtain the optimal leaching efficiency, the uncontrollable components in waste feed and various leaching parameters cause numerous replicated optimal experiments, increasing the recovery cost and environmental risks. To solve the issues, we employed machine learning (ML) techniques to construct models to predict Zn and Mn leaching from spent disposable batteries without optimizing experiments. Among four ML algorithms tested, the extreme gradient boosting demonstrated superior predictive performance, achieving an R<sup>2</sup> of 0.85–0.98 across the training, test, and verification datasets. An analysis of feature importance indicated that the particle size, waste composition, acid concentration, temperature, and time affected the metal leaching most. This study also revealed the interaction effects of the waste properties and leaching process on the metal leaching. Furthermore, we created a user-friendly graphical user interface (GUI) that enables quick acquisition of metal leaching results, requiring only the measurement of waste particle size and component. Finally, experimental verification confirmed the practicability of the GUI. This study achieves intelligent metal leaching from spent batteries and overcomes the high recovery cost and environmental risks associated with traditional experimental optimizing methods.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"195 ","pages":"Pages 145-154"},"PeriodicalIF":7.1,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143337954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1016/j.wasman.2025.01.032
Jacopo De Tommaso , Federico Galli , Tien Dat Nguyen , Yanfa Zhuang , Jean-Luc Dubois , Gregory S. Patience
Artificial marble, a composite material consisting of 40 % (g g−1) Poly Methyl Methacrylate (PMMA) and 60 % (g g−1) aluminium hydroxide , combines the durability and aesthetics of real marble with the lightweight and moldability of plastic. It is the most sought-after synthetic stone in the world, with a production volume of over 1 million t in 2021. However, due to a high level of cross-linking, mechanical recycling of the composite is impossible, while chemical recycling is achievable, yet unprofitable. The only economically viable recycling solution is to retain the value of both the organic and inorganic fraction of the composite. We investigated the pyrolysis and hydrolysis of post-consumer end-of-life artificial marble to identify possible valorization routes, examining the effects of temperature, water content, catalyst presence, and heating style. Temperature directly accelerates thermolysis, and indirectly hydrolysis. The water inherently present in drives initial hydrolysis, and temperature expedites inorganic fraction dehydration, increasing local water partial pressure near polymer ester sites. Above 350 °C, PMMAeq depolymerizes faster than it hydrolyzes, balancing the effects of temperature on water dehydration with the depletion of available ester sites for hydrolysis. Contrary to intuition, PMMA does not depolymerize to its monomer MMA and then hydrolyze its acid (methacrylic acid); instead, PMMA partially hydrolyzes to poly methacrylic acid (PMAA) while also depolymerizing to MMA. PMAA then dehydrates and degrades, releasing CO and CO2. The optimal method involves a heating ramp that first releases water at 300 °C, minimizing hydrolysis, and then favors MMA production at 400 °C, achieving a 66 % (g g−1) MMA yield. Regardless of the operative conditions, the inorganic fraction transforms from to a -alumina precursor, boehmite. Additionally, the remaining polymer in the residue, about 9 % (g g−1), has the required heat capacity for an energy-self sufficient calcination to -alumina. This dual-phase process not only maximizes MMA recovery but also retains the value of the inorganic fraction, providing a sustainable and economically viable recycling method for artificial marble.
{"title":"Waste artificial marble pyrolysis and hydrolysis","authors":"Jacopo De Tommaso , Federico Galli , Tien Dat Nguyen , Yanfa Zhuang , Jean-Luc Dubois , Gregory S. Patience","doi":"10.1016/j.wasman.2025.01.032","DOIUrl":"10.1016/j.wasman.2025.01.032","url":null,"abstract":"<div><div>Artificial marble, a composite material consisting of 40 % (g g<sup>−1</sup>) Poly Methyl Methacrylate (PMMA) and 60 % (g g<sup>−1</sup>) aluminium hydroxide <span><math><mrow><mtext>Al(OH)3</mtext></mrow></math></span>, combines the durability and aesthetics of real marble with the lightweight and moldability of plastic. It is the most sought-after synthetic stone in the world, with a production volume of over 1 million t in 2021. However, due to a high level of cross-linking, mechanical recycling of the composite is impossible, while chemical recycling is achievable, yet unprofitable. The only economically viable recycling solution is to retain the value of both the organic and inorganic fraction of the composite. We investigated the pyrolysis and hydrolysis of post-consumer end-of-life artificial marble to identify possible valorization routes, examining the effects of temperature, water content, catalyst presence, and heating style. Temperature directly accelerates thermolysis, and indirectly hydrolysis. The water inherently present in <span><math><mrow><mtext>Al(OH)3</mtext></mrow></math></span> drives initial hydrolysis, and temperature expedites inorganic fraction dehydration, increasing local water partial pressure near polymer ester sites. Above 350<!--> <!-->°C, PMMAeq depolymerizes faster than it hydrolyzes, balancing the effects of temperature on water dehydration with the depletion of available ester sites for hydrolysis. Contrary to intuition, PMMA does not depolymerize to its monomer MMA and then hydrolyze its acid (methacrylic acid); instead, PMMA partially hydrolyzes to poly methacrylic acid (PMAA) while also depolymerizing to MMA. PMAA then dehydrates and degrades, releasing CO and CO<sub>2</sub>. The optimal method involves a heating ramp that first releases water at 300<!--> <!-->°C, minimizing hydrolysis, and then favors MMA production at 400<!--> <!-->°C, achieving a 66 % (g g<sup>−1</sup>) MMA yield. Regardless of the operative conditions, the inorganic fraction transforms from <span><math><mrow><mtext>Al(OH)3</mtext></mrow></math></span> to a <span><math><mi>γ</mi></math></span>-alumina precursor, boehmite. Additionally, the remaining polymer in the residue, about 9 % (g g<sup>−1</sup>), has the required heat capacity for an energy-self sufficient calcination to <span><math><mi>γ</mi></math></span>-alumina. This dual-phase process not only maximizes MMA recovery but also retains the value of the inorganic fraction, providing a sustainable and economically viable recycling method for artificial marble.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"195 ","pages":"Pages 129-144"},"PeriodicalIF":7.1,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143337953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1016/j.wasman.2025.01.039
Binaya Sapkota, Agamutu Pariatamby
Although healthcare waste management (HCWM) legislations prevail in Association of Southeast Asian Nations (ASEAN), there appears a prominent gap in standalone pharmaceutical waste management (PWM) legislation making harmonization of PWM challenging in the region. This review is aimed to comprehensively overview the PWM-related legislations in ASEAN, comprising of 10 economically rising countries in Southeast Asia. The relevant regulatory documents, that were promulgated till August 31, 2024 and that were in English or officially translated in English, were extracted from PubMed/Medline, Scopus, Science Direct, Google Scholar, and respective country’s government websites. The documents were considered suitable based on their relevance, accessibility, and timeliness. The policy analysis revealed that all Member States in ASEAN lack specific legislations on PWM, and are managing pharmaceutical waste (PW) within the umbrella legislation of HCWM or biomedical waste management. The review discussed implications of joint ASEAN legislations, relevant guiding principles of waste management, and international guidelines relevant to PWM such as Basel Convention, Stockholm Convention, and the status of their endorsement in ASEAN. Some ASEAN countries such as Indonesia, Malaysia, Philippines, Singapore, Thailand and Vietnam have established infrastructures and regulatory setup for HCWM but still lack specific PWM legislations. ASEAN can foster harmonized legislative frameworks, facilities and technologies in PWM, raising public awareness and active participation to mitigate PW problem. The hard laws such as Acts, regulations, and ordinances are definitely aimed for PWM in ASEAN, but at least harmonized soft laws in the form of guidelines are imperative to harmonize PWM practice.
{"title":"Pharmaceutical waste management legislations: Where do ASEAN countries stand in harmonization? A review of regulatory documents","authors":"Binaya Sapkota, Agamutu Pariatamby","doi":"10.1016/j.wasman.2025.01.039","DOIUrl":"10.1016/j.wasman.2025.01.039","url":null,"abstract":"<div><div>Although healthcare waste management (HCWM) legislations prevail in Association of Southeast Asian Nations (ASEAN), there appears a prominent gap in standalone pharmaceutical waste management (PWM) legislation making harmonization of PWM challenging in the region. This review is aimed to comprehensively overview the PWM-related legislations in ASEAN, comprising of 10 economically rising countries in Southeast Asia. The relevant regulatory documents, that were promulgated till August 31, 2024 and that were in English or officially translated in English, were extracted from PubMed/Medline, Scopus, Science Direct, Google Scholar, and respective country’s government websites. The documents were considered suitable based on their relevance, accessibility, and timeliness. The policy analysis revealed that all Member States in ASEAN lack specific legislations on PWM, and are managing pharmaceutical waste (PW) within the umbrella legislation of HCWM or biomedical waste management. The review discussed implications of joint ASEAN legislations, relevant guiding principles of waste management, and international guidelines relevant to PWM such as Basel Convention, Stockholm Convention, and the status of their endorsement in ASEAN. Some ASEAN countries such as Indonesia, Malaysia, Philippines, Singapore, Thailand and Vietnam have established infrastructures and regulatory setup for HCWM but still lack specific PWM legislations. ASEAN can foster harmonized legislative frameworks, facilities and technologies in PWM, raising public awareness and active participation to mitigate PW problem. The hard laws such as Acts, regulations, and ordinances are definitely aimed for PWM in ASEAN, but at least harmonized soft laws in the form of guidelines are imperative to harmonize PWM practice.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"195 ","pages":""},"PeriodicalIF":7.1,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1016/j.wasman.2025.01.026
Hongyong Fan , Olusegun K. Abass , Chaoxiang Liu , Chenghao Li , Yingjie Sun , Huawei Wang , Wushan Chen
Regulation of labile fraction of excreted manure represents a promising advance for environmental pollution mitigation. However, investigation of the properties of various pollutant fractions within manure and potential influence of dietary nutrient fractions on the release of labile manure remains unclear. Feeding trials involving pigs at three distinct growth stages fed by diets with nine different energy levels were conducted and the characteristics of labile manure generated under various treatments based on nutrient profiles were analyzed. The impact of dietary nutrient fractions on variables such as labile manure pollutants, pig performance, manure weight and dominant microorganisms were evaluated via theoretical modeling and correlation analysis. The results indicated that critical dietary nutrient factors such as dietary C fraction, protein N-materials and dietary P fraction varied respectively with pig growth stages. The labile manure composition and proportion were influenced by dietary C/N/P fractions and indigestible components, through regulation of the structure of the gut microbiota and the relative abundance of gut microbes. This study finds that initiating dietary regulatory measures could effectively control the release of labile manure and reduce its proportion in the overall manure and thus, provides a novel approach to achieve manure source pollution control, ensure environmental-friendly diet formula and mitigate manure-related environmental pollution.
{"title":"Impact of C/N/P dietary nutrient on manure characteristics: Pollutant fractions and microbial community","authors":"Hongyong Fan , Olusegun K. Abass , Chaoxiang Liu , Chenghao Li , Yingjie Sun , Huawei Wang , Wushan Chen","doi":"10.1016/j.wasman.2025.01.026","DOIUrl":"10.1016/j.wasman.2025.01.026","url":null,"abstract":"<div><div>Regulation of labile fraction of excreted manure represents a promising advance for environmental pollution mitigation. However, investigation of the properties of various pollutant fractions within manure and potential influence of dietary nutrient fractions on the release of labile manure remains unclear. Feeding trials involving pigs at three distinct growth stages fed by diets with nine different energy levels were conducted and the characteristics of labile manure generated under various treatments based on nutrient profiles were analyzed. The impact of dietary nutrient fractions on variables such as labile manure pollutants, pig performance, manure weight and dominant microorganisms were evaluated via theoretical modeling and correlation analysis. The results indicated that critical dietary nutrient factors such as dietary C fraction, protein N-materials and dietary P fraction varied respectively with pig growth stages. The labile manure composition and proportion were influenced by dietary C/N/P fractions and indigestible components, through regulation of the structure of the gut microbiota and the relative abundance of gut microbes. This study finds that initiating dietary regulatory measures could effectively control the release of labile manure and reduce its proportion in the overall manure and thus, provides a novel approach to achieve manure source pollution control, ensure environmental-friendly diet formula and mitigate manure-related environmental pollution.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"194 ","pages":"Pages 401-413"},"PeriodicalIF":7.1,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-03DOI: 10.1016/j.wasman.2025.01.041
Mrunal S. Bokade, Surender Singh, Devendra Narain Singh
We read with great interest the paper by Xie et al. (2024) that describes the methodology for recycling and reusing microplastics, MPs, by utilizing it into the geopolymer, GP, matrix made from fly ash, FA, and ground granulated blast furnace slag, GGBFS. The GP was created by activating the FA and GGBFS (7:3 ratio) using 16 M NaOH. Herein the MPs of various sizes (viz. 50, 150, and 500 µm) and varying percentages (viz. 2.5, 5, 7.5, and 10) were encapsulated in the GP matrix and further, they were cured at 40 and 80 ˚C for 24 h and later at ambient temperatures. Several experiments were performed to investigate the physical (viz. bulk density, fluidity, thermal resistance), mechanical (viz. compressive strength, flexural strength), mineralogical, and microstructural properties of synthesized GP. Furthermore, these samples were exposed to elevated temperatures viz. 200, 400, and 600 ˚C to investigate the effect of MPs on the thermal resistance of GP matrix. Although, Xie et al. (2024) have presented some intriguing findings, however there are serious issues concerning the proposed ideology and subsequently, its justification, which the authors would like to highlight through this discussion.
{"title":"Discussion on “Potential improvement in the mechanical performance and thermal resistance of geopolymer with appropriate microplastic incorporation: A sustainable solution for recycling and reusing microplastics”","authors":"Mrunal S. Bokade, Surender Singh, Devendra Narain Singh","doi":"10.1016/j.wasman.2025.01.041","DOIUrl":"10.1016/j.wasman.2025.01.041","url":null,"abstract":"<div><div>We read with great interest the paper by <span><span>Xie et al. (2024)</span></span> that describes the methodology for recycling and reusing microplastics, <em>MP</em>s, by utilizing it into the geopolymer, <em>GP</em>, matrix made from fly ash, <em>FA</em>, and ground granulated blast furnace slag, <em>GGBFS</em>. The <em>GP</em> was created by activating the <em>FA</em> and <em>GGBFS</em> (7:3 ratio) using 16 M NaOH. Herein the <em>MPs</em> of various sizes (viz. 50, 150, and 500 µm) and varying percentages (viz. 2.5, 5, 7.5, and 10) were encapsulated in the <em>GP</em> matrix and further, they were cured at 40 and 80 <sup>˚</sup>C for 24 h and later at ambient temperatures. Several experiments were performed to investigate the physical (viz. bulk density, fluidity, thermal resistance), mechanical (viz. compressive strength, flexural strength), mineralogical, and microstructural properties of synthesized <em>GP</em>. Furthermore, these samples were exposed to elevated temperatures viz. 200, 400, and 600 <sup>˚</sup>C to investigate the effect of <em>MP</em>s on the thermal resistance of <em>GP</em> matrix. Although, <span><span>Xie et al. (2024)</span></span> have presented some intriguing findings, however there are serious issues concerning the proposed ideology and subsequently, its justification, which the authors would like to highlight through this discussion.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"195 ","pages":"Pages 104-106"},"PeriodicalIF":7.1,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-02DOI: 10.1016/j.wasman.2025.01.038
Chengjie Xue , Yifu Peng , Zhanqiang Fang , Peichun Lu , Junyao Yang
Biomass has been utilized in the carbothermal reduction method to reduce iron cations, thereby synthesizing nano zero-valent iron (nZVI). The effect of the biomass components on the regulation of the performance of prepared nZVI is not clear and the mechanism of action remains to be explored. Biomass components such as cellulose, hemicellulose, lignin, and amylum were used to prepare carbon-loaded nano zero-valent iron. It was demonstrated that increasing the cellulose content of the mixture led to higher Fe0 content by 2–6 times and a greater activation efficiency of peroxydisulfate (PDS) by 2–5 times. nZVI prepared by carbothermal reduction using bagasse (Fe0/CB) removed 99.8 % of metronidazole in 60 min. The bagasse’s cellulose content was found to be 59.5 % and the results demonstrated that the composites prepared with the cellulose content exceeded 60 % had unusual properties. The pyrolysis process of the mixtures showed that cellulose promotes the production of nZVI by generating more reducing gases (e.g. CO, CH4). Furthermore, the efficiency of activated PDS in removing metronidazole was confirmed, with cellulose-prepared nZVI (c-Fe0/C) proving to be the most effective activator. Its removal rate was 1.3 times higher than that of Fe0/CB. Physical characterization and mechanistic investigations demonstrated that c-Fe0/C has the same active sites as Fe0/CB and produces the same type and amount of reactive oxygen species. These demonstrates that cellulose is a critical component in the preparation of nZVI during carbothermal reduction. This study provides guidelines for preparing carbothermal reduced nZVI and establishes a theoretical basis for its engineering application.
{"title":"Performance of nano zero-valent iron activated peroxydisulfates prepared by carbothermal reduction using various bagasse components","authors":"Chengjie Xue , Yifu Peng , Zhanqiang Fang , Peichun Lu , Junyao Yang","doi":"10.1016/j.wasman.2025.01.038","DOIUrl":"10.1016/j.wasman.2025.01.038","url":null,"abstract":"<div><div>Biomass has been utilized in the carbothermal reduction method to reduce iron cations, thereby synthesizing nano zero-valent iron (nZVI). The effect of the biomass components on the regulation of the performance of prepared nZVI is not clear and the mechanism of action remains to be explored. Biomass components such as cellulose, hemicellulose, lignin, and amylum were used to prepare carbon-loaded nano zero-valent iron. It was demonstrated that increasing the cellulose content of the mixture led to higher Fe<sup>0</sup> content by 2–6 times and a greater activation efficiency of peroxydisulfate (PDS) by 2–5 times. nZVI prepared by carbothermal reduction using bagasse (Fe<sup>0</sup>/CB) removed 99.8 % of metronidazole in 60 min. The bagasse’s cellulose content was found to be 59.5 % and the results demonstrated that the composites prepared with the cellulose content exceeded 60 % had unusual properties. The pyrolysis process of the mixtures showed that cellulose promotes the production of nZVI by generating more reducing gases (e.g. CO, CH<sub>4</sub>). Furthermore, the efficiency of activated PDS in removing metronidazole was confirmed, with cellulose-prepared nZVI (c-Fe<sup>0</sup>/C) proving to be the most effective activator. Its removal rate was 1.3 times higher than that of Fe<sup>0</sup>/CB. Physical characterization and mechanistic investigations demonstrated that c-Fe<sup>0</sup>/C has the same active sites as Fe<sup>0</sup>/CB and produces the same type and amount of reactive oxygen species. These demonstrates that cellulose is a critical component in the preparation of nZVI during carbothermal reduction. This study provides guidelines for preparing carbothermal reduced nZVI and establishes a theoretical basis for its engineering application.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"195 ","pages":"Pages 92-103"},"PeriodicalIF":7.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143123775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.wasman.2024.11.039
Ana García-Rández , Luciano Orden , Evan A.N. Marks , Javier Andreu-Rodríguez , Samuel Franco-Luesma , Encarnación Martínez-Sabater , José Antonio Saéz-Tovar , María Dolores Pérez-Murcia , Enrique Agulló , María Ángeles Bustamante , Maite Cháfer , Raúl Moral
Olive mill wastes (OMW) management by composting allows to obtain valuable fertilizing products, but also implies significant fluxes of greenhouse gases (GHG). For a proper OMW composting, high C- and N co-substrates are necessary, but little is known concerning their effect on GHG emissions in OMW-industrial scale composting. In this study, different co-composting agents (cattle manure (CM), poultry manure (PM), sheep manure (SM) and pig slurry solid fraction (PSSF) as N sources and olive leaves (OLW) and urban pruning residues (UPR) as bulking agents and C sources) were used for OMW composting at industrial scale. Physico-chemical and chemical properties in the composting samples, and GHG (CO2, CH4 and N2O) fluxes were monitored in 12 industrial-scale windrows. GHG emissions were firstly influenced by N source, with the highest accumulated global warming potential (GWP) associated with PM (512 kg CO2eq pile-1), since PM composts were associated with the greatest N2O (0.33 kg pile-1) and CH4 emissions (15.67 kg pile-1). Meanwhile, PSSF was associated with the highest CO2 emissions (1113 kg pile-1). UPR as a bulking agent facilitated 10 % greater mineralization of the biomass than OLW, however this C-source was not associated with higher GHG emissions. The results showed that while mineralization dynamics may be impacted by C sources, GHG emissions were mainly conditioned by the characteristics of nutrient-heavy feedstocks (PM and SM). Moreover, manures as nitrogen-laden co-substrates had widely differing effects on total GWP, and that of individual gases, but further research is necessary to understand the mechanisms explaining such differences.
通过堆肥管理橄榄厂废物（OMW）可以获得有价值的肥料产品，但也意味着大量的温室气体（GHG）通量。高碳、高氮共基质对于合理的OMW堆肥是必要的，但它们对OMW工业规模堆肥中温室气体排放的影响知之甚少。本研究采用牛粪（CM）、禽粪（PM）、羊粪（SM）和猪浆固体组分（PSSF）作为N源，橄榄叶（OLW）和城市修剪残渣（UPR）作为膨化剂和C源，在工业规模上进行了OMW堆肥。在12个工业尺度窗口中监测了堆肥样品的物理化学和化学性质以及温室气体（CO2， CH4和N2O）通量。温室气体排放首先受到N源的影响，累积全球变暖潜势（GWP）与PM相关（512 kg CO2eq pile-1）最高，因为PM堆肥与最大的N2O （0.33 kg pile-1）和CH4 （15.67 kg pile-1）相关。同时，PSSF与最高的CO2排放量（1113 kg桩-1）相关。UPR作为膨胀剂比OLW促进了10%的生物质矿化，但这种碳源与更高的温室气体排放无关。结果表明，矿化动态受碳源影响，而温室气体排放主要受重养分原料（PM和SM）的影响。此外，作为含氮共基质的肥料对总GWP和单个气体的影响差异很大，但需要进一步研究以了解解释这种差异的机制。
{"title":"Monitoring of greenhouse gas emissions and compost quality during olive mill waste co-composting at industrial scale: The effect of N and C sources","authors":"Ana García-Rández , Luciano Orden , Evan A.N. Marks , Javier Andreu-Rodríguez , Samuel Franco-Luesma , Encarnación Martínez-Sabater , José Antonio Saéz-Tovar , María Dolores Pérez-Murcia , Enrique Agulló , María Ángeles Bustamante , Maite Cháfer , Raúl Moral","doi":"10.1016/j.wasman.2024.11.039","DOIUrl":"10.1016/j.wasman.2024.11.039","url":null,"abstract":"<div><div>Olive mill wastes (OMW) management by composting allows to obtain valuable fertilizing products, but also implies significant fluxes of greenhouse gases (GHG). For a proper OMW composting, high C- and N co-substrates are necessary, but little is known concerning their effect on GHG emissions in OMW-industrial scale composting. In this study, different co-composting agents (cattle manure (CM), poultry manure (PM), sheep manure (SM) and pig slurry solid fraction (PSSF) as N sources and olive leaves (OLW) and urban pruning residues (UPR) as bulking agents and C sources) were used for OMW composting at industrial scale. Physico-chemical and chemical properties in the composting samples, and GHG (CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O) fluxes were monitored in 12 industrial-scale windrows. GHG emissions were firstly influenced by N source, with the highest accumulated global warming potential (GWP) associated with PM (512 kg CO<sub>2</sub>eq pile<sup>-1</sup>), since PM composts were associated with the greatest N<sub>2</sub>O (0.33 kg pile<sup>-1</sup>) and CH<sub>4</sub> emissions (15.67 kg pile<sup>-1</sup>). Meanwhile, PSSF was associated with the highest CO<sub>2</sub> emissions (1113 kg pile<sup>-1</sup>). UPR as a bulking agent facilitated 10 % greater mineralization of the biomass than OLW, however this C-source was not associated with higher GHG emissions. The results showed that while mineralization dynamics may be impacted by C sources, GHG emissions were mainly conditioned by the characteristics of nutrient-heavy feedstocks (PM and SM). Moreover, manures as nitrogen-laden co-substrates had widely differing effects on total GWP, and that of individual gases, but further research is necessary to understand the mechanisms explaining such differences.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"193 ","pages":"Pages 33-43"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142787328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.wasman.2024.12.003
Stavros A. Theofanidis , Evangelos Delikonstantis , Vasileia-Loukia Yfanti , Vladimir V. Galvita , Angeliki A. Lemonidou , Kevin Van Geem
In contemporary times, global plastic waste production has doubled in comparison to two decades ago, with only 9% effectively recycled. The polymer industry is undergoing a transition to address the disparity between plastic production and end-of-life waste management. Chemical recycling offers a solution by converting plastic waste into its constituent building blocks, or monomers, which can be utilized in the production of new, high-quality plastics. This concise review provides an overview of conventional chemical recycling technologies employing heated reactors, before delving into ongoing efforts towards electrifying the chemical recycling process. A conceptual framework for a fully electrified value chain aimed at achieving plastics circularity is outlined and analyzed. Additionally, attention is given to the challenges posed by industry inertia towards adopting electrified technologies, as well as performance issues stemming from the intermittent nature of renewable energy sources and the availability of long-duration renewable electricity storage options.
{"title":"An electricity-powered future for mixed plastic waste chemical recycling","authors":"Stavros A. Theofanidis , Evangelos Delikonstantis , Vasileia-Loukia Yfanti , Vladimir V. Galvita , Angeliki A. Lemonidou , Kevin Van Geem","doi":"10.1016/j.wasman.2024.12.003","DOIUrl":"10.1016/j.wasman.2024.12.003","url":null,"abstract":"<div><div>In contemporary times, global plastic waste production has doubled in comparison to two decades ago, with only 9% effectively recycled. The polymer industry is undergoing a transition to address the disparity between plastic production and end-of-life waste management. Chemical recycling offers a solution by converting plastic waste into its constituent building blocks, or monomers, which can be utilized in the production of new, high-quality plastics. This concise review provides an overview of conventional chemical recycling technologies employing heated reactors, before delving into ongoing efforts towards electrifying the chemical recycling process. A conceptual framework for a fully electrified value chain aimed at achieving plastics circularity is outlined and analyzed. Additionally, attention is given to the challenges posed by industry inertia towards adopting electrified technologies, as well as performance issues stemming from the intermittent nature of renewable energy sources and the availability of long-duration renewable electricity storage options.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"193 ","pages":"Pages 155-170"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142814477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.wasman.2024.12.012
Maohui Wang , Zhanfu Yong
The world’s three leading tire manufacturers have proposed specific timelines for using recycled materials. For instance, Michelin targets an increase in the proportion of sustainable materials in tires to 40 % by 2030 and aims to produce 100 % of its tires from bio-based, renewable, or recyclable materials as of 2050. In such a context, this study introduced wet mixing technology to apply recycled rubber (RR) in highly wear-resistant tire tread compounds. This technique leverages the rubber’s inherent crosslink density to enhance the mechanical performance of final products. The results indicated that wet mixing effectively addressed the high viscosity issue of RR. In the traditional dry mixing method, physical blending typically results in large particle sizes and suboptimal performance. In contrast, wet mixing reduced the rubber’s hysteresis loss by 75 % and improved its rebound performance by 35.6 % at 23 °C, 60 °C, and 100 °C compared to traditional dry mixing. DIN volume abrasion was also reduced by 23.3 %. Remarkably, Akron abrasion nearly doubled its effect. Additionally, wet mixing regulated aggregate structure and formed a densely packed honeycomb-like structure within RR. Incorporating RR using wet mixing demonstrates noticeable advantages in carbon black/natural rubber/RR composite materials. This approach also presents a viable path to sustainable development in the rubber manufacturing industry.
{"title":"Enhancing the sustainability of rubber materials: Dual benefits of wet mixing technology and recycled rubber’s honeycomb reinforcement structure","authors":"Maohui Wang , Zhanfu Yong","doi":"10.1016/j.wasman.2024.12.012","DOIUrl":"10.1016/j.wasman.2024.12.012","url":null,"abstract":"<div><div>The world’s three leading tire manufacturers have proposed specific timelines for using recycled materials. For instance, Michelin targets an increase in the proportion of sustainable materials in tires to 40 % by 2030 and aims to produce 100 % of its tires from bio-based, renewable, or recyclable materials as of 2050. In such a context, this study introduced wet mixing technology to apply recycled rubber (RR) in highly wear-resistant tire tread compounds. This technique leverages the rubber’s inherent crosslink density to enhance the mechanical performance of final products. The results indicated that wet mixing effectively addressed the high viscosity issue of RR. In the traditional dry mixing method, physical blending typically results in large particle sizes and suboptimal performance. In contrast, wet mixing reduced the rubber’s hysteresis loss by 75 % and improved its rebound performance by 35.6 % at 23 °C, 60 °C, and 100 °C compared to traditional dry mixing. DIN volume abrasion was also reduced by 23.3 %. Remarkably, Akron abrasion nearly doubled its effect. Additionally, wet mixing regulated aggregate structure and formed a densely packed honeycomb-like structure within RR. Incorporating RR using wet mixing demonstrates noticeable advantages in carbon black/natural rubber/RR composite materials. This approach also presents a viable path to sustainable development in the rubber manufacturing industry.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"193 ","pages":"Pages 190-198"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142822215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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