Sophie Hai Yen Guillaume-Ruty, J. Pueyo-Ros, Joaquim Comas, N. Forquet
Treatment wetlands (TWs) effectively remove target pollutants and enhance urban water circularity and resilience. They constitute a prominent solution for urban wastewater treatment, thanks to their adaptability across various types of wastewater, scales and climatic conditions. However, the disparity in TW designs and the focus on a restricted set of variables applicable to research studies impede any comprehensive evaluation and comparison of TW performance. Our study introduces a methodology for data validation, in concurrently establishing a workflow specific to TW. This approach is aimed at defining the scope and relationships within the data, implementing checks and concatenating them into a quality flag, as an initial step towards building reliable statistical models. We underscore the importance of both mobilising comprehensive knowledge and identifying customary, yet implicit, choices intertwined in data processing. As for the application workflow, we collected and analysed data sourced from peer-reviewed papers on horizontal and vertical flow TW. Deficiencies were noted in key data elements like dimensions, concentrations and operational conditions. For the data analysis, relationships are highlighted between variables introduced for modelling purposes. These methodologies and workflows assess the quality of the data, in paving the way towards more dependable statistical models for TW design and implementation.
{"title":"A validation workflow for treatment wetland performance data","authors":"Sophie Hai Yen Guillaume-Ruty, J. Pueyo-Ros, Joaquim Comas, N. Forquet","doi":"10.2166/wst.2024.182","DOIUrl":"https://doi.org/10.2166/wst.2024.182","url":null,"abstract":"\u0000 \u0000 Treatment wetlands (TWs) effectively remove target pollutants and enhance urban water circularity and resilience. They constitute a prominent solution for urban wastewater treatment, thanks to their adaptability across various types of wastewater, scales and climatic conditions. However, the disparity in TW designs and the focus on a restricted set of variables applicable to research studies impede any comprehensive evaluation and comparison of TW performance. Our study introduces a methodology for data validation, in concurrently establishing a workflow specific to TW. This approach is aimed at defining the scope and relationships within the data, implementing checks and concatenating them into a quality flag, as an initial step towards building reliable statistical models. We underscore the importance of both mobilising comprehensive knowledge and identifying customary, yet implicit, choices intertwined in data processing. As for the application workflow, we collected and analysed data sourced from peer-reviewed papers on horizontal and vertical flow TW. Deficiencies were noted in key data elements like dimensions, concentrations and operational conditions. For the data analysis, relationships are highlighted between variables introduced for modelling purposes. These methodologies and workflows assess the quality of the data, in paving the way towards more dependable statistical models for TW design and implementation.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141381779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Urban drainage channels act as significant routers of microplastics (MPs) originating from terrestrial to aquatic systems. In the present study, contamination of MPs (250–5,000 μm size) has been investigated in an interlinked urban aquatic system comprising Najafgarh drain, corresponding secondary drains, and Yamuna River in Delhi, India. A range of 100–4,300 MPs/m3 (pre-monsoon) and 100–6,700 MPs/m3 (post-monsoon) were detected in secondary drains, which meet the Najafgarh drain through its course in the city. Najafgarh drain showed an average abundance of 771 and 342 MPs/m3 during pre- and post-monsoon season, respectively. The discharge of microplastic (MP)-laden wastewater from the Najafgarh drain into the Yamuna River created a rise in MP abundance in the river at the drain's downstream location. Thus, revealing that secondary drains play a significant role in MP channelization to the Najafgarh drain and subsequently Yamuna River. White fragments were the dominant MP types in the study area. Chemical characterization revealed 11 types of MP polymers, with a predominance of polyethylene. Considering the knowledge gap in the MP database of interconnected urban aquatic systems in India, this study might help in providing baseline information and encourage more studies addressing the magnitude of this problem for predicting long-term environmental risks.
{"title":"Urban drainage channels as a pathway for microplastics in riverine systems: A case study of Delhi, India","authors":"Mansi Vaid, K. Sarma, Anshu Gupta","doi":"10.2166/wst.2024.181","DOIUrl":"https://doi.org/10.2166/wst.2024.181","url":null,"abstract":"\u0000 \u0000 Urban drainage channels act as significant routers of microplastics (MPs) originating from terrestrial to aquatic systems. In the present study, contamination of MPs (250–5,000 μm size) has been investigated in an interlinked urban aquatic system comprising Najafgarh drain, corresponding secondary drains, and Yamuna River in Delhi, India. A range of 100–4,300 MPs/m3 (pre-monsoon) and 100–6,700 MPs/m3 (post-monsoon) were detected in secondary drains, which meet the Najafgarh drain through its course in the city. Najafgarh drain showed an average abundance of 771 and 342 MPs/m3 during pre- and post-monsoon season, respectively. The discharge of microplastic (MP)-laden wastewater from the Najafgarh drain into the Yamuna River created a rise in MP abundance in the river at the drain's downstream location. Thus, revealing that secondary drains play a significant role in MP channelization to the Najafgarh drain and subsequently Yamuna River. White fragments were the dominant MP types in the study area. Chemical characterization revealed 11 types of MP polymers, with a predominance of polyethylene. Considering the knowledge gap in the MP database of interconnected urban aquatic systems in India, this study might help in providing baseline information and encourage more studies addressing the magnitude of this problem for predicting long-term environmental risks.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"12 2‐3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141383539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The radiolytic degradation of 4-hydroxybenzoate (4-HBA–) in aerated, oxygen-free and N2O-saturated aqueous solutions at concentrations of 0.10 and 0.25 mmol/dm3 were gamma irradiated at different doses in a source of Co-60. The results show that ·OH adds predominantly to the third position of the aromatic ring, and elimination of the acid group leads to the degradation of 4-HBA–. With an N2O-saturated 0.10 mmol/dm3 4-HBA– solution, total degradation occurred at 1.6 kGy, and with a 0.25 mmol/dm3 solution, total degradation occurred at 3.5 kGy. In the aerated and oxygen-free 0.25 mmol/dm3 4-HBA– solutions, the behavior was similar, degradation occurring at a dose of 13.1 kGy. At the concentration of 0.10 mmol/dm3, total degradation occurred at 7.0 kGy, with small amounts of radiolytic products and byproducts. We propose a mechanism for the degradation of 4-HBA– caused by water radicals produced in the three environments, leading to formation of the identified stable products. Oxidation was followed by chemical oxygen demand (COD), which decreased as the 4-HBA− concentration increased. The kinetics showed a pseudo-first-order behavior. The rate constant of degradation was similar for the solutions with and without oxygen.
{"title":"Radiolytic degradation of 4-hydroxybenzoate in aerated and deoxygenated aqueous solutions","authors":"Guadalupe Albarrán, E. Mendoza","doi":"10.2166/wst.2024.167","DOIUrl":"https://doi.org/10.2166/wst.2024.167","url":null,"abstract":"\u0000 \u0000 The radiolytic degradation of 4-hydroxybenzoate (4-HBA–) in aerated, oxygen-free and N2O-saturated aqueous solutions at concentrations of 0.10 and 0.25 mmol/dm3 were gamma irradiated at different doses in a source of Co-60. The results show that ·OH adds predominantly to the third position of the aromatic ring, and elimination of the acid group leads to the degradation of 4-HBA–. With an N2O-saturated 0.10 mmol/dm3 4-HBA– solution, total degradation occurred at 1.6 kGy, and with a 0.25 mmol/dm3 solution, total degradation occurred at 3.5 kGy. In the aerated and oxygen-free 0.25 mmol/dm3 4-HBA– solutions, the behavior was similar, degradation occurring at a dose of 13.1 kGy. At the concentration of 0.10 mmol/dm3, total degradation occurred at 7.0 kGy, with small amounts of radiolytic products and byproducts. We propose a mechanism for the degradation of 4-HBA– caused by water radicals produced in the three environments, leading to formation of the identified stable products. Oxidation was followed by chemical oxygen demand (COD), which decreased as the 4-HBA− concentration increased. The kinetics showed a pseudo-first-order behavior. The rate constant of degradation was similar for the solutions with and without oxygen.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"69 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141101459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinyi Zhang, Wenhao Liu, Jiaxing Lu, Muhammad Tanveer, Zhen Qi, Chengkai Fu, Huijun Xie, L. Zhuang, Zhen Hu
Coastal wetlands are the main distribution of blue carbon in coastal zones and well known for their high carbon sequestration capacity. Investigating the variation of carbon budget is crucial for understanding the functionality of coastal wetlands and effectively addressing climate change. In this study, a bibliometric analysis of 4,509 articles was conducted to reveal research progress, hot issues, and emerging trends in the coastal wetland carbon budget field. The number of publications and citations in this field increased exponentially from 1991 to 2022. The leading subject category was Environmental Sciences with 1,844 articles (40.9%). At present, studies have been focused on blue carbon, the effects of climate change and man-made disturbances on carbon cycle, and the restoration of coastal wetlands. Based on the hotspots and trends in this field, the future researches should include (1) exploring the functional mechanisms of various factors affecting carbon cycle and establishing a methodological system for the estimation of blue carbon in coastal wetlands; (2) researching restoration techniques of coastal wetland and constructing wetland restoration evaluation index system; and (3) formulating enforceable carbon trading policy and strengthening international cooperation.
{"title":"Current research hotspots and frontier trends on carbon budget of coastal wetlands: A bibliometric analysis","authors":"Xinyi Zhang, Wenhao Liu, Jiaxing Lu, Muhammad Tanveer, Zhen Qi, Chengkai Fu, Huijun Xie, L. Zhuang, Zhen Hu","doi":"10.2166/wst.2024.171","DOIUrl":"https://doi.org/10.2166/wst.2024.171","url":null,"abstract":"\u0000 \u0000 Coastal wetlands are the main distribution of blue carbon in coastal zones and well known for their high carbon sequestration capacity. Investigating the variation of carbon budget is crucial for understanding the functionality of coastal wetlands and effectively addressing climate change. In this study, a bibliometric analysis of 4,509 articles was conducted to reveal research progress, hot issues, and emerging trends in the coastal wetland carbon budget field. The number of publications and citations in this field increased exponentially from 1991 to 2022. The leading subject category was Environmental Sciences with 1,844 articles (40.9%). At present, studies have been focused on blue carbon, the effects of climate change and man-made disturbances on carbon cycle, and the restoration of coastal wetlands. Based on the hotspots and trends in this field, the future researches should include (1) exploring the functional mechanisms of various factors affecting carbon cycle and establishing a methodological system for the estimation of blue carbon in coastal wetlands; (2) researching restoration techniques of coastal wetland and constructing wetland restoration evaluation index system; and (3) formulating enforceable carbon trading policy and strengthening international cooperation.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"2 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141100425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zheng Zhang, Yangyang Tang, Cong Tao, Jinchang Zhang, Fulin Dong, Song Liu, Duohuai Zhang, Xiaoling Wang
In a fluid environment, biofilms usually form and grow into streamers attached to solid surfaces. Existing research on single streamers studied their formation and failure modes. In the experiment on biofilm growth in a microfluidic channel, we found that rings composed of bacteria and an extracellular matrix are important elements on a mesoscopic scale. In the fluid environment, the failure of these ring elements causes damage to streamers. We simulated the growth and deformation of the ring structure in the micro-channel using multi-agent simulation and fluid–structure coupling of a porous elastic body. Based on this, we simulated the biofilm evolution involving multi-ring deformation, which provides a new length scale to study the biofilm streamer dynamics in fluid environments.
{"title":"Mesoscopic ring element growth and deformation induced biofilm streamer evolution in microfluidic channels","authors":"Zheng Zhang, Yangyang Tang, Cong Tao, Jinchang Zhang, Fulin Dong, Song Liu, Duohuai Zhang, Xiaoling Wang","doi":"10.2166/wst.2024.168","DOIUrl":"https://doi.org/10.2166/wst.2024.168","url":null,"abstract":"\u0000 \u0000 In a fluid environment, biofilms usually form and grow into streamers attached to solid surfaces. Existing research on single streamers studied their formation and failure modes. In the experiment on biofilm growth in a microfluidic channel, we found that rings composed of bacteria and an extracellular matrix are important elements on a mesoscopic scale. In the fluid environment, the failure of these ring elements causes damage to streamers. We simulated the growth and deformation of the ring structure in the micro-channel using multi-agent simulation and fluid–structure coupling of a porous elastic body. Based on this, we simulated the biofilm evolution involving multi-ring deformation, which provides a new length scale to study the biofilm streamer dynamics in fluid environments.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141098751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Increasingly frequent urban floods strain the traditional grey infrastructure, overwhelming the capacity of drainage networks and causing challenges in managing stormwater. The heavy precipitation leads to flooding and damage to drainage systems. Consequently, efficient mitigation strategies for flooding have been researched deeply. Green infrastructure (GI) has proved to be effective in responding the increasing risk of flood and alleviate pressure on drainage systems. However, as the primary infrastructure of stormwater management, there is still a lack of attention to the dynamic operation feature of urban sewer systems during precipitation events. To fill this gap, we proposed a novel approach that integrates hydraulic characteristics and the topological structure of a sewer network system. This approach aims to identify influential nodes, which contribute to the connectivity of the sewer network amidst dynamic changes in inflow during precipitation events. Furthermore, we adopted rain barrels to serve as exemplars of GI, and 14 GI layout schemes are produced based on the different ranks of influential nodes. Implementing GI measures on both poorly performing and well-performing nodes can yield distinct benefits in mitigating node flooding. This approach provides a new perspective for stormwater management, establishing effective synergy between GI and the drainage system.
日益频繁的城市洪水使传统的灰色基础设施不堪重负，排水网络不堪重负，给雨水管理带来挑战。强降水会导致洪水泛滥，损坏排水系统。因此，人们一直在深入研究有效的洪水缓解策略。事实证明，绿色基础设施（GI）可以有效地应对不断增加的洪水风险，减轻排水系统的压力。然而，作为雨水管理的主要基础设施，城市下水道系统在降水事件中的动态运行特征仍然缺乏关注。为了填补这一空白，我们提出了一种将下水道网络系统的水力特征和拓扑结构相结合的新方法。这种方法旨在识别有影响力的节点，这些节点在降水事件期间流入量的动态变化中对下水道网络的连通性做出了贡献。此外，我们还采用雨水桶作为地理信息系统的范例，并根据有影响力节点的不同等级制定了 14 个地理信息系统布局方案。在性能较差和性能较好的节点上实施 GI 措施，可在缓解节点洪水方面产生明显的效益。这种方法为雨水管理提供了一个新的视角，在地理信息系统和排水系统之间建立了有效的协同作用。
{"title":"Green infrastructure layout based on a dynamic operation feature of drainage systems","authors":"Chen Shen, Xin Dong, Luyao Wang, Xinhao Wang","doi":"10.2166/wst.2024.169","DOIUrl":"https://doi.org/10.2166/wst.2024.169","url":null,"abstract":"\u0000 \u0000 Increasingly frequent urban floods strain the traditional grey infrastructure, overwhelming the capacity of drainage networks and causing challenges in managing stormwater. The heavy precipitation leads to flooding and damage to drainage systems. Consequently, efficient mitigation strategies for flooding have been researched deeply. Green infrastructure (GI) has proved to be effective in responding the increasing risk of flood and alleviate pressure on drainage systems. However, as the primary infrastructure of stormwater management, there is still a lack of attention to the dynamic operation feature of urban sewer systems during precipitation events. To fill this gap, we proposed a novel approach that integrates hydraulic characteristics and the topological structure of a sewer network system. This approach aims to identify influential nodes, which contribute to the connectivity of the sewer network amidst dynamic changes in inflow during precipitation events. Furthermore, we adopted rain barrels to serve as exemplars of GI, and 14 GI layout schemes are produced based on the different ranks of influential nodes. Implementing GI measures on both poorly performing and well-performing nodes can yield distinct benefits in mitigating node flooding. This approach provides a new perspective for stormwater management, establishing effective synergy between GI and the drainage system.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"8 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141101105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Siyi Wang, Jiaying Wang, K. Xin, Hexiang Yan, Shuping Li, Tao Tao
Drainage modeling that accurately captures urban storm inundation serves as the foundation for flood warning and drainage scheduling. In this paper, we proposed a novel coupling ideology that, by integrating 2D-1D and 1D-2D unidirectional processes, overcomes the drawback of the conventional unidirectional coupling approach that fails to properly represent the rainfall surface catchment dynamics, and provides more coherent hydrological implications compared to the bidirectional coupling concept. This paper first referred to a laboratory experimental case from the literature, applied and analyzed the coupling scheme proposed in this paper and the bidirectional coupling scheme that has been widely studied in recent years, compared the two coupling solutions in terms of the resulting accuracy and applicability, and discussed their respective strengths and weaknesses to validate the reliability of the proposed method. The verified proposed coupling scheme was then applied to the modeling of a real drainage system in a region of Nanjing, China, and the results proved that the coupling mechanism proposed in this study is of practical application value.
{"title":"Urban flood modeling with a novel coupling method of surface and sewer hydrodynamic processes","authors":"Siyi Wang, Jiaying Wang, K. Xin, Hexiang Yan, Shuping Li, Tao Tao","doi":"10.2166/wst.2024.172","DOIUrl":"https://doi.org/10.2166/wst.2024.172","url":null,"abstract":"\u0000 Drainage modeling that accurately captures urban storm inundation serves as the foundation for flood warning and drainage scheduling. In this paper, we proposed a novel coupling ideology that, by integrating 2D-1D and 1D-2D unidirectional processes, overcomes the drawback of the conventional unidirectional coupling approach that fails to properly represent the rainfall surface catchment dynamics, and provides more coherent hydrological implications compared to the bidirectional coupling concept. This paper first referred to a laboratory experimental case from the literature, applied and analyzed the coupling scheme proposed in this paper and the bidirectional coupling scheme that has been widely studied in recent years, compared the two coupling solutions in terms of the resulting accuracy and applicability, and discussed their respective strengths and weaknesses to validate the reliability of the proposed method. The verified proposed coupling scheme was then applied to the modeling of a real drainage system in a region of Nanjing, China, and the results proved that the coupling mechanism proposed in this study is of practical application value.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141100248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmed Mahal, Maysoon Al-Haideri, Anas Alkhouri, A. Obaidullah, Meitao Duan
Recent decades have seen a shortage of water, which has led scientists to concentrate on solar desalination technologies. The present study examines the solar water desalination system with inclined steps, while considering various phase change materials (PCMs). The findings suggest that the incorporation of PCM generally enhances the productivity of the solar desalination system. Additionally, the combination of nanoparticles has been used to PCM, which is a popular technique utilized nowadays to improve the efficiency of these systems. The current investigation involves the transient modeling of a solar water desalination system, utilizing energy conservation equations. The equations were solved using the Runge–Kutta technique of the ODE23s order. The temperatures of the salt water, the absorbent plate of the glass cover, and the PCM were calculated at each time. Without a phase changer, the rate at which fresh water is produced is around 5.15 kg/m2·h. The corresponding mass flow rates of paraffin, n-PCM I, n-PCM III, n-PCM II, and stearic acid are 22.9, 28.9, 5.9, 11.9, and 73 kg/m2·h. PCMs, with the exception of stearic acid, exhibit similar energy efficiency up to an ambient temperature of around 29°. However, at temperatures over 29°, n-PCM II outperforms other PCM.
{"title":"Functional and financial analysis of an inclined step solar desalination using phase change nanomaterials","authors":"Ahmed Mahal, Maysoon Al-Haideri, Anas Alkhouri, A. Obaidullah, Meitao Duan","doi":"10.2166/wst.2024.170","DOIUrl":"https://doi.org/10.2166/wst.2024.170","url":null,"abstract":"\u0000 Recent decades have seen a shortage of water, which has led scientists to concentrate on solar desalination technologies. The present study examines the solar water desalination system with inclined steps, while considering various phase change materials (PCMs). The findings suggest that the incorporation of PCM generally enhances the productivity of the solar desalination system. Additionally, the combination of nanoparticles has been used to PCM, which is a popular technique utilized nowadays to improve the efficiency of these systems. The current investigation involves the transient modeling of a solar water desalination system, utilizing energy conservation equations. The equations were solved using the Runge–Kutta technique of the ODE23s order. The temperatures of the salt water, the absorbent plate of the glass cover, and the PCM were calculated at each time. Without a phase changer, the rate at which fresh water is produced is around 5.15 kg/m2·h. The corresponding mass flow rates of paraffin, n-PCM I, n-PCM III, n-PCM II, and stearic acid are 22.9, 28.9, 5.9, 11.9, and 73 kg/m2·h. PCMs, with the exception of stearic acid, exhibit similar energy efficiency up to an ambient temperature of around 29°. However, at temperatures over 29°, n-PCM II outperforms other PCM.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"63 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141101971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphitic carbon nitride (g-C3N4) is a widely studied visible-light-active photocatalyst for low cost, non-toxicity, and facile synthesis. Nonetheless, its photocatalytic efficiency is below par, due to fast recombination of charge carriers, low surface area, and insufficient visible light absorption. Thus, the research on the modification of g-C3N4 targeting at enhanced photocatalytic performance has attracted extensive interest. A considerable amount of review articles have been published on the modification of g-C3N4 for applications. However, limited effort has been specially contributed to providing an overview and comparison on available modification strategies for improved photocatalytic activity of g-C3N4-based catalysts in antibiotics removal. There has been no attempt on the comparison of photocatalytic performances in antibiotics removal between modified g-C3N4 and other known catalysts. To address these, our study reviewed strategies that have been reported to modify g-C3N4, including metal/non-metal doping, defect tuning, structural engineering, heterostructure formation, etc. as well as compared their performances for antibiotics removal. The heterostructure formation was the most widely studied and promising route to modify g-C3N4 with superior activity. As compared to other known photocatalysts, the heterojunction g-C3N4 showed competitive performances in degradation of selected antibiotics. Related mechanisms were discussed, and finally, we revealed current challenges in practical application.
{"title":"Recent progresses in synthesis and modification of g-C3N4 for improving visible-light-driven photocatalytic degradation of antibiotics","authors":"Kingsley Igenepo John, Goen Ho, Dan Li","doi":"10.2166/wst.2024.166","DOIUrl":"https://doi.org/10.2166/wst.2024.166","url":null,"abstract":"\u0000 \u0000 Graphitic carbon nitride (g-C3N4) is a widely studied visible-light-active photocatalyst for low cost, non-toxicity, and facile synthesis. Nonetheless, its photocatalytic efficiency is below par, due to fast recombination of charge carriers, low surface area, and insufficient visible light absorption. Thus, the research on the modification of g-C3N4 targeting at enhanced photocatalytic performance has attracted extensive interest. A considerable amount of review articles have been published on the modification of g-C3N4 for applications. However, limited effort has been specially contributed to providing an overview and comparison on available modification strategies for improved photocatalytic activity of g-C3N4-based catalysts in antibiotics removal. There has been no attempt on the comparison of photocatalytic performances in antibiotics removal between modified g-C3N4 and other known catalysts. To address these, our study reviewed strategies that have been reported to modify g-C3N4, including metal/non-metal doping, defect tuning, structural engineering, heterostructure formation, etc. as well as compared their performances for antibiotics removal. The heterostructure formation was the most widely studied and promising route to modify g-C3N4 with superior activity. As compared to other known photocatalysts, the heterojunction g-C3N4 showed competitive performances in degradation of selected antibiotics. Related mechanisms were discussed, and finally, we revealed current challenges in practical application.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"18 26","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As urbanization progresses and the impacts of climate change become more pronounced, urban flooding has emerged as a critical challenge for resilient cities, particularly concerning urban underground spaces where flooding can lead to significant loss of life and property. Drawing upon a comprehensive review of global research on underground space flood simulation and evacuation, this paper undertakes the modelling of inundation in a substantial underground area during the extraordinary rainfall event on 7 September 2023, in Shenzhen, China. Specifically, it introduces a two-step method to simulate the coupled surface-underground inundation process with high accuracy. The study simulates the inflow processes into three types of underground spaces: parking lots, metro stations, and underpasses. Utilizing the specific force per unit width evaluation, the research examines how varying flood barrier heights influence evacuation time and inundation risk. Subsequently, the paper proposes corresponding evacuation strategies based on the obtained findings. By highlighting the vulnerability of urban underground spaces to flooding, the study underscores the urgent need for further research in this domain.
{"title":"Assessment of urban underground spaces inundation during extreme rainfall events","authors":"Jiazhi Zhong, Dian Li, Ke Jiang","doi":"10.2166/wst.2024.165","DOIUrl":"https://doi.org/10.2166/wst.2024.165","url":null,"abstract":"\u0000 As urbanization progresses and the impacts of climate change become more pronounced, urban flooding has emerged as a critical challenge for resilient cities, particularly concerning urban underground spaces where flooding can lead to significant loss of life and property. Drawing upon a comprehensive review of global research on underground space flood simulation and evacuation, this paper undertakes the modelling of inundation in a substantial underground area during the extraordinary rainfall event on 7 September 2023, in Shenzhen, China. Specifically, it introduces a two-step method to simulate the coupled surface-underground inundation process with high accuracy. The study simulates the inflow processes into three types of underground spaces: parking lots, metro stations, and underpasses. Utilizing the specific force per unit width evaluation, the research examines how varying flood barrier heights influence evacuation time and inundation risk. Subsequently, the paper proposes corresponding evacuation strategies based on the obtained findings. By highlighting the vulnerability of urban underground spaces to flooding, the study underscores the urgent need for further research in this domain.","PeriodicalId":298320,"journal":{"name":"Water Science & Technology","volume":"25 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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