Tohren C. G. Kibbey, Denis M. O'Carroll, Andrew Safulko and Greg Coyle
{"title":"Multi-class machine learning classification of PFAS in environmental water samples: a blinded test of performance on unknowns†","authors":"Tohren C. G. Kibbey, Denis M. O'Carroll, Andrew Safulko and Greg Coyle","doi":"10.1039/D3VA00266G","DOIUrl":"10.1039/D3VA00266G","url":null,"abstract":"<p >The ability to identify the origin of detected PFAS in environmental samples is of great interest. This work used a blinded test to explore the ability of a recently-developed multiclass classification approach to classify unknown PFAS water samples based on composition. The approach was adapted from previous work to identify similarities between the patterns of unknown samples and classes defined by the compositions of samples from more than one hundred different PFAS data sources, in addition to making an overall assessment of whether PFAS is likely of AFFF or non-AFFF origin. Methods permitting the use of data with different subsets of analyzed PFAS components allowed for the use of a training dataset of more than 13 000 samples from a highly diverse range of sites. For this work, researchers at Brown and Caldwell (BC) provided a set of 252 unknown samples to researchers at The University of Oklahoma (OU) and The University of New South Wales (UNSW) for classification. Unknown samples were provided by clients of BC, and also included a number of artificial sample compositions created to test the ability of a rejection method to identify samples too unlike the training dataset for accurate classification. Unknown samples were de-identified and placed in random order prior to being sent to OU and UNSW researchers. Only after classification results had been sent by OU and UNSW researchers to BC researchers did BC provide the actual sample descriptions to OU and UNSW. Results showed extremely strong performance of the method, both in terms of its ability to identify similarities between unknown samples and samples of known origin, and its ability to make more subtle distinctions between sample origin, such as, for example, recognizing unknown samples from an airport wastewater collection system as being compositionally similar to known samples in another airport wastewater collection system. A rejection algorithm was tested and found to be able to identify artificial sample compositions as different from those in the training dataset, a critical feature of a practical supervised machine learning application, necessary to avoid misclassification of unknown samples that are unlike those in the training dataset.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00266g?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139483446","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}
Anabela Rebelo, Andreia Franco, Felisbina Quadrado, Vanda Reis, Sofia Batista, Ana Isabel Garcia, Rodrigo Ferreira, António Quintas and Albertina M. Marques
{"title":"Substantial damage to surface water in the context of environmental crimes","authors":"Anabela Rebelo, Andreia Franco, Felisbina Quadrado, Vanda Reis, Sofia Batista, Ana Isabel Garcia, Rodrigo Ferreira, António Quintas and Albertina M. Marques","doi":"10.1039/D3VA00381G","DOIUrl":"10.1039/D3VA00381G","url":null,"abstract":"<p >Water resources are very important for maintaining an adequate food supply and a productive environment for all living organisms. However, illicit activities can pose a severe threat to water quality and subsequently its uses through pollution with heavy metals, petroleum-derived oils, organic substances, pathogenic microorganisms, <em>etc.</em> Environmental crimes rank fourth among international illicit activities after drug trafficking, counterfeiting of currency and art, and trafficking of human beings and the intentional pollution of water is one of the three most common types of water crimes identified in European countries. Assessing and measuring water damage is challenging due to the complexity of water resources, including hydrogeological and hydromorphological characteristics, water uses, ecosystem services and other characteristics. Therefore, this study portrays the development of a conceptual framework supported by multicriteria decision analysis (MCDA) techniques to determine an index to quantify the magnitude of water damage (surface water) caused by a suspected illicit act (release of chemical products or waste disposal containing chemicals or other deposition, including agro-industrial or agricultural waste or by-products) and verify its feasibility through assessment of two case studies.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00381g?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139483420","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}
Cristina Moyaert, Philippe Nimmegeers, Bilal Mellouk, Dimitri Voordeckers, Paul De Meulenaere and Pieter Billen
{"title":"Evaluating spatial material distributions: adopting geospatial entropy definitions into resource management†","authors":"Cristina Moyaert, Philippe Nimmegeers, Bilal Mellouk, Dimitri Voordeckers, Paul De Meulenaere and Pieter Billen","doi":"10.1039/D3VA00166K","DOIUrl":"10.1039/D3VA00166K","url":null,"abstract":"<p >Human activity depends on resources that are often consumed without regard for their future availability. Consequently, resources in the form of raw materials and finished products are widely dispersed across society, creating energetic challenges for resource management, since the processes of procuring materials, purifying and processing them, distributing goods, and collecting waste all require significant amounts of energy. The costs and energy requirements for these activities depend on factors such as the mode of transportation and the distance travelled. Efficient transportation strategies can help reduce the negative environmental impact of human activities and ensure the sustainable use of resources for future generations. Quantifying the impact of this transport requires specific and expert logistics management knowledge. The current approach relies on information that is often not readily available, making it impractical and costly. Fast and quantitative methods to support decision making are especially needed when evaluating different potential circular economy (CE) strategies and business models that aim to reduce environmental impact by keeping materials at a high functionality level by closing material cycles (<em>e.g.</em>, through reuse, reparation, refurbishment, remanufacturing, repurposing, recycling or material recovery). As a consequence, in this article, geospatial entropy definitions are studied as novel metrics to quantify the geospatial distribution of resources. The overall goal of this article is to review existing geospatial entropy definitions and evaluate their potential to be applied for assessing resource management strategies in view of a circular economy. In doing so, insight into the decision making behind the location of a value-added activity through a collection and processing of resources is gained, as well as how entropy can be used to support this. To achieve this, we analyse several definitions used in the field of urban sprawling, illustrate how they are calculated using conceptual examples, and translate these to relevant research questions for resource management. This analysis results in several promising definitions, which, in our view, are able to quantify the geospatial distribution of resources accurately. The resulting entropy value can then serve as a proxy for collection efforts. As a result, a viewpoint is presented on how these geospatial entropy definitions can support resource management decisions, such as the appraisal of resource/waste collection schemes and the location of processing and recycling facilities.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00166k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139468998","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}
Sara L. Nason, Sara Thomas, Chelli Stanley, Richard Silliboy, Maggie Blumenthal, Weilan Zhang, Yanna Liang, Jasmine P. Jones, Nubia Zuverza-Mena, Jason C. White, Christy L. Haynes, Vasilis Vasiliou, Michael P. Timko and Bryan W. Berger
{"title":"A comprehensive trial on PFAS remediation: hemp phytoextraction and PFAS degradation in harvested plants†","authors":"Sara L. Nason, Sara Thomas, Chelli Stanley, Richard Silliboy, Maggie Blumenthal, Weilan Zhang, Yanna Liang, Jasmine P. Jones, Nubia Zuverza-Mena, Jason C. White, Christy L. Haynes, Vasilis Vasiliou, Michael P. Timko and Bryan W. Berger","doi":"10.1039/D3VA00340J","DOIUrl":"10.1039/D3VA00340J","url":null,"abstract":"<p >Per- and polyfluoroalkyl substances (PFAS) are a class of recalcitrant, highly toxic contaminants, with limited remediation options. Phytoremediation – removal of contaminants using plants – is an inexpensive, community-friendly strategy for reducing PFAS concentrations and exposures. This project is a collaboration between the Mi'kmaq Nation, Upland Grassroots, and researchers at several institutions who conducted phytoremediation field trials using hemp to remove PFAS from soil at the former Loring Air Force base, which has now been returned to the Mi'kmaq Nation. PFAS were analyzed in paired hemp and soil samples using targeted and non-targeted analytical approaches. Additionally, we used hydrothermal liquefaction (HTL) to degrade PFAS in the harvested hemp tissue. We identified 28 PFAS in soil and found hemp uptake of 10 of these PFAS. Consistent with previous studies, hemp exhibited greater bioconcentration for carboxylic acids compared to sulfonic acids, and for shorter-chain compounds compared to longer-chain. In total, approximately 1.4 mg of PFAS was removed from the soil <em>via</em> uptake into hemp stems and leaves, with an approximate maximum of 2% PFAS removed from soil in the most successful area. Degradation of PFAS by HTL was nearly 100% for carboxylic acids, but a portion of sulfonic acids remained. HTL also decreased precursor PFAS and extractable organic fluorine. In conclusion, while hemp phytoremediation does not currently offer a comprehensive solution for PFAS-contaminated soil, this project has effectively reduced PFAS levels at the Loring site and underscores the importance of involving community members in research aimed at remediating their lands.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00340j?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139104323","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":"The electric vehicle transition","authors":"Boucar Diouf","doi":"10.1039/D3VA00322A","DOIUrl":"10.1039/D3VA00322A","url":null,"abstract":"<p >Automobiles are the main sources of pollution; decarbonization of road transport is a major objective around the world. The electric vehicle (EV) technology is mature and somehow competitive with the development of lithium-ion (Li-ion) batteries. Affordability, performance, and the range are the first criteria that attract drivers to invest in EVs. Countries with the same objective of EVs to represent 100% of new registrations witness different progress, depending on the context and policy, and Norway and Iceland are currently leading. Countries with the highest EV penetration are almost systematically those with the highest cost of ownership of internal combustion engine (ICE) vehicles and those with most important subsidies. In this paper, the interplay between context, policy, and technology to drive EV transition is presented. Acquisition and operation cost, a combination of technology and policy, represent the factors that will guarantee the sustainability of EVs as the next generation of vehicles. For EVs to be more affordable it will largely depend on battery cost. Batteries are key in the performance, reliability, competitiveness, acquisition, and operation cost of EVs. Despite the undeniable progress, for EVs to match the performance of ICE vehicles in the range and lifespan, current battery technology needs to be improved. As novelties introduced in this field, along with a non-subsidy approach to the development of EVs, in this paper an upgraded diffusion model of EV technology based on the traditional S-curve is presented. An analysis of a potential secondhand market that is necessary to guarantee a full and sustainable EV transition is also presented.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00322a?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139095456","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":"What can Blyholder teach us about PFAS degradation on metal surfaces?†","authors":"Glen R. Jenness and Manoj K. Shukla","doi":"10.1039/D3VA00281K","DOIUrl":"10.1039/D3VA00281K","url":null,"abstract":"<p >Per- and poly-fluoroalkyl substances (PFAS) molecules have long been used in a variety of applications as they are chemically robust and resistant to chemical transformations. However, it has recently come to light that these compounds are toxic, and remediation efforts are required to remove them from our society. In a recent study (Jenness <em>et al.</em>, <em>Env. Sci. Proc. Impacts</em>, 2022, <strong>24</strong>, 2085) we explored the use of silylium-carborane for the degradation of perfluorobutanoic acid (PFBA) and three derivatives. In the course of our study, we found the degradation of the C–F bond was facilitated by a low-lying unoccupied anti-bonding orbital. Based on this finding, we propose the usage of metal catalysts for the degradation of the C–F bond as metals have been shown to take advantage of such low-lying anti-bonding orbitals. Utilizing density functional theory (DFT) calculations, we explored how the C–F bond in PFBA can be split by the entirety of the d-block metals. Deriving a series of linear scaling relationships, we demonstrate that metals conforming to the bcc point-group perform the best for this chemistry. In particular, iron (Fe) has a good balance of fluorine and PFBA binding and reaction energies and would be a worthy candidate for further studies.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00281k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139082957","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}
Min Li, Xudong Liu, Zhinan Xie, Chunfang Du and Yiguo Su
{"title":"Anchoring defective metal-free catalysts on montmorillonite nanosheets for tetracycline removal: synergetic adsorption-catalysis and mechanism insights†","authors":"Min Li, Xudong Liu, Zhinan Xie, Chunfang Du and Yiguo Su","doi":"10.1039/D3VA00331K","DOIUrl":"10.1039/D3VA00331K","url":null,"abstract":"<p >A one-step thermal polymerization approach was adopted to combine C<small><sub>3</sub></small>N<small><sub>5</sub></small> with montmorillonite nanosheets (MMT Ns) to form <em>x</em>CN-MMT for the degradation of pollutants in water. Benefitting from the abundant hydroxyl groups on the MMT surfaces, double defects (–C<img>N and N defects) were introduced in <em>x</em>CN-MMT catalysts to promote the adsorption of tetracycline (TC), peroxymonosulfate (PMS), and oxygen. 10CN-MMT exhibited superior adsorption performance toward TC, with the adsorption capacity being 5.65-fold that of MMT Ns and 2.64-fold that of C<small><sub>3</sub></small>N<small><sub>5</sub></small>. Further, 10CN-MMT exhibited better PMS activation performance than MMT Ns and C<small><sub>3</sub></small>N<small><sub>5</sub></small>, which could degrade 95% of TC within 120 min. Moreover, the total organic carbon (TOC) removal efficiency of the present system reached 81.1%, and the chemical oxygen demand (COD) decreased from 50.7 to 12.2 mg L<small><sup>−1</sup></small>. The degradation process of TC was characterized using liquid chromatography-tandem mass spectrometry (LC-MS), and a reasonable degradation pathway and catalytic mechanism were given by combining with active species analysis. The toxicological analysis of the degradation products also showed a significant decrease in toxicity. The degradation experiments in different water environments were also simulated, and it was found that 10CN-MMT showed good adsorption effects. This study provides a green metal-free clay-based catalyst and shows good applicability in removing antibiotics.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00331k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139029769","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":"Life cycle assessment, quo vadis? Supporting or deterring greenwashing? A survey of practitioners†","authors":"Miguel Brandão, Pablo Busch and Alissa Kendall","doi":"10.1039/D3VA00317E","DOIUrl":"10.1039/D3VA00317E","url":null,"abstract":"<p >Life cycle assessment (LCA) has been recognised as an important environmental systems analysis tool due to its potential for providing systematic results about the environmental impacts of alternative production and consumption systems that can lead to decisions towards greater sustainability in both private and public-policy contexts. However, LCA has been under increased scrutiny due to the wide range of published results on similar systems, such as biofuels, which can be contrasting. This variability is, in part, due to the proliferation of guidelines that have emerged over the last 20 years, which may undermine the perceived robustness of LCA as a decision-support tool. Following some interesting discussions on this topic in different fora, we took the pulse of the LCA community <em>via</em> a survey. We received 124 responses from respondents who varied in their background and experience in LCA (most were academics and/or had more than 10 years' experience), as well as in their opinions on whether they saw the inconsistency of published results problematic, or not, for decision making. Results suggest that respondents are of the opinion that (i) there is no single right way of performing LCA; (ii) the ISO 14040-44 standards were failing in their guiding of LCA practice, and that (iii) further efforts in harmonizing LCA practice would be beneficial, despite mixed opinions shown by respondents, which indicates the divisive nature of this topic in the LCA community. For example, there was no clear agreement on whether the significant flexibility with which practitioners perform LCA undermines its validity as a robust tool for decision making, though practitioners concerned with greenwashing were unified in the need for improved guidelines and harmonisation. Further harmonisation would help to ensure consistency in the application of the tool by practitioners which, in turn, would ensure results would be less variable, arguably more meaningful, and less prone to greenwashing. It is likely that methodological issues will remain unresolved in the near future, as some practitioners value the flexibility with which the ISO standards can be applied, even if that leads to inconsistent results. We recommended tighter standardization.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00317e?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138825066","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}
Selvarasu Maheshwaran, Wei-Hsin Chen, Sheng-Lun Lin, Mohammad Ghorbani and Anh Tuan Hoang
{"title":"Metal oxide-based electrochemical sensors for pesticide detection in water and food samples: a review","authors":"Selvarasu Maheshwaran, Wei-Hsin Chen, Sheng-Lun Lin, Mohammad Ghorbani and Anh Tuan Hoang","doi":"10.1039/D3VA00313B","DOIUrl":"10.1039/D3VA00313B","url":null,"abstract":"<p >The increasing need for food and agricultural resources necessitates using pesticides to protect plants, but this approach also poses pesticide poisoning and environmental hazards. Although designing an effective pesticide detection method is challenging, various technologies collaborate to develop an effective electrochemical sensor for detection of various pesticides. This review article examines the various metal oxides, their synthesis techniques, and their applications in electrochemical sensors, particularly for environmental applications, to detect pesticides in a variety of contaminated environmental samples. Metal oxides have unique properties that make them useful for pesticide detection because of their more active sites and electrical, optical, and semiconducting properties. Samarium molybdate-based electrode materials are considered the most promising direction for the development of electrode materials for pesticide sensors due to their economy, chemical stability, multiple valences, low detection limit, high sensitivity, and high electrocatalytic activity performance. In addition, this study investigates the current research trend in the detection of pesticides using metal oxide-based sensors in environmental samples, and researchers should expect new research perspectives and ideas. Overall, the metal oxide-based pesticide detection sensors will surely aid in meeting the growing demands for food and environmental monitoring and protection.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00313b?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138745838","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}
Kamilla Arnesen, Vegar Andersen, Katarina Jakovljevic, Ellen Katrin Enge, Heiko Gaertner, Thor Anders Aarhaug, Kristian Etienne Einarsrud and Gabriella Tranell
{"title":"Analysis of nitro- and oxy-PAH emissions from a pilot scale silicon process with flue gas recirculation†","authors":"Kamilla Arnesen, Vegar Andersen, Katarina Jakovljevic, Ellen Katrin Enge, Heiko Gaertner, Thor Anders Aarhaug, Kristian Etienne Einarsrud and Gabriella Tranell","doi":"10.1039/D3VA00187C","DOIUrl":"10.1039/D3VA00187C","url":null,"abstract":"<p >Silicon alloys are produced by carbothermic reduction of quartz in a submerged arc furnace. This high-temperature pyrolytic process is a source of polycyclic aromatic hydrocarbons (PAHs), which are a group of aromatic organic molecules with known mutagenic and carcinogenic properties. In this study, the emission of oxy- and nitro-PAHs from a pilot-scale Si furnace, with varying process conditions such as oxygen level, flue gas recirculation (FGR), and off-gas flow, was investigated. Analysis shows the presence of both oxy- and nitro-PAH species in all experiments, believed to be formed from radical-induced substitution reactions initiated by SiO combustion and NO<small><sub><em>x</em></sub></small> formation. During Si production without FGR, the levels of oxy- and nitro-PAHs range between 1.1 and 4.4 μg Nm<small><sup>−3</sup></small>, independent of the flue gas flow rate. With increasing FGR (0–82.5%) and decreasing oxygen level (20.7–13.3%), the concentrations of both oxy- and nitro-PAHs increase to 36.6 and 65.9 μg Nm<small><sup>−3</sup></small>, respectively. When the levels of substituted PAHs increase, species such as 4-nitropyrene and 1,2-benzanthraquinone are in abundance compared to their parent PAHs. Experiments at lower flue gas flow (500 Nm<small><sup>3</sup></small> h<small><sup>−1</sup></small><em>versus</em> 1000 Nm<small><sup>3</sup></small> h<small><sup>−1</sup></small>) generally produce less substituted PAHs, as well as SiO<small><sub>2</sub></small> particulate matter and NO<small><sub><em>x</em></sub></small>, where the latter two parameters have a 99% correlation in this study.</p>","PeriodicalId":72941,"journal":{"name":"Environmental science. Advances","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/va/d3va00187c?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138714581","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}