Nuclear waste management is a crucial aspect as the most significant threat to the ecosystem is caused by radioactive waste in which thorium contamination remains a prominent issue. This work represents an integrated approach for the elimination of thorium through the adsorption technique and subsequent electrochemical sensing using Magnetite@Graphene Oxide@Chitosan (M@GO@Cs). Moreover, the sorption of Th(IV) ions is optimized through batch studies, which are consistent with the results derived from ANOVA using the Box-Behnken Design model, and the ideal parameters resulted in 95.79% removal efficiency of Th(IV) ions using 6 mg of adsorbent in 10 mL of 50 mg/L Th(IV) ions solution at a pH of 5 within 20 min. Maximum adsorption capacity (833.33 mg/g) is obtained from Langmuir adsorption isotherm and process was aligned with the pseudo-second-order kinetic model. M@GO@Cs exhibited high recyclability sustaining high performance across nine consecutive adsorption-desorption cycles while maintaining excellent removal efficiency up to 85%. Furthermore, the electrochemical characterization of the synthesized M@GO@Cs nanoadsorbent was studied using the Cyclic Voltammetry, and Electron Impedance Spectroscopy techniques and quantification of Th(IV) ions was done utilizing the Differential Pulse Voltammetry method with the Limit of Detection (LOD) of 0.2 mg/L within a linear range of 10–100 mg/L.
{"title":"Integrated adsorption and electrochemical sensing of Th(IV) ions using graphene oxide and chitosan decorated magnetite-based adsorbent","authors":"Manish Sharma , Payal Taneja , Priya Sharma , Md Zainul Abedeen , Vikash Chandra Janu , Ragini Gupta","doi":"10.1016/j.chemosphere.2024.143595","DOIUrl":"10.1016/j.chemosphere.2024.143595","url":null,"abstract":"<div><div>Nuclear waste management is a crucial aspect as the most significant threat to the ecosystem is caused by radioactive waste in which thorium contamination remains a prominent issue. This work represents an integrated approach for the elimination of thorium through the adsorption technique and subsequent electrochemical sensing using Magnetite@Graphene Oxide@Chitosan (M@GO@Cs). Moreover, the sorption of Th(IV) ions is optimized through batch studies, which are consistent with the results derived from ANOVA using the Box-Behnken Design model, and the ideal parameters resulted in 95.79% removal efficiency of Th(IV) ions using 6 mg of adsorbent in 10 mL of 50 mg/L Th(IV) ions solution at a pH of 5 within 20 min. Maximum adsorption capacity (833.33 mg/g) is obtained from Langmuir adsorption isotherm and process was aligned with the pseudo-second-order kinetic model. M@GO@Cs exhibited high recyclability sustaining high performance across nine consecutive adsorption-desorption cycles while maintaining excellent removal efficiency up to 85%. Furthermore, the electrochemical characterization of the synthesized M@GO@Cs nanoadsorbent was studied using the Cyclic Voltammetry, and Electron Impedance Spectroscopy techniques and quantification of Th(IV) ions was done utilizing the Differential Pulse Voltammetry method with the Limit of Detection (LOD) of 0.2 mg/L within a linear range of 10–100 mg/L.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483102","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 : 2024-10-20DOI: 10.1016/j.chemosphere.2024.143580
Seoyeon Kim , Yoojin Cheon , Boo-Keun Khim , Hoon Young Jeong
The sorption of Eu(III) by Na+-substituted bentonite (Na-bentonite) was investigated as a function of pH and NaNO3 concentration ([NaNO3]0). At pH < ∼7.5, Eu(III) sorption decreased with the increasing [NaNO3]0, whereas at pH > ∼7.5, it remained nearly complete, independent of [NaNO3]0. Our thermodynamic model indicated that the sorption at pH < ∼7.5 occurred via a combination of cation exchange and surface complexation, with the former diminishing as [NaNO3]0 increased. Meanwhile, the sorption at pH > ∼7.5 was primarily due to surface complexation. By X-ray diffraction, the incorporation of hydrated Eu(III) in the interlayers of montmorillonite increased its lattice spacing and crystallinity along the c-axis, where cation exchange was predominant. Also, Eu LIII-edge X-ray absorption spectroscopy revealed that the sample dominated by cation exchange had an absorption edge energy and coordination structure similar to aqueous Eu(III), indicating outersphere complex formation. In other cases, Eu(III) sorption was characterized by innersphere complexation, as indicated by increased covalency and the presence of more pronounced second coordination shells. Importantly, the analysis of dissolved Si and Al suggested that the increased stability of Na-bentonite was likely due to the surface complexation of Eu(III) with aluminol groups at the edges, especially at higher surface coverages. Given its high sorption capacity for Eu(III) and stabilization effect mediated by sorption, Na-bentonite could be serve as an effective backfill material and migration barrier for containing actinides in nuclear waste repositories.
{"title":"Sorption of trivalent europium Eu(III) by Na+-substituted bentonite: Mechanistic insight and stabilization effect","authors":"Seoyeon Kim , Yoojin Cheon , Boo-Keun Khim , Hoon Young Jeong","doi":"10.1016/j.chemosphere.2024.143580","DOIUrl":"10.1016/j.chemosphere.2024.143580","url":null,"abstract":"<div><div>The sorption of Eu(III) by Na<sup>+</sup>-substituted bentonite (Na-bentonite) was investigated as a function of pH and NaNO<sub>3</sub> concentration ([NaNO<sub>3</sub>]<sub>0</sub>). At pH < ∼7.5, Eu(III) sorption decreased with the increasing [NaNO<sub>3</sub>]<sub>0</sub>, whereas at pH > ∼7.5, it remained nearly complete, independent of [NaNO<sub>3</sub>]<sub>0</sub>. Our thermodynamic model indicated that the sorption at pH < ∼7.5 occurred via a combination of cation exchange and surface complexation, with the former diminishing as [NaNO<sub>3</sub>]<sub>0</sub> increased. Meanwhile, the sorption at pH > ∼7.5 was primarily due to surface complexation. By X-ray diffraction, the incorporation of hydrated Eu(III) in the interlayers of montmorillonite increased its lattice spacing and crystallinity along the <em>c</em>-axis, where cation exchange was predominant. Also, Eu L<sub>III</sub>-edge X-ray absorption spectroscopy revealed that the sample dominated by cation exchange had an absorption edge energy and coordination structure similar to aqueous Eu(III), indicating outersphere complex formation. In other cases, Eu(III) sorption was characterized by innersphere complexation, as indicated by increased covalency and the presence of more pronounced second coordination shells. Importantly, the analysis of dissolved Si and Al suggested that the increased stability of Na-bentonite was likely due to the surface complexation of Eu(III) with aluminol groups at the edges, especially at higher surface coverages. Given its high sorption capacity for Eu(III) and stabilization effect mediated by sorption, Na-bentonite could be serve as an effective backfill material and migration barrier for containing actinides in nuclear waste repositories.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483034","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143576
Silva Beltrán Eduardo , Abdel Ghafour El Hachimi , Miguel Monge , José M. López-de-Luzuriaga , Vivechana Agarwal , Naveen Kumar Reddy Bogireddy
4-Nitrophenol (4-NP) is an organic contaminant attached to textiles, pharmaceuticals, and pesticides. Its presence has been increasingly detected in various water bodies such as lakes, rivers, and occasionally in drinking water. The present work shows the reduction of 4-NP using a hybrid catalytic system composed of gold and silver nanoparticles supported onto the biogenic porous silica (AgAu–SiO2). The AgAu nanoparticles were fabricated in situ onto the salinized biogenic silica substrates through a green synthesis. The catalytic reaction was analyzed with NaBH4 and the proposed AgAu–SiO2 catalyst. Mimicking 4-NP reduction reaction in different spiked river/marine water samples revealed superior catalytic activity in marine water. Subsequently, interference studies performed in the presence of different metal salts and pHs (found in the marine water) showed the vital role played by NaCl in the 4-NP reduction as the increase in the NaCl concentration enhances the catalytic activity of the proposed catalyst. Additional reusability of the proposed catalyst demonstrated its efficacy up to 10 cycles. The density functional theory (DFT) results supported the experimental findings, confirming the crucial role of Na+ and Cl− in the catalytic process. Our experimental results, which have significant implications for the field, have been explained by comparing them with DFT calculations. The main reason behind the enhanced catalysis performance in our systems was deduced at the atomic scale. The study included the adsorption energies and electronic density of molecular structures (4-NP and 4-AP) on different surface coverages. In exceptional cases, at the intermediate of 4-NP on Au(111)-NaCl, a displacement of the electronic density is observed, leading to a quinoline-type ring weakening the N–O bond and favoring the catalytic performance.
{"title":"Na+ and Cl− adsorption derived enhancement in 4-nitrophenol reduction using Au/Ag nanoparticle: An experimental and theoretical study","authors":"Silva Beltrán Eduardo , Abdel Ghafour El Hachimi , Miguel Monge , José M. López-de-Luzuriaga , Vivechana Agarwal , Naveen Kumar Reddy Bogireddy","doi":"10.1016/j.chemosphere.2024.143576","DOIUrl":"10.1016/j.chemosphere.2024.143576","url":null,"abstract":"<div><div>4-Nitrophenol (4-NP) is an organic contaminant attached to textiles, pharmaceuticals, and pesticides. Its presence has been increasingly detected in various water bodies such as lakes, rivers, and occasionally in drinking water. The present work shows the reduction of 4-NP using a hybrid catalytic system composed of gold and silver nanoparticles supported onto the biogenic porous silica (AgAu–SiO<sub>2</sub>). The AgAu nanoparticles were fabricated in situ onto the salinized biogenic silica substrates through a green synthesis. The catalytic reaction was analyzed with NaBH<sub>4</sub> and the proposed AgAu–SiO<sub>2</sub> catalyst. Mimicking 4-NP reduction reaction in different spiked river/marine water samples revealed superior catalytic activity in marine water. Subsequently, interference studies performed in the presence of different metal salts and pHs (found in the marine water) showed the vital role played by NaCl in the 4-NP reduction as the increase in the NaCl concentration enhances the catalytic activity of the proposed catalyst. Additional reusability of the proposed catalyst demonstrated its efficacy up to 10 cycles. The density functional theory (DFT) results supported the experimental findings, confirming the crucial role of Na<sup>+</sup> and Cl<sup>−</sup> in the catalytic process. Our experimental results, which have significant implications for the field, have been explained by comparing them with DFT calculations. The main reason behind the enhanced catalysis performance in our systems was deduced at the atomic scale. The study included the adsorption energies and electronic density of molecular structures (4-NP and 4-AP) on different surface coverages. In exceptional cases, at the intermediate of 4-NP on Au(111)-NaCl, a displacement of the electronic density is observed, leading to a quinoline-type ring weakening the N–O bond and favoring the catalytic performance.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483107","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143546
Amy-Louise Johnston , Edward Lester , Orla Williams , Rachel L. Gomes
Sorption by layered double hydroxides (LDH) is gaining substantial interest for remediating emerging contaminants, including pharmaceuticals from wastewaters. Findings from a sorbent material performing successfully in lab-based studies using non-environmental (laboratory-sourced) water cannot be assumed to translate to equal performance under environmental downstream applications. However, studies evaluating sorbent material performance for removal of pollutants and understanding material interactions with environmental waters are limited. This study evaluates the removal of the antibiotic amoxicillin (AMX) using a Mg2Al–NO3-LDH sorbent material from laboratory-grade water and wastewater effluent (WWE). AMX is successfully removed (94.53 ± 4.30 % within 24 h) in laboratory-grade water (under batch sorption conditions: 100 μg/L AMX, 0.2 g/L LDH, 20 °C). The comparison of LDH removal performance in laboratory grade and WWE shows a decreased maximum removal of AMX in WWE (13.39 ± 5.53 %). A lower final AMX concentration is observed in the WWE without the presence of LDH, compared to the ‘removal’ experiments in WWE with the presence of LDH, indicating a contribution of non-sorption removal pathways of AMX. This is proposed to be due to the difference in metal concentrations in the WWE with and without LDH present. The presence of LDH is found to decrease concentrations of metal pollutants in WWE, such as Zn concentration decreasing by 85 % over 24 h, changing water characteristics. Overall, this paper reports that an LDH performs differently in laboratory-sourced water and a wastewater effluent. This provides evidence that sorbent material performance needs to be evaluated in complex water matrices to ensure that it is representative of how a sorbent material will perform in an environmental application, which is the end goal of developing such technologies. Finally, good practice recommendations are provided for future lab-scale sorption experiments evaluating the performance of any new sorbent materials for water treatment applications.
{"title":"Interactions between antibiotic removal, water matrix characteristics and layered double hydroxide sorbent material","authors":"Amy-Louise Johnston , Edward Lester , Orla Williams , Rachel L. Gomes","doi":"10.1016/j.chemosphere.2024.143546","DOIUrl":"10.1016/j.chemosphere.2024.143546","url":null,"abstract":"<div><div>Sorption by layered double hydroxides (LDH) is gaining substantial interest for remediating emerging contaminants, including pharmaceuticals from wastewaters. Findings from a sorbent material performing successfully in lab-based studies using non-environmental (laboratory-sourced) water cannot be assumed to translate to equal performance under environmental downstream applications. However, studies evaluating sorbent material performance for removal of pollutants and understanding material interactions with environmental waters are limited. This study evaluates the removal of the antibiotic amoxicillin (AMX) using a Mg<sub>2</sub>Al–NO<sub>3</sub>-LDH sorbent material from laboratory-grade water and wastewater effluent (WWE). AMX is successfully removed (94.53 ± 4.30 % within 24 h) in laboratory-grade water (under batch sorption conditions: 100 μg/L AMX, 0.2 g/L LDH, 20 °C). The comparison of LDH removal performance in laboratory grade and WWE shows a decreased maximum removal of AMX in WWE (13.39 ± 5.53 %). A lower final AMX concentration is observed in the WWE without the presence of LDH, compared to the ‘removal’ experiments in WWE with the presence of LDH, indicating a contribution of non-sorption removal pathways of AMX. This is proposed to be due to the difference in metal concentrations in the WWE with and without LDH present. The presence of LDH is found to decrease concentrations of metal pollutants in WWE, such as Zn concentration decreasing by 85 % over 24 h, changing water characteristics. Overall, this paper reports that an LDH performs differently in laboratory-sourced water and a wastewater effluent. This provides evidence that sorbent material performance needs to be evaluated in complex water matrices to ensure that it is representative of how a sorbent material will perform in an environmental application, which is the end goal of developing such technologies. Finally, good practice recommendations are provided for future lab-scale sorption experiments evaluating the performance of any new sorbent materials for water treatment applications.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483103","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143562
Yuwei Wu , Guohe Huang , Peng Zhang , Yao Yao , Kai Zhao , Jian Shen , Renfei Feng , Ning Chen
Coal ashes in Canada have gained attention as a potential source for recovering rare earth elements (REE) from industrial waste. However, the complex chemical properties of coal ashes have made it difficult to determine the desirability, feasibility, and viability of REE recovery. To address this issue, this study systematically investigated distribution and structural information, speciation and chemical-binding state, and purity and extraction capacity of REE in multiple Canadian coal ashes (i.e., 2 fly ash and 1 bottom ash samples) through synchrotron-based X-ray fluorescence mapping and adsorption spectrum analyses, as well as high-resolution REE sequential extraction quantitation. The results showed that Y, Ce, and La were present in the glass phase of the bottom ash, and the distributions of these REE elements correlated with Ca. The XANES analysis revealed that the dominant form of REE in coal fly ash (CFA) was REE oxides, indicating a transformation during combustion, while Y2O3 and Y2(CO3)3 were the predominant Y species identified in CFA. The study found that there is no correlation between P and REEs, suggesting that REEs in CFA may exist as discrete particles rather than being associated with amorphous glass. The extractability of REEs in bottom ash samples was lower than that in fly ash samples. Additionally, the benefits of REE recovery were estimated to be USD 99.82 to 215.21 per ton of fly ash through life cycle analysis, indicating that REE recovery from fly ashes is a promising path to supplement the REE supply chain in Canada.
加拿大的煤灰作为从工业废料中回收稀土元素 (REE) 的潜在来源，已经引起了人们的关注。然而，由于煤灰的化学性质复杂，很难确定回收稀土元素的可取性、可行性和生存能力。针对这一问题，本研究通过同步辐射 X 射线荧光图谱和吸附光谱分析，以及高分辨率 REE 顺序萃取定量，系统地研究了加拿大多种煤灰（即 2 个粉煤灰和 1 个底灰样）中 REE 的分布和结构信息、种类和化学结合状态，以及纯度和萃取能力。结果表明，Y、Ce 和 La 存在于底灰的玻璃相中，且这些 REE 元素的分布与 Ca 相关。XANES 分析表明，粉煤灰（CFA）中 REE 的主要形式是 REE 氧化物，表明在燃烧过程中发生了转化，而 Y2O3 和 Y2(CO3)3 是在 CFA 中鉴定出的主要 Y 物种。研究发现，P 与 REEs 之间没有相关性，这表明 CFA 中的 REEs 可能以离散颗粒的形式存在，而不是与无定形玻璃相关联。底灰样品中 REEs 的萃取率低于粉煤灰样品。此外，通过生命周期分析，每吨粉煤灰的 REE 回收效益估计在 99.82 美元到 215.21 美元之间，这表明从粉煤灰中回收 REE 是补充加拿大 REE 供应链的一条很有前景的途径。
{"title":"Synchrotron-aided exploration of REE recovery from coal fly ashes within a Canadian context","authors":"Yuwei Wu , Guohe Huang , Peng Zhang , Yao Yao , Kai Zhao , Jian Shen , Renfei Feng , Ning Chen","doi":"10.1016/j.chemosphere.2024.143562","DOIUrl":"10.1016/j.chemosphere.2024.143562","url":null,"abstract":"<div><div>Coal ashes in Canada have gained attention as a potential source for recovering rare earth elements (REE) from industrial waste. However, the complex chemical properties of coal ashes have made it difficult to determine the desirability, feasibility, and viability of REE recovery. To address this issue, this study systematically investigated distribution and structural information, speciation and chemical-binding state, and purity and extraction capacity of REE in multiple Canadian coal ashes (i.e., 2 fly ash and 1 bottom ash samples) through synchrotron-based X-ray fluorescence mapping and adsorption spectrum analyses, as well as high-resolution REE sequential extraction quantitation. The results showed that Y, Ce, and La were present in the glass phase of the bottom ash, and the distributions of these REE elements correlated with Ca. The XANES analysis revealed that the dominant form of REE in coal fly ash (CFA) was REE oxides, indicating a transformation during combustion, while Y<sub>2</sub>O<sub>3</sub> and Y<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub> were the predominant Y species identified in CFA. The study found that there is no correlation between P and REEs, suggesting that REEs in CFA may exist as discrete particles rather than being associated with amorphous glass. The extractability of REEs in bottom ash samples was lower than that in fly ash samples. Additionally, the benefits of REE recovery were estimated to be USD 99.82 to 215.21 per ton of fly ash through life cycle analysis, indicating that REE recovery from fly ashes is a promising path to supplement the REE supply chain in Canada.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483117","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143590
Ashirafu Miiro , Oghenekaro Nelson Odume , George William Nyakairu , Silver Odongo , Henry Matovu , Charles Drago Kato , Ivan Špánik , Mika Sillanpaä , Edward Mubiru , Patrick Ssebugere
The increasing levels of industrialization and urbanization have led to the generation of significant amounts of wastewater and waste products, often containing chemicals like per- and poly-fluoroalkyl substances (PFASs) commonly found in consumer products. PFASs are known for their persistence, ubiquity, and ecotoxicological impacts, raising concerns about potential harm to ecosystems. This paper reports the occurrence and evaluates the ecological risks of PFASs in aquatic ecosystems and wastewater treatment works (WWTWs) across Africa. We reviewed 32 papers published in the period 2009–2024 and identified a total of 35 PFAS compounds in surface waters, wastewater, sediments, fish, crocodiles, and invertebrates. Much of the reported studies came from South Africa, followed by Kenya and Nigeria. PFAS concentrations in Africa were <0.7–390.0 ng L−1 in surface waters, 0.05–772 ng g−1 dw in sediments, and <0.2–832 ng L−1 in wastewater, while the highest levels in fish and invertebrates were 460.7 and 35.5 ng g−1 ww, respectively. The PFAS levels were in the same range of data as those reported globally. However, the high concentrations of PFASs in sediments and wastewater suggest areas of point contamination and a growing risk to aquatic ecosystems from effluent discharges. Calculated risk quotients suggested that, in Africa, organisms in river systems face greater risks due to exposure to PFASs compared to those in lakes, while marine organisms might face higher risks compared to freshwater organisms. Future studies should focus on PFAS contamination sources, especially WWTWs, as emerging sources of PFASs in aquatic systems.
{"title":"Per- and poly-fluoroalkyl substances in aquatic ecosystems and wastewater treatment works in Africa: Occurrence, ecological implications, and future perspectives","authors":"Ashirafu Miiro , Oghenekaro Nelson Odume , George William Nyakairu , Silver Odongo , Henry Matovu , Charles Drago Kato , Ivan Špánik , Mika Sillanpaä , Edward Mubiru , Patrick Ssebugere","doi":"10.1016/j.chemosphere.2024.143590","DOIUrl":"10.1016/j.chemosphere.2024.143590","url":null,"abstract":"<div><div>The increasing levels of industrialization and urbanization have led to the generation of significant amounts of wastewater and waste products, often containing chemicals like per- and poly-fluoroalkyl substances (PFASs) commonly found in consumer products. PFASs are known for their persistence, ubiquity, and ecotoxicological impacts, raising concerns about potential harm to ecosystems. This paper reports the occurrence and evaluates the ecological risks of PFASs in aquatic ecosystems and wastewater treatment works (WWTWs) across Africa. We reviewed 32 papers published in the period 2009–2024 and identified a total of 35 PFAS compounds in surface waters, wastewater, sediments, fish, crocodiles, and invertebrates. Much of the reported studies came from South Africa, followed by Kenya and Nigeria. PFAS concentrations in Africa were <0.7–390.0 ng L<sup>−1</sup> in surface waters, 0.05–772 ng g<sup>−1</sup> dw in sediments, and <0.2–832 ng L<sup>−1</sup> in wastewater, while the highest levels in fish and invertebrates were 460.7 and 35.5 ng g<sup>−1</sup> ww, respectively. The PFAS levels were in the same range of data as those reported globally. However, the high concentrations of PFASs in sediments and wastewater suggest areas of point contamination and a growing risk to aquatic ecosystems from effluent discharges. Calculated risk quotients suggested that, in Africa, organisms in river systems face greater risks due to exposure to PFASs compared to those in lakes, while marine organisms might face higher risks compared to freshwater organisms. Future studies should focus on PFAS contamination sources, especially WWTWs, as emerging sources of PFASs in aquatic systems.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483021","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143593
Sara R.D. Gamelas , Carla Pereira , M. Amparo F. Faustino , Adelaide Almeida , Leandro M.O. Lourenço
Water pollution is a significant concern worldwide, and it includes contaminants such as antibiotic-resistant pathogens. Antimicrobial photodynamic therapy (aPDT) offers a non-invasive and non-toxic alternative for the inactivation of these microorganisms. So, this study reports the synthesis, structural characterisation, photophysical properties, and aPDT efficacy of cationic free-base and zinc(II) chlorin (Chl) derivatives bearing N,N-dimethylpyrrolydinium groups (H2Chl 1a and ZnChl 1b). The aPDT assays were performed against two bacterial models: Staphylococcus aureus (Gram-(+)) and Escherichia coli (Gram-(−)). The H2Chl 1a and ZnChl 1b distinct's solubility profile, coupled with their ability to generate singlet oxygen (1O2) under light exposure, (H2Chl 1a, ФΔ = 0.58 < TPP, ФΔ = 0.65 < ZnChl 1b, ФΔ = 0.83) opens up their potential application as photosensitizers (PS) in aPDT. The effectiveness of H2Chl 1a and ZnChl 1b at 1.0 and 5.0 μM in aPDT against S. aureus and E. coli at 500 W m−2 (total exposure time: 60–120 min) showed a viability reduction >6.0 log10 CFU mL−1. Additionally, KI was used as a coadjuvant to potentiate the photoinactivation of E. coli, reaching the method's detection limit (>4.0 log10 RLU). As most of the PS developed to inactivate Gram-negative bacteria are cationic with three or more charges, the fact that the H2Chl 1a and ZnChl 1b with only one cationic charge photoinactivate E. coli at low concentrations and with a reduced light dose, it is an importing discovery that deserves further exploration. These monocharged chlorin dyes have the potential for water remediation.
{"title":"Unveiling the potent antimicrobial photodynamic therapy in Gram-positive and Gram-negative bacteria – Water remediation with monocharged chlorins","authors":"Sara R.D. Gamelas , Carla Pereira , M. Amparo F. Faustino , Adelaide Almeida , Leandro M.O. Lourenço","doi":"10.1016/j.chemosphere.2024.143593","DOIUrl":"10.1016/j.chemosphere.2024.143593","url":null,"abstract":"<div><div>Water pollution is a significant concern worldwide, and it includes contaminants such as antibiotic-resistant pathogens. Antimicrobial photodynamic therapy (aPDT) offers a non-invasive and non-toxic alternative for the inactivation of these microorganisms. So, this study reports the synthesis, structural characterisation, photophysical properties, and aPDT efficacy of cationic free-base and zinc(II) chlorin (Chl) derivatives bearing <em>N</em>,<em>N</em>-dimethylpyrrolydinium groups (H<sub>2</sub>Chl <strong>1a</strong> and ZnChl <strong>1b</strong>). The aPDT assays were performed against two bacterial models: <em>Staphylococcus aureus</em> (Gram-(+)) and <em>Escherichia coli</em> (Gram-(−)). The H<sub>2</sub>Chl <strong>1a</strong> and ZnChl <strong>1b</strong> distinct's solubility profile, coupled with their ability to generate singlet oxygen (<sup>1</sup>O<sub>2</sub>) under light exposure, (H<sub>2</sub>Chl <strong>1a</strong>, Ф<sub>Δ</sub> = 0.58 < <strong>TPP</strong>, Ф<sub>Δ</sub> = 0.65 < ZnChl <strong>1b</strong>, Ф<sub>Δ</sub> = 0.83) opens up their potential application as photosensitizers (PS) in aPDT. The effectiveness of H<sub>2</sub>Chl <strong>1a</strong> and ZnChl <strong>1b</strong> at 1.0 and 5.0 μM in aPDT against <em>S. aureus</em> and <em>E. coli</em> at 500 W m<sup>−2</sup> (total exposure time: 60–120 min) showed a viability reduction >6.0 log<sub>10</sub> CFU mL<sup>−1</sup>. Additionally, KI was used as a coadjuvant to potentiate the photoinactivation of <em>E. coli</em>, reaching the method's detection limit (>4.0 log<sub>10</sub> RLU). As most of the PS developed to inactivate Gram-negative bacteria are cationic with three or more charges, the fact that the H<sub>2</sub>Chl <strong>1a</strong> and ZnChl <strong>1b</strong> with only one cationic charge photoinactivate <em>E. coli</em> at low concentrations and with a reduced light dose, it is an importing discovery that deserves further exploration. These monocharged chlorin dyes have the potential for water remediation.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483121","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143586
Xihong Liu , Xiaohui Ma , Jiale Liu , Baozhong Zhang , Xi Wang , Jiaoxue Yang , Kunjie Hou , Yahui Shi , Hanyu Chen
Isoprene epoxydiol (IEPOX) is an important reactive gas-phase intermediate produced by the photooxidation of isoprene under low NOx conditions, playing a key role in the formation of secondary organic aerosols (SOA). Previous studies have mostly focused on the liquid-phase reactions of IEPOX within aerosols; however, interfacial heterogeneous chemical reactions are equally important in SOA formation. This study systematically explores the reaction mechanisms of IEPOX at the acidic aerosol interface and in the bulk phase using classical molecular dynamics (MD) and ab initio molecular dynamics simulations (AIMD). The study found that the free energy of IEPOX at the aerosol interface significantly decreases, indicating that interfacial heterogeneous chemical reactions are indispensable for the formation of IEPOX-derived SOA. The research reveals the formation pathways of 2-methyltetrols (2-MTO) and 1,3,4-trihydroxy-3-methylbutan-2-yl sulfates (2-MTOOS), finding that the protonation of the epoxy O atom and the cleavage of the C–O bond are the rate-controlling steps, while the nucleophilic addition is a spontaneous process. Through multiple sets of simulations, it was observed that the formation frequency of 2-MTO at the acidic aerosol interface and in the bulk phase reached 53.8%, significantly higher than the 30.8% of 2-MTOOS, which is consistent with field observation data. Additionally, through metadynamics (MTD) simulations, it was suggested that IEPOX could undergoes acid-catalyzed ring-opening reactions at the interface, potentially followed by the transfer of H atoms from primary alcohols into the aerosol, leading to the possible formation of the intermediate product 3-methylbut-3-ene-1,2,4-triol (one of the proposed structures of C5-alkene triols). These findings provide new insights into the formation mechanism of IEPOX-derived SOA and offer a scientific basis for future studies on their physicochemical properties and atmospheric fate.
异戊二烯环氧二醇（IEPOX）是异戊二烯在低氮氧化物条件下发生光氧化反应产生的一种重要的气相活性中间体，在二次有机气溶胶（SOA）的形成过程中起着关键作用。以往的研究大多集中于气溶胶中 IEPOX 的液相反应；然而，界面异相化学反应在 SOA 形成过程中同样重要。本研究利用经典分子动力学（MD）和非线性分子动力学模拟（AIMD）系统地探讨了 IEPOX 在酸性气溶胶界面和体相的反应机理。研究发现，气溶胶界面上 IEPOX 的自由能显著降低，表明界面异相化学反应是 IEPOX 衍生 SOA 形成不可或缺的因素。研究揭示了 2-甲基四醇（2-MTO）和 1,3,4-三羟基-3-甲基丁-2-基硫酸盐（2-MTOOS）的形成途径，发现环氧 O 原子的质子化和 C-O 键的裂解是速率控制步骤，而亲核加成是自发过程。通过多组模拟观察发现，2-MTO 在酸性气溶胶界面和体相的形成频率达到 53.8%，明显高于 2-MTOOS 的 30.8%，这与现场观测数据一致。此外，通过元动力学（MTD）模拟，IEPOX 可能会在界面上发生酸催化的开环反应，随后可能会将伯醇中的 H 原子转移到气溶胶中，从而可能形成中间产物 3-甲基丁-3-烯-1,2,4-三醇（C5-烯三醇的拟议结构之一）。这些发现为了解 IEPOX 衍生的 SOA 的形成机制提供了新的视角，并为今后研究其物理化学特性和大气归宿提供了科学依据。
{"title":"Molecular dynamics investigation of IEPOX chemical behavior at the interface and in the bulk phase of acidic aerosols","authors":"Xihong Liu , Xiaohui Ma , Jiale Liu , Baozhong Zhang , Xi Wang , Jiaoxue Yang , Kunjie Hou , Yahui Shi , Hanyu Chen","doi":"10.1016/j.chemosphere.2024.143586","DOIUrl":"10.1016/j.chemosphere.2024.143586","url":null,"abstract":"<div><div>Isoprene epoxydiol (IEPOX) is an important reactive gas-phase intermediate produced by the photooxidation of isoprene under low NO<sub>x</sub> conditions, playing a key role in the formation of secondary organic aerosols (SOA). Previous studies have mostly focused on the liquid-phase reactions of IEPOX within aerosols; however, interfacial heterogeneous chemical reactions are equally important in SOA formation. This study systematically explores the reaction mechanisms of IEPOX at the acidic aerosol interface and in the bulk phase using classical molecular dynamics (MD) and ab initio molecular dynamics simulations (AIMD). The study found that the free energy of IEPOX at the aerosol interface significantly decreases, indicating that interfacial heterogeneous chemical reactions are indispensable for the formation of IEPOX-derived SOA. The research reveals the formation pathways of 2-methyltetrols (2-MTO) and 1,3,4-trihydroxy-3-methylbutan-2-yl sulfates (2-MTOOS), finding that the protonation of the epoxy O atom and the cleavage of the C–O bond are the rate-controlling steps, while the nucleophilic addition is a spontaneous process. Through multiple sets of simulations, it was observed that the formation frequency of 2-MTO at the acidic aerosol interface and in the bulk phase reached 53.8%, significantly higher than the 30.8% of 2-MTOOS, which is consistent with field observation data. Additionally, through metadynamics (MTD) simulations, it was suggested that IEPOX could undergoes acid-catalyzed ring-opening reactions at the interface, potentially followed by the transfer of H atoms from primary alcohols into the aerosol, leading to the possible formation of the intermediate product 3-methylbut-3-ene-1,2,4-triol (one of the proposed structures of C<sub>5</sub>-alkene triols). These findings provide new insights into the formation mechanism of IEPOX-derived SOA and offer a scientific basis for future studies on their physicochemical properties and atmospheric fate.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483106","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143587
N. Cattaneo , M. Zarantoniello , F. Conti , A. Tavano , A. Frontini , I. Sener , G. Cardinaletti , I. Olivotto
Dietary microplastics (MPs) can be consumed by fish, crossing through the gastrointestinal tract. MPs smaller than 20 μm can easily translocate to other organs, such as liver, commonly triggering oxidative stress in fish. Given the current unlikelihood of their short-term elimination, strategies to mitigate MPs-related issues on fish are of considerable interest to the scientific community. In the present study, to reduce both the dietary MPs-induced oxidative stress and the accumulation of MPs, the effectiveness of microencapsulated astaxanthin (ASX) was evaluated in zebrafish (Danio rerio). Specifically, zebrafish were reared from larvae to adults (6 months) and fed diets containing MPs different in range-size (polymer A: 1–5 μm; polymer B: 40–47 μm) at different concentrations (50 or 500 mg/kg). After this period, fish from each experimental group were divided in two sub-groups that were fed, for an additional month, with the previous diets or with the same diets containing implemented with microencapsulated ASX (7 g/kg), respectively. Results showed that microencapsulated ASX was able to counteract the negative effects caused by MPs different in size. Particularly, in zebrafish fed diets containing polymer B microbeads, microencapsulated astaxanthin was able to restore the intestinal epithelium, affected by the abrasive role of MPs during gut transit. Differently, in zebrafish fed diets containing polymer A microbeads, absorbed at intestinal level and translocated mainly to the liver, the microencapsulated ASX decreased the oxidative stress response and reduced the MPs accumulation in target organs due to the antioxidant and the coagulant properties of the ASX and microcapsules wall, respectively. Taken together, the results highlighted that the aquafeeds’ implementation with microencapsulated astaxanthin is a prospective tool to prevent MPs-related issues in fish.
{"title":"Natural-based solutions to mitigate dietary microplastics side effects in fish","authors":"N. Cattaneo , M. Zarantoniello , F. Conti , A. Tavano , A. Frontini , I. Sener , G. Cardinaletti , I. Olivotto","doi":"10.1016/j.chemosphere.2024.143587","DOIUrl":"10.1016/j.chemosphere.2024.143587","url":null,"abstract":"<div><div>Dietary microplastics (MPs) can be consumed by fish, crossing through the gastrointestinal tract. MPs smaller than 20 μm can easily translocate to other organs, such as liver, commonly triggering oxidative stress in fish. Given the current unlikelihood of their short-term elimination, strategies to mitigate MPs-related issues on fish are of considerable interest to the scientific community. In the present study, to reduce both the dietary MPs-induced oxidative stress and the accumulation of MPs, the effectiveness of microencapsulated astaxanthin (ASX) was evaluated in zebrafish (<em>Danio rerio</em>). Specifically, zebrafish were reared from larvae to adults (6 months) and fed diets containing MPs different in range-size (polymer A: 1–5 μm; polymer B: 40–47 μm) at different concentrations (50 or 500 mg/kg). After this period, fish from each experimental group were divided in two sub-groups that were fed, for an additional month, with the previous diets or with the same diets containing implemented with microencapsulated ASX (7 g/kg), respectively. Results showed that microencapsulated ASX was able to counteract the negative effects caused by MPs different in size. Particularly, in zebrafish fed diets containing polymer B microbeads, microencapsulated astaxanthin was able to restore the intestinal epithelium, affected by the abrasive role of MPs during gut transit. Differently, in zebrafish fed diets containing polymer A microbeads, absorbed at intestinal level and translocated mainly to the liver, the microencapsulated ASX decreased the oxidative stress response and reduced the MPs accumulation in target organs due to the antioxidant and the coagulant properties of the ASX and microcapsules wall, respectively. Taken together, the results highlighted that the aquafeeds’ implementation with microencapsulated astaxanthin is a prospective tool to prevent MPs-related issues in fish.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483020","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 : 2024-10-19DOI: 10.1016/j.chemosphere.2024.143585
Miao Hu , Hongzhu Ma , Baoshan Xing
Microplastics (MPs) inevitably experienced various aging processes in nature may exhibit varied and complex interfacial interactions with adjacent species. Therefore, clarifying the possible interfacial interactions between naturally aged MPs and organic pollutants is of great significance to assess the actual behaviors of MPs in the environment. Here several plastic packaging materials after use were employed as the raw materials and representatives of naturally aged MPs, the alteration of surface characteristics, especially the degree of aging and the adsorption properties of MPs for anionic and cationic dyes were investigated. The types and the degree of aging of MPs were identified, and the variation of oxygen-containing functional groups (carbonyl, hydroxyl, and ester groups), the hydrophilicity and surface charge character were characterized. The fitting results of kinetics and isotherm models indicated that the adsorption was mainly multi-layer on heterogeneous surfaces, with hydrogen bonding, electrostatic attraction, polar interaction, and hydrophobic partitioning possibly involving. The hydrogen bond interaction was further confirmed by FTIR spectra. The increased temperature promoted the adsorption of cationic dyes on MPs, and the increased salinity of the solution enhanced the uptake of most of the tested dyes by MPs. This research deepened the understanding on the aging degree of MPs and their interfacial interactions with hydrophilic pollutants, and provided vital information for MPs as pollutant carriers.
{"title":"Identification of the degree of aging and adsorption behaviors of the naturally aged microplastics","authors":"Miao Hu , Hongzhu Ma , Baoshan Xing","doi":"10.1016/j.chemosphere.2024.143585","DOIUrl":"10.1016/j.chemosphere.2024.143585","url":null,"abstract":"<div><div>Microplastics (MPs) inevitably experienced various aging processes in nature may exhibit varied and complex interfacial interactions with adjacent species. Therefore, clarifying the possible interfacial interactions between naturally aged MPs and organic pollutants is of great significance to assess the actual behaviors of MPs in the environment. Here several plastic packaging materials after use were employed as the raw materials and representatives of naturally aged MPs, the alteration of surface characteristics, especially the degree of aging and the adsorption properties of MPs for anionic and cationic dyes were investigated. The types and the degree of aging of MPs were identified, and the variation of oxygen-containing functional groups (carbonyl, hydroxyl, and ester groups), the hydrophilicity and surface charge character were characterized. The fitting results of kinetics and isotherm models indicated that the adsorption was mainly multi-layer on heterogeneous surfaces, with hydrogen bonding, electrostatic attraction, polar interaction, and hydrophobic partitioning possibly involving. The hydrogen bond interaction was further confirmed by FTIR spectra. The increased temperature promoted the adsorption of cationic dyes on MPs, and the increased salinity of the solution enhanced the uptake of most of the tested dyes by MPs. This research deepened the understanding on the aging degree of MPs and their interfacial interactions with hydrophilic pollutants, and provided vital information for MPs as pollutant carriers.</div></div>","PeriodicalId":276,"journal":{"name":"Chemosphere","volume":null,"pages":null},"PeriodicalIF":8.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142483098","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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