Pub Date : 2022-08-01DOI: 10.3390/pollutants2030025
O. Okon, E. Inam, Nnanake-Abasi O. Offiong, U. Akpabio
The adsorption of bisphenol A into untreated montmorillonite clay, doped titanium composite and cationic polymer modified tripartite magnetic montmorillonite composite was investigated under different conditions. The magnetic property of the modified adsorbent was ascertained by action of external magnetic field on the materials when dispersed in aqueous media. The XRD results for the unmodified and modified adsorbents showed that interlayer spacing of the clay material increases due to intercalation of the precursor molecules. The textural properties of the adsorbents from BET analysis showed that pore size and specific surface area of the tripartite magnetic composite was calculated to be 288.08 m2/g while that of the unmodified clay was 90.39 m2/g. The TGA results showed the tripartite magnetic composite was more stable with the lowest percentage mass loss compared to the unmodified montmorillonite. The tripartite magnetic composite showed higher adsorption capacity. Adsorption was best described by the Freundlich isotherm model, which confirmed that the adsorption process was multilayer coverage unto the uneven surface of the adsorbents. Kinetic treatment of the adsorption data confirmed the the process followed a pseudo-second-order kinetic model and predominantly chemisorption process. The standard Gibb’s free energy computed for the adsorbents showed that the adsorption processes were favourably spontaneous with highly negative energy values of −336.70, −533.76 and −1438.38 KJ/mol, respectively, for the unmodified montmorillonite, doped titanium composite and the tripartite magnetic composite. It was observed that the addition of cationic aromatic moiety to the clay material increased pollutant-adsorbent interactions and improved adsorption capacity for micro-pollutants in a simulated industrial effluent.
{"title":"Aqueous Adsorptive Removal of Bisphenol A Using Tripartite Magnetic Montmorillonite Composites","authors":"O. Okon, E. Inam, Nnanake-Abasi O. Offiong, U. Akpabio","doi":"10.3390/pollutants2030025","DOIUrl":"https://doi.org/10.3390/pollutants2030025","url":null,"abstract":"The adsorption of bisphenol A into untreated montmorillonite clay, doped titanium composite and cationic polymer modified tripartite magnetic montmorillonite composite was investigated under different conditions. The magnetic property of the modified adsorbent was ascertained by action of external magnetic field on the materials when dispersed in aqueous media. The XRD results for the unmodified and modified adsorbents showed that interlayer spacing of the clay material increases due to intercalation of the precursor molecules. The textural properties of the adsorbents from BET analysis showed that pore size and specific surface area of the tripartite magnetic composite was calculated to be 288.08 m2/g while that of the unmodified clay was 90.39 m2/g. The TGA results showed the tripartite magnetic composite was more stable with the lowest percentage mass loss compared to the unmodified montmorillonite. The tripartite magnetic composite showed higher adsorption capacity. Adsorption was best described by the Freundlich isotherm model, which confirmed that the adsorption process was multilayer coverage unto the uneven surface of the adsorbents. Kinetic treatment of the adsorption data confirmed the the process followed a pseudo-second-order kinetic model and predominantly chemisorption process. The standard Gibb’s free energy computed for the adsorbents showed that the adsorption processes were favourably spontaneous with highly negative energy values of −336.70, −533.76 and −1438.38 KJ/mol, respectively, for the unmodified montmorillonite, doped titanium composite and the tripartite magnetic composite. It was observed that the addition of cationic aromatic moiety to the clay material increased pollutant-adsorbent interactions and improved adsorption capacity for micro-pollutants in a simulated industrial effluent.","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86452699","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}
Pub Date : 2022-07-27DOI: 10.3390/pollutants2030023
Jean Bedel Batchamen Mougnol, F. Waanders, E. Fosso-Kankeu, A. A. Al Alili
Wastewater treatment has been widely focused on the undesirable pollutants derived from various activities such as coking, coal gasification, oil spills, and petroleum. These activities tend to release organic pollutants, however polycyclic aromatic hydrocarbons (PAHs) happen to be highlighted as the most carcinogenic pollutant that easily comes into contact with the environment and humans. It causes major challenges due to its lingering in the environment and chemical properties. Although various techniques such as ions exchange, advanced oxidation, and reverse osmosis have been conducted, some of them have been ignored due to their cost-effectiveness and ability to produce a by-product. Therefore, there is a need to develop and implement an effective technique that will alleviate the organic pollutants (PAHs) in various water sources. In this study, a self-made flat-bed photoreactor was introduced to degrade PAHs in various water sources such as acidic mine drainage, alkaline mine drainage, and sewage wastewater. A previous study was conducted, and only 7.074 mg/L, 0.3152 mg/L and 1.069 mg/L in 4 weeks and thereafter 19.255 mg/L, 1.615 mg/L and 1.813 mg/L in 8 weeks in acidic mine drainage, alkaline mined, drainage, and sewage wastewater leachate from a 2916.47 mg/L of PAHs in coal tar, was analysed. It was found that the flat-bed photoreactor was highly effective and able to obtain a removal efficiency of 64%, 55%, and 58%, respectively; without the flat-bed photoreactor, happened the removal efficiency was of 53%, 33%, and 39%, respectively, in 60 min in acidic mine drainage, alkaline mine drainage, and sewage wastewater. The photodegradation of PAHs was favoured in the acidic mine drainage, followed by sewage wastewater and alkaline mine drainage respective, showing time and solar irradiation dependence.
{"title":"Photodegradation of Polycyclic Aromatic Hydrocarbons from Coal Tar into Mine Wastewaters and Sewage Wastewater on a Flat-Bed Photoreactor","authors":"Jean Bedel Batchamen Mougnol, F. Waanders, E. Fosso-Kankeu, A. A. Al Alili","doi":"10.3390/pollutants2030023","DOIUrl":"https://doi.org/10.3390/pollutants2030023","url":null,"abstract":"Wastewater treatment has been widely focused on the undesirable pollutants derived from various activities such as coking, coal gasification, oil spills, and petroleum. These activities tend to release organic pollutants, however polycyclic aromatic hydrocarbons (PAHs) happen to be highlighted as the most carcinogenic pollutant that easily comes into contact with the environment and humans. It causes major challenges due to its lingering in the environment and chemical properties. Although various techniques such as ions exchange, advanced oxidation, and reverse osmosis have been conducted, some of them have been ignored due to their cost-effectiveness and ability to produce a by-product. Therefore, there is a need to develop and implement an effective technique that will alleviate the organic pollutants (PAHs) in various water sources. In this study, a self-made flat-bed photoreactor was introduced to degrade PAHs in various water sources such as acidic mine drainage, alkaline mine drainage, and sewage wastewater. A previous study was conducted, and only 7.074 mg/L, 0.3152 mg/L and 1.069 mg/L in 4 weeks and thereafter 19.255 mg/L, 1.615 mg/L and 1.813 mg/L in 8 weeks in acidic mine drainage, alkaline mined, drainage, and sewage wastewater leachate from a 2916.47 mg/L of PAHs in coal tar, was analysed. It was found that the flat-bed photoreactor was highly effective and able to obtain a removal efficiency of 64%, 55%, and 58%, respectively; without the flat-bed photoreactor, happened the removal efficiency was of 53%, 33%, and 39%, respectively, in 60 min in acidic mine drainage, alkaline mine drainage, and sewage wastewater. The photodegradation of PAHs was favoured in the acidic mine drainage, followed by sewage wastewater and alkaline mine drainage respective, showing time and solar irradiation dependence.","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83965430","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}
Pub Date : 2022-07-26DOI: 10.3390/pollutants2030022
G. Giacosa, C. Barnett, Daniel G. Rainham, T. Walker
The comment by Berthiaume et al. [...]
Berthiaume等人的评论…
{"title":"Reply to Berthiaume et al. Comment on “Giacosa et al. Characterization of Annual Air Emissions Reported by Pulp and Paper Mills in Atlantic Canada. Pollutants 2022, 2, 135–155”","authors":"G. Giacosa, C. Barnett, Daniel G. Rainham, T. Walker","doi":"10.3390/pollutants2030022","DOIUrl":"https://doi.org/10.3390/pollutants2030022","url":null,"abstract":"The comment by Berthiaume et al. [...]","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90430795","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}
Pub Date : 2022-07-26DOI: 10.3390/pollutants2030021
A. Berthiaume, A. Monette, Jody Rosenberger, B. Lupien
We are writing to respectfully offer clarification on interpretations of the National Pollutant Release Inventory (NPRI) presented in the recent paper “Characterization of Annual Air Emissions Reported by Pulp and Paper Mills in Atlantic Canada” by Giacosa et al. [...]
{"title":"Comment on Giacosa et al. Characterization of Annual Air Emissions Reported by Pulp and Paper Mills in Atlantic Canada. Pollutants 2022, 2, 135–155","authors":"A. Berthiaume, A. Monette, Jody Rosenberger, B. Lupien","doi":"10.3390/pollutants2030021","DOIUrl":"https://doi.org/10.3390/pollutants2030021","url":null,"abstract":"We are writing to respectfully offer clarification on interpretations of the National Pollutant Release Inventory (NPRI) presented in the recent paper “Characterization of Annual Air Emissions Reported by Pulp and Paper Mills in Atlantic Canada” by Giacosa et al. [...]","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87069950","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}
Pub Date : 2022-07-04DOI: 10.3390/pollutants2030020
Ibrahim El Ghazi, I. Berni, A. Menouni, M. Amane, M. Kestemont, S. El Jaafari
For monitoring spatio-temporal variations of nitrogen dioxide (NO2) content, passive diffusive samplers have been deployed in 14 near-road and residential sites for 14 days. In parallel with the winter campaign to measure the NO2 tracer, road traffic counting sessions were carried out on the city’s main roads. The coupling of the results of the measurement campaigns and the counting sessions under Arcgis 9.3 made it possible to determine the areas most affected by automobile pollution and to carry out a high spatial resolution mapping of the pollutant prospected. The results of this study show that atmospheric NO2 concentrations reach maximum values in the city center and decrease towards its periphery. The analysis of the epidemiological situation of the principal diseases related to air pollution in the city of Meknes during the study period (2010–2014) showed that among subjects aged five years and older, acute respiratory diseases occurred more in women than men. The most affected age group was between 15 and 49 years, while asthma attacks were noted mainly among women aged 50 years and older. Acute respiratory illness and asthma attacks were prevalent in the winter and fall. Among children under five years of age, the age group most affected by pneumonia was those under 11 months. Our integrative approach combined spatialized GIS-based health indicators of these diseases, the location of stationary and mobile sources of air pollution, and measured NO2 levels. This combination has made it possible to detect that residents in areas with heavy road traffic are likely to be more affected than those in areas near industrial activity. The habitat type also contributes significantly to the development and exacerbation of the pathologies studied, especially in the districts of the old Medina.
{"title":"Exposure to Air Pollution from Road Traffic and Incidence of Respiratory Diseases in the City of Meknes, Morocco","authors":"Ibrahim El Ghazi, I. Berni, A. Menouni, M. Amane, M. Kestemont, S. El Jaafari","doi":"10.3390/pollutants2030020","DOIUrl":"https://doi.org/10.3390/pollutants2030020","url":null,"abstract":"For monitoring spatio-temporal variations of nitrogen dioxide (NO2) content, passive diffusive samplers have been deployed in 14 near-road and residential sites for 14 days. In parallel with the winter campaign to measure the NO2 tracer, road traffic counting sessions were carried out on the city’s main roads. The coupling of the results of the measurement campaigns and the counting sessions under Arcgis 9.3 made it possible to determine the areas most affected by automobile pollution and to carry out a high spatial resolution mapping of the pollutant prospected. The results of this study show that atmospheric NO2 concentrations reach maximum values in the city center and decrease towards its periphery. The analysis of the epidemiological situation of the principal diseases related to air pollution in the city of Meknes during the study period (2010–2014) showed that among subjects aged five years and older, acute respiratory diseases occurred more in women than men. The most affected age group was between 15 and 49 years, while asthma attacks were noted mainly among women aged 50 years and older. Acute respiratory illness and asthma attacks were prevalent in the winter and fall. Among children under five years of age, the age group most affected by pneumonia was those under 11 months. Our integrative approach combined spatialized GIS-based health indicators of these diseases, the location of stationary and mobile sources of air pollution, and measured NO2 levels. This combination has made it possible to detect that residents in areas with heavy road traffic are likely to be more affected than those in areas near industrial activity. The habitat type also contributes significantly to the development and exacerbation of the pathologies studied, especially in the districts of the old Medina.","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87792209","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}
Pub Date : 2022-06-08DOI: 10.3390/pollutants2020017
J. Richardson, Ivan C. Mischenko, M. Butler
Quantifying the sequestration in forest soils and watershed transport of Hg is key to reducing exposure of aquatic food chains to the toxic pollutant. We explored if forest soils, proximity in human developments, or watershed characteristics could shed light on sediment driven Hg transport in the Connecticut River, Merrimack River, and Thames River watersheds, in the northeastern USA. We sampled 48 upland forest soils and 32 riparian forest soils and collected bottled and trapped suspended sediments from April 2020 to November 2020 across the three watersheds. Forest soil Hg concentrations were greater in riparian forest soils (median = 153 ng g−1) than in upland forest soils (median = 71 ng g−1) across all three watersheds and developed sites near urbanization had higher Hg concentrations in the Merrimack River watershed (median = 407 ± 119 ng g−1). The Connecticut River had the highest suspended sediment Hg export rate but when normalized by total area of the watershed, the Merrimack River had 0.19 kg km−2 month−1 while the Connecticut River had 0.13 kg km−2 month−1 and 0.04 km−2 for the Thames River. Our findings suggest that riparian forest soils sequester while suspended sediments transport historical Hg pollution within the Merrimack River Watershed.
量化森林土壤中汞的固存和流域运输是减少水生食物链暴露于有毒污染物的关键。我们探索了美国东北部康涅狄格河、梅里马克河和泰晤士河流域的森林土壤、人类发展的邻近或流域特征是否可以揭示沉积物驱动的汞运输。从2020年4月至2020年11月，我们在三个流域取样了48个高地森林土壤和32个河岸森林土壤，并收集了瓶装和捕获的悬浮沉积物。在所有三个流域，河流森林土壤中汞的浓度(中位数= 153 ng g - 1)高于高地森林土壤(中位数= 71 ng g - 1)，梅里马克河流域城市化附近发达地区的汞浓度较高(中位数= 407±119 ng g - 1)。康涅狄格河的悬浮沉积物汞输出率最高，但当按流域总面积标准化时，梅里马克河为0.19 kg km - 2月−1，而康涅狄格河为0.13 kg km - 2月−1，泰晤士河为0.04 km - 2。我们的研究结果表明，在梅里马克河流域内，河岸森林土壤在悬浮沉积物运输历史汞污染的同时进行了隔离。
{"title":"Mercury in Temperate Forest Soils and Suspended Sediments in the Connecticut River, Merrimack River, and Thames River Watersheds, USA","authors":"J. Richardson, Ivan C. Mischenko, M. Butler","doi":"10.3390/pollutants2020017","DOIUrl":"https://doi.org/10.3390/pollutants2020017","url":null,"abstract":"Quantifying the sequestration in forest soils and watershed transport of Hg is key to reducing exposure of aquatic food chains to the toxic pollutant. We explored if forest soils, proximity in human developments, or watershed characteristics could shed light on sediment driven Hg transport in the Connecticut River, Merrimack River, and Thames River watersheds, in the northeastern USA. We sampled 48 upland forest soils and 32 riparian forest soils and collected bottled and trapped suspended sediments from April 2020 to November 2020 across the three watersheds. Forest soil Hg concentrations were greater in riparian forest soils (median = 153 ng g−1) than in upland forest soils (median = 71 ng g−1) across all three watersheds and developed sites near urbanization had higher Hg concentrations in the Merrimack River watershed (median = 407 ± 119 ng g−1). The Connecticut River had the highest suspended sediment Hg export rate but when normalized by total area of the watershed, the Merrimack River had 0.19 kg km−2 month−1 while the Connecticut River had 0.13 kg km−2 month−1 and 0.04 km−2 for the Thames River. Our findings suggest that riparian forest soils sequester while suspended sediments transport historical Hg pollution within the Merrimack River Watershed.","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84966306","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}
Pub Date : 2022-05-07DOI: 10.3390/pollutants2020015
S. Loperte
This article focuses on the importance of a trans-disciplinary and participatory planning approach aiming at promoting a more resilient community. The COVID-19 outbreak is not just a health pandemic, but also a compound crisis in a globalized world, which emphasizes the need for, and urgency of, an ecological transition towards a new development model. This paper presents the outcomes of a research experience aimed at implementing a new development model inspired by integral sustainability for a transformative resilience of Basilicata region (Southern Italy). The research approach was implemented according to a participatory planning methodology to overcome the significant impacts of the pandemic and guide the transition towards real, sustainable development in all its dimensions (economic, social, environmental, and institutional). Community engagement in a research partnership allowed stakeholders to benefit from collective wisdom, creating more meaningful findings in preparing the regional community to face the challenges of the ecological transition. Scientific support of the research was fundamental in supporting political decision making in identifying strategic actions for a more sustainable and resilient Basilicata in this delicate historical moment of awareness, where the future will depend on today’s choices.
{"title":"A Trans-Disciplinary and Integral Model of Participatory Planning for a More Sustainable and Resilient Basilicata","authors":"S. Loperte","doi":"10.3390/pollutants2020015","DOIUrl":"https://doi.org/10.3390/pollutants2020015","url":null,"abstract":"This article focuses on the importance of a trans-disciplinary and participatory planning approach aiming at promoting a more resilient community. The COVID-19 outbreak is not just a health pandemic, but also a compound crisis in a globalized world, which emphasizes the need for, and urgency of, an ecological transition towards a new development model. This paper presents the outcomes of a research experience aimed at implementing a new development model inspired by integral sustainability for a transformative resilience of Basilicata region (Southern Italy). The research approach was implemented according to a participatory planning methodology to overcome the significant impacts of the pandemic and guide the transition towards real, sustainable development in all its dimensions (economic, social, environmental, and institutional). Community engagement in a research partnership allowed stakeholders to benefit from collective wisdom, creating more meaningful findings in preparing the regional community to face the challenges of the ecological transition. Scientific support of the research was fundamental in supporting political decision making in identifying strategic actions for a more sustainable and resilient Basilicata in this delicate historical moment of awareness, where the future will depend on today’s choices.","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87569008","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}
Pub Date : 2022-05-07DOI: 10.3390/pollutants2020016
N. Mintcheva, G. Gicheva, M. Panayotova
This paper presents attempts to reduce the concentration of organic pollutants in oilfield produced wastewater before its discharge into natural water bodies or reinjection into the wells. The contaminant content was significantly decreased by wastewater treatment, based on solid phase adsorption, photocatalytic degradation of organic molecules and chemical oxidation of oily compounds. The study was conducted with real wastewater, which is in practice released in the environment. The produced water samples, taken from four sampling points in the oilfield site, were analyzed for physicochemical (temperature, redox potential (Eh), conductivity, pH, dissolved oxygen) and specific (chemical oxygen demand (COD), total oily hydrocarbons (TOH), phenols) parameters, cations (Ca2+, Mg2+, Na+, K+) and anions (Cl−, HCO3−, SO42−, S2−), in order to determine the initial water status. The organic contaminants in oilfield produced water showed COD of 39–58 mg/L, TOH of 152–363 mg/L and phenols of 0.07–0.21 mg/L. The TOH was chosen as a suitable parameter for the evaluation of the treatment method efficiency. The adsorption on activated charcoal decreased the TOH levels up to 52 mg/L, which corresponds to 85% removal of oily compounds. Chemical oxidation, carried out with Ca(ClO)2 in a concentration of 400 mg/L for 1 h at room temperature, showed TOH removal in the range of 80–94% for different wastewater samples. The use of 300 mg/L TiO2 or ZnO under UV irradiation for 12 h led to TOH removal of 25–78% and 82–92%, respectively. Both photocatalysts were characterized by using X-ray diffraction, reflectance UV-vis spectroscopy and scanning electron microscopy. The crystal forms anatase and wurtzite for TiO2 and ZnO, respectively, were found. The estimated band gap of 3.48 eV for direct transition in TiO2 and 3.25 eV for ZnO agrees well with that reported in the literature. Higher photodegradation of organic compounds was observed for ZnO, indicating that it absorbed more light photons than TiO2 did. A mechanism for photocatalytic degradation over a more efficient photocatalyst, ZnO, was proposed based on the GC-MS analysis of raw water and treated effluents produced for 6 and 12 h.
{"title":"Reduction of Heavy Hydrocarbons from Oilfield Produced Water","authors":"N. Mintcheva, G. Gicheva, M. Panayotova","doi":"10.3390/pollutants2020016","DOIUrl":"https://doi.org/10.3390/pollutants2020016","url":null,"abstract":"This paper presents attempts to reduce the concentration of organic pollutants in oilfield produced wastewater before its discharge into natural water bodies or reinjection into the wells. The contaminant content was significantly decreased by wastewater treatment, based on solid phase adsorption, photocatalytic degradation of organic molecules and chemical oxidation of oily compounds. The study was conducted with real wastewater, which is in practice released in the environment. The produced water samples, taken from four sampling points in the oilfield site, were analyzed for physicochemical (temperature, redox potential (Eh), conductivity, pH, dissolved oxygen) and specific (chemical oxygen demand (COD), total oily hydrocarbons (TOH), phenols) parameters, cations (Ca2+, Mg2+, Na+, K+) and anions (Cl−, HCO3−, SO42−, S2−), in order to determine the initial water status. The organic contaminants in oilfield produced water showed COD of 39–58 mg/L, TOH of 152–363 mg/L and phenols of 0.07–0.21 mg/L. The TOH was chosen as a suitable parameter for the evaluation of the treatment method efficiency. The adsorption on activated charcoal decreased the TOH levels up to 52 mg/L, which corresponds to 85% removal of oily compounds. Chemical oxidation, carried out with Ca(ClO)2 in a concentration of 400 mg/L for 1 h at room temperature, showed TOH removal in the range of 80–94% for different wastewater samples. The use of 300 mg/L TiO2 or ZnO under UV irradiation for 12 h led to TOH removal of 25–78% and 82–92%, respectively. Both photocatalysts were characterized by using X-ray diffraction, reflectance UV-vis spectroscopy and scanning electron microscopy. The crystal forms anatase and wurtzite for TiO2 and ZnO, respectively, were found. The estimated band gap of 3.48 eV for direct transition in TiO2 and 3.25 eV for ZnO agrees well with that reported in the literature. Higher photodegradation of organic compounds was observed for ZnO, indicating that it absorbed more light photons than TiO2 did. A mechanism for photocatalytic degradation over a more efficient photocatalyst, ZnO, was proposed based on the GC-MS analysis of raw water and treated effluents produced for 6 and 12 h.","PeriodicalId":20301,"journal":{"name":"Pollutants","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74238819","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}
Pub Date : 2022-05-03DOI: 10.3390/pollutants2020014
Natalie Bain-Reguis, Andrew Smith, Caroline Hollins Martin, J. Currie
Healthy indoor environments influence the comfort, health and wellbeing of the occupants. Monitoring the indoor temperature, relative humidity and CO2 levels in primary schools during the COVID-19 pandemic was mandated by a local authority in Scotland. The aim was to investigate the comfort and safety of the teachers and their pupils. This paper presents the measurements of indoor climate in 20 classrooms in four different primary schools in Scotland. The schools were of different architypes. The classrooms were of different sizes, orientations and occupancy, and had different ventilation systems. Ventilation was achieved either by manually opening the windows, or by a mechanical ventilation system. Indoor air temperature, relative humidity and carbon dioxide (CO2) concentrations were continuously monitored for one week during the heating season 2020/21. Occupancy and opening of the windows were logged in by the teachers. The ventilation rates in the classrooms were estimated by measuring the CO2 concentrations. On the 20 classrooms of the study, data of 19 were analysed. The results show that four of the five mechanically ventilated classrooms performed better than natural ventilation, which indicates that opening the windows depended on the customs and habits. Classrooms in naturally ventilated Victorian buildings have the worst average ventilation rate (4.38 L/s per person) compared to the other classrooms (5.8 L/s per person for the more recent naturally ventilated ones, and 6.08 L/s per person for the mechanically ventilated ones). The results of this preliminary study will be used as the basis to find ways to ensure adequate ventilation in natural ventilated classrooms.
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Pub Date : 2022-05-01DOI: 10.3390/pollutants2020013
G. Notarstefano
Sustainability is a paradigm of generative action if combined with the principle of antifragility. This contribution, adhering to a transdisciplinary approach, proposes a reinterpretation of the principles of the 2030 Agenda, orienting them towards a community-building model. Sustainability can be seen as passive (care) and active (custody), determining paths to be activated at the territorial level. Sustainability is a communitarian learning path measured by one’s antifragility capacity. The effectiveness of the Agenda is linked to the dissemination and accountability of the challenges contained in the 17 objectives. The local scale is perhaps the most suitable for activating this process. However, this requires a strengthening of the anti-fragility of communities and organizations, which must be more capable of recognizing and reducing vulnerabilities and weaknesses. A promising field of application is that of impact assessment, to be reworked in the light of the antifragility approach.
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