| 1. |
- Al-Hazmi, Hussein E., et al.
(författare)
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Polysaccharide nanocomposites in wastewater treatment : A review
- 2024
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 347
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Forskningsöversikt (refereegranskat)abstract
- In modern times, wastewater treatment is vital due to increased water contamination arising from pollutants such as nutrients, pathogens, heavy metals, and pharmaceutical residues. Polysaccharides (PSAs) are natural, renewable, and non-toxic biopolymers used in wastewater treatment in the field of gas separation, liquid filtration, adsorption processes, pervaporation, and proton exchange membranes. Since addition of nanoparticles to PSAs improves their sustainability and strength, nanocomposite PSAs has gained significant attention for wastewater treatment in the past decade. This review presents a comprehensive analysis of PSA-based nanocomposites used for efficient wastewater treatment, focusing on adsorption, photocatalysis, and membrane-based methods. It also discusses potential future applications, challenges, and opportunities in adsorption, filtration, and photocatalysis. Recently, PSAs have shown promise as adsorbents in biological-based systems, effectively removing heavy metals that could hinder microbial activity. Cellulose-mediated adsorbents have successfully removed various pollutants from wastewater, including heavy metals, dyes, oil, organic solvents, pesticides, and pharmaceutical residues. Thus, PSA nanocomposites would support biological processes in wastewater treatment plants. A major concern is the discharge of antibiotic wastes from pharmaceutical industries, posing significant environmental and health risks. PSA-mediated bio-adsorbents, like clay polymeric nanocomposite hydrogel beads, efficiently remove antibiotics from wastewater, ensuring water quality and ecosystem balance. The successful use of PSA-mediated bio-adsorbents in wastewater treatment depends on ongoing research to optimize their application and evaluate their potential environmental impacts. Implementing these eco-friendly adsorbents on a large scale holds great promise in significantly reducing water pollution, safeguarding ecosystems, and protecting human health.
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| 2. |
- Azam, Kshaf, et al.
(författare)
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A review on activated carbon modifications for the treatment of wastewater containing anionic dyes
- 2022
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 306
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Forskningsöversikt (refereegranskat)abstract
- Polluted water resources, particularly those polluted with industrial effluents' dyes, are carcinogenic and hence pose a severe threat to sustainable and longstanding worldwide development. Meanwhile, adsorption is a promising process for polluted/wastewater treatment. In particular, activated carbon (AC) is popular among various wastewater treatment adsorbents, especially in the organic contaminants' remediation in wastewater. Hence, the AC's synthesis from degradable and non-degradable resources, the carbon activation involved in the AC synthesis, and the AC's modification to cutting-edge and effective materials have been modern-research targets in recent years. Likewise, the main research focuses worldwide have been the salient AC characteristics, such as its surface chemistry, porosity, and enhanced surface area. Notably, various modified-AC synthesis methods have been employed to enhance the AC's potential for improved contaminants-removal. Hence, we critically analyze the different modified ACs (with enhanced (surface) functional groups and textural properties) of their capacity to remove different-natured anionic dyes in wastewater. We also discuss the corresponding AC modification techniques, the factors affecting the AC properties, and the modifying agents' influence on the AC's morphological/adsorptive properties. Finally, the AC research of future interest has been proposed by identifying the current AC research gaps, especially related to the AC's application in wastewater treatment.
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| 3. |
- Brits, Martin, et al.
(författare)
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Critical review of the analysis of brominated flame retardants and their environmental levels in Africa
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 164, s. 174-189
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Forskningsöversikt (refereegranskat)abstract
- World-wide, the prevalence of brominated flame retardants (BFRs) is well documented for routine analysis of environmental and biological matrices. There is, however, limited information on these compounds in the African environment and insufficient information on the analytical approaches used to obtain data. This paper presents a review on BFR levels in the African environment and the various analytical methodologies specifically applied in Africa for polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls and alternative-BFRs. The analyses include liquid sample preparation using liquid-liquid and solid phase extraction and solid sample preparation involving Soxhlet extraction, with ultrasound-assisted extraction increasingly being applied. Instrumental detection techniques were limited to gas chromatography coupled with electron capture detector and electron impact ionisation with single quadrupole mass spectrometers. Information on congener profile prevalence in indoor dust, soil, aquatic environment (water, sediment, and aquatic organisms), eggs, wastewater treatment plant compartments, landfills (leachate and sediment) and breast milk are presented. Although PBDEs were inconsistently detected, contamination was reported for all investigated matrices in the African environment. The manifestation in remote regions indicates the ubiquitous prevalence and long-range transport of these compounds. Levels in sediment, and breast milk from some African countries were higher than reported for Asia and Europe. Due to limited data or non-detection of alternative-BFRs, it is unclear whether banned formulations were replaced in Africa. Most of the data reported for BFR levels in Africa were obtained in non-African laboratories or in South Africa and formed the basis for our discussion of reported contamination levels and related methodologies.
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| 4. |
- Hale, Sarah E., et al.
(författare)
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A synthesis of parameters related to the binding of neutral organic compounds to charcoal
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 144, s. 65-74
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Forskningsöversikt (refereegranskat)abstract
- The sorption strength of neutral organic compounds to charcoal, also called biochar was reviewed and related to charcoal and compound properties. From 29 studies, 507 individual Freundlich sorption.coefficients were compiled that covered the sorption strength of 107 organic contaminants. These sorption coefficients were converted into charcoal-water distribution coefficients (K-D) at aqueous concentrations of 1 ng/L, 1 mu g/L and 1 mg/L. Reported log K-D values at 1 mu g/L varied from 0.38 to 8.25 across all data. Variation was also observed within the compound classes; pesticides, herbicides and insecticides, PAHs, phthalates, halogenated organics, small organics, alcohols and PCBs. Five commonly reported variables; charcoal production temperature T, surface area SA, H/C and 0/C ratios and organic compound octanolwater partitioning coefficient, were correlated with K-D values using single and multiple-parameter linear regressions. The sorption strength of organic compounds to charcoals increased with increasing charcoal production temperature T, charcoal SA and organic pollutant octanol-water partitioning coefficient and decreased with increasing charcoal O/C ratio and charcoal H/C ratio. T was found to be correlated with SA (r(2) = 0.66) and O/C (r(2) = 0.50), particularly for charcoals produced from wood feedstocks (r2 = 0.73 and 0.80, respectively). The resulting regression: log K-D = (0.18 +/- 0.06) log K-ow + (5.74 +/- 1.40) log T + (0.85 +/- 0.15) log SA + (1.60 +/- 0.29) log OC + (-0.89 +/- 0.20) log HC + (-13.20 +/- 3.69), r(2) = 0.60, root mean squared error = 0.95, n = 151 was obtained for all variables. This information can be used as an initial screening to identify charcoals for contaminated soil and sediment remediation.
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| 5. |
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| 6. |
- Li, Jing, et al.
(författare)
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Quick detection method for paralytic shellfish toxins (PSTs) monitoring in freshwater : A review
- 2021
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Ingår i: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 265
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Forskningsöversikt (refereegranskat)abstract
- The objective of this critical review was to provide a comprehensive summary of paralytic shellfish toxins(PSTs) producing species and knowledge gaps in detecting PSTs in drinking water resources, with a focuson recent development of PSTs monitoring methods and tools for drinking water monitoring. PSTs, whichare also called Saxitoxins (STXs), are a group of neurotoxins not only produced by marine dinoflagellatesbut also freshwater cyanobacteria. The presence of PSTs in freshwater has been reported from all con-tinents except Antarctica. PSTs in poisoned sea food such as shellfish, molluscs and crustaceans mayattack the nerve system after consumption. The high incidences of PSTs occurring in drinking watersources showed another route of potential human exposure. A development of simple and fast screeningtools for drinking water surveillance of PSTs is needed. Neurotoxins produced by freshwater cyanobac-teria are understudied relative to microcystin and little study is done around PSTs in drinking watermonitoring. Some fast screening methods exist. The critical issues for using them in water surveillance,particularly matrix effect and cross-reactivity are summarized, and future research directions are high-lighted. We conclude that monitoring routines at drinking water resources should start from specieslevel, followed by a profound screening of toxin profile. For practical monitoring routine, fast screeningmethods should be combined with highly sensitive and accurate analytical methods such as liquidchromatography/liquid chromatographyemass spectrometry (LC/LC-MS). A thorough understanding oftoxin profile in source water is necessary for screening tool selection.
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| 7. |
- Rasmusson, Kristina, et al.
(författare)
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Per- and polyfluoroalkyl substances (PFAS) as contaminants in groundwater resources : A comprehensive review of subsurface transport processes
- 2024
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 362
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Forskningsöversikt (refereegranskat)abstract
- Per- and polyfluorinated alkyl substances (PFAS) are persistent contaminants in the environment. An increased awareness of adverse health effects related to PFAS has further led to stricter regulations for several of these substances in e.g. drinking water in many countries. Groundwater constitutes an important source of raw water for drinking water production. A thorough understanding of PFAS subsurface fate and transport mechanisms leading to contamination of groundwater resources is therefore essential for management of raw water resources. A review of scientific literature on the subject of processes affecting subsurface PFAS fate and transport was carried out. This article compiles the current knowledge of such processes, mainly focusing on perfluoroalkyl acids (PFAA), in soil- and groundwater systems. Further, a compilation of data on transport parameters such as solubility and distribution coefficients, as well as, insight gained and conclusions drawn from the reviewed material are presented. As the use of certain fire-fighting foams has been identified as the major source of groundwater contamination in many countries, research related to this type of pollution source has been given extra focus. Uptake of PFAS in biota is outside the scope of this review. The review showed a large spread in the magnitude of distribution coefficients and solubility for individual PFAS. Also, it is clear that the influence of multiple factors makes site-specific evaluation of distribution coefficients valuable. This article aims at giving the reader a comprehensive overview of the subject, and providing a base for further work.
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| 8. |
- Velarde, Lisbania, et al.
(författare)
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Adsorption of heavy metals on natural zeolites: A review
- 2023
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 328
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Forskningsöversikt (refereegranskat)abstract
- Water pollution has jeopardized human health, and a safe supply of drinking water has been recognized as a worldwide issue. The increase in the accumulation of heavy metals in water from different sources has led to the search for efficient and environmentally friendly treatment methods and materials for their removal. Natural zeolites are promising materials for removing heavy metals from different sources contaminating the water. It is important to know the structure, chemistry, and performance of the removal of heavy metals from water, of the natural zeolites to design water treatment processes. This review focuses on critical analyses of the application of distinct natural zeolites for the adsorption of heavy metals from water, specifically, arsenic (As(III), As(V)), cadmium (Cd(II)), chromium (Cr(III), Cr(VI)), lead (Pb(II)), mercury(Hg(II)) and nickel (Ni(II)). The reported results of heavy-metal removal by natural zeolites are summarized, and the chemical modification of natural zeolites by acid/base/salt reagent, surfactants, and metallic reagents has been analyzed, compared, and described. Furthermore, the adsorption/desorption capacity, systems, operating parameters, isotherms, and kinetics for natural zeolites were described and compared. According to the analysis, clinoptilolite is the most applied natural zeolite to remove heavy metals. It is effective in removing As, Cd, Cr, Pb, Hg, and Ni. Additionally, an interesting fact is a variation between the natural zeolites from different geological origins regarding the sorption properties and capacities for heavy metals suggesting that natural zeolites from different regions of the world are unique.
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| 9. |
- Wallace, M. Ariel Geer, et al.
(författare)
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A review of sample collection and analytical methods for detecting per- and polyfluoroalkyl substances in indoor and outdoor air
- 2024
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 358
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Forskningsöversikt (refereegranskat)abstract
- Per- and polyfluoroalkyl substances (PFAS) are a unique class of chemicals synthesized to aid in industrial processes, fire-fighting products, and to benefit consumer products such as clothing, cosmetics, textiles, carpets, and coatings. The widespread use of PFAS and their strong carbon-fluorine bonds has led to their ubiquitous presence throughout the world. Airborne transport of PFAS throughout the atmosphere has also contributed to environmental pollution. Due to the potential environmental and human exposure concerns of some PFAS, research has extensively focused on water, soil, and organismal detection, but the presence of PFAS in the air has become an area of growing concern. Methods to measure polar PFAS in various matrices have been established, while the investigation of polar and nonpolar PFAS in air is still in its early development. This literature review aims to present the last two decades of research characterizing PFAS in outdoor and indoor air, focusing on active and passive air sampling and analytical methods. The PFAS classes targeted and detected in air samples include fluorotelomer alcohols (FTOHs), perfluoroalkane sulfonamides (FASAs), perfluoroalkane sulfonamido ethanols (FASEs), perfluorinated carboxylic acids (PFCAs), and perfluorinated sulfonic acids (PFSAs). Although the manufacturing of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) has been largely phased out, these two PFAS are still often detected in air samples. Additionally, recent estimates indicate that there are thousands of PFAS that are likely present in the air that are not currently monitored in air methods. Advances in air sampling methods are needed to fully characterize the atmospheric transport of PFAS.
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| 10. |
- Wanner, Philipp, 1986
(författare)
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Plastic in agricultural soils – A global risk for groundwater systems and drinking water supplies? – A review
- 2021
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 264:1
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Forskningsöversikt (refereegranskat)abstract
- The global plastic contamination is one of the major challenges facing mankind as plastic is ubiquitously present in all environmental compartments. In contrast to freshwater and marine environments, plastic contamination of agricultural soils was only recently subject to investigations although it represents a significant amount (14%) of the global plastic pollution. Of concern is the vertical migration of plastic particles in agricultural soils and plastic-induced enhancement of pesticide transport towards underlying groundwater systems. To assess the risk of the large plastic inventory in agricultural soils for groundwater systems and drinking water supplies, this review critically synthesizes the current knowledge of the plastic mobility and plastic-pesticide interactions in agricultural soils, identifies future research directions and evaluates associated analytical challenges. The reviewed studies provide consistent evidence for vertical migration of plastic in agricultural soils towards aquifer systems, especially for sub-micrometer sized plastic particles, analogously to the well-known migration of natural particles in the sub-micrometer range (colloids). The reviewed investigations also showed that plastic changes the sorption behavior of pesticides in agricultural soils and enhances their transport towards underlying groundwater systems. Hence, the deposited plastic in agricultural soils likely poses a major risk for underlying aquifers and drinking water supplies that rely on groundwater resources below farmlands to be contaminated by plastic and pesticides. This demonstrates that improved regulatory measures are necessary regarding the general usage of plastic in the farming process to protect aquifers and drinking water supplies from plastic and pesticide contamination and to avoid a potential human health hazard.
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