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Boffa V, Fabbri D, Calza P, Revelli D, Christensen PV. Potential of nanofiltration technology in recirculating aquaculture systems in a context of circular economy. CHEMICAL ENGINEERING JOURNAL ADVANCES 2022. [DOI: 10.1016/j.ceja.2022.100269] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Wang M, Rivenbark K, Gong J, Wright FA, Phillips TD. Application of Edible Montmorillonite Clays for the Adsorption and Detoxification of Microcystin. ACS APPLIED BIO MATERIALS 2021; 4:7254-7265. [PMID: 34746680 PMCID: PMC8570584 DOI: 10.1021/acsabm.1c00779] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Exposure to microcystins (MCs) in humans and animals commonly occurs through the consumption of drinking water and food contaminated with cyanobacteria. Although studies have focused on developing water filtration treatments for MCs using activated carbon, dietary sorbents to reduce the bioavailability of MCs from the stomach and intestines have not been reported. To address this need, edible calcium and sodium montmorillonite clays were characterized for their ability to bind MC containing leucine and arginine (MC-LR) under conditions simulating the gastrointestinal tract and compared with a medical-grade activated carbon. Results of in vitro adsorption isotherms and thermodynamics showed that binding plots for MC-LR on montmorillonites fit the Langmuir model with high binding capacity, affinity, Gibbs free energy, and enthalpy. The in silico results from molecular modeling predicted that the major binding mechanisms involved electrostatics and hydrogen bonds, and that interlayers were important binding sites. The safety and detoxification efficacy of the sorbents against MC-LR were validated in a battery of living organisms, including Hydra vulgaris, Lemna minor, and Caenorhabditis elegans. The inclusion of 0.05% and 0.1% montmorillonite clays in hydra media significantly reduced MC-LR toxicity and protected hydra by 60-80%, whereas only slight protection was shown with the heat-collapsed clay. In the Lemna minor assay, montmorillonites significantly enhanced the growth of lemna, as supported by the increase in frond number, surface area, chlorophyll content, and growth rate, as well as the decrease in inhibition rate. Similar results were shown in the C. elegans assay, where montmorillonite clays reduced MC-LR effects on body length and brood size. All 3 bioassays confirmed dose-dependent protection from MC-LR, validated the in vitro and in silico findings, and suggested that edible montmorillonites are safe and efficacious binders for MC-LR. Moreover, their inclusion in diets during algal blooming seasons could protect vulnerable populations of humans and animals.
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Affiliation(s)
- Meichen Wang
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843, United States
| | - Kelly Rivenbark
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843, United States
| | - Joonho Gong
- Departments of Biological Sciences and Statistics and Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Fred A. Wright
- Departments of Biological Sciences and Statistics and Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Timothy D. Phillips
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843, United States
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Yang Y, Yu G, Chen Y, Jia N, Li R. Four decades of progress in cylindrospermopsin research: The ins and outs of a potent cyanotoxin. JOURNAL OF HAZARDOUS MATERIALS 2021; 406:124653. [PMID: 33321325 DOI: 10.1016/j.jhazmat.2020.124653] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
The cyanotoxin cylindrospermopsin (CYN), a toxic metabolite from cyanobacteria, is of particular concern due to its cosmopolitan occurrence, aquatic bioaccumulation, and multi-organ toxicity. CYN is the second most often recorded cyanotoxin worldwide, and cases of human morbidity and animal mortality are associated with ingestion of CYN contaminated water. The toxin poses a great challenge for drinking water treatment plants and public health authorities. CYN, with the major toxicity manifested in the liver, is cytotoxic, genotoxic, immunotoxic, neurotoxic and may be carcinogenic. Adverse effects are also reported for endocrine and developmental processes. We present a comprehensive review of CYN over the past four decades since its first reported poisoning event, highlighting its global occurrence, biosynthesis, toxicology, removal, and monitoring. In addition, current data gaps are identified, and future directions for CYN research are outlined. This review is beneficial for understanding the ins and outs of this environmental pollutant, and for robustly assessing health hazards posed by CYN exposure to humans and other organisms.
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Affiliation(s)
- Yiming Yang
- Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangzhou, Guangdong 510182, China
| | - Gongliang Yu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Youxin Chen
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Nannan Jia
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Renhui Li
- College of Life and Environmental Science, Wenzhou University, Wenzhou, Zhejiang 325035, China.
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Ren Z, Cheng X, Li P, Luo C, Tan F, Zhou W, Liu W, Zheng L, Wu D. Ferrous-activated sodium percarbonate pre-oxidation for membrane fouling control during ultrafiltration of algae-laden water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:140030. [PMID: 32758948 DOI: 10.1016/j.scitotenv.2020.140030] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/04/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Membrane technology has been shown to be promising for the treatment of algae-laden water, but membrane fouling is still an obstacle influencing the purification efficiency and effluent quality. To mitigate ultrafiltration membrane fouling during Microcystis aeruginosa-laden water treatment, a strategy of sodium percarbonate pre-oxidation activated with ferrous ion (Fe2+/SPC) was put forward in this study. Due to the synergistic effect of Fe2+ and SPC, this process was significantly more efficient with the terminal specific flux increased from 0.097 to 0.397, and the reversible fouling resistance reduced by approximately 80%. It was also found that subsequent sedimentation followed by Fe2+/SPC could further improve the fouling control efficiency. The model fitting results indicated that Fe2+/SPC pre-oxidation delayed the transition from standard blocking to cake filtration. Extracellular organic matter and algal cells were extracted from algal foulants to explore the contribution of each component, and the fouling control efficiencies were systematically studied. The characteristics of the algal foulants were determined with fluorescence excitation-emission matrix spectrum, and the results suggested that macromolecular proteinaceous substances were more efficiently removed by Fe2+/SPC, in comparison with humic-like matters. The alleviation of membrane fouling was also verified by the characterization methods of scanning electron microscopy and attenuated total reflection-Fourier infrared spectroscopy. Overall, the proposed strategy of Fe2+/SPC has an application prospect for membrane fouling control in algal-laden water treatment.
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Affiliation(s)
- Zixiao Ren
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Xiaoxiang Cheng
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China.
| | - Peijie Li
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Congwei Luo
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Fengxun Tan
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Weiwei Zhou
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China; Shandong Urban Construction Vocational College, Jinan 250103, PR China
| | - Wenchen Liu
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Lu Zheng
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Daoji Wu
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
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Schreidah CM, Ratnayake K, Senarath K, Karunarathne A. Microcystins: Biogenesis, Toxicity, Analysis, and Control. Chem Res Toxicol 2020; 33:2225-2246. [PMID: 32614166 DOI: 10.1021/acs.chemrestox.0c00164] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microcystins are cyclic peptide toxins formed by cyanobacteria. These toxins are recognized for their association with algal blooms, posing a significant threat to ecosystems and drinking water quality. Due to the growing environmental concerns they raise, a comprehensive review on microcystins' genesis, toxicity, and analytical methods for their quantitative determination is outlined. Genes, including the mcyABC cluster, regulate microcystin biogenesis. Bioanalytical experiments have identified key environmental factors, such as temperature and nitrogen availability, that promote microcystin production. Microcystin toxicity is explored based on its modulatory effects on protein phosphatases 1 and 2A in specific tissues and organs. Additionally, biochemical mechanisms of chelation, transportation, resultant oxidative stress, and tumor promotion abilities of microcystins are also discussed. Various analytical methods to separate, detect, and quantify microcystins, including the quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, nuclear magnetic resonance spectroscopy, and chromatographic platforms-linked tandem mass spectrometry (LC-MS) for unequivocal structural identification, are also reviewed. Since control of microcystins in water is of great necessity, both water treatment and mechanisms of abiotic transformation and microbial degradation are also discussed.
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Affiliation(s)
- Celine M Schreidah
- Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032, United States
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Kanishka Senarath
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
- Department of Chemistry, University of Colombo, Colombo 00300, Sri Lanka
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
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Kong X, Ma J, Le-Clech P, Wang Z, Tang CY, Waite TD. Management of concentrate and waste streams for membrane-based algal separation in water treatment: A review. WATER RESEARCH 2020; 183:115969. [PMID: 32721703 DOI: 10.1016/j.watres.2020.115969] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/09/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
Frequent occurrence of harmful algal blooms (HABs) and red tides in freshwater and seawater poses serious threats to water treatment and drives the application of membrane-based technologies in algal separation. Despite the high removal efficiency of algal cells and their metabolites (e.g. organic matter and toxins) by membranes, the generation of concentrate and waste streams presents a major challenge. In this paper, we review the scenarios under which membrane-based processes are integrated with algal separation, with particular attention given to (i) drinking water production and desalination at low algal concentrations and (ii) cyanobacteria-laden water treatment/desalination. The concentrate and waste streams from backwashing and membrane cleaning in each scenario are characterised with this information facilitating a better understanding of the transport of algal cells and metabolites in membrane processes. Current strategies and gaps in managing concentrate and waste streams are identified with guidance and perspectives for future studies discussed in an Eisenhower framework.
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Affiliation(s)
- Xiangtong Kong
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Jinxing Ma
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Pierre Le-Clech
- UNESCO Centre for Membrane Science and Technology, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Zhiwei Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
| | - Chuyang Y Tang
- Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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Hena S, Rozi R, Tabassum S, Huda A. Simultaneous removal of potent cyanotoxins from water using magnetophoretic nanoparticle of polypyrrole: adsorption kinetic and isotherm study. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:14868-14880. [PMID: 27072032 DOI: 10.1007/s11356-016-6540-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 03/21/2016] [Indexed: 06/05/2023]
Abstract
Cyanotoxins, microcystins and cylindrospermopsin, are potent toxins produced by cyanobacteria in potable water supplies. This study investigated the removal of cyanotoxins from aqueous media by magnetophoretic nanoparticle of polypyrrole adsorbent. The adsorption process was pH dependent with maximum adsorption occurring at pH 7 for microcystin-LA, LR, and YR and at pH 9 for microcystin-RR and cylindrospermopsin (CYN). Kinetic studies and adsorption isotherms reflected better fit for pseudo-second-order rate and Langmuir isotherm model, respectively. Thermodynamic calculations showed that the cyanotoxin adsorption process is endothermic and spontaneous in nature. The regenerated adsorbent can be successfully reused without appreciable loss of its original capacity.
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Affiliation(s)
- S Hena
- School of Industrial Technology, University Sains Malaysia, George Town, Penang, 11800, Malaysia.
| | - R Rozi
- School of Industrial Technology, University Sains Malaysia, George Town, Penang, 11800, Malaysia
| | - S Tabassum
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - A Huda
- School of Industrial Technology, University Sains Malaysia, George Town, Penang, 11800, Malaysia
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Patiño Y, Díaz E, Ordóñez S, Gallegos-Suarez E, Guerrero-Ruiz A, Rodríguez-Ramos I. Adsorption of emerging pollutants on functionalized multiwall carbon nanotubes. CHEMOSPHERE 2015; 136:174-180. [PMID: 25989605 DOI: 10.1016/j.chemosphere.2015.04.089] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 03/04/2015] [Accepted: 04/19/2015] [Indexed: 06/04/2023]
Abstract
Adsorption of three representative emerging pollutants - 1,8-dichlorooctane, nalidixic acid and 2-(4-methylphenoxy)ethanol- on different carbon nanotubes was studied in order to determine the influence of the morphological and chemical properties of the materials on their adsorption properties. As adsorbents, multiwall carbon nanotubes (MWCNTs) without functionalization and with oxygen or nitrogen surface groups, as well as carbon nanotubes doped with nitrogen were used. The adsorption was studied in aqueous phase using batch adsorption experiments, results being fitted to both Langmuir and Freundlich models. The adsorption capacity is strongly dependent on both the hydrophobicity of the adsorbates and the morphology of the adsorbents. Thermodynamic parameters were determined observing strong interactions between the aromatic rings of the emerging pollutant and the nitrogen modified adsorbents.
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Affiliation(s)
- Yolanda Patiño
- Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo, Spain
| | - Eva Díaz
- Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo, Spain
| | - Salvador Ordóñez
- Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo, Spain.
| | - Esteban Gallegos-Suarez
- Instituto de Catálisis y Petroleoquímica, CSIC, c/Marie Curie No. 2, Cantoblanco, 28049 Madrid, Spain; Dpto. Química Inorgánica y Técnica, Fac. de Ciencias, UNED, C/ Senda del Rey n° 9, 28040 Madrid, Spain
| | - Antonio Guerrero-Ruiz
- Dpto. Química Inorgánica y Técnica, Fac. de Ciencias, UNED, C/ Senda del Rey n° 9, 28040 Madrid, Spain
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Ibrahim WM, Salim EH, Azab YA, Ismail AHM. Monitoring and removal of cyanobacterial toxins from drinking water by algal-activated carbon. Toxicol Ind Health 2015; 32:1752-62. [PMID: 25964240 DOI: 10.1177/0748233715583203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Microcystins (MCs) are the most potent toxins that can be produced by cyanobacteria in drinking water supplies. This study investigated the abundance of toxin-producing algae in 11 drinking water treatment plants (DWTPs). A total of 26 different algal taxa were identified in treated water, from which 12% were blue green, 29% were green, and 59% were diatoms. MC levels maintained strong positive correlations with number of cyanophycean cells in raw and treated water of different DWTPs. Furthermore, the efficiency of various algal-based adsorbent columns used for the removal of these toxins was evaluated. The MCs was adsorbed in the following order: mixed algal-activated carbon (AAC) ≥ individual AAC > mixed algal powder > individual algal powder. The results showed that the AAC had the highest efficient columns capable of removing 100% dissolved MCs from drinking water samples, thereby offering an economically feasible technology for efficient removal and recovery of MCs in DWTPs.
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Affiliation(s)
- Wael M Ibrahim
- Botany Department, Faculty of Science, Fayoum University, Fayoum, Egypt
| | | | - Yahia A Azab
- Mansoura Drinking Water Treatment Plant, Mansoura, Egypt
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Merel S, Walker D, Chicana R, Snyder S, Baurès E, Thomas O. State of knowledge and concerns on cyanobacterial blooms and cyanotoxins. ENVIRONMENT INTERNATIONAL 2013; 59:303-27. [PMID: 23892224 DOI: 10.1016/j.envint.2013.06.013] [Citation(s) in RCA: 462] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 06/12/2013] [Accepted: 06/18/2013] [Indexed: 05/17/2023]
Abstract
Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surface and drinking water, including economic impacts and research needs. Cyanobacterial blooms usually occur according to a combination of environmental factors e.g., nutrient concentration, water temperature, light intensity, salinity, water movement, stagnation and residence time, as well as several other variables. These environmental variables, in turn, have promoted the evolution and biosynthesis of strain-specific, gene-controlled metabolites (cyanotoxins) that are often harmful to aquatic and terrestrial life, including humans. Cyanotoxins are primarily produced intracellularly during the exponential growth phase. Release of toxins into water can occur during cell death or senescence but can also be due to evolutionary-derived or environmentally-mediated circumstances such as allelopathy or relatively sudden nutrient limitation. Consequently, when cyanobacterial blooms occur in drinking water resources, treatment has to remove both cyanobacteria (avoiding cell lysis and subsequent toxin release) and aqueous cyanotoxins previously released. Cells are usually removed with limited lysis by physical processes such as clarification or membrane filtration. However, aqueous toxins are usually removed by both physical retention, through adsorption on activated carbon or reverse osmosis, and chemical oxidation, through ozonation or chlorination. While the efficient oxidation of the more common cyanotoxins (microcystin, cylindrospermopsin, anatoxin and saxitoxin) has been extensively reported, the chemical and toxicological characterization of their by-products requires further investigation. In addition, future research should also investigate the removal of poorly considered cyanotoxins (β-methylamino-alanine, lyngbyatoxin or aplysiatoxin) as well as the economic impact of blooms.
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Affiliation(s)
- Sylvain Merel
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 James E. Rogers Way, Tucson, AZ 85721, USA.
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Qu F, Liang H, Wang Z, Wang H, Yu H, Li G. Ultrafiltration membrane fouling by extracellular organic matters (EOM) of Microcystis aeruginosa in stationary phase: influences of interfacial characteristics of foulants and fouling mechanisms. WATER RESEARCH 2012; 46:1490-500. [PMID: 22178303 DOI: 10.1016/j.watres.2011.11.051] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 09/29/2011] [Accepted: 11/17/2011] [Indexed: 05/26/2023]
Abstract
This paper focused on the membrane fouling caused by extracellular organic matters (EOM) which was extracted from lab-cultured Microcystis aeruginosa in stationary phase. The characteristics of EOM such as molecular weight distribution, hydrophobicity and fluorescence were measured. It was found that high molecular weight (MW) and hydrophilic organics accounted for the major parts of algal EOM which was comprised of protein-like, polysaccharide-like and humic-like substances. Ultrafiltration (UF) experiments were carried out in a stirring cell and hydrophobic polyethersulfone (PES) membranes which carried negative charge were used. Prefiltration, calcium addition and XAD fractionation were employed to change the interfacial characteristics of EOM. Then the effects of these interfacial characteristics on flux decline, reversibility and mass balance of organics were compared. Algal EOM proved to cause serious membrane fouling during UF. The fraction of algal EOM between 0.45 μm and 100 kDa contributed a significant portion of the fouling. Hydrophobic organics in EOM tended to adhere to membrane surface causing irreversible fouling, while the cake layer formed by hydrophilic organics caused greater resistance to water flow due to hydrophilic interaction such as hydrogen bond and led to faster flux decline during UF. The results also indicated that the algal EOM was negatively charged and the electrostatic repulsion could prevent organics from adhering to membrane surface. In term of fouling mechanisms, cake layer formation, hydrophobic adhesion and pore plugging were the main mechanisms for membrane fouling caused by algal EOM.
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Affiliation(s)
- Fangshu Qu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China.
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Dixon MB, Falconet C, Ho L, Chow CWK, O'Neill BK, Newcombe G. Removal of cyanobacterial metabolites by nanofiltration from two treated waters. JOURNAL OF HAZARDOUS MATERIALS 2011; 188:288-295. [PMID: 21339048 DOI: 10.1016/j.jhazmat.2011.01.111] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/10/2011] [Accepted: 01/26/2011] [Indexed: 05/30/2023]
Abstract
Cyanobacterial metabolites, both toxic and non-toxic, are a major problem for the water industry. Nanofiltration (NF) may be an effective treatment option for removing organic micropollutants, such as cyanobacterial metabolites, from drinking water due to its size exclusion properties. A rapid bench scale membrane test (RBSMT) unit was utilised to trial four NF membranes to remove the cyanobacterial metabolites, microcystin, cylindrospermopsin (CYN), 2-methylisoborneol (MIB) and geosmin (GSM) in two treated waters sourced from the Palmer and Myponga water treatment plants. Membrane fouling was observed for both treated waters; however, only minor differences were observed between feed waters of differing natural organic matter (NOM) concentration. Low molecular weight cut-off (MWCO), or 'tight' NF, membranes afforded average removals above 90% for CYN, while removal by higher MWCO, or 'loose' NF membranes was lower. MIB and GSM were removed effectively (above 75%) by tight NF but less effectively by loose NF. Microcystin variants (MCRR, MCYR, MCLR, MCLA) were removed to above 90% by tight NF membranes; however, removal using loose NF membranes depended on the hydrophobicity and charge of the variant. Different NOM concentration in the treated waters had no effect on the removal of cyanobacterial metabolites.
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Affiliation(s)
- Mike B Dixon
- Australian Water Quality Centre, SA Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia.
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Ho L, Lambling P, Bustamante H, Duker P, Newcombe G. Application of powdered activated carbon for the adsorption of cylindrospermopsin and microcystin toxins from drinking water supplies. WATER RESEARCH 2011; 45:2954-2964. [PMID: 21459402 DOI: 10.1016/j.watres.2011.03.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 03/08/2011] [Accepted: 03/09/2011] [Indexed: 05/30/2023]
Abstract
Cylindrospermopsin (CYN) and microcystin are two potent toxins that can be produced by cyanobacteria in drinking water supplies. This study investigated the application of powdered activated carbon (PAC) for the removal of these toxins under conditions that could be experienced in a water treatment plant. Two different PACs were evaluated for their ability to remove CYN and four microcystin variants from various drinking water supplies. The removal of natural organic material by the PACs was also determined by measuring the levels of dissolved organic carbon and UV absorbance (at 254 nm). The PACs effectively removed CYN and the microcystins from each of the waters studied, with one of the PACs shown to be more effective, possibly due to its smaller particle diameter. No difference in removal of the toxins was observed using PAC contact times of 30, 45 and 60 min. Furthermore, the effect of water quality on the removal of the toxins was minimal. The microcystin variants were adsorbed in the order: MCRR > MCYR > MCLR > MCLA. CYN was found to be adsorbed similarly to MCRR.
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Affiliation(s)
- Lionel Ho
- Australian Water Quality Centre, SA Water Corporation, Adelaide, SA, Australia.
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Affiliation(s)
- Daniel M Evans
- School of Chemistry, Bangor University, Bangor, Gwynedd, UK
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