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Tang S, Zhang L, Zhu H, Jiang SC. Coupling physiochemical adsorption with biodegradation for enhanced removal of microcystin-LR in water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 937:173370. [PMID: 38772489 DOI: 10.1016/j.scitotenv.2024.173370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 05/23/2024]
Abstract
To innovate the design of water treatment technology for algal toxin removal, this research investigated the mechanisms of cyanotoxin microcystin-LR (MC-LR) removal by a coupled adsorption-biodegradation. Eight types of woody carbonaceous adsorbents with and without Sphingopyxis sp. m6, a MC-LR degrading bacterium, were tested for MC-LR removal in water. All adsorbents showed good adsorption capability, removing 40 % to almost 100 % of the MC-LR (4.5 mg/L) within 48 h in batch experiments. Adding Sphingopyxis sp. m6 continuously promoted MC-LR biological removal, and successfully broke the barrier of adsorption capacity of tested adsorbents, removing >90 % of the MC-LR in most of the coupled adsorption-biodegradation tests, especially for those adsorbents had low physiochemical adsorption capacity. Variance partitioning analysis indicated that mesopore was the dominant contributor to adsorption capacity of MC-LR in pure adsorption treatments, which acted synergistically with electrical conductivity, polarity and total functional groups on the absorbent. Pore structure was the key factor beneficial for the growth of Sphingopyxis sp. m6 (51% contribution) and subsequent MC-LR biological removal rate (80 % contribution). Overall, pinewood-based carbonaceous adsorbents (especially pinewood activated carbon) exhibited the highest adsorption capacity towards MC-LR and provided the most favorable conditions for biological removal of MC-LR, largely because of their high mesopore volume, total functional groups and electric conductivity. The research outcomes not only deepened the quantitative understanding of mechanisms for MC-LR removal by the coupled process, but also provided theoretical basis for future materials' selection and modification during the practical application of coupled process.
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Affiliation(s)
- Shengyin Tang
- Department of Civil and Environmental Engineering, University of California, Irvine, 92697, United States; Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Lixun Zhang
- Department of Civil and Environmental Engineering, University of California, Irvine, 92697, United States; Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Haoxin Zhu
- Department of Civil and Environmental Engineering, University of California, Irvine, 92697, United States
| | - Sunny C Jiang
- Department of Civil and Environmental Engineering, University of California, Irvine, 92697, United States.
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Kulabhusan PK, Campbell K. Physico-chemical treatments for the removal of cyanotoxins from drinking water: Current challenges and future trends. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170078. [PMID: 38242472 DOI: 10.1016/j.scitotenv.2024.170078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/21/2024]
Abstract
Cyanobacteria are highly prevalent blue-green algae that grow in stagnant and nutrient-rich water bodies. Environmental conditions, such as eutrophication and human activities, increased the cyanobacterial blooms in freshwater resources worldwide. The excessive bloom formation has also resulted in an alarming surge of cyanobacterial toxins. Prolonged exposure to cyanotoxins is a potential threat to natural ecosystems, animal and human health by the spoilage of the quality of bathing and drinking water. Various molecular and analytical methods have been proposed to monitor their occurrence and understand their global distribution. Moreover, different physical, chemical, and biological approaches have been employed to control cyanobacterial blooms and their toxins to mitigate their occurrence. Numerous strategies have been engaged in drinking water treatment plants (DWTPs). However, the degree of treatment varies greatly and is primarily determined by the source, water properties, and operating parameters such as temperature, pH, and cyanotoxin variants and levels. A comprehensive compilation of methods, from traditional approaches to more advanced oxidation processes (AOPs), are presented for the removal of intracellular and extracellular cyanotoxins. This review discusses the effectiveness of various physicochemical operations and their limitations in a DWTP, for the removal of various cyanotoxins. These operations span from simple to advanced treatment levels with varying degrees of effectiveness and differing costs of implementation. Furthermore, mitigation measures applied in other toxin systems have been considered as alternative strategies.
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Affiliation(s)
- Prabir Kumar Kulabhusan
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, UK BT9 5DL; International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330, Braga, Portugal
| | - Katrina Campbell
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, UK BT9 5DL.
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Huang Y, Lenhart JJ. The dependence in microcystin removal with powdered activated carbon on variant properties, carbon properties, and dissolved organic matter. CHEMOSPHERE 2024; 351:141205. [PMID: 38219990 DOI: 10.1016/j.chemosphere.2024.141205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/02/2024] [Accepted: 01/11/2024] [Indexed: 01/16/2024]
Abstract
Powdered activated carbon (PAC) is commonly used by water treatment plants to remove harmful cyanotoxins such as microcystins (MCs) produced during seasonal harmful algal blooms. MC removal by PAC depends upon the properties of the PAC, the properties of the MC variant, and the presence and properties of dissolved organic matter (DOM). To identify which of these factors has the greatest impact on the removal of MC by PAC, we evaluated the removal of four different MC variants (MC-LR, MC-LA, MC-RR and desmethylated MC-RR) by three different PAC types (wood-based, coal-blend and coal-based). The role of DOM properties was evaluated using DOM isolated from two different sources, a terrestrial source (Suwannee River Fulvic Acid, SRFA) and a microbial source (Grand Lake St Marys DOM, GLSM). The results of adsorption experiments conducted over a period of 72 h demonstrated the wood-based PAC, which had the highest surface area and mesopore volume of the PAC tested, had the highest adsorption rate and capacity for all four MC variants. Of the variants studied, neutrally charged MC-RR was adsorbed more rapidly and to a greater extent on all of the PAC types than were the other variants. Although MC-LA and MC-LR had the greatest hydrophobicity, their negative charges resulted in their being adsorbed the least. As expected, DOM inhibited microcystin adsorption to PAC. The degree of inhibition, however, did not significantly vary for the two DOM types evaluated, indicating the properties of the DOM on MC adsorption to PAC was less important than the PAC properties or MC variant properties. Overall, PAC properties were a more important factor in MC removal than were the MC properties or DOM conditions.
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Affiliation(s)
- Yuzhou Huang
- Environmental Science Graduate Program, The Ohio State University, USA; Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, USA
| | - John J Lenhart
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, USA.
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4
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Silveri F, Paolini D, Della Pelle F, Bollella P, Scroccarello A, Suzuki Y, Fukawa E, Sowa K, Di Franco C, Torsi L, Compagnone D. Lab-made flexible third-generation fructose biosensors based on 0D-nanostructured transducers. Biosens Bioelectron 2023; 237:115450. [PMID: 37343312 DOI: 10.1016/j.bios.2023.115450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/26/2023] [Accepted: 06/04/2023] [Indexed: 06/23/2023]
Abstract
Herein, we report a scalable benchtop electrode fabrication method to produce highly sensitive and flexible third-generation fructose dehydrogenase amperometric biosensors based on water-dispersed 0D-nanomaterials. The electrochemical platform was fabricated via Stencil-Printing (StPE) and insulated via xurography. Carbon black (CB) and mesoporous carbon (MS) were employed as 0D-nanomaterials promoting an efficient direct electron transfer (DET) between fructose dehydrogenase (FDH) and the transducer. Both nanomaterials were prepared in water-phase via a sonochemical approach. The nano-StPE exhibited enhanced electrocatalytic currents compared to conventional commercial electrodes. The enzymatic sensors were exploited for the determination of D-fructose in model solutions and various food and biological samples. StPE-CB and StPE-MS integrated biosensors showed appreciable sensitivity (∼150 μA cm-2 mM-1) with μmolar limit of detection (0.35 and 0.16 μM, respectively) and extended linear range (2-500 and 1-250 μM, respectively); the selectivity of the biosensors, ensured by the low working overpotential (+0.15 V), has been also demonstrated. Good accuracy (recoveries between 95 and 116%) and reproducibility (RSD ≤8.6%) were achieved for food and urine samples. The proposed approach because of manufacturing versatility and the electro-catalytic features of the water-nanostructured 0D-NMs opens new paths for affordable and customizable FDH-based bioelectronics.
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Affiliation(s)
- Filippo Silveri
- Department of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Campus "Aurelio Saliceti" Via R. Balzarini 1, 64100 Teramo, Italy
| | - Davide Paolini
- Department of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Campus "Aurelio Saliceti" Via R. Balzarini 1, 64100 Teramo, Italy
| | - Flavio Della Pelle
- Department of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Campus "Aurelio Saliceti" Via R. Balzarini 1, 64100 Teramo, Italy.
| | - Paolo Bollella
- Department of Chemistry, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy; Centre for Colloid and Surface Science - University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy
| | - Annalisa Scroccarello
- Department of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Campus "Aurelio Saliceti" Via R. Balzarini 1, 64100 Teramo, Italy
| | - Yohei Suzuki
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Eole Fukawa
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Keisei Sowa
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Cinzia Di Franco
- Istituto di Fotonica e Nanotecnologie CNR, C/o Dipartimento Interateneo di Fisica, University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy
| | - Luisa Torsi
- Department of Chemistry, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy; Centre for Colloid and Surface Science - University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy; Faculty of Science and Engineering, Åbo Akademi University, 20500 Turku Finland
| | - Dario Compagnone
- Department of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Campus "Aurelio Saliceti" Via R. Balzarini 1, 64100 Teramo, Italy.
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Roberts JL, Zetterholm SG, Gurtowski L, Fernando PAI, Evans A, Puhnaty J, Wyss KM, Tour JM, Fernando B, Jenness G, Thompson A, Griggs C. Graphene as a rational interface for enhanced adsorption of microcystin-LR from water. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131737. [PMID: 37453354 DOI: 10.1016/j.jhazmat.2023.131737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 05/27/2023] [Accepted: 05/28/2023] [Indexed: 07/18/2023]
Abstract
Cyanotoxins such as microcystin-LR (MC-LR) represent a global environmental threat to ecosystems and drinking water supplies. The study investigated the direct use of graphene as a rational interface for removal of MC-LR via interactions with the aromatic ring of the ADDA1 chain of MC-LR and the sp2 hybridized carbon network of graphene. Intra-particle diffusion model fit indicated the high mesoporosity of graphene provided significant enhancements to both adsorption capacities and kinetics when benchmarked against microporous granular activated carbon (GAC). Graphene showed superior MC-LR adsorption capacity of 75.4 mg/g (Freundlich model) compared to 0.982 mg/g (Langmuir model) for GAC. Sorption kinetic studies showed graphene adsorbs 99% of MC-LR in 30 min, compared to zero removal for GAC after 24 hr using the same MC-LR concentration. Density functional theory (DFT), calculations showed that postulated π-based interactions align well with the NMR-based experimental work used to probe primary interactions between graphene and MC-LR adduct. This study proved that π-interactions between the aromatic ring on MC-LR and graphene sp2 orbitals are a dominant interaction. With rapid kinetics and adsorption capacities much higher than GAC, it is anticipated that graphene will offer a novel molecular approach for removal of toxins and emerging contaminants with aromatic systems.
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Affiliation(s)
- Jesse L Roberts
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA.
| | - Sarah Grace Zetterholm
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Luke Gurtowski
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Pu Ashvin I Fernando
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA; Bennett Aerospace, 1 Glenwood Avenue, Raleigh, NC 27603, USA; SIMETRI, Inc. 937 S Semoran Blvd Suite 100, Winter Park, FL 32792
| | - Angela Evans
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Justin Puhnaty
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Kevin M Wyss
- Department of Chemistry, NanoCarbon Center, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - James M Tour
- Department of Chemistry, NanoCarbon Center, Rice University, 6100 Main Street, Houston, TX 77005, USA; Rice Advanced Materials Institute, NanoCarbon Center, Rice University, 6100 Main Street, Houston, TX 77005, USA; Welch Institute for Advanced Materials, NanoCarbon Center, Rice University, 6100 Main Street, Houston, TX 77005, USA; Smalley-Curl Institute, NanoCarbon Center, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Brianna Fernando
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Glen Jenness
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Audie Thompson
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Chris Griggs
- US Army Engineer Research and Development Center (ERDC) Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
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Pressurized liquid extraction coupled in-line with SPE and on-line with HPLC (PLE-SPExHPLC) for the recovery and purification of anthocyanins from SC-CO2 semi-defatted Açaí (Euterpe oleracea). Food Res Int 2022; 160:111711. [DOI: 10.1016/j.foodres.2022.111711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/01/2022] [Accepted: 07/15/2022] [Indexed: 12/11/2022]
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7
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Adsorbents Used for Microcystin Removal from Water Sources: Current Knowledge and Future Prospects. Processes (Basel) 2022. [DOI: 10.3390/pr10071235] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The increasing occurrence of toxic cyanobacteria in water sources, driven by climate change and eutrophication, is of great concern worldwide today. Cyanobacterial blooms can negatively affect water bodies and generate harmful secondary metabolites, namely microcystins (MCs), which significantly impair water quality. Various adsorbents used for MC removal from water sources were assessed in this investigation. Activated carbon constitutes the most widely used adsorbent for treating contaminated waters due to its high affinity for adsorbing MCs. Alternative adsorbents have also been proposed and reported to provide higher efficiency, but the studies carried out so far in this regard are still insufficient. The mechanisms implicated in MC adsorption upon different adsorbents should be further detailed for a better optimization of the adsorption process. Certainly, adsorbent characteristics, water pH and temperature are the main factors influencing the adsorption of MCs. In this context, optimization studies must be performed considering the effectiveness, economic aspects associated with each adsorbent. This review provides guidelines for more practical field applications of the adsorption in the treatment of waters actually contaminated with MCs.
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Albuquerque MVDC, Ramos RDO, Leite VD, de Sousa JT, de Araújo MCU, de Ceballos BSO, Lopes WS. Studies of the liposolubility and the ecotoxicity of MC-LR degradation by-products using computational molecular modeling and in-vivo tests with Chlorella vulgaris and Daphnia magna. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 245:106127. [PMID: 35248895 DOI: 10.1016/j.aquatox.2022.106127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/23/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Computational molecular modelling, mass spectrometry and in-vivo tests with Chlorella vulgaris (C. vulgaris) and Daphnia magna (D. magna) were used to investigate the liposolubility and ecotoxicity of MC-LR degradation by-products generated after oxidation by OH• radicals in Fenton process. Exposure of MC-LR (5 µg.L-1) to the most severe oxidation conditions (Fe2+ 20 mM and H2O2 60 mM) resulted in a reduction in the toxin concentration of 96% (0.16 µg.L-1), however, with the formation of many by-products. The by-product of m/z 445 was the most resistant to degradation and retained a toxic structure of diene bonds present in the Adda amino acid. Computational modeling revealed that m/z 445 (tPSA = 132.88 Ų; KOW = 2.02) is more fat-soluble than MC-LR (tPSA = 340.64 Ų; KOW = 0.68), evidencing an easier transport process of this by-product. Given this, toxicity tests using C. vulgaris and D. magna indicated greater toxicity of the by-product m/z 445 compared to MC-LR. When the conversion of MC-LR to by-products was 77%, the growth inhibition of C. vulgaris and the D. magna immobility were, respectively, 6.14 and 0%, with 96% conversion; growth inhibition and the immobility were both 100% for both species.
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Affiliation(s)
| | - Railson de Oliveira Ramos
- Departamento de Engenharia Sanitária e Ambiental, Universidade Estadual da Paraíba, Campina Grande, Paraíba 58429-500, Brazil.
| | - Valderi Duarte Leite
- Departamento de Engenharia Sanitária e Ambiental, Universidade Estadual da Paraíba, Campina Grande, Paraíba 58429-500, Brazil
| | - José Tavares de Sousa
- Departamento de Engenharia Sanitária e Ambiental, Universidade Estadual da Paraíba, Campina Grande, Paraíba 58429-500, Brazil
| | - Mário César Ugulino de Araújo
- Departamento de Química, Universidade Federal da Paraíba, CCEN, Caixa Postal 5093, João Pessoa, Paraíba CEP 58051-970, Brazil
| | | | - Wilton Silva Lopes
- Departamento de Engenharia Sanitária e Ambiental, Universidade Estadual da Paraíba, Campina Grande, Paraíba 58429-500, Brazil
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Zeng S, Kan E. Thermally enhanced adsorption and persulfate oxidation-driven regeneration on FeCl 3-activated biochar for removal of microcystin-LR in water. CHEMOSPHERE 2022; 286:131950. [PMID: 34426274 DOI: 10.1016/j.chemosphere.2021.131950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/02/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
In this study, a cyclic process of adsorption and persulfate (PS) oxidation-driven regeneration using FeCl3-activated biochar (FA-BC) was suggested as a novel remediation process to remove microcystin-LR (MC-LR) from water. For enhancing overall treatment efficiency and cost effectiveness, the impacts of temperature on adsorption and PS oxidation-driven regeneration were investigated. The increase of temperature resulted in the increase of MC-LR adsorption rate on FA-BC due to the enhanced MC-LR diffusivity in water. Moreover, the MC-LR oxidation and PS reaction rates during the PS regeneration on FA-BC were remarkably improved by factors of 3.4 and 3.5 with increasing temperature from 20 °C to 50 °C. Both diffusion and desorption of MC-LR from FA-BC were thought to be the key factors for controlling the MC-LR oxidation rate during the PS regeneration of MC-LR. In addition, the decrease of pH (from 10 to 4) and increase of PS concentration (from 100 to 400 mg/L) enhanced the regeneration efficiency for MC-LR-spent FA-BC. The four cycles of adsorption-PS regeneration (200 mg/L PS, pH 6, and 50 °C) resulted in 92.81% regeneration efficiency in DI water and 82.89% in lake water. However, the four cycles of adsorption-PS regeneration led to the reduction of surface area (from 835 to 413 m2/g), oxidation of carbon surface and slight reduction of Fe0 on FA-BC. In overall, the cyclic adsorption-PS regeneration at higher temperature could provide practical reuse of FA-BC for cost-effective treatment of aqueous MC-LR.
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Affiliation(s)
- Shengquan Zeng
- Department of Biological and Agricultural Engineering & Texas A&M AgriLife Research Center, Texas A&M University, TX, 77843, USA
| | - Eunsung Kan
- Department of Biological and Agricultural Engineering & Texas A&M AgriLife Research Center, Texas A&M University, TX, 77843, USA; Department of Wildlife, Sustainability, and Ecosystem Sciences, Tarleton State University, TX, 76401, USA.
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Pivokonsky M, Kopecka I, Cermakova L, Fialova K, Novotna K, Cajthaml T, Henderson RK, Pivokonska L. Current knowledge in the field of algal organic matter adsorption onto activated carbon in drinking water treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 799:149455. [PMID: 34364285 DOI: 10.1016/j.scitotenv.2021.149455] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/30/2021] [Accepted: 07/31/2021] [Indexed: 06/13/2023]
Abstract
The increasing occurrence of algal and cyanobacterial blooms and the related formation of algal organic matter (AOM) is a worldwide issue that endangers the quality of freshwater sources and affects water treatment processes. The associated problems involve the production of toxins or taste and odor compounds, increasing coagulant demand, inhibition of removal of other polluting compounds, and in many cases, AOM acts as a precursor of disinfection by-products. Previous research has shown that for sufficient AOM removal, the conventional drinking water treatment based on coagulation/flocculation must be often accompanied by additional polishing technologies such as adsorption onto activated carbon (AC). This state-of-the-art review is intended to serve as a summary of the most current research on the adsorption of AOM onto AC concerning drinking water treatment. It summarizes emerging trends in this field with an emphasis on the type of AOM compounds removed and on the adsorption mechanisms and influencing factors involved. Additionally, also the principles of competitive adsorption of AOM and other organic pollutants are elaborated. Further, this paper also synthesizes previous knowledge on combining AC adsorption with other treatment techniques for enhanced AOM removal in order to provide a practical resource for researchers, water treatment plant operators and engineers. Finally, research gaps regarding the AOM adsorption onto AC are identified, including, e.g., adsorption of AOM residuals recalcitrant to coagulation/flocculation, suitability of pre-oxidation of AOM prior to the AC adsorption, relationships between the solution properties and AOM adsorption behaviour, or AOM as a cause of competitive adsorption. Also, focus should be laid on continuous flow column experiments using water with multi-component composition, because these would greatly contribute to transferring the theoretical knowledge to practice.
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Affiliation(s)
- Martin Pivokonsky
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 30/5, 166 12 Prague 6, Czech Republic.
| | - Ivana Kopecka
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 30/5, 166 12 Prague 6, Czech Republic
| | - Lenka Cermakova
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 30/5, 166 12 Prague 6, Czech Republic
| | - Katerina Fialova
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 30/5, 166 12 Prague 6, Czech Republic
| | - Katerina Novotna
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 30/5, 166 12 Prague 6, Czech Republic
| | - Tomas Cajthaml
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Rita K Henderson
- School of Chemical Engineering, The University of New South Wales, Sydney 2052, Australia
| | - Lenka Pivokonska
- Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 30/5, 166 12 Prague 6, Czech Republic
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11
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Zeng S, Kan E. Adsorption and regeneration on iron-activated biochar for removal of microcystin-LR. CHEMOSPHERE 2021; 273:129649. [PMID: 33497982 DOI: 10.1016/j.chemosphere.2021.129649] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 06/12/2023]
Abstract
Novel iron activated biochars (FA-BCs) were prepared via simultaneous pyrolysis and activation of FeCl3-pretreated bermudagrass (BG) for removing microcystin-LR (MC-LR) in aqueous solution. Compared to the raw BC (without activation), the surface area and adsorption capacity of FA-BC at iron impregnation ratio of 2 (2 g FeCl3/g BG) were enhanced from 86 m2/g and 0.76 mg/g to 835 m2/g and 9.00 mg/g. Moreover, FA-BC possessed various iron oxides at its surface which provided the catalytic capacity for regeneration of MC-LR spent FA-BC and magnetic separation after the MC-LR adsorption. Possible mechanisms for the MC-LR adsorption onto FA-BC would include electrostatic attraction, π+-π, hydrogen bond, and hydrophobic interactions. The detailed adsorption studies indicated mainly chemisorption and intra-particle diffusion limitation would participate in the adsorption process. The thermal regeneration at 300 °C kept high regeneration efficiency (99-100%) for the MC-LR spent FA-BC during four cycles of adsorption-regeneration. In addition, the high regeneration efficiency (close to 100%) was also achieved by persulfate oxidation-driven regeneration. FA-BC also exhibited high adsorption capacity for the MC-LR from the real lake water to meet the MC-LR concentration below 1 μg/L as a safe guideline suggested by WHO.
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Affiliation(s)
- Shengquan Zeng
- Department of Biological and Agricultural Engineering & Texas A&M AgriLife Research Center, Texas A&M University, TX, 77843, USA
| | - Eunsung Kan
- Department of Biological and Agricultural Engineering & Texas A&M AgriLife Research Center, Texas A&M University, TX, 77843, USA; Department of Wildlife, Sustainability, and Ecosystem Sciences, Tarleton State University, TX, 76401, USA.
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12
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First Report on Cyanotoxin (MC-LR) Removal from Surface Water by Multi-Soil-Layering (MSL) Eco-Technology: Preliminary Results. WATER 2021. [DOI: 10.3390/w13101403] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cyanobacteria blooms occur frequently in freshwaters around the world. Some can produce and release toxic compounds called cyanotoxins, which represent a danger to both the environment and human health. Microcystin-LR (MC-LR) is the most toxic variant reported all over the world. Conventional water treatment methods are expensive and require specialized personnel and equipment. Recently, a multi-soil-layering (MSL) system, a natural and low-cost technology, has been introduced as an attractive cost-effective, and environmentally friendly technology that is likely to be an alternative to conventional wastewater treatment methods. This study aims to evaluate, for the first time, the efficiency of MSL eco-technology to remove MC-LR on a laboratory scale using local materials. To this end, an MSL pilot plant was designed to treat distilled water contaminated with MC-LR. The pilot was composed of an alternation of permeable layers (pozzolan) and soil mixture layers (local sandy soil, sawdust, charcoal, and metallic iron on a dry weight ratio of 70, 10, 10, and 10%, respectively) arranged in a brick-layer-like pattern. MSL pilot was continuously fed with synthetic water containing distilled water contaminated with increasing concentrations of MC-LR (0.18–10 µg/L) at a hydraulic loading rate (HLR) of 200 L m−2 day−1. The early results showed MC-LR removal of above 99%. Based on these preliminary results, the multi-soil-layering eco-technology could be considered as a promising solution to treat water contaminated by MC-LR in order to produce quality water for irrigation or recreational activities.
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Recent Advancements in the Removal of Cyanotoxins from Water Using Conventional and Modified Adsorbents—A Contemporary Review. WATER 2020. [DOI: 10.3390/w12102756] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The prevalence of cyanobacteria is increasing in freshwaters due to climate change, eutrophication, and their ability to adapt and thrive in changing environmental conditions. In response to various environmental pressures, they produce toxins known as cyanotoxins, which impair water quality significantly. Prolonged human exposure to cyanotoxins, such as microcystins, cylindrospermopsin, saxitoxins, and anatoxin through drinking water can cause severe health effects. Conventional water treatment processes are not effective in removing these cyanotoxins in water and advanced water treatment processes are often used instead. Among the advanced water treatment methods, adsorption is advantageous compared to other methods because of its affordability and design simplicity for cyanotoxins removal. This article provides a current review of recent developments in cyanotoxin removal using both conventional and modified adsorbents. Given the different cyanotoxins removal capacities and cost of conventional and modified adsorbents, a future outlook, as well as suggestions are provided to achieve optimal cyanotoxin removal through adsorption.
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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: 27] [Impact Index Per Article: 6.8] [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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Park JA, Kang JK, Jung SM, Choi JW, Lee SH, Yargeau V, Kim SB. Investigating Microcystin-LR adsorption mechanisms on mesoporous carbon, mesoporous silica, and their amino-functionalized form: Surface chemistry, pore structures, and molecular characteristics. CHEMOSPHERE 2020; 247:125811. [PMID: 31945720 DOI: 10.1016/j.chemosphere.2020.125811] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/20/2019] [Accepted: 01/01/2020] [Indexed: 06/10/2023]
Abstract
Microcystin-LR (MC-LR) is the most common cyanotoxin released from algal-blooms. The study investigated the MC-LR adsorption mechanisms by comparing adsorption performance of protonated mesoporous carbon/silica (MC-H, MS-H) and their amino-functionalized forms (MC-NH2 and MS-NH2) considering surface chemistry and pore characteristics. The maximum MC-LR adsorption capacity (Langmuir model) of MC-H (37.87 mg/g) was the highest followed by MC-NH2 (29.25 mg/g) and MS-NH2 (23.03 mg/g), because pore structure is partly damaged during amino-functionalization. However, MC-NH2 (k2 = 0.042 g/mg/min) reacted faster with MC-LR than MC-H during early-stage adsorption due to enhancing electrostatic interactions. Intra-particle diffusion model fit indicated Kp,1 of MC-H (2.11 mg/g/min1/2) was greater than MC-NH2 due to its greater surface area and pore volume. Also, large mesopore diameters are favorable to MC-LR adsorption by pore diffusion. The effect of adsorbate molecular size on adsorption trend against MC-H, MC-NH2 and MS-NH2 was determined by kinetic experiments using two dyes, reactive blue and acid orange: MS-NH2 achieved the highest adsorption for both dyes due to the large number of amino groups on its surface (41.2 NH2/nm2). Overall, it was demonstrated that adsorption of MC-LR on mesoporous materials is governed by (meso-)pore diffusion and π - π (and hydrophobic) interactions induced by carbon materials; in addition, positively-charged grafted amino groups enhance initial MC-LR adsorption rate.
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Affiliation(s)
- Jeong-Ann Park
- Department of Chemical Engineering, McGill University, 3610 University St., Montréal, H3A 0C5, Québec, Canada; Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jin-Kyu Kang
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Environmental Functional Materials and Water Treatment Laboratory, Department of Rural Systems Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sung-Mok Jung
- Korea Water and Wastewater Works Association, Seoul, 07379, Republic of Korea
| | - Jae-Woo Choi
- Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea; Division of Energy & Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Sang-Hyup Lee
- Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea; KU-KIST Green School, Graduate School of Energy and Environment, Korea University, Seoul, 02841, Republic of Korea
| | - Viviane Yargeau
- Department of Chemical Engineering, McGill University, 3610 University St., Montréal, H3A 0C5, Québec, Canada
| | - Song-Bae Kim
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Environmental Functional Materials and Water Treatment Laboratory, Department of Rural Systems Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
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Xu L, Zhou Z, Zhu L, Han Y, Lin Z, Feng W, Liu Y, Shuai X, Chen H. Antibiotic resistance genes and microcystins in a drinking water treatment plant. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 258:113718. [PMID: 31838385 DOI: 10.1016/j.envpol.2019.113718] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/08/2019] [Accepted: 12/01/2019] [Indexed: 06/10/2023]
Abstract
Problems with antibiotic resistance genes (ARGs) and secondary pollution from microcystins (MCs), caused by cyanobacterial blooms have become significant global issues. These two pollutants co-occur in drinking water treatment plants (DWTPs), but the exact relationships between them requires further clarification. Here, a high-throughput quantitative real-time PCR and enzyme-linked immunosorbent assay were used to investigate the behavior of ARGs and MCs in a practical DWTP in the first place. After the on-site investigation, the effect of MCs on the horizontal transfer of ARGs was studied under laboratory conditions, and mechanisms explored at both cellular and molecular levels. MCs could promote the spread of ARGs, especially in relatively stationary and stable environments such as biofilms. MC-LR was the most efficient microcystin subtype promoting conjugative transfer, which was 25.13 times higher than for the control group. MCs affected the horizontal transfer of ARGs by regulating a series of gene systems involved in conjugative transfer, stimulating the formation of reactive oxygen species (ROS), and increasing cell membrane permeability. This study can provide a theoretical basis for the control of ARGs and MCs in DWTPs, which is of great significance for the scientific assessment of drinking water safety.
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Affiliation(s)
- Lan Xu
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Zhenchao Zhou
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Lin Zhu
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yue Han
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Zejun Lin
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Wanqiu Feng
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yang Liu
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xinyi Shuai
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Hong Chen
- Institute of Environmental Technology, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
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Tang Y, Chai Y, Liu X, Li L, Yang L, Liu P, Zhou Y, Ju H, Cheng Y. A photoelectrochemical aptasensor constructed with core-shell CuS-TiO 2 heterostructure for detection of microcystin-LR. Biosens Bioelectron 2018; 117:224-231. [PMID: 29906770 DOI: 10.1016/j.bios.2018.06.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/29/2018] [Accepted: 06/04/2018] [Indexed: 01/15/2023]
Abstract
In this work, a CuS-TiO2 heterojunction composite was prepared by dispersedly depositing CuS nanoparticles on TiO2 nanospheres surface with a hydrothermal method, and was then used to construct a photoelectrochemical (PEC) aptasensor for sensitive detection of microcystin-LR (MC-LR) in aquatic environment. The energy bands of CuS nanoparticles and spherical anatase TiO2 were well matched, which enhanced the photo-to-current conversion efficiency. The composite exhibited the enhanced visible light absorption, the improved separation of photo-generated charges, and the reduced self-aggregation of CuS nanoparticles, leading to the enhanced photocurrent response. The PEC aptasensor was constructed by immobilizing CuS-TiO2 composite on ITO electrode with chitosan film that further covalently bound aminated aptamer. After the target, microcystin-LR (MC-LR) as an analyte model, was captured by the aptamer on the aptasensor, it could be oxidized by the photo-generated hole to impede the electron-hole recombination and further amplify the photocurrent. The PEC aptasensor showed superior analytical performance for MC-LR with a linear range of 5.0 × 10-5 nM to 250 nM and a detection limit of 2.0 × 10-5 nM. The detection results with the aptasensor for practical water samples indicated its promising application in environmental monitoring.
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Affiliation(s)
- Yunfei Tang
- Henan Joint International Research Laboratory of environmental pollution control materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China
| | - Yun Chai
- Henan Joint International Research Laboratory of environmental pollution control materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China
| | - Xiaoqiang Liu
- Henan Joint International Research Laboratory of environmental pollution control materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China.
| | - Lele Li
- Henan Joint International Research Laboratory of environmental pollution control materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China
| | - Liwei Yang
- Henan Joint International Research Laboratory of environmental pollution control materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China
| | - Peipei Liu
- Henan Joint International Research Laboratory of environmental pollution control materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China
| | - Yanmei Zhou
- Henan Joint International Research Laboratory of environmental pollution control materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China
| | - Huangxian Ju
- State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210023, PR China.
| | - Yunzhi Cheng
- Journal of Henan University (Medical Science), Henan University, Kaifeng, Henan Province 475004, PR China
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Mashile PP, Mpupa A, Nomngongo PN. Adsorptive removal of microcystin-LR from surface and wastewater using tyre-based powdered activated carbon: Kinetics and isotherms. Toxicon 2018; 145:25-31. [PMID: 29501826 DOI: 10.1016/j.toxicon.2018.02.044] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 02/16/2018] [Accepted: 02/23/2018] [Indexed: 12/01/2022]
Abstract
Microcystin LR (MC-LR) is a highly toxic compound and it is known for its adverse health effect on both humans and animals. Due to the ineffectiveness of conventional water treatments methods, for the past decades, researchers have been developing cost-effective ways of removing MC-LR from water bodies. This study reports the application of powdered activated carbon (PAC) obtained from the waste tyre for the removal of MC-LR. The choice of the adsorbent was chosen due to its attractive properties. The prepared tyre-based PAC was found to have the large surface area (1111 m2 g-1). The detection of MC-LR was achieved using high performance liquid chromatography (HPLC) coupled with a PDA detector. The experimental parameters (such as optimum pH, dosage and contact time) affecting the removal of MC-LR using tyre based-powdered activated carbon were optimized using response surface methodology (RSM). Maximum removal of MC-LR was achieved under the following optimum conditions; sample pH 4, carbon dosage concentration 10,000 mg L-1 and contact time of 34 min. Under optimum conditions, kinetic studies and adsorption isotherms reflected better fit for pseudo-second-order rate and Langmuir isotherm model, respectively. The optimized method was applied for the removal of MC-LR in wastewater sample. The effluent and influent sample contained initial concentrations ranging from 0.52 to 8.54 μg L-1 and the removal efficiency was 100%.
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Affiliation(s)
- Phodiso P Mashile
- Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Johannesburg, 2028, South Africa
| | - Anele Mpupa
- Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Johannesburg, 2028, South Africa
| | - Philiswa N Nomngongo
- Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Johannesburg, 2028, South Africa.
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Wan Z, Li K. Effect of pre-pyrolysis mode on simultaneous introduction of nitrogen/oxygen-containing functional groups into the structure of bagasse-based mesoporous carbon and its influence on Cu(II) adsorption. CHEMOSPHERE 2018; 194:370-380. [PMID: 29223116 DOI: 10.1016/j.chemosphere.2017.11.181] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/13/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
A convenient effective microwave pre-pyrolysis treatment to synthesize biomass-based mesoporous carbon with higher nitrogen/oxygen-chelating adsorption for Cu(II) is reported here, in which phosphoric acid impregnated bagasse was used as a microwave absorber and porogen. For comparison, conventional electric-heating pyrolyzed carbon was prepared and doped with nitrogen/oxygen groups. Nitrogen adsorption, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS) and batch adsorption were employed to investigate the effects of the two pre-pyrolysis modes on the sample physicochemical and Cu(II) adsorptive properties. The 22-min-microwave-pyrolyzed bagasse mesoporous activated carbon (MBAC, 85.32% mesoporosity) contained 10.52% O, which is 3.94% more than electric-heating pyrolyzed mesoporous activated carbon (89.52% mesoporosity). After electrophilic aromatic substitutions of N/O doping, the former possessed more N (5.83%) and more O (21.40%), confirming that time-saving energy-efficient microwave pyrolysis favors the formation of defective C/O atoms in or at the edges of the graphite layer of MBAC, which are highly active and tend to act as preferred reactive positions for the doping of N/O-containing groups simultaneously compared with conventional electric-heating pyrolysis. These N and O species existed mainly as COOH, OH, NH and NH2 functional groups, and were confirmed by XPS to be active sites for metal binding via electrostatic attraction, hydrogen bonding, a chelate effect and complexation, resulting in the great enhancement of Cu(II) adsorption. Langmuir isotherm and pseudo-second-order kinetic fitting further proved that Cu(II) adsorption by N/O-doped MBAC is ascribed mainly to chemisorption. Therefore, rapid microwave pre-pyrolysis provides a promising route to prepare excellent-performance N/O-doped carbon adsorbents.
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Affiliation(s)
- Zeqing Wan
- College of Engineering, Nanjing Agricultural University, Nanjing 210031, China.
| | - Kunquan Li
- College of Engineering, Nanjing Agricultural University, Nanjing 210031, China.
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Dugan NR, Smith S, Sanan TT. The Impacts of Potassium Permanganate and Powdered Activated Carbon on Cyanotoxin Release. ACTA ACUST UNITED AC 2018; 110:31-42. [PMID: 31073245 DOI: 10.1002/awwa.1125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bench-scale trials were performed to: (1) Expose Microcystis aeruginosa cells to potassium permanganate doses of 1, 3 and 5 mg/L, at contact times of 15, 30 and 90 minutes, pH levels of 7 and 9, and turbidities of 0.1, 5 and 20 NTU; (2) Compare the impacts of oxidation alone and oxidation plus powdered activated carbon for the final 60 minutes of contact time and (3) evaluate the impact of these treatment conditions on extracellular microcystins, extra- plus intracellular (combined) microcystins, cell membrane integrity and chlorophyll-a concentrations. Toxin releases from the cells were observed at both pH levels. The greatest toxin releases were observed at the lowest KMnO4 doses. The toxin releases were accompanied by relatively stable total cell counts, increases in membrane compromised cells and decreases in chlorophyll-a. The application of 10 mg/L PAC resulted in extracellular toxin concentrations that were markedly lower than those observed in oxidant-only situations.
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Affiliation(s)
- Nicholas R Dugan
- U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, 513-569-7239,
| | - Samantha Smith
- Pegasus Technical Services, 46 East Hollister Street, Cincinnati, OH 45219, 513-569-7681,
| | - Toby T Sanan
- U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, 513-569-7667,
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Wei J, Qileng A, Yan Y, Lei H, Zhang S, Liu W, Liu Y. A novel visible-light driven photoelectrochemical immunosensor based on multi-amplification strategy for ultrasensitive detection of microcystin-LR. Anal Chim Acta 2017; 994:82-91. [DOI: 10.1016/j.aca.2017.09.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/12/2017] [Accepted: 09/15/2017] [Indexed: 01/07/2023]
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