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Rivenbark KJ, Fawkes LS, Nikkhah H, Wang M, Sansom GT, Beykal B, Wade TL, Phillips TD. Using L. minor and C. elegans to assess the ecotoxicity of real-life contaminated soil samples and their remediation by clay- and carbon-based sorbents. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 347:123762. [PMID: 38479705 PMCID: PMC11323775 DOI: 10.1016/j.envpol.2024.123762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/21/2024] [Accepted: 03/09/2024] [Indexed: 03/18/2024]
Abstract
Toxic substances, such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals, can accumulate in soil, posing a risk to human health and the environment. To reduce the risk of exposure, rapid identification and remediation of potentially hazardous soils is necessary. Adsorption of contaminants by activated carbons and clay materials is commonly utilized to decrease the bioavailability of chemicals in soil and environmental toxicity in vitro, and this study aims to determine their efficacy in real-life soil samples. Two ecotoxicological models (Lemna minor and Caenorhabditis elegans) were used to test residential soil samples, known to contain an average of 5.3, 262, and 9.6 ppm of PAHs, lead, and mercury, for potential toxicity. Toxicity testing of these soils indicated that 86% and 58% of soils caused ≤50% inhibition of growth and survival of L. minor and C. elegans, respectively. Importantly, 3 soil samples caused ≥90% inhibition of growth in both models, and the toxicity was positively correlated with levels of heavy metals. These toxic soil samples were prioritized for remediation using activated carbon and SM-Tyrosine sorbents, which have been shown to immobilize PAHs and heavy metals, respectively. The inclusion of low levels of SM-Tyrosine protected the growth and survival of L. minor and C. elegans by 83% and 78%, respectively from the polluted soil samples while activated carbon offered no significant protection. These results also indicated that heavy metals were the driver of toxicity in the samples. Results from this study demonstrate that adsorption technologies are effective strategies for remediating complex, real-life soil samples contaminated with hazardous pollutants and protecting natural soil and groundwater resources and habitats. The results highlight the applicability of these ecotoxicological models as rapid screening tools for monitoring soil quality and verifying the efficacy of remediation practices.
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Affiliation(s)
- Kelly J Rivenbark
- Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA; Department of Veterinary Physiology and Pharmacology, School of Veterinary Medicine, Texas A&M University, College Station, TX, USA
| | - Leanne S Fawkes
- Department of Environmental and Occupational Health, University of Texas School of Public Health San Antonio at the University of Texas Health Science Center at San Antonio, TX, USA
| | - Hasan Nikkhah
- Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs, CT, USA; Center for Clean Energy Engineering, University of Connecticut, Storrs, CT, USA
| | - Meichen Wang
- Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA; Department of Veterinary Physiology and Pharmacology, School of Veterinary Medicine, Texas A&M University, College Station, TX, USA
| | - Garett T Sansom
- Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA; Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, College Station, TX, USA
| | - Burcu Beykal
- Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs, CT, USA; Center for Clean Energy Engineering, University of Connecticut, Storrs, CT, USA
| | - Terry L Wade
- Geochemical & Environmental Research Group, Texas A&M University, College Station, TX, USA
| | - Timothy D Phillips
- Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA; Department of Veterinary Physiology and Pharmacology, School of Veterinary Medicine, Texas A&M University, College Station, TX, USA.
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Rivenbark KJ, Lilly K, Wang M, Tamamis P, Phillips TD. Green-engineered clay- and carbon-based composite materials for the adsorption of benzene from air. JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 2024; 12:111836. [PMID: 38576544 PMCID: PMC10993424 DOI: 10.1016/j.jece.2023.111836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Benzene is a carcinogenic volatile organic compound (VOC) that is ubiquitously detected in enclosed spaces due to emissions from cooking activities, building materials, and cleaning products. To remove benzene and other VOCs from indoor air and protect public health, traditional fabric filters have been modified to contain activated carbons to enhance the filtration efficacy. In this study, composites derived from natural clay minerals and activated carbon were individually green-engineered with chlorophylls and were attached to the surface of filter materials. These systems were assessed for their adsorption of benzene from air using in vitro and in silico methods. Isothermal, thermodynamic, and kinetic experiments indicated that all green-engineered composites had improved binding profiles for benzene, as demonstrated by increased binding affinities (Kf ≥ 900 vs 472) and lower values of Gibbs free energy (ΔG = -16.8 vs -15.2) compared to activated carbon. Adsorption of benzene to all composites was achieved quickly (< 30 min), and the green-engineered composites also showed low levels of desorption (≤ 25%). While free chlorophyll is known to be photosensitive, chlorophylls in the green-engineered composites showed photostability and maintained high binding rates (≥ 70%). Additionally, the in silico simulations demonstrated the significant contribution of chlorophyll for the overall binding of benzene in clay systems and that chlorophyll could contribute to benzene binding in the carbon-based systems. Together, these studies indicated that novel, green-engineered composite materials can be effective filter sorbents to enhance the removal of benzene from air.
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Affiliation(s)
- Kelly J. Rivenbark
- Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA
- Department of Veterinary Physiology and Pharmacology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Kendall Lilly
- Department of Materials Science and Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Meichen Wang
- Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA
- Department of Veterinary Physiology and Pharmacology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Phanourios Tamamis
- Department of Materials Science and Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
- Artie McFerrin Department of Chemical Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Timothy D. Phillips
- Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA
- Department of Veterinary Physiology and Pharmacology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
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Wang M, Lilly K, Martin LMA, Xu W, Tamamis P, Phillips TD. Adsorption and removal of polystyrene nanoplastics from water by green-engineered clays. WATER RESEARCH 2024; 249:120944. [PMID: 38070346 DOI: 10.1016/j.watres.2023.120944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/24/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024]
Abstract
Human exposure to micro- and nanoplastics (MNPs) commonly occurs through the consumption of contaminated drinking water. Among these, polystyrene (PS) is well-characterized and is one of the most abundant MNPs, accounting for 10 % of total plastics. Previous studies have focused on carbonaceous materials to remove MNPs by filtration, but most of the work has involved microplastics since nanoplastics (NPs) are smaller in size and more difficult to measure and remove. To address this need, green-engineered chlorophyll-amended sodium and calcium montmorillonites (SMCH and CMCH) were tested for their ability to bind and detoxify parent and fluorescently labeled PSNP using in vitro, in silico, and in vivo assays. In vitro dosimetry, isothermal analyses, thermodynamics, and adsorption/desorption kinetic models demonstrated 1) high binding capacities (173-190 g/kg), 2) high affinities (103), and 3) chemisorption as suggested by low desorption (≤42 %) and high Gibbs free energy and enthalpy (>|-20| kJ/mol) in the Langmuir and pseudo-second-order models. Computational dynamics simulations for 30 and 40 monomeric units of PSNP depicted that chlorophyll amendments increased the binding percentage and contributed to the sustained binding. Also, 64 % of PSNP bind to both the head and tail of chlorophyll aggregates, rather than the head or tail only. Fluorescent PSNP at 100 nm and 30 nm that were exposed to Hydra vulgaris showed concentration-dependent toxicity at 20-100 µg/mL. Importantly, the inclusion of 0.05-0.3 % CMCH and SMCH significantly (p ≤ 0.01) and dose-dependently reduced PSNP toxicity in morphological changes and feeding rate. The bioassay validated the in vitro and in silico predictions about adsorption efficacy and mechanisms and suggested that CMCH and SMCH are efficacious binders for PSNP in water.
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Affiliation(s)
- Meichen Wang
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; Interdisciplinary Faculty of Toxicology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Kendall Lilly
- Department of Materials Science and Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA; Artie McFerrin Department of Chemical Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Leisha M A Martin
- Department of Life Sciences, Texas A&M University, Corpus Christi, TX 78412, USA
| | - Wei Xu
- Department of Life Sciences, Texas A&M University, Corpus Christi, TX 78412, USA
| | - Phanourios Tamamis
- Department of Materials Science and Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA; Artie McFerrin Department of Chemical Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Timothy D Phillips
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; Interdisciplinary Faculty of Toxicology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
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Wang M, Rivenbark KJ, Phillips TD. Kinetics of glyphosate and aminomethylphosphonic acid sorption onto montmorillonite clays in soil and their translocation to genetically modified corn. J Environ Sci (China) 2024; 135:669-680. [PMID: 37778837 PMCID: PMC10542765 DOI: 10.1016/j.jes.2023.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 10/03/2023]
Abstract
The co-occurrence of glyphosate (GLP) and aminomethylphosphonic acid (AMPA) in contaminated water, soil, sediment and plants is a cause for concern due to potential threats to the ecosystem and human health. A major route of exposure is through contact with contaminated soil and consumption of crops containing GLP and AMPA residues. However, clay-based sorption strategies for mixtures of GLP and AMPA in soil, plants and garden produce have been very limited. In this study, in vitro soil and in vivo genetically modified corn models were used to establish the proof of concept that the inclusion of clay sorbents in contaminated soils will reduce the bioavailability of GLP and AMPA in soils and their adverse effects on plant growth. Effects of chemical concentration (1-10 mg/kg), sorbent dose (0.5%-3% in soil and 0.5%-1% in plants) and duration (up to 28 days) on sorption kinetics were studied. The time course results showed a continuous GLP degradation to AMPA. The inclusion of calcium montmorillonite (CM) and acid processed montmorillonite (APM) clays at all doses significantly and consistently reduced the bioavailability of both chemicals from soils to plant roots and leaves in a dose- and time-dependent manner without detectable dissociation. Plants treated with 0.5% and 1% APM inclusion showed the highest growth rate (p ≤ 0.05) and lowest chemical bioavailability with up to 76% reduction in roots and 57% reduction in leaves. Results indicated that montmorillonite clays could be added as soil supplements to reduce hazardous mixtures of GLP and AMPA in soils and plants.
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Affiliation(s)
- Meichen Wang
- Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TX 77845, USA
| | - Kelly J Rivenbark
- Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TX 77845, USA
| | - Timothy D Phillips
- Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TX 77845, USA.
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Zhang Y, Yan Y, Dai Q, Tan J, Wang C, Zhou H, Hu Z. Glyphosate spraying exacerbates nitrogen and phosphorus loss in karst slope farmland. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 196:80. [PMID: 38141083 DOI: 10.1007/s10661-023-12238-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023]
Abstract
Glyphosate herbicide is an indispensable material in agricultural production. In order to explore the potential environmental effects of glyphosate application in karst slope farmland, this paper used a variable slope steel tank to simulate the surface microtopography and underground pore structure characteristics of karst slope farmland, and combined with artificial rainfall experiments to explore the migration path of glyphosate in karst slope farmland and the impact of spraying glyphosate on soil nitrogen and phosphorus loss. The results showed that under the condition of heavy rain, glyphosate in karst slope farmland was mainly transported and diffused by surface runoff, supplemented by underground runoff; secondly, in different hydrological paths, glyphosate directly affected the content of nitrogen and phosphorus in runoff, and all showed extremely significant positive correlation (p < 0.001). In addition, rainfall conditions such as rainfall intensity, rainfall duration, and runoff affected the content of nitrogen and phosphorus in runoff to varying degrees. In conclusion, the application of glyphosate significantly increased the content of nitrogen and phosphorus in different runoff and accelerated the loss of nitrogen and phosphorus from soil, which not only led to soil degradation, but also threatened the safety of aquatic ecosystem. Therefore, in the prevention and control of agricultural non-point source pollution, the threat of glyphosate to the surrounding aquatic ecosystem cannot be ignored, especially in karst areas with frequent rainstorms and serious water erosion, long-term monitoring and risk assessment of glyphosate are needed.
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Affiliation(s)
- You Zhang
- College of Forestry, Guizhou University, Guiyang, 550025, People's Republic of China
- Tongren Polytechnic College, Tongren, 554300, People's Republic of China
- Institute of Soil Erosion and Ecological Restoration, Guizhou University, Guiyang, 550025, People's Republic of China
| | - Youjin Yan
- College of Forestry, Guizhou University, Guiyang, 550025, People's Republic of China
- Institute of Soil Erosion and Ecological Restoration, Guizhou University, Guiyang, 550025, People's Republic of China
| | - Quanhou Dai
- College of Forestry, Guizhou University, Guiyang, 550025, People's Republic of China.
- Institute of Soil Erosion and Ecological Restoration, Guizhou University, Guiyang, 550025, People's Republic of China.
| | - Juan Tan
- College of Forestry, Guizhou University, Guiyang, 550025, People's Republic of China
- Institute of Soil Erosion and Ecological Restoration, Guizhou University, Guiyang, 550025, People's Republic of China
| | - Chenyang Wang
- College of Forestry, Guizhou University, Guiyang, 550025, People's Republic of China
- Institute of Soil Erosion and Ecological Restoration, Guizhou University, Guiyang, 550025, People's Republic of China
| | - Hong Zhou
- College of Forestry, Guizhou University, Guiyang, 550025, People's Republic of China
- Institute of Soil Erosion and Ecological Restoration, Guizhou University, Guiyang, 550025, People's Republic of China
| | - Zeyin Hu
- College of Forestry, Guizhou University, Guiyang, 550025, People's Republic of China
- Institute of Soil Erosion and Ecological Restoration, Guizhou University, Guiyang, 550025, People's Republic of China
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Wimmer B, Langarica-Fuentes A, Schwarz E, Kleindienst S, Huhn C, Pagel H. Mechanistic modeling indicates rapid glyphosate dissipation and sorption-driven persistence of its metabolite AMPA in soil. JOURNAL OF ENVIRONMENTAL QUALITY 2023; 52:393-405. [PMID: 36417923 DOI: 10.1002/jeq2.20437] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
Residual concentrations of glyphosate and its main transformation product aminomethylphosphonic acid (AMPA) are often observed in soils. The factors controlling their biodegradation are currently not well understood. We analyzed sorption-limited biodegradation of glyphosate and AMPA in soil with a set of microcosm experiments. A mechanistic model that accounts for equilibrium and kinetic sorption facilitated interpretation of the experimental results. Both compounds showed a biphasic dissipation with an initial fast (up to Days 7-10) and subsequent slower transformation rate, pointing to sorption-limited degradation. Glyphosate transformation was well described by considering only equilibrium sorption. Model simulations suggested that only 0.02-0.13% of total glyphosate was present in the soil solution and thus bioavailable. Glyphosate transformation was rapid in solution (time required for 50 % dissipation of the total initially added chemical [DT50 ] = 3.9 min), and, despite strong equilibrium sorption, total glyphosate in soil dissipated quickly (DT50 = 2.4 d). Aminomethylphosphonic acid dissipation kinetics could only be described when considering both equilibrium and kinetic sorption. In comparison to glyphosate, the model simulations showed that a higher proportion of total AMPA was dissolved and directly bioavailable (0.27-3.32%), but biodegradation of dissolved AMPA was slower (DT50 = 1.9 h). The model-based data interpretation suggests that kinetic sorption strongly reduces AMPA bioavailability, leading to increased AMPA persistence in soil (DT50 = 12 d). Thus, strong sorption combined with rapid degradation points to low risks of glyphosate leaching by vertical transport through soil in the absence of preferential flow. Ecotoxicological effects on soil microorganisms might be reduced. In contrast, AMPA persists, rendering these risks more likely.
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Affiliation(s)
- Benedikt Wimmer
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Univ., Tübingen, Germany
| | - Adrian Langarica-Fuentes
- Center for Applied Geosciences/Geo- and Environmental Research Center, Eberhard Karls Univ., Tübingen, Germany
| | - Erik Schwarz
- Dep. of Biogeophysics, Institute of Soil Science and Land Evaluation, Univ. of Hohenheim, Stuttgart, Germany
- Dep. of Physical Geography and Bolin Centre for Climate Research, Stockholm Univ., Stockholm, Sweden
| | - Sara Kleindienst
- Center for Applied Geosciences/Geo- and Environmental Research Center, Eberhard Karls Univ., Tübingen, Germany
- Dep. of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), Univ. of Stuttgart, Stuttgart, Germany
| | - Carolin Huhn
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Univ., Tübingen, Germany
| | - Holger Pagel
- Dep. of Biogeophysics, Institute of Soil Science and Land Evaluation, Univ. of Hohenheim, Stuttgart, Germany
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Wang M, Rivenbark KJ, Phillips TD. Adsorption and detoxification of glyphosate and aminomethylphosphonic acid by montmorillonite clays. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:11417-11430. [PMID: 36097303 PMCID: PMC10022482 DOI: 10.1007/s11356-022-22927-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/03/2022] [Indexed: 06/03/2023]
Abstract
The co-occurrence of mixtures of glyphosate (GLP) and aminomethylphosphonic acid (AMPA) in contaminated water, soil, sediment, and plants is a cause for concern due to potential threats to the ecosystem and human health. Major routes of exposure include contact with contaminated water and soil and through consumption of crops containing GLP and AMPA residues. Calcium montmorillonite (CM) and acid-processed montmorillonite (APM) clays were investigated for their ability to tightly sorb and detoxify GLP and AMPA mixtures. In vitro adsorption and desorption isotherms and thermodynamic analysis indicated saturable Langmuir binding of both chemicals with high capacities, affinities, enthalpies, and free energies of sorption and low desorption rates. In silico computational modeling indicated that both GLP and AMPA can be readily absorbed onto clay surfaces through electrostatic interactions and hydrogen bonding. The safety and efficacy of the clays were confirmed using well-established living organisms, including an aquatic cnidarian (Hydra vulgaris), a soil nematode (Caenorhabditis elegans), and a floating plant (Lemna minor). Low levels of clay inclusion (0.05% and 0.2%) in the culture medium resulted in increased growth and protection against chemical mixtures based on multiple endpoints. Results indicated that montmorillonite clays may be used to bind mixtures of GLP and AMPA in water, soil, and plants.
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Affiliation(s)
- Meichen Wang
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Kelly J Rivenbark
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Timothy D Phillips
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA.
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Ghavamifar S, Naidu R, Mozafari V, Li Z. Can calcite play a role in the adsorption of glyphosate? A comparative study with a new challenge. CHEMOSPHERE 2023; 311:136922. [PMID: 36273612 DOI: 10.1016/j.chemosphere.2022.136922] [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: 08/15/2022] [Revised: 09/14/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
Calcite as a sorbent can interact with both inorganic and organic substances through their functional groups. To measure its adsorption ability, another sorbent, saponite was selected because it can sorb glyphosate, an organic compound with a polar molecule and widely used as a herbicide. In this study, the two sorbents calcite and saponite were saturated by calcium chloride, and characterized by SEM-EDX, X-ray diffraction, and Zeta Potential Analyzer to investigate their capacity to sorb glyphosate. After saturation, the saponite became homoionic Ca-saponite with minor changes in morphology and specific surface area. But, the morphology of calcite transformed from rhombohedron to scalenohedron, with an increase of 75-folds in its specific surface, and the zeta potential became positive in alkaline pH, which contradicts the results of all previous research. The modified sorbents (Ca-calcite and Ca-saponite) were added to two soil samples to investigate each sorbent's effect on glyphosate sorption. Adsorption isotherm and percentage of glyphosate desorbed revealed the difference in binding and adsorption sites. The Langmuir and Temkin models fitted isotherm data in low concentrations better and suggested chemosorption for the uptake of glyphosate. FTIR analyses of samples with and without glyphosate were compared and results suggested that the bulk of adsorption happened in siloxane groups and on calcium carbonates surfaces.
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Affiliation(s)
- Sara Ghavamifar
- Department of Soil Science, College of Agricultural Science, Vali-e-Asr University of Rafsanjan, Iran.
| | - Ravi Naidu
- Global Centre for Environmental Remediation (GCER), College of Engineering Science and Environment, The University of Newcastle, Callaghan, NSW, 2308, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Vahid Mozafari
- Department of Soil Science, College of Agricultural Science, Vali-e-Asr University of Rafsanjan, Iran
| | - Zhaohui Li
- Department of Geosciences, University of Wisconsin - Parkside, Kenosha, WI, 53144, USA
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Rivenbark KJ, Wang M, Lilly K, Tamamis P, Phillips TD. Development and characterization of chlorophyll-amended montmorillonite clays for the adsorption and detoxification of benzene. WATER RESEARCH 2022; 221:118788. [PMID: 35777320 PMCID: PMC9662585 DOI: 10.1016/j.watres.2022.118788] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
After disasters, such as forest fires and oil spills, high levels of benzene (> 1 ppm) can be detected in the water, soil, and air surrounding the disaster site, which poses a significant health risk to human, animal, and plant populations in the area. While remediation methods with activated carbons have been employed, these strategies are limited in their effectiveness due to benzene's inherent stability and limited retention to most surfaces. To address this problem, calcium and sodium montmorillonite clays were amended with a mixture of chlorophyll (a) and (b); their binding profile and ability to detoxify benzene were characterized using in vitro, in silico, and well-established ecotoxicological (ecotox) bioassay methods. The results of in vitro isothermal analyses indicated that chlorophyll-amended clays showed an improved binding profile in terms of an increased binding affinity (Kf = 668 vs 67), increased binding percentage (52% vs 11%), and decreased rates of desorption (28% vs 100%), compared to the parent clay. In silico simulation studies elucidated the adsorption mechanism and validated that the addition of the chlorophyll to the clays increased the adsorption of benzene through Van der Waals forces (i.e., aromatic π-π stacking and alkyl-π interactions). The sorbents were also assessed for their safety and ability to protect sensitive ecotox organisms (Lemna minor and Caenorhabditis elegans) from the toxicity of benzene. The inclusion of chlorophyll-amended clays in the culture medium significantly reduced benzene toxicity to both organisms, protecting C. elegans by 98-100% from benzene-induced mortality and enhancing the growth rates of L. minor. Isothermal analyses, in silico modeling, and independent bioassays all validated our proof of concept that benzene can be sequestered, tightly bound, and stabilized by chlorophyll-amended montmorillonite clays. These novel sorbents can be utilized during disasters and emergencies to decrease unintentional exposures from contaminated water, soil, and air.
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Affiliation(s)
- Kelly J Rivenbark
- Interdisciplinary Faculty of Toxicology, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Meichen Wang
- Interdisciplinary Faculty of Toxicology, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Kendall Lilly
- Department of Materials Science and Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Phanourios Tamamis
- Department of Materials Science and Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA; Artie McFerrin Department of Chemical Engineering, College of Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Timothy D Phillips
- Interdisciplinary Faculty of Toxicology, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
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Batch and Column Adsorption of Phosphorus by Modified Montmorillonite. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12115703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Phosphorus pollutants are a crucial component of water eutrophication. In this study, montmorillonite modified by Keggin Al13 and hexadecyltrimethyl ammonium (Al13-O-MMt) was used as an adsorbent to remove phosphorus from solutions and thus simulate the practice of a field trial, such as in wastewater. The ammonium molybdate spectrophotometric method was used to determine the concentrations of phosphorus in samples. In the batch experiment, phosphorus was adsorbed by original montmorillonite (MMt) and Al13-O-MMt at various pH values (6–9) to identify the effect of pH during the adsorption process. The batch adsorption results demonstrate that Al13-O-MMt can adsorb up to 93% of phosphorus at pH = 8. Six graduated amounts (0.01–0.25 g) of montmorillonite were tested at three different temperatures to determine the most suitable temperature and the minimum dosage of Al13-O-MMt needed for the adsorption of 200 mg/L phosphorus in a 30 mL solution, which was 0.1 g at 25 °C. Therefore, the adsorption capacity of Al13-O-MMt was found to be 60 mg/g. Subsequently, a column experiment was conducted. The results showed that the optimized dosage of Al13-O-MMt was 6.667 g for phosphorus adsorption with a concentration of 200 mg/L in 2000 mL solution, and the breakthrough time was 4794.67 min.
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11
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Wang M, Phillips TD. Inclusion of Montmorillonite Clays in Environmental Barrier Formulations to Reduce Skin Exposure to Water-Soluble Chemicals from Polluted Water. ACS APPLIED MATERIALS & INTERFACES 2022; 14:10.1021/acsami.2c04676. [PMID: 35536196 PMCID: PMC9646935 DOI: 10.1021/acsami.2c04676] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Dermal exposures to environmental chemicals can significantly affect the morphology and integrity of skin structure, leading to enhanced and deeper penetration of toxic chemicals. This problem can be magnified during disasters where hazardous water-soluble chemicals are readily mobilized and redistributed in the environment, threatening the health of vulnerable populations at the impacted sites. To address this issue, barrier emulsion formulations (EVB) have been developed consisting of materials that are generally recognized as safe, with the inclusion of medical grade carbon or calcium and sodium montmorillonite clays (CM and SM). In this study, the adsorption efficacy of five highly toxic and commonly occurring contaminants of concern, including important hydrophilic pesticides (glyphosate, acrolein, and paraquat) and per- and polyfluoroalkyl substances were characterized. EVB showed properties such as high stability, spreadability, low rupture strength, and neutral pH that were suitable for topical application on the skin. The in vitro adsorption results indicated that EVB and EVB-SM were effective, economically feasible, and favorable barrier formulations for hazardous chemical adsorption, as supported by high binding percentage, low desorption rates for an extended period of time, and high binding affinity. A pseudo-second-order kinetic model was best fitted for the adsorption process and the Freundlich model fit the adsorption isotherms with negative enthalpy values indicating spontaneous reactions that involve physisorption. The study, with varying temperatures and pH, showed that the adsorption reaction was exothermic and persistent. The results indicated that EVB and EVB-SM can be used as effective barriers to block dermal contact from water-soluble toxic pollutants during disasters.
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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
| | - 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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12
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Hearon SE, Orr AA, Moyer H, Wang M, Tamamis P, Phillips TD. Montmorillonite clay-based sorbents decrease the bioavailability of per- and polyfluoroalkyl substances (PFAS) from soil and their translocation to plants. ENVIRONMENTAL RESEARCH 2022; 205:112433. [PMID: 34875259 PMCID: PMC8760172 DOI: 10.1016/j.envres.2021.112433] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/06/2021] [Accepted: 11/23/2021] [Indexed: 05/23/2023]
Abstract
Consumption of food and water contaminated with per- and polyfluoroalkyl substances (PFAS) presents a significant risk for human exposure. There is limited data on high affinity sorbents that can be used to reduce the bioavailability of PFAS from soil and translocation to plants and garden produce. To address this need, montmorillonite clay was amended with the nutrients carnitine and choline to increase the hydrophobicity of the sorbent and the interlayer spacing. In this study, the binding of PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid) to parent and amended clays was characterized. Isothermal analyses were conducted at pH 7 and ambient temperature to simulate environmentally-relevant conditions. The data for all tested sorbents fit the Langmuir model indicating saturable binding sites with high capacities and affinities under neutral conditions. Amended montmorillonite clays had increased capacities for PFOA and PFOS (0.51-0.71 mol kg-1) compared to the parent clay (0.37-0.49 mol kg-1). Molecular dynamics (MD) simulations suggested that hydrophobic and electrostatic interactions at the terminal fluorinated carbon chains of PFAS compounds were major modes of surface interaction. The safety and efficacy of the clays were confirmed in a living organism (Lemna minor), where clays (at 0.1% inclusion) allowed for increased growth compared to PFOA and PFOS controls (p ≤ 0.01). Importantly, soil studies showed that 2% sorbent inclusion could significantly reduce PFAS bioavailability from soil (up to 74%). Studies in plants demonstrated that inclusion of 2% sorbent significantly reduced PFAS residues in cucumber plants (p ≤ 0.05). These results suggest that nutrient-amended clays could be included in soil to decrease PFAS bioavailability and translocation of PFAS to plants.
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Affiliation(s)
- Sara E Hearon
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77845, USA
| | - Asuka A Orr
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Haley Moyer
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77845, USA
| | - Meichen Wang
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77845, USA
| | - Phanourios Tamamis
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843, USA; Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Timothy D Phillips
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77845, USA.
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Martwong E, Chuetor S, Junthip J. Adsorption of Cationic Contaminants by Cyclodextrin Nanosponges Cross-Linked with 1,2,3,4-Butanetetracarboxylic Acid and Poly(vinyl alcohol). Polymers (Basel) 2022; 14:342. [PMID: 35054747 PMCID: PMC8778113 DOI: 10.3390/polym14020342] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/06/2022] [Accepted: 01/14/2022] [Indexed: 02/04/2023] Open
Abstract
Cationic organic pollutants (dyes and pesticides) are mainly hydrosoluble and easily contaminate water and create a serious problem for biotic and abiotic species. The elimination of these dangerous contaminants from water was accomplished by adsorption using cyclodextrin nanosponges. These nanosponges were elaborated by the cross-linking between 1,2,3,4-butanetetracarboxylic acid and β-cyclodextrin in the presence of poly(vinyl alcohol). Their physicochemical characteristics were characterized by gravimetry, acid-base titration, TGA, 13C NMR, ATR-FTIR, Raman, X-ray diffraction, and Stereomicroscopy. The BP5 nanosponges displayed 68.4% yield, 3.31 mmol/g COOH groups, 0.16 mmol/g β-CD content, 54.2% swelling, 97.0% PQ removal, 96.7% SO removal, and 98.3% MG removal for 25 mg/L of initial concentration. The pseudo-second-order model was suitable for kinetics using 180 min of contact time. Langmuir isotherm was suitable for isotherm with the maximum adsorption of 120.5, 92.6, and 64.9 mg/g for paraquat (PQ), safranin (SO), and malachite green (MG) adsorption, respectively. Finally, the reusability performance after five regeneration times reached 94.1%, 91.6%, and 94.6% for PQ, SO, and MG adsorption, respectively.
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Affiliation(s)
- Ekkachai Martwong
- Division of Science (Chemistry), Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, Phra Nakhon Si Ayutthaya 13000, Thailand;
| | - Santi Chuetor
- Department of Chemical Engineering, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok, Bangkok 10800, Thailand;
| | - Jatupol Junthip
- Faculty of Science and Technology, Nakhon Ratchasima Rajabhat University, Nakhon Ratchasima 30000, Thailand
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14
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Martwong E, Chuetor S, Junthip J. Adsorption of Paraquat by Poly(Vinyl Alcohol)-Cyclodextrin Nanosponges. Polymers (Basel) 2021; 13:4110. [PMID: 34883612 PMCID: PMC8658895 DOI: 10.3390/polym13234110] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/21/2021] [Accepted: 11/22/2021] [Indexed: 11/16/2022] Open
Abstract
The contamination of hydrosoluble pesticides in water could generate a serious problem for biotic and abiotic components. The removal of a hazardous agrochemical (paraquat) from water was achieved by adsorption processes using poly(vinyl alcohol)-cyclodextrin nanosponges, which were prepared with various formulations via the crosslinking between citric acid and β-cyclodextrin in the presence of poly(vinyl alcohol). The physicochemical properties of nanosponges were also characterized by different techniques, such as gravimetry, thermogravimetry, microscopy (SEM and Stereo), spectroscopy (UV-visible, NMR, ATR-FTIR, and Raman), acid-base titration, BET surface area analysis, X-ray diffraction, and ion exchange capacity. The C10D-P2 nanosponges displayed 60.2% yield, 3.14 mmol/g COOH groups, 0.335 mmol/g β-CD content, 96.4% swelling, 94.5% paraquat removal, 0.1766 m2 g-1 specific surface area, and 5.2 × 10-4 cm3 g-1 pore volume. The presence of particular peaks referring to specific functional groups on spectroscopic spectra confirmed the successful polycondensation on the reticulated nanosponges. The pseudo second-order model (with R2 = 0.9998) and Langmuir isotherm (with R2 = 0.9979) was suitable for kinetics and isotherm using 180 min of contact time and a pH of 6.5. The maximum adsorption capacity was calculated at 112.2 mg/g. Finally, the recyclability of these nanosponges was 90.3% of paraquat removal after five regeneration times.
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Affiliation(s)
- Ekkachai Martwong
- Division of Science (Chemistry), Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, Phra Nakhon Si Ayutthaya 13000, Thailand;
| | - Santi Chuetor
- Department of Chemical Engineering, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok, Bangkok 10800, Thailand;
| | - Jatupol Junthip
- Faculty of Science and Technology, Nakhon Ratchasima Rajabhat University, Nakhon Ratchasima 30000, Thailand
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15
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Guidelines to Study the Adsorption of Pesticides onto Clay Minerals Aiming at a Straightforward Evaluation of Their Removal Performance. MINERALS 2021. [DOI: 10.3390/min11111282] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Natural and modified clay minerals have been extensively used for the adsorption/desorption of organic substances, especially pesticides, from waters and wastewater, aiming at pollution control and more efficient use of the herbicides through controlled release. While natural clay minerals efficiently remove organic cations such as paraquat and diquat, the adsorption of anionic or neutral species demands surface chemical modification with, for instance, quaternary ammonium salts containing long alkyl chains. Basic pesticides, on the other hand, are better absorbed in clay minerals modified with polycations. Kinetic studies and adsorption/desorption isotherms provide the parameters needed to evaluate the clay mineral’s adsorptive performance towards the pollutant target. However, the direct comparison of these parameters is complicated because the experimental conditions, the analytical techniques, the kinetic and isotherm models, and the numerical fitting method differ among the various studies. The free-energy-related Langmuir constant depends on the degree of site occupation; that is, it depends on the concentration window used to construct the adsorption isotherm and, consequently, on the analytical technique used to quantify the free concentrations. This paper reviews pesticides’ adsorption on natural and modified clay minerals and proposes guidelines for designing batch adsorption/desorption studies to obtain easily comparable and meaningful adsorption parameters. Articles should clearly describe the experimental conditions such as temperature, contact time, total concentration window, the solution to adsorbent ratio, the analytical technique, and its detection and quantification limits, besides the fitting models. Research should also evaluate the competitive effects of humic substances, colloidal inorganic particles, and ionic strength to emulate real-world adsorption experiments.
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16
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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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17
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Orr A, Wang M, Beykal B, Ganesh HS, Hearon SE, Pistikopoulos EN, Phillips TD, Tamamis P. Combining Experimental Isotherms, Minimalistic Simulations, and a Model to Understand and Predict Chemical Adsorption onto Montmorillonite Clays. ACS OMEGA 2021; 6:14090-14103. [PMID: 34124432 PMCID: PMC8190805 DOI: 10.1021/acsomega.1c00481] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 05/11/2021] [Indexed: 05/05/2023]
Abstract
An attractive approach to minimize human and animal exposures to toxic environmental contaminants is the use of safe and effective sorbent materials to sequester them. Montmorillonite clays have been shown to tightly bind diverse toxic chemicals. Due to their promise as sorbents to mitigate chemical exposures, it is important to understand their function and rapidly screen and predict optimal clay-chemical combinations for further testing. We derived adsorption free-energy values for a structurally and physicochemically diverse set of toxic chemicals using experimental adsorption isotherms performed in the current and previous studies. We studied the diverse set of chemicals using minimalistic MD simulations and showed that their interaction energies with calcium montmorillonite clays calculated using simulation snapshots in combination with their net charge and their corresponding solvent's dielectric constant can be used as inputs to a minimalistic model to predict adsorption free energies in agreement with experiments. Additionally, experiments and computations were used to reveal structural and physicochemical properties associated with chemicals that can be adsorbed to calcium montmorillonite clay. These properties include positively charged groups, phosphine groups, halide-rich moieties, hydrogen bond donor/acceptors, and large, rigid structures. The combined experimental and computational approaches used in this study highlight the importance and potential applicability of analogous methods to study and design novel advanced sorbent systems in the future, broadening their applicability for environmental contaminants.
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Affiliation(s)
- Asuka
A. Orr
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, United States
- Texas
A&M Energy Institute, Texas A&M
University, College
Station, Texas 77843-3372, United States
| | - Meichen Wang
- Veterinary
Integrative Biosciences Department, College of Veterinary Medicine
and Biomedical Sciences, Texas A&M University, College Station, Texas 77843-3122, United States
| | - Burcu Beykal
- Texas
A&M Energy Institute, Texas A&M
University, College
Station, Texas 77843-3372, United States
| | - Hari S. Ganesh
- Texas
A&M Energy Institute, Texas A&M
University, College
Station, Texas 77843-3372, United States
| | - Sara E. Hearon
- Veterinary
Integrative Biosciences Department, College of Veterinary Medicine
and Biomedical Sciences, Texas A&M University, College Station, Texas 77843-3122, United States
| | - Efstratios N. Pistikopoulos
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, United States
- Texas
A&M Energy Institute, Texas A&M
University, College
Station, Texas 77843-3372, United States
| | - Timothy D. Phillips
- Veterinary
Integrative Biosciences Department, College of Veterinary Medicine
and Biomedical Sciences, Texas A&M University, College Station, Texas 77843-3122, United States
| | - Phanourios Tamamis
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843-3122, United States
- Texas
A&M Energy Institute, Texas A&M
University, College
Station, Texas 77843-3372, United States
- Department
of Materials Science and Engineering, Texas
A&M University, College
Station, Texas 77843-3003, United States
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18
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Wang M, Chen Z, Rusyn I, Phillips TD. Testing the efficacy of broad-acting sorbents for environmental mixtures using isothermal analysis, mammalian cells, and H. vulgaris. JOURNAL OF HAZARDOUS MATERIALS 2021; 408:124425. [PMID: 33162237 PMCID: PMC7904642 DOI: 10.1016/j.jhazmat.2020.124425] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 05/04/2023]
Abstract
The hazards associated with frequent exposure to polycyclic aromatic hydrocarbons (PAHs), pesticides, Aroclors, plasticizers, and mycotoxins are well established. Adsorption strategies have been proposed for the remediation of soil and water, although few have focused on the mitigation of mixtures. This study tested a hypothesis that broad-acting sorbents can be developed for diverse chemical mixtures. Adsorption of common and hazardous chemicals was characterized using isothermal analysis from Langmuir and Freundlich equations. The most effective sorbents included medical-grade activated carbon (AC), parent montmorillonite clay, acid-processed montmorillonite (APM), and nutrient-amended montmorillonite clays. Next, we tested the ability of broad-acting sorbents to prevent cytotoxicity of class-specific mixtures using 3 mammalian in vitro models (HLF, ESD3, and 3T3 cell lines) and the hydra assay. AC showed the highest efficacy for mitigating pesticides, plasticizers, PAHs, and mycotoxins. Clays, such as APM, were effective against pesticides, Aroclors, and mycotoxins, while amended clays were most effective against plasticizers. Finally, a sorbent mixture was shown to be broadly active. These results are supported by the high correlation coefficients for the Langmuir model with high capacity, affinity, and free energy, as well as the significant protection of cells and hydra (p < 0.05). The protection percentages in 3T3 cells and hydra showed the highest correlation as suggested by both Pearson and Spearman with r = 0.84 and rho = 0.73, respectively (p < 0.0001). Collectively, these studies showed that broad-acting sorbents may be effective in preventing toxic effects of chemical mixtures and provided information on the most effective sorbents based on adsorption isotherms, and in vitro and aquatic organism test methods.
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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, TX 77843, USA
| | - Zunwei Chen
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Ivan Rusyn
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Timothy D Phillips
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
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19
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Hearon SE, Wang M, McDonald TJ, Phillips TD. Decreased bioavailability of aminomethylphosphonic acid (AMPA) in genetically modified corn with activated carbon or calcium montmorillonite clay inclusion in soil. J Environ Sci (China) 2021; 100:131-143. [PMID: 33279026 PMCID: PMC7719843 DOI: 10.1016/j.jes.2020.06.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/24/2020] [Accepted: 06/24/2020] [Indexed: 05/20/2023]
Abstract
The widespread use of pesticides has resulted in detectable residues throughout the environment, sometimes at concentrations well above regulatory limits. Therefore, the development of safe, effective, field-practical, and economically feasible strategies to mitigate the effects of pesticides is warranted. Glyphosate is an organophosphorus herbicide that is degraded to aminomethylphosphonic acid (AMPA), a toxic and persistent metabolite that can accumulate in soil and sediment and translocate to plants. In this study, we investigated the binding efficacy of activated carbon (AC) and calcium montmorillonite (CM) clay to decrease AMPA bioavailability from soil and AMPA translocation to plants. Adsorption isotherms and thermodynamic studies on AC and CM were conducted and showed tight binding (enthalpy values >-20 kJ/mol) for AMPA with high capacities (0.25 mol/kg and 0.38 mol/kg, respectively), based on derivations from the Langmuir model. A hydra assay was utilized to indicate toxicity of AMPA and the inclusion of 1% AC and CM both resulted in 90% protection of the hydra (**p ≤ 0.01). Further studies in glyphosate-contaminated soil showed that AC and CM significantly reduced AMPA bioavailability by 53% and 44%, respectively. Results in genetically modified (GM) corn showed a conversion of glyphosate to AMPA in roots and sprouts over a 10-day exposure duration. Inclusion of AC and CM reduced AMPA residues in roots and sprouts by 47%-61%. These studies collectively indicate that AC and CM are effective sorbents for AMPA and could be used to reduce AMPA bioavailability from soil and AMPA residues in GM corn plants.
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Affiliation(s)
- Sara E Hearon
- Veterinary Integrative Biosciences Department College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station, TX 77845, USA
| | - Meichen Wang
- Veterinary Integrative Biosciences Department College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station, TX 77845, USA
| | - Thomas J McDonald
- Department of Environmental and Occupational Health School of Public Health, Texas A&M University, College Station, 400 Bizzell St College Station, TX 77843, USA
| | - Timothy D Phillips
- Veterinary Integrative Biosciences Department College of Veterinary Medicine and Biomedical Sciences, Texas A&M University College Station, TX 77845, USA.
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20
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Wang M, Bera G, Mitra K, Wade TL, Knap AH, Phillips TD. Tight sorption of arsenic, cadmium, mercury, and lead by edible activated carbon and acid-processed montmorillonite clay. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:6758-6770. [PMID: 33009611 PMCID: PMC7855320 DOI: 10.1007/s11356-020-10973-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 09/21/2020] [Indexed: 05/21/2023]
Abstract
Heavy metal exposure in humans and animals commonly occurs through the consumption of metal-contaminated drinking water and food. Although many studies have focused on the remediation of metals by purification of water using sorbents, limited therapeutic sorbent strategies have been developed to minimize human and animal exposures to contaminated water and food. To address this need, a medical grade activated carbon (MAC) and an acid processed montmorillonite clay (APM) were characterized for their ability to bind heavy metals and mixtures. Results of screening and adsorption/desorption isotherms showed that binding plots for arsenic, cadmium, and mercury sorption on surfaces of MAC (and lead on APM) fit the Langmuir model. The highest binding percentage, capacity, and affinity were shown in a simulated stomach model, and the lowest percentage desorption (< 18%) was shown in a simulated intestine model. The safety and protective ability of MAC and APM were confirmed in a living organism (Hydra vulgaris) where 0.1% MAC significantly protected the hydra against As, Cd, Hg, and a mixture of metals by 30-70%. In other studies, APM showed significant reduction (75%) of Pd toxicity, compared with MAC and heat-collapsed APM, suggesting that the interlayer of APM was important for Pb sorption. This is the first report showing that edible sorbents can bind mixtures of heavy metals in a simulated gastrointestinal tract and prevent their toxicity in a living organism. Graphical abstract.
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Affiliation(s)
- Meichen Wang
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Gopal Bera
- Geochemical & Environmental Research Group, Texas A&M University, College Station, TX, 77845, USA
| | - Kusumica Mitra
- Geochemical & Environmental Research Group, Texas A&M University, College Station, TX, 77845, USA
| | - Terry L Wade
- Geochemical & Environmental Research Group, Texas A&M University, College Station, TX, 77845, USA
| | - Anthony H Knap
- Geochemical & Environmental Research Group, Texas A&M University, College Station, TX, 77845, USA
| | - Timothy D Phillips
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA.
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Wang M, Orr AA, Jakubowski JM, Bird KE, Casey CM, Hearon SE, Tamamis P, Phillips TD. Enhanced adsorption of per- and polyfluoroalkyl substances (PFAS) by edible, nutrient-amended montmorillonite clays. WATER RESEARCH 2021; 188:116534. [PMID: 33125992 PMCID: PMC7725962 DOI: 10.1016/j.watres.2020.116534] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/15/2020] [Accepted: 10/17/2020] [Indexed: 05/21/2023]
Abstract
Humans and animals are frequently exposed to PFAS (per- and polyfluoroalkyl substances) through drinking water and food; however, no therapeutic sorbent strategies have been developed to mitigate this problem. Montmorillonites amended with the common nutrients, carnitine and choline, were characterized for their ability to bind 4 representative PFAS (PFOA, PFOS, GenX, and PFBS). Adsorption/desorption isothermal analysis showed that PFOA, PFOS (and a mixture of the two) fit the Langmuir model with high binding capacity, affinity and enthalpy at conditions simulating the stomach. A low percentage of desorption occurred at conditions simulating the intestine. The results suggested that hydrophobic and electrostatic interactions, and hydrogen bonding were responsible for sequestering PFAS into clay interlayers. Molecular dynamics (MD) simulations suggested the key mode of interaction of PFAS was through fluorinated carbon chains, and confirmed that PFOA and PFOS had enhanced binding to amended clays compared to GenX and PFBS. The safety and efficacy of amended montmorillonite clays were confirmed in Hydra vulgaris, where a mixture of amended sorbents delivered the highest protection against a PFAS mixture. These important results suggest that the inclusion of edible, nutrient-amended clays with optimal affinity, capacity, and enthalpy can be used to decrease the bioavailability of PFAS from contaminated drinking water and diets.
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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, TX 77843, USA
| | - Asuka A Orr
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Joseph M Jakubowski
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Kelsea E Bird
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Colleen M Casey
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Sara E Hearon
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Phanourios Tamamis
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA; Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Timothy D Phillips
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
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Wang M, Phillips TD. Edible clay inclusion in the diet of oysters can reduce tissue residues of polychlorinated biphenyls. TOXICOLOGY AND ENVIRONMENTAL HEALTH SCIENCES 2020; 12:355-361. [PMID: 33738241 PMCID: PMC7968863 DOI: 10.1007/s13530-020-00058-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/14/2020] [Indexed: 05/21/2023]
Abstract
OBJECTIVE Polychlorinated biphenyls (PCBs) are lipophilic and persistent environmental pollutants that are readily absorbed and accumulated in high concentrations in fatty tissues of humans and animals. Invertebrate animals, such as oysters, are vulnerable and sensitive to PCB contamination. METHODS Previously, our in vitro isothermal studies have shown that acid processed montmorillonites (APM) can effectively bind PCBs and Aroclors. Therefore, in a novel application of this work, a dietary strategy for shellfish was developed using APM, and its parent clay to reduce exposures to PCBs in oysters. PCB residues in oysters with clay treatment at different dietary inclusion rates and durations were measured and compared to a washout treatment. RESULTS The efficacy and safety of this strategy were supported by a significant reduction of PCB residues with the inclusion of a low level of APM (0.05%) during a 4-day treatment. Moreover, this sorbent strategy reduced PCB residues in oysters in a dose- and time-dependent manner. CONCLUSIONS Based on our results, it is possible that clay-based sorbents such as APM, can be included in the diet to significantly reduce exposures to PCBs.
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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, TX 77843, USA
| | - Timothy D. Phillips
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
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Zhang L, Gadd GM, Li Z. Microbial biomodification of clay minerals. ADVANCES IN APPLIED MICROBIOLOGY 2020; 114:111-139. [PMID: 33934851 DOI: 10.1016/bs.aambs.2020.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Clay minerals are important reactive centers in the soil system. Their interactions with microorganisms are ubiquitous and wide-ranging, affecting growth and function, interactions with other organisms, including plants, biogeochemical processes and the fate of organic and inorganic pollutants. Clay minerals have a large specific surface area and cation exchange capacity (CEC) per unit mass, and are abundant in many soil systems, especially those of agricultural significance. They can adsorb microbial cells, exudates, and enzymes, organic and inorganic chemical species, nutrients, and contaminants, and stabilize soil organic matter. Bacterial modification of clays appears to be primarily due to biochemical mechanisms, while fungi can exhibit both biochemical and biomechanical mechanisms, the latter aided by their exploratory filamentous growth habit. Such interactions between microorganisms and clays regulate many critical environmental processes, such as soil development and transformation, the formation of soil aggregates, and the global cycling of multiple elements. Applications of biomodified clay minerals are of relevance to the fields of both agricultural management and environmental remediation. This review provides an overview of the interactions between bacteria, fungi and clay minerals, considers some important gaps in current knowledge, and indicates perspectives for future research.
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Affiliation(s)
- Lin Zhang
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China; Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Geoffrey Michael Gadd
- Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom; State Key Laboratory of Heavy Oil Processing, State Key Laboratory of Petroleum Pollution Control, College of Science and Environment, China University of Petroleum, Beijing, China
| | - Zhen Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China; Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China.
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Insights into the interactions of bisphenol and phthalate compounds with unamended and carnitine-amended montmorillonite clays. Comput Chem Eng 2020; 143. [PMID: 33122868 PMCID: PMC7591107 DOI: 10.1016/j.compchemeng.2020.107063] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Montmorillonite clays could be promising sorbents to mitigate toxic compound exposures. Bisphenols A (BPA) and S (BPS) as well as phthalates, dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP), are ubiquitous environmental contaminants linked to adverse health effects. Here, we combined computational and experimental methods to investigate the ability of montmorillonite clays to sorb these compounds. Molecular dynamics simulations predicted that parent, unamended, clay has higher binding propensity for BPA and BPS than for DBP and DEHP; carnitine-amended clay improved BPA and BPS binding, through carnitine simultaneously anchoring to the clay through its quaternary ammonium cation and forming hydrogen bonds with BPA and BPS. Experimental isothermal analysis confirmed that carnitine-amended clay has enhanced BPA binding capacity, affinity and enthalpy. Our studies demonstrate how computational and experimental methods, combined, can characterize clay binding and sorption of toxic compounds, paving the way for future investigation of clays to reduce BPA and BPS exposure.
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Wang M, Phillips TD. Potential Applications of Clay-Based Therapy for the Reduction of Pesticide Exposures in Humans and Animals. APPLIED SCIENCES (BASEL, SWITZERLAND) 2019; 9:5325. [PMID: 32944385 PMCID: PMC7494192 DOI: 10.3390/app9245325] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The risk of pesticide exposure in humans and animals may be magnified following natural and man-made disasters such as hurricanes and floods that can result in mobilization and redistribution of contaminated sediments. To develop broad-acting sorbents for mixtures of diverse toxins, we have processed calcium and sodium montmorillonite clays with high concentrations of sulfuric acid. These acid-processed montmorillonite clays (APMs) have shown limited hydration and swelling in water, higher surface areas, and lower trace metal levels than the parent clays, prior to processing. Isothermal analyses have indicated that newly developed APMs are highly active sorbents, with significantly increased binding capacities for a wide range of pesticides, including pentachlorophenol (PCP), 2,4,6-trichlorophenol (2,4,6-TCP), lindane, diazinon, linuron, trifluralin and paraquat. The safety and protective effects of APMs, against pesticide design mixtures, were confirmed in a living organism (Hydra vulgaris). Further work is planned to confirm the safety of the APMs in long-term rodent studies. This is the first report of a sorbent material (other than carbon) with high binding efficacy for mixtures of these pesticides. Based on our results, APMs (and similar clays), may be able to decrease human and animal pesticide exposures during disasters and emergencies.
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Affiliation(s)
- Meichen Wang
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Timothy D. Phillips
- Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
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