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Zhang Z, Miller LM, He H, Nadagouda MN, Borch T, O'Shea KE, Dionysiou DD. Molecular insights into the bonding mechanisms between selenium and dissolved organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:169429. [PMID: 38123086 DOI: 10.1016/j.scitotenv.2023.169429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/11/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Natural organic matter (NOM) plays a critical role in the mobilization and bioavailability of metals and metalloids in the aquatic environment. Selenium (Se), an environmental contaminant of aquatic systems, has drawn increasing attention over the years. While Se is a vital micronutrient to human beings, animals and plants, excess Se intake may pose serious long-term risks. However, the interaction between Se and dissolved organic matter (DOM) remains relatively unexplored, especially the reaction mechanisms and interactions of specific NOM components of certain molecular weight and the corresponding functional group change. Herein, we report an investigation on the interactions between Se and DOM by focusing on the mass distribution profile change of operationally defined molecular weight fractions of humic acid (HA) and fulvic acid (FA). The results showed that across all molecular weights studied, HA fractions were more prone to enhanced aggregation upon introduction of Se into the system. For FA, the presence of Se species results in aggregation, dissociation, and redox reactions with the first two being the major mechanisms. Total organic carbon analysis (TOC), UV-vis spectroscopy (UV-vis), and Orbitrap MS data showed that [10, 30] kDa MW fraction had the largest aromatic decrease (CRAM-like, lignin-like and tannin-like) upon addition of SeO2 via dissociation as the dominant mechanism. Fourier transform infrared spectroscopy (FT-IR) revealed that Se based bridging or chelation of functional groups from individual DOM components through hydrogen bonding in the form of SeO⋯H and possibly Se⋯H and/or attractive electrostatic interactions lead to aggregated DOM1⋯Se⋯DOM2. It was concluded from two-dimensional correlation analyses of excitation emission matrix (EEM) and FT-IR that the preferred Se-binding follows lipid ➔ peptide ➔ tannin ➔ aromatic functionalities. These results provide new understanding of Se interactions with various NOM components in aquatic environments and provide insight for Se assessing health risk and/or treatment of Se contaminated water.
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Affiliation(s)
- Zhe Zhang
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (DCEE), University of Cincinnati, OH 45221, USA
| | - Lance M Miller
- Department of Chemical Engineering, Purdue University, IN 47907, USA
| | - Huan He
- Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Mallikarjuna N Nadagouda
- The U.S. Environmental Protection Agency, ORD, CESER, WID, CMTB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268, USA
| | - Thomas Borch
- Department of Soil and Crop Sciences and Department of Chemistry, Colorado State University, 1170 Campus Delivery, Fort Collins, CO 80523, USA
| | - Kevin E O'Shea
- Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199, USA.
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (DCEE), University of Cincinnati, OH 45221, USA.
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Hodgson LM, Cox BA, Lopez-Ruiz FJ, Gibberd MR, Thomas GJ, Zerihun A. Optimized Sample Processing Pipeline for PCR-Based Fungicide Resistance Quantification of Stubble-Borne Fungal Pathogens. PHYTOPATHOLOGY 2023; 113:321-333. [PMID: 36075052 DOI: 10.1094/phyto-07-22-0239-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Globally, yield losses associated with failed crop protection due to fungicide-resistant pathogens present an increasing problem. For stubble-borne pathogens, assessment of crop residues during the off-season could provide early fungicide resistance quantification for informed management decisions to mitigate yield losses. However, stubble assessment is hampered by assay inhibitors that are derived from decaying organic matter. To overcome assay inhibition from weathered stubble samples, we used a systems approach to quantify the frequency of resistance to demethylase inhibitor fungicides of the barley pathogen Pyrenophora teres f. teres. The system canvassed (i) 10 ball-milling conditions; (ii) four DNA extraction methodologies; and (iii) three column purification techniques for the provision of sufficient yield, quality, and purity of fungal DNA for a PCR-based fungicide resistance assay. Results show that DNA quantity and purity differed within each of the above three categories, with the optimized pipeline being (i) ball-milling samples in a 50-ml stainless steel canister for 5 min using a 20-mm ball at 30 revolutions s-1; (ii) a modified Brandfass method (extracted 64% more DNA than other methods assessed); and (iii) use of silica resin columns for the highest DNA concentration with optimal DNA purity. The chip-digital PCR assay, which quantified fungicide resistance from field samples, was unaffected by the DNA extraction method or purification technique, provided that thresholds of template quantity and purity were satisfied. In summary, this study has developed molecular pipeline options for pathogen fungicide resistance quantification from cereal stubbles, which can guide management for improved crop protection outcomes.
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Affiliation(s)
- Leon M Hodgson
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Belinda A Cox
- School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Francisco J Lopez-Ruiz
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Mark R Gibberd
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Geoff J Thomas
- Department of Primary Industries and Regional Development, South Perth, WA 6151, Australia
| | - Ayalsew Zerihun
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
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Humic Acids Preparation, Characterization, and Their Potential Adsorption Capacity for Aflatoxin B 1 in an In Vitro Poultry Digestive Model. Toxins (Basel) 2023; 15:toxins15020083. [PMID: 36828398 PMCID: PMC9962053 DOI: 10.3390/toxins15020083] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/11/2023] [Accepted: 01/14/2023] [Indexed: 01/19/2023] Open
Abstract
Vermicompost was used for humic acid (HA) preparation, and the adsorption of aflatoxin B1 (AFB1) was investigated. Two forms of HA were evaluated, natural HA and sodium-free HA (SFHA). As a reference, a non-commercial zeolitic material was employed. The adsorbents were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), energy-dispersive X-ray spectroscopy (EDS), zeta potential (ζ-potential), scanning electron microscopy (SEM), and point of zero charge (pHpzc). The adsorbent capacity of the materials when added to an AFB1-contaminated diet (100 µg AFB1/kg) was evaluated using an in vitro model that simulates the digestive tract of chickens. Characterization results revealed the primary functional groups in HA and SFHA were carboxyl and phenol. Furthermore, adsorbents have a highly negative ζ-potential at the three simulated pH values. Therefore, it appears the main influencing factors for AFB1 adsorption are electrostatic interactions and hydrogen bonding. Moreover, the bioavailability of AFB1 in the intestinal section was dramatically decreased when sorbents were added to the diet (0.2%, w/w). The highest AFB1 adsorption percentages using HA and SFHA were 97.6% and 99.7%, respectively. The zeolitic material had a considerable adsorption (81.5%). From these results, it can be concluded that HA and SFHA from vermicompost could be used as potential adsorbents to remove AFB1 from contaminated feeds.
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Linkevich EV, Yudina NV, Savel’eva AV. Formation of Humic Colloids in Aqueous Solutions at Different pH Values. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2020. [DOI: 10.1134/s0036024420040093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Worms IAM, Chmiel HE, Traber J, Tofield-Pasche N, Slaveykova VI. Dissolved Organic Matter and Associated Trace Metal Dynamics from River to Lake, Under Ice-Covered and Ice-Free Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:14134-14143. [PMID: 31738528 DOI: 10.1021/acs.est.9b02184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The present study investigates the changes in dissolved organic matter (DOM) composition and its influences on trace metal dispersion from the Shuya River (SR) in the Petrozavodsk Bay of Lake Onega during ice-covered and ice-free periods. Humic substances (HS) found in the SR dominated the composition of DOM through the river-bay-lake continuum in both periods. When the bay was ice-covered, both the aromaticity and the size of HS varied in the water column according to a horizontal stratification and decreased in the bay, while under ice-free conditions, they decreased along the river-lake gradient, suggesting in both cases a decrease in the proportion of HS with high aromatic character. These findings were associated with an overall decrease in the proportion of HS components that have the highest molecular masses. The quantification of metal bound to HS revealed that these characteristics were associated with a decrease in the binding capacity of the HS for Fe and Al but not Cu while dispersing in the bay to the lake. Pb was found to bind on HS, but its behavior in the bay could not be related to the HS dispersion nor to the changes in HS properties.
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Affiliation(s)
- Isabelle A M Worms
- Environmental Biogeochemistry and Ecotoxicology, Department F.-A. Forel for environmental and aquatic sciences, Earth and Environmental Sciences, Faculty of Sciences , University of Geneva , 66, boulevard Carl-Vogt , CH-1211 Geneva , Switzerland
| | - Hannah E Chmiel
- Limnological Center , Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 2, 1015 Lausanne , Switzerland
| | - Jacqueline Traber
- Process Engineering , Eawag , Überlandstrasse 133 , 8600 Dübendorf , Switzerland
| | - Natacha Tofield-Pasche
- Limnological Center , Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 2, 1015 Lausanne , Switzerland
| | - Vera I Slaveykova
- Environmental Biogeochemistry and Ecotoxicology, Department F.-A. Forel for environmental and aquatic sciences, Earth and Environmental Sciences, Faculty of Sciences , University of Geneva , 66, boulevard Carl-Vogt , CH-1211 Geneva , Switzerland
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Olaetxea M, Mora V, Bacaicoa E, Baigorri R, Garnica M, Fuentes M, Zamarreño AM, Spíchal L, García‐Mina JM. Root ABA and H +-ATPase are key players in the root and shoot growth-promoting action of humic acids. PLANT DIRECT 2019; 3:e00175. [PMID: 31624800 PMCID: PMC6785783 DOI: 10.1002/pld3.175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/18/2019] [Accepted: 09/07/2019] [Indexed: 05/02/2023]
Abstract
Although the ability of humic (HA) and fulvic acids (FA) to improve plant growth has been demonstrated, knowledge about the mechanisms responsible for the direct effects of HA and FA on the promotion of plant growth is scarce and fragmentary. Our study investigated the causal role of both root PM H+-ATPase activity and ABA in the SHA-promoting action on both root and shoot growth. The involvement of these processes in the regulation of shoot cytokinin concentration and activity was also studied. Our aim was to integrate such plant responses for providing new insights to the current model on the mode of action of HA for promoting root and shoot growth. Experiments employing specific inhibitors and using Cucumis sativus L. plants show that both the root PM H+-ATPase activity and root ABA play a crucial role in the root growth-promoting action of SHA. With regard to the HA-promoting effects on shoot growth, two pathways of events triggered by the interaction of SHA with plant roots are essential for the increase in root PM H+-ATPase activity-which also mediates an increase in cytokinin concentration and action in the shoot-and the ABA-mediated increase in hydraulic conductivity (Lpr).
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Affiliation(s)
- Maite Olaetxea
- Department of Environmental Biology (Biological and Agricultural Chemistry Group (BACh) CMI-Roullier GroupFaculty of SciencesUniversity of NavarraPamplonaSpain
| | - Verónica Mora
- Plant Physiology and Plant‐Microorganism Interaction LaboratoryInstituto de Investigaciones Agrobiotecnológicas (INIAB-CONICET) y Universidad Nacional de Río Cuarto (UNRC)CórdobaArgentina
| | - Eva Bacaicoa
- Department of Environmental Biology (Biological and Agricultural Chemistry Group (BACh) CMI-Roullier GroupFaculty of SciencesUniversity of NavarraPamplonaSpain
| | - Roberto Baigorri
- Technical and Development DepartmentTimac Agro EspañaLodosaSpain
| | - Maria Garnica
- Department of Environmental Biology (Biological and Agricultural Chemistry Group (BACh) CMI-Roullier GroupFaculty of SciencesUniversity of NavarraPamplonaSpain
| | - Marta Fuentes
- Department of Environmental Biology (Biological and Agricultural Chemistry Group (BACh) CMI-Roullier GroupFaculty of SciencesUniversity of NavarraPamplonaSpain
| | - Angel Maria Zamarreño
- Department of Environmental Biology (Biological and Agricultural Chemistry Group (BACh) CMI-Roullier GroupFaculty of SciencesUniversity of NavarraPamplonaSpain
| | - Lukáš Spíchal
- Department of Chemical Biology and Genetics Palacký University, Centre of the Region Haná for Biotechnological and Agricultural ResearchFaculty of SciencePalacky´ UniversityOlomoucCzech Republic
| | - José María García‐Mina
- Department of Environmental Biology (Biological and Agricultural Chemistry Group (BACh) CMI-Roullier GroupFaculty of SciencesUniversity of NavarraPamplonaSpain
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Charging, aggregation, and aggregate strength of humic substances in the presence of cationic surfactants: Effects of humic substances hydrophobicity and surfactant tail length. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.05.071] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Řezáčová V, Conte P, Komendová R, Novák F, Repková M, Kučerík J. Factors influencing structural heat-induced structural relaxation of dissolved organic matter. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 167:422-428. [PMID: 30368135 DOI: 10.1016/j.ecoenv.2018.10.050] [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: 08/06/2018] [Revised: 10/07/2018] [Accepted: 10/09/2018] [Indexed: 06/08/2023]
Abstract
Physical and chemical structure affect properties of dissolved organic matter (DOM). Recent observations revealed that heating and cooling cycles at higher temperature amplitude lead to a change in DOM physical conformation assumingly followed by a slow structural relaxation. In this study, changes at lower temperature amplitudes and their relation to DOM composition were investigated using simultaneous measurements of density and ultrasonic velocity in order to evaluate the adiabatic compressibility, which is sensitive indicator of DOM structural microelasticity. Six fulvic acids (FAs) having various origins were analyzed at concentrations of 0.12, 0.6 and 1.2 g L-1 and at different temperature amplitudes. First, we validated that the used technique is sensitive to distinguish conclusively the structural changes upon heating and cooling of DOM with heating/cooling amplitude of ± 3 °C and higher. This amplitude was then applied to observe the relationship between change in adiabatic compressibility and chemical composition of FA. No correlation was observed with elemental composition and aromatic structures. Positive correlations were observed with content of alkyl moieties, carboxylic and carbonyl carbons and biological activity. Based on literature data, it was concluded that alkyl moieties undergo (re)crystalization during thermal fluctuation and their structural relaxation back is very slow (if occurs). The polar moieties form a flexible hydrogel responding to thermal fluctuation by moderate dissolution and re-aggregation. Negative correlation was observed in relation to the amount of peptide and O-alkyl systems, which can be attributed to very fast structural relaxation of proteinaceous materials, i.e. their larger content leads to lower difference between original and heat-induced compressibility. Last, the increase of the heating/cooling amplitude from ± 3 to ± 15 °C resulted in an increase of the change of the adiabatic compressibility and in the extension of the relaxation time needed for DOM structure to return to the equilibrium. We conclude that this increase is caused by the increase in inner energy, and DOM conformation can reach a cascade of energy minima, which may influence DOM reactivity and biodegradability.
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Affiliation(s)
- Veronika Řezáčová
- Institute of Chemistry and Technology of Environmental Protection, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic
| | - Pellegrino Conte
- Dipartimento di Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, v.le delle Scienze edificio 4, 90128 Palermo, Italy
| | - Renata Komendová
- Institute of Chemistry and Technology of Environmental Protection, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic
| | - František Novák
- Technopark Kralupy, University of Chemistry and Technology Prague, Technická 1905, 166 28 Prague 6, Czech Republic
| | - Martina Repková
- Institute of Chemistry and Technology of Environmental Protection, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic
| | - Jiří Kučerík
- Institute of Chemistry and Technology of Environmental Protection, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic.
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Klučáková M. Size and Charge Evaluation of Standard Humic and Fulvic Acids as Crucial Factors to Determine Their Environmental Behavior and Impact. Front Chem 2018; 6:235. [PMID: 30027090 PMCID: PMC6041962 DOI: 10.3389/fchem.2018.00235] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/04/2018] [Indexed: 11/22/2022] Open
Abstract
In this work, the size and charge of humic and fulvic standards purchased from the International Humic Substances Society are presented and discussed. The secondary structure of humic substances in water environment as well as the size and shape of the dissolved humic species and their changes are ill-defined, very dynamic and can be strongly affected by environmental conditions as the concentration, pH, and ionic strength. They have a strong propensity to aggregate which control their interactions with other components, mobility, and functioning in the environment. Particle size distributions were determined by means of dynamic light scattering, zeta potential by Doppler electrophoresis. The intensity, volume, and number particle size distribution were obtained. Two or three different size fractions were detected in the studied systems. Large macroparticles (>1 μm) were observed in the majority of them, mainly in the case of more concentrated solutions. Medium fractions of fulvic submicroparticles had higher average diameters (500–1,200 nm) than those in humic acids (300–600 nm). Small nanoparticles (<100 nm) were detected mainly in alkaline solutions. Fulvic acids with more functional groups (active sites) can form more easily bigger particles mainly in medium concentration region. Alkaline conditions supported the expansion of humic and fulvic coils and liberation of small particles from them. The colloidal stability, indicated by more negative zeta potentials, was higher for humic acids. In the case of fulvic acids, the colloidal stability increased with increasing pH as a result of the dissociation of their functional groups. The increase of particle size corresponded usually with higher stability.
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Affiliation(s)
- Martina Klučáková
- Faculty of Chemistry, Materials Research Centre, Brno University of Technology, Brno, Czechia
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Ashworth H, Abrahamsen-Mills L, Bryan N, Foster L, Lloyd JR, Kellet S, Heath S. Effect of humic acid & bacterial exudates on sorption-desorption interactions of 90Sr with brucite. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:956-964. [PMID: 29774347 DOI: 10.1039/c8em00073e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
One of the nuclear fuel storage ponds at Sellafield (United Kingdom) is open to the air, and has contained a significant inventory of corroded magnox fuel and sludge for several decades. As a result, some fission products have also been released into solution. 90Sr is known to constitute a small mass of the radionuclides present in the pond, but due to its solubility and activity, it is at risk of challenging effluent discharge limits. The sludge is predominantly composed of brucite (Mg(OH)2), and organic molecules are known to be present in the pond liquor with occasional algal blooms restricting visibility. Understanding the chemical interactions of these components is important to inform ongoing sludge retrievals and effluent management. Additionally, interactions of radionuclides with organics at high pH will be an important consideration for the evolution of cementitious backfilled disposal sites in the UK. Batch sorption-desorption experiments were performed with brucite, 90Sr and natural organic matter (NOM) (humic acid (HA) and Pseudanabaena catenata cyanobacterial growth supernatant) in both binary and ternary systems at high pH. Ionic strength, pH and order of addition of components were varied. 90Sr was shown not to interact strongly with the bulk brucite surface in binary systems under pH conditions relevant to the pond. HA in both binary and ternary systems demonstrated a strong affinity for the brucite surface. Ternary systems containing HA demonstrated enhanced sorption of 90Sr at pH 11.5 and vice versa, likely via formation of strontium-humate complexes regardless of the order of addition of components. The distribution coefficients show HA sorption to be reversible at all pH values studied, and it appeared to control 90Sr behaviour at pH 11.5. Ternary systems containing cyanobacterial supernatant demonstrated a difference in 90Sr behaviour when the culture had been subjected to irradiation in the first stages of its growth.
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Affiliation(s)
- Hollie Ashworth
- Centre for Radiochemistry Research, School of Chemistry, University of Manchester, M13 9PL, UK
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Tan L, Tan X, Mei H, Ai Y, Sun L, Zhao G, Hayat T, Alsaedi A, Chen C, Wang X. Coagulation behavior of humic acid in aqueous solutions containing Cs +, Sr 2+ and Eu 3+: DLS, EEM and MD simulations. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 236:835-843. [PMID: 29462778 DOI: 10.1016/j.envpol.2018.02.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 02/04/2018] [Accepted: 02/06/2018] [Indexed: 05/12/2023]
Abstract
The coagulation behaviors of humic acid (HA) with Cs+ (10-500 mM), Sr2+ (0.8-10.0 mM) and Eu3+ (0.01-1.0 mM) at different pH values (2.8, 7.1 and 10.0) were acquired through a dynamic light scattering (DLS) technique combined with spectroscopic analysis and molecular dynamic (MD) simulations. The coagulation rate and the average hydrodynamic diameter (<Dh>) increased significantly as the concentration of nuclides increased. <Dh> could be scaled to time t as <Dh>∝ ta at higher Sr2+ concentrations, which shows that HA coagulation is consistent with the diffusion-limited colloid aggregation (DLCA) model. Trivalent Eu3+ induced HA coagulation at a much lower concentration than bivalent Sr2+ and monovalent Cs+. The coagulation value ratio of Sr2+ and Eu3+ to Cs+ is almost proportional to Z-6, indicating that the HA coagulation process is generally consistent with the Schulze-Hardy rule. Spectroscopic analysis indicated that the complexation between nuclides and carboxylic/phenolic groups of HA molecules played important roles in the coagulation of HA. MD modelling suggested that Sr2+ and Eu3+ ions increased the coagulation process through the formation of intra- or inter-molecular bridges between negatively charged HA molecules, whereas for Cs+, no inter-molecular bridges were formed. This work offers new insight into the interactions between HA and radionuclides and provides a prediction for the roles of HA in the transportation and elimination of radionuclides in severely polluted environments.
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Affiliation(s)
- Liqiang Tan
- College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China; CAS Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, PR China
| | - Xiaoli Tan
- College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China; CAS Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, PR China; Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, PR China
| | - Huiyang Mei
- CAS Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, PR China
| | - Yuejie Ai
- College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China
| | - Lu Sun
- Institute of Modern Optics, Nankai University, Tianjin 300350, PR China
| | - Guixia Zhao
- College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China
| | - Tasawar Hayat
- NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ahmed Alsaedi
- NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Changlun Chen
- CAS Key Laboratory of Photovoltaic and Energy Conservation Materials, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, PR China; Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, PR China; NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Xiangke Wang
- College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China; Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, PR China; NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
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Wang M, Gao B, Tang D, Sun H, Yin X, Yu C. Effects of temperature on aggregation kinetics of graphene oxide in aqueous solutions. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2017.10.061] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Swiech WM, Hamerton I, Zeng H, Watson DJ, Mason E, Taylor SE. Water-based fractionation of a commercial humic acid. Solid-state and colloidal characterization of the solubility fractions. J Colloid Interface Sci 2017; 508:28-38. [PMID: 28818654 DOI: 10.1016/j.jcis.2017.08.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND HYPOTHESIS Humic acid (HA) is of considerable environmental significance, being a major component of soil, as well as being considered for application in other technological areas. However, its structure and colloidal properties continue to be the subject of debate, largely owing to its molecular complexity and association with other humic substances and mineral matter. As a class, HA is considered to comprise supramolecular assemblies of heterogeneous species, and herein we consider a simple route for the separation of some HA sub-fractions. EXPERIMENTS A commercial HA sample from Sigma-Aldrich has been fractionated into two soluble (S1, S2) and two insoluble (I1, I2) fractions by successive dissolution in deionized water at near-neutral pH. These sub-fractions have been characterized by solution and solid-state approaches. FINDINGS Using this simple approach, the HA has been shown to contain non-covalently bonded species with different polarity and water solubility. The soluble and insoluble fractions have very different chemical structures, as revealed particularly by their solid-state properties (13C NMR and IR spectroscopy, and TGA); in particular, S1 and S2 are characterized by higher carbonyl and aromatic contents, compared with I1 and I2. As shown by solution SAXS measurements and AFM, the soluble fractions behave as hydrophilic colloidal aggregates of at least 50nm diameter.
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Affiliation(s)
- Weronika M Swiech
- Centre for Petroleum and Surface Chemistry, Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Ian Hamerton
- Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Huang Zeng
- BP America, Upstream Technology, 501 Westlake Blvd., Houston, TX 77079, USA
| | - David J Watson
- Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Eleonore Mason
- Department of Chemistry, University of Reading, Reading RG6 6AD, UK
| | - Spencer E Taylor
- Centre for Petroleum and Surface Chemistry, Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
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He W, Chen M, Schlautman MA, Hur J. Dynamic exchanges between DOM and POM pools in coastal and inland aquatic ecosystems: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 551-552:415-428. [PMID: 26881732 DOI: 10.1016/j.scitotenv.2016.02.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 06/05/2023]
Abstract
Dynamic exchanges between dissolved organic matter (DOM) and particulate organic matter (POM) plays a critical role in organic carbon cycling in coastal and inland aquatic ecosystems, interactions with aquatic organisms, mobility and bioavailability of pollutants, among many other ecological and geochemical phenomena. Although DOM-POM exchange processes have been widely studied from different aspects, little to no effort has been made to date to provide a comprehensive, mechanistic, and micro-spatial schema for understanding various exchange processes occurring in different aquatic ecosystems in a unified way. The phenomena occurring between DOM and POM were explained here with the homogeneous and heterogeneous mechanisms. In the homogeneous mechanism, the participating components are only organic matter (OM) constituents themselves with aggregation and dissolution involved, whereas OM is associated with other components such as minerals and particulate colloids in the heterogeneous counterpart. Besides the generally concerned processes of aggregation/dissolution and adsorption/desorption, other ecological factors such as sunlight and organisms can also participate in DOM-POM exchanges through altering the chemical nature of OM. Despite the limitation of current analytical technologies, many unknown and/or unquantified processes need to be identified to unravel the complicated exchanges of OM between its dissolved and particulate states. Based on the review of several previous mathematical models, we proposed a unified conceptual model to describe all major dynamic exchange mechanisms on the basis of exergy theory. More knowledge of dynamic DOM-POM exchanges is warranted to overcome the potential problems arising from a simple division of OM into dissolved versus particulate states and to further develop more sophisticated mathematic models.
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Affiliation(s)
- Wei He
- Department of Environment and Energy, Sejong University, Seoul 143-747, South Korea
| | - Meilian Chen
- Department of Environment and Energy, Sejong University, Seoul 143-747, South Korea
| | - Mark A Schlautman
- Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC 29625-6510, United States
| | - Jin Hur
- Department of Environment and Energy, Sejong University, Seoul 143-747, South Korea.
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16
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Conte P, Kucerik J. Water Dynamics and Its Role in Structural Hysteresis of Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:2210-2216. [PMID: 26815011 DOI: 10.1021/acs.est.5b04639] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Knowledge of structural dynamics of dissolved organic matter (DOM) is of paramount importance for understanding DOM stability and role in the fate of solubilized organic and inorganic compounds (e.g., nutrients and pollutants), either in soils or aquatic systems. In this study, fast field cycling (FFC) (1)H NMR relaxometry was applied to elucidate structural dynamics of terrestrial DOM, represented by two structurally contrasting DOM models such as Suwanee River (SRFA) and Pahokee peat (PPFA) fulvic acids purchased by the International Humic Substance Society. Measurement of NMR relaxation rate of water protons in heating-cooling cycles revealed structural hysteresis in both fulvic acids. In particular, structural hysteresis was related to the delay in re-establishing water network around fulvic molecules as a result of temperature fluctuations. The experiments revealed that the structural temperature dependency and hysteresis were more pronounced in SRFA than in PPFA. This was attributed to the larger content of hydrogel-like structure in SRFA stabilized, at a larger extent, by H-bonds between carboxylic and phenolic groups. Moreover, results supported the view that terrestrial DOM consist of a hydrophobic rigid core surrounded by progressively assembling amphiphilic and polar molecules, which form an elastic structure that can mediate reactivity of the whole DOM.
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Affiliation(s)
- Pellegrino Conte
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo , Viale delle Scienze edificio 4, 90128 Palermo, Italy
| | - Jiri Kucerik
- Institute for Environmental Sciences, University of Koblenz-Landau , Campus Landau, Fortstrasse 7, 768 29 Landau, Germany
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17
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Esfahani MR, Stretz HA, Wells MJM. Abiotic reversible self-assembly of fulvic and humic acid aggregates in low electrolytic conductivity solutions by dynamic light scattering and zeta potential investigation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 537:81-92. [PMID: 26282742 DOI: 10.1016/j.scitotenv.2015.08.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 08/01/2015] [Accepted: 08/01/2015] [Indexed: 05/19/2023]
Abstract
The aggregation of humic substances and their interaction with filtration media (membranes, soils) has implications for our understanding of membrane fouling during water treatment, the facilitated transport of contaminants, and the transport of organic matter through the microbial loop. To investigate the aggregation of fulvic and humic acids in low electrolytic conductivity solutions, laboratory studies of simulated environmental water samples as well as actual environmental water samples were examined. Intensity-, volume-, and number-based particle size distributions (PSDs) were obtained by dynamic light scattering. Aggregates were categorized into three ranges, i.e., 10-100 nm, 100-1000 nm, and >1 μm. Individual biomacromolecules and the aggregates between 10 nm and 1 μm were presumed to be precursors for the formation of a large 5-μm-sized-particle. The self-assembly of the large-in-volume, few-in-number, 5-μm-sized particle was observed in real-time and occurred in unfiltered samples and in samples filtered (0.45 μm) at a nominal size one order of magnitude smaller. The supramicrometer-sized particle formed, dissipated, and spontaneously re-formed over turbulent/quiescent cycles in the presence of sodium azide indicating reversible abiotic self-assembly. Zeta potential analyses demonstrated that colloidal stability increased as concentration increased. DLS studies of the environmental water samples were comparable to those of the simulated laboratory samples. The operational range of the instrumentation used in these experiments was 0.6 nm-6 μm; therefore, aggregates larger than 6 μm may exist in these solutions.
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Affiliation(s)
- Milad Rabbani Esfahani
- Department of Chemical Engineering, Tennessee Technological University, Cookeville, TN 38505, United States; Center for the Management, Utilization and Protection of Water Resources, Tennessee Technological University, Cookeville, TN 38505, United States
| | - Holly A Stretz
- Department of Chemical Engineering, Tennessee Technological University, Cookeville, TN 38505, United States
| | - Martha J M Wells
- EnviroChem Services, 224 Windsor Drive, Cookeville, TN 38506, United States.
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18
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Roger GM, Mériguet G, Bernard O, Durand-Vidal S, Turq P. Effect of ionic condensation and interactions between humic substances on their mobility: An experimental and simulation study. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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19
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Wang LF, Wang LL, Ye XD, Li WW, Ren XM, Sheng GP, Yu HQ, Wang XK. Coagulation kinetics of humic aggregates in mono- and di-valent electrolyte solutions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:5042-9. [PMID: 23590432 DOI: 10.1021/es304993j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Coagulation behaviors of humic acids (HAs) aggregates in electrolyte solutions at different pHs, valences and concentrations of electrolyte cations were investigated using dynamic light scattering technique in combination of other analytical tools. For monovalent electrolyte sodium chloride (NaCl) solution, at its low concentrations the average hydrodynamic radius (<Rh>) of aggregates kept nearly constant. However, at high NaCl concentrations, <Rh> could be scaled to the time t as <Rh> ∝ t(a), suggesting a diffusion-limited colloid aggregation (DLCA). The coagulation value of NaCl in a buffer at pH 7.1 was calculated to be in a range of 61.3-84.4 mM. Divalent cation Mg(2+) was far more effective in enhancing the HA coagulation, as evidenced by a lower coagulation value (between 1.0 and 1.7 mM) and a more rapid coagulation rate. Such an enhancement could be explained by the combined effects of electrostatic repulsion, complexation and bridging. The highest coagulation rate (d<Rh>/dt) and coagulation value at different pHs followed the order of: acidic > neutral > alkaline, and alkaline > neutral > acidic, respectively. Such a difference was associated with the extent of hydrogen bond and electrostatic repulsion at different protonation/deprotonation states of carboxyl and phenolic -OH groups. Transmission electron microscopic imaging reveals that HA was predominantly globular aggregates with a rough periphery at pH 5.26, and was changed to smooth spherical particles at pH 10.00. These results are useful for better understanding the coagulation behaviors of HAs in both natural and engineered aqueous systems.
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Affiliation(s)
- Long-Fei Wang
- Department of Chemistry, University of Science & Technology of China, Hefei, 230026, China
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Ambrosone L, Canzano S, Iovino P, Salvestrini S, Capasso S, Colella C. A Phenomenological Interpretation of Two-Step Adsorption Kinetics of Humic Acids on Zeolitic Tuff. ADSORPT SCI TECHNOL 2013. [DOI: 10.1260/0263-6174.31.4.373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Luigi Ambrosone
- Consorzio Interuniversitario per lo sviluppo dei Sistemi a Grande Interfase (CSGI-Firenze) c/o Department of Bioscience and Territory (DIBT), Molise University, Contrada Conte Lappone Pesche, 86090 Isernia, Italy
| | - Silvana Canzano
- Consorzio Interuniversitario Nazionale La Chimica per l'Ambiente, c/o Department of Environmental Science, Seconda Università di Napoli, via Vivaldi, 43, 81100 Caserta, Italy
| | - Pasquale Iovino
- Consorzio Interuniversitario Nazionale La Chimica per l'Ambiente, c/o Department of Environmental Science, Seconda Università di Napoli, via Vivaldi, 43, 81100 Caserta, Italy
| | - Stefano Salvestrini
- Consorzio Interuniversitario Nazionale La Chimica per l'Ambiente, c/o Department of Environmental Science, Seconda Università di Napoli, via Vivaldi, 43, 81100 Caserta, Italy
| | - Sante Capasso
- Consorzio Interuniversitario Nazionale La Chimica per l'Ambiente, c/o Department of Environmental Science, Seconda Università di Napoli, via Vivaldi, 43, 81100 Caserta, Italy
| | - Carmine Colella
- Department of Materials Engineering and Production, Università Federico II, Napoli, Italy
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21
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Xue G, Liu H, Chen Q, Hills C, Tyrer M, Innocent F. Synergy between surface adsorption and photocatalysis during degradation of humic acid on TiO2/activated carbon composites. JOURNAL OF HAZARDOUS MATERIALS 2011; 186:765-772. [PMID: 21163573 DOI: 10.1016/j.jhazmat.2010.11.063] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 10/21/2010] [Accepted: 11/16/2010] [Indexed: 05/30/2023]
Abstract
A photocatalyst comprising nano-sized TiO(2) particles on granular activated carbon (GAC) was prepared by a sol-dipping-gel process. The TiO(2)/GAC composite was characterized by scanning electron microscopy (SEM), X-ray diffractiometry (XRD) and nitrogen sorptometry, and its photocatalytic activity was studied through the degradation of humic acid (HA) in a quartz glass reactor. The factors influencing photocatalysis were investigated and the GAC was found to be an ideal substrate for nano-sized TiO(2) immobilization. A 99.5% removal efficiency for HA from solution was achieved at an initial concentration of 15 mg/L in a period of 3h. It was found that degradation of HA on the TiO(2)/GAC composite was facilitated by the synergistic relationship between surface adsorption characteristics and photocatalytic potential. The fitting of experimental results with the Langmuir-Hinshelwood (L-H) model showed that the reaction rate constant and the adsorption constant values were 0.1124 mg/(L min) and 0.3402 L/mg. The latter is 1.7 times of the calculated value by fitting the adsorption equilibrium data into the Langmuir equation.
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Affiliation(s)
- Gang Xue
- School of Environmental Science and Engineering, Donghua University, Shanghai, PR China
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22
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Mora V, Bacaicoa E, Zamarreño AM, Aguirre E, Garnica M, Fuentes M, García-Mina JM. Action of humic acid on promotion of cucumber shoot growth involves nitrate-related changes associated with the root-to-shoot distribution of cytokinins, polyamines and mineral nutrients. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:633-42. [PMID: 20185204 DOI: 10.1016/j.jplph.2009.11.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 11/23/2009] [Accepted: 11/23/2009] [Indexed: 05/02/2023]
Abstract
Numerous studies have reported the ability of humic substances to increase shoot growth in different plant species cultivated under diverse growth conditions. However, the mechanism responsible for this effect of humic substances is poorly understood. It is possible that the shoot promoting effect of humic substances involves a primary effect on root H(+)-ATPase activity and nitrate root-shoot distribution that, in turn, causes changes in the root-shoot distribution of certain cytokinins, polyamines and abscisic acid, thus affecting shoot growth. We investigated this hypothesis in the present study. The results showed that the root application of a purified humic acid causes a significant increase in shoot growth that is associated with an enhancement in root H(+)-ATPase activity, an increase in nitrate shoot concentration, and a decrease in roots. These effects were associated with significant increases in the shoot concentration of several cytokinins and polyamines (principally putrescine), concomitant with decreases in roots. Likewise, these changes in the root-shoot distribution of diverse active cytokinins correlated well to significant changes in the root-shoot distribution of several mineral nutrients. These results, taken together, indicate that the beneficial effects of humic substances on shoot development in cucumber could be directly associated with nitrate-related effects on the shoot concentration of several active cytokinins and polyamines (principally putrescine).
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Affiliation(s)
- Verónica Mora
- Department of Chemistry and Soil Chemistry, Faculty of Sciences, University of Navarra, P.O. Box 273, 31080 Pamplona (Navarra), Spain
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23
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Pédrot M, Dia A, Davranche M. Dynamic structure of humic substances: Rare earth elements as a fingerprint. J Colloid Interface Sci 2010; 345:206-13. [DOI: 10.1016/j.jcis.2010.01.069] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/21/2010] [Accepted: 01/25/2010] [Indexed: 10/19/2022]
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24
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Orsetti S, Andrade EM, Molina FV. Modeling ion binding to humic substances: elastic polyelectrolyte network model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:3134-3144. [PMID: 20055366 DOI: 10.1021/la903086s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new model for the electrostatic contribution to ion binding to humic substances is proposed and applied to published data for proton binding to fulvic and humic acids. The elastic polyelectrolyte network model treats humic substance particles as composed by two parts, an external one directly in contact with the solution, and an internal part or gel fraction which is considered, from a statistical point of view, as a charged polymer network swelled by the electrolyte solution, in the framework of the Flory polymer network theory. The electrostatic effect is given by a Donnan-like potential, which can be regarded as an average value over the gel fraction of the humic particle. The gel fraction expands as the pH and humic charge are increased, determining the Donnan potential and consequently the ion activity inside the gel. The model was fitted to published experimental data with good agreement. The model predictions are discussed, and the behavior suggests, for some cases, the presence of a transition between closed and open structures attributed to the presence, at low pH, of intramolecular hydrogen bonds which are removed as the carboxylic sites become deprotonated.
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Affiliation(s)
- Silvia Orsetti
- INQUIMAE, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, pabellon II, C1428EHA Buenos Aires, Argentina
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25
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Roger GM, Durand-Vidal S, Bernard O, Mériguet G, Altmann S, Turq P. Characterization of humic substances and polyacrylic acid: A high precision conductimetry study. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2009.12.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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26
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Brigante M, Zanini G, Avena M. Effect of pH, anions and cations on the dissolution kinetics of humic acid particles. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.04.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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27
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Ačai P, Sorrenti E, Gorner T, Polakovič M, Kongolo M, de Donato P. Pyrite passivation by humic acid investigated by inverse liquid chromatography. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2008.11.052] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Aguirre E, Leménager D, Bacaicoa E, Fuentes M, Baigorri R, Zamarreño AM, García-Mina JM. The root application of a purified leonardite humic acid modifies the transcriptional regulation of the main physiological root responses to Fe deficiency in Fe-sufficient cucumber plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:215-23. [PMID: 19119016 DOI: 10.1016/j.plaphy.2008.11.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 11/30/2008] [Indexed: 05/02/2023]
Abstract
The aim of this study is to investigate the effect of a well-characterized purified humic acid (non-measurable concentrations of the main plant hormones were detected) on the transcriptional regulation of the principal molecular agents involved in iron assimilation. To this end, non-deficient cucumber plants were treated with different concentrations of a purified humic acid (PHA) (2, 5, 100 and 250 mg of organic carbonL(-1)) and harvested 4, 24, 48, 76 and 92 h from the onset of the treatment. At harvest times, the mRNA transcript accumulation of CsFRO1 encoding for Fe(III) chelate-reductase (EC 1.16.1.7); CsHa1 and CsHa2 encoding for plasma membrane H+-ATPase (EC 3.6.3.6); and CsIRT1 encoding for Fe(II) high-affinity transporter, was quantified by real-time RT-PCR. Meanwhile, the respective enzyme activity of the Fe(III) chelate-reductase and plasma membrane H+-ATPase was also investigated. The results obtained indicated that PHA root treatments affected the regulation of the expression of the studied genes, but this effect was transient and differed (up-regulation or down-regulation) depending on the genes studied. Thus, principally the higher doses of PHA caused a transient increase in the expression of the CsHa2 isoform for 24 and 48 h whereas the CsHa1 isoform was unaffected or down-regulated. These effects were accompanied by an increase in the plasma membrane H+-ATPase activity for 4, 48 and 96 h. Likewise, PHA root treatments (principally the higher doses) up-regulated CsFRO1 and CsIRT1 expression for 48 and 72 h; whereas these genes were down-regulated by PHA for 96 h. These effects were associated with an increase in the Fe(III) chelate-reductase activity for 72 h. These effects were not associated with a significant decrease in the Fe root or leaf concentrations, although an eventual effect on the Fe root assimilation pattern cannot be ruled out. These results stress the close relationships between the effects of humic substances on plant development and iron nutrition. However, further studies are needed in order to elucidate if these effects at molecular level are caused by mechanisms involving hormone-like actions and/or nutritional factors.
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Affiliation(s)
- Elena Aguirre
- CIPAV (Centro de Investigación en Producción Animal y Vegetal), Timac Agro Int-Roullier Group, Polígono Arazuri-Orcoyen, Calle C n Degrees 32, 31160 Orcoyen, Spain
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29
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Furukawa Y, Watkins JL, Kim J, Curry KJ, Bennett RH. Aggregation of montmorillonite and organic matter in aqueous media containing artificial seawater. GEOCHEMICAL TRANSACTIONS 2009; 10:2. [PMID: 19166595 PMCID: PMC2654465 DOI: 10.1186/1467-4866-10-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 01/23/2009] [Indexed: 05/23/2023]
Abstract
BACKGROUND The dispersion-aggregation behaviors of suspended colloids in rivers and estuaries are affected by the compositions of suspended materials (i.e., clay minerals vs. organic macromolecules) and salinity. Laboratory experiments were conducted to investigate the dispersion and aggregation mechanisms of suspended particles under simulated river and estuarine conditions. The average hydrodynamic diameters of suspended particles (representing degree of aggregation) and zeta potential (representing the electrokinetic properties of suspended colloids and aggregates) were determined for systems containing suspended montmorillonite, humic acid, and/or chitin at the circumneutral pH over a range of salinity (0 - 7.2 psu). RESULTS The montmorillonite-only system increased the degree of aggregation with salinity increase, as would be expected for suspended colloids whose dispersion-aggregation behavior is largely controlled by the surface electrostatic properties and van der Waals forces. When montmorillonite is combined with humic acid or chitin, the aggregation of montmorillonite was effectively inhibited. The surface interaction energy model calculations reveal that the steric repulsion, rather than the increase in electronegativity, is the primary cause for the inhibition of aggregation by the addition of humic acid or chitin. CONCLUSION These results help explain the range of dispersion-aggregation behaviors observed in natural river and estuarine systems. It is postulated that the composition of suspended particles, specifically the availability of steric polymers such as those contained in humic acid, determine whether the river suspension is rapidly aggregated and settled or remains dispersed in suspension when it encounters increasingly saline environments of estuaries and oceans.
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Affiliation(s)
- Yoko Furukawa
- Naval Research Laboratory, Seafloor Sciences Branch, Stennis Space Center, Mississippi, USA
| | - Janet L Watkins
- Naval Research Laboratory, Seafloor Sciences Branch, Stennis Space Center, Mississippi, USA
| | - Jinwook Kim
- Yonsei University, Department of Earth System Sciences, Seoul, South Korea
| | - Kenneth J Curry
- University of Southern Mississippi, Department of Biological Sciences, Hattiesburg, Mississippi, USA
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Smejkalová D, Piccolo A. Aggregation and disaggregation of humic supramolecular assemblies by NMR diffusion ordered spectroscopy (DOSY-NMR). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:699-706. [PMID: 18323090 DOI: 10.1021/es071828p] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Diffusion ordered nuclear magnetic resonance spectroscopy (DOSY-NMR) was applied to a number of fulvic (FA) and humic (HA) acids of different origin. Spectral separation achieved by DOSY based on diffusion coefficients (D), and correlated to molecular sizes by calibration standards, showed that carbohydrates had the largest molecular size in FA, whereas alkyl or aromatic components were the most slowly diffusing moieties in HA. At increasing concentrations, these components had invariably lower D values in DOSY spectra for all humic samples,thereby indicating an aggregation into apparently larger associations, whose increased hydrodynamic radius was confirmed by viscosity measurements. When humic solutions were broughtfrom alkaline to acidic pH (3.6), components diffusivity detected by DOSY increased significantly, suggesting a decrease of aggregation and molecular size. A general comparison of HA and FA molecular sizes was achieved by multivariate statistical analysis. While a larger extent of aggregation and disaggregation was observed for HA than for FA, no aggregation was detected, under similar conditions, for a true macropolymeric standard. Such difference in diffusion between a polymeric molecule and humic samples, is in line with the supramolecular nature of humic matter. The possible formation of humic micelles was also investigated by both changes of diffusivity in DOSY spectra and shift of 1H NMR signals. Except for HA of peat and soil origin, revealing a self-assembling in micelle-like structures at the 4 mg mL(-1) concentration, no other humic sample showed evidence of critical micelle concentration (cmc) up to 20 mg mL(-1). These results indicated that DOSY-NMR spectroscopy is a useful technique to evaluate components of different molecular size in natural humic superstructures.
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Affiliation(s)
- Daniela Smejkalová
- Dipartimento di Scienze del Suolo, della Pianta, dell'Ambiente e delle Produzioni Animali, Università di Napoli Federico II, Via Università 100, 80055 Portici, Italy
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31
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Baigorri R, Fuentes M, Gonzalez-Gaitano G, García-Mina JM. Simultaneous Presence of Diverse Molecular Patterns in Humic Substances in Solution. J Phys Chem B 2007; 111:10577-82. [PMID: 17696392 DOI: 10.1021/jp0738154] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chemical and structural nature of humic substances (HS) is the object of an intense debate in the literature involving two main theoretical positions: the classical view defending the macromolecular pattern, and the new, more recent, view proposing a supramolecular pattern. In this study, we observe that both molecular patterns are present in different whole humic systems in solution. We also identify these molecular patterns with a specific fraction of HS. Thus, the HS family formed by the gray humic acids studied presented a clear macromolecular pattern, whereas the HS family formed by the fulvic acids studied presented the coexistence of supramolecular assemblies and individual molecules. The third HS family studied, the brown humic acids, presented both the macromolecular pattern and the supramolecular pattern. We also find that molecular aggregation-disaggregation has a strong influence in the fluorescence pattern of HS, thus indicating that the current concepts of HS structure derived from fluorescence studies need revision.
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Affiliation(s)
- Roberto Baigorri
- R&D-AFI Department, Inabonos-Roullier Group, Polígono Arazuri-Orcoyen, 31160 Orcoyen, Spain
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