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Arroyave JM, Avena M, Tan W, Wang M. The two-species phosphate adsorption kinetics on goethite. Chemosphere 2022; 307:135782. [PMID: 35870613 DOI: 10.1016/j.chemosphere.2022.135782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 07/14/2022] [Accepted: 07/16/2022] [Indexed: 06/15/2023]
Abstract
Studying the adsorption-desorption kinetics of ions and molecules is crucial to understand the mobility of nutrients and pollutants in the environment. This article reports the adsorption-desorption kinetics of phosphate on goethite, as measured by ATR-FTIR spectroscopy at pH 4.5, 7.0 and 9.5. The system phosphate-goethite has become a model system to test new experimental setups and theories to understand the behavior of pollutants with phosphonic or phosphinic moieties such as glyphosate or glufosinate. One of the main difficulties in the analysis of ATR-FTIR spectra in adsorption-desorption kinetics is to calibrate the equipment to convert absorbance vs. t curves into adsorption vs. t curves, and thus the methodology to achieve a good calibration using spectroscopic data in combination with adsorption isotherms is clearly described. The time evolution of the different surface species was monitored simultaneously during adsorption and desorption at different pH, showing the advantages of this spectroscopy over traditional adsorption methods that only quantify total adsorption. Results were analysed in terms of a simple adsorption-desorption model that takes into account transport, attachment, detachment and surface transformation of the adsorbed species. The same rate parameters at a given pH could predict well the adsorption-desorption kinetics of the two formed surface species and the corresponding adsorption isotherm, giving new insights into the dynamics of phosphate on the surface of goethite. It was found that phosphate desorbed faster from goethite at low pH than at high pH, which is counterintuitive, but has good practical and environmental applications.
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Affiliation(s)
- Jeison Manuel Arroyave
- INQUISUR, Departamento de Química, Universidad Nacional Del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Marcelo Avena
- INQUISUR, Departamento de Química, Universidad Nacional Del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina.
| | - Wenfeng Tan
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Mingxia Wang
- State Environmental Protection Key Laboratory of Soil Health and Green Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, PR China
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2
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Lu L, Rao W, Song Y, Lei M, Tie B, Du H. Natural dissolved organic matter (DOM) affects W(VI) adsorption onto Al (hydr)oxide: Mechanisms and influencing factors. Environ Res 2022; 205:112571. [PMID: 34919961 DOI: 10.1016/j.envres.2021.112571] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 11/23/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Tungsten (W) is a contaminant with health implications whose environmental behaviors are not understood well. Sorption to mineral surfaces is one of the primary processes controlling the mobility and fate of W in soils, sediments, and aquifers. However, few papers published hitherto have not yet figured out the influences of dissolved organic matter (DOM) on this process. Here, we examine W(VI) adsorption behaviors onto Al (hydr)oxide (AAH) in the presence or absence of DOM derived from plant rhizosphere, using batch experiments coupled with X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The morphology and functional group analyses results show that DOM can facilitate the aggregation of AAH and block surface Al-OH groups. Coexisting DOM inhibits W(VI) adsorption onto AAH at acidic to neutral pH (4-7), and the presence of either Na + or PO43- can exert a completely different impact on W(VI) adsorption. XPS and FTIR characterizations further demonstrate surface W complexes with the Al-OH groups of AAH and carboxyl groups of DOM. There is no reduction of W(VI) during the adsorption processes, and poly-tungstate species are formed on the surface of both AAH and AAH-DOM coprecipitates. This study provides the first evidence of the roles of natural DOM on W sequestration at the mineral-water surface, which has an important implication for the prediction of the migration and bioavailability of W in natural environments.
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Affiliation(s)
- Lei Lu
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Wenkai Rao
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Yuyan Song
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Ming Lei
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Boqing Tie
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, People's Republic of China
| | - Huihui Du
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, People's Republic of China.
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3
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Xu J, Wu Y, Ma M, Luo T, Xia J, Zhang X. A novel transformation pathway of p-arsanilic acid in water by colloid ferric hydroxide under UVA light. Environ Sci Pollut Res Int 2022; 29:5043-5051. [PMID: 34415520 DOI: 10.1007/s11356-021-15975-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Iron species that occur in natural surface water could affect the photochemical behavior of pollutants. Complexation between iron species and polycarboxylate or heavy metals has been widely reported, where the ligands could be oxidized via ligand-to-metal charge transfer (LMCT) by light inducement. Such complexation and photochemical reactions might also occur for low valance metal-containing organic compounds, which is worthy of investigation. This work studied the phototransformation of p-arsanilic acid (ASA), an organic arsenic compound that is widely used as a feed additive in the poultry industry, by colloidal ferric hydroxide (CFH) using black light lamps (λ = 365 nm) as the light source. The results revealed the contribution to ASA transformation at circumneutral conditions by CFH through an LMCT process, which is the same as that for As(III). The complexation between ASA and CFH was investigated using UV-vis spectroscopy. The estimated equilibrium constant for the CFH-ASA complex was log Kf271 = 4.22. The analysis of the photoproducts found the generation of both inorganic and organic arsenic. Our findings confirmed the similarities in the photochemical mechanisms of ASA and As(III) in the presence of CFH. The results help in further understanding the fate of organoarsenicals in the surface water environment.
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Affiliation(s)
- Jing Xu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China
- Hubei Key Laboratory of Water System Science for Sponge City Construction, Wuhan University, Wuhan, 430072, China
| | - Yi Wu
- Department of Environmental Science, School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, China
| | - Mengling Ma
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China
- Hubei Key Laboratory of Water System Science for Sponge City Construction, Wuhan University, Wuhan, 430072, China
| | - Tao Luo
- Department of Environmental Science, School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, China
| | - Jun Xia
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China
- Hubei Key Laboratory of Water System Science for Sponge City Construction, Wuhan University, Wuhan, 430072, China
| | - Xiang Zhang
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China.
- Hubei Key Laboratory of Water System Science for Sponge City Construction, Wuhan University, Wuhan, 430072, China.
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4
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Li X, Ma X, Lang X. Blue light-powered hydroxynaphthoic acid-titanium dioxide photocatalysis for the selective aerobic oxidation of amines. J Colloid Interface Sci 2021; 602:534-543. [PMID: 34144307 DOI: 10.1016/j.jcis.2021.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/14/2021] [Accepted: 06/02/2021] [Indexed: 01/26/2023]
Abstract
Solar photocatalysis is the key to resolve many environmental challenges but is usually hard to achieve over a metal oxide semiconductor. Therefore, assembling π-conjugated molecules onto semiconductors becomes an efficient approach to solar conversion via ligand-to-metal charge transfer. Here, a rational design of ligands for titanium dioxide (TiO2) is presented to produce robust visible light photocatalysts. Three hydroxynaphthoic acids (HNAs) were selected as ligands by extending an extra benzene ring of salicylic acid (SA) at 3,4 or 4,5 or 5,6 positions. These ligands could regulate the performance of TiO2 in which 2-hydroxy-1-naphthoic acid (2H1NA) endows the best outcome. In detail, blue light-powered cooperative photocatalysis of 2H1NA-TiO2 with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO, 5 mol%) inaugurates the expeditious formation of imines by oxidation of amines with atmospheric oxygen (O2). Interestingly, the increase of the O2 pressure from 1 atm to 0.4 MPa promoted the selective oxidation of benzylamine but thereafter declined with a further boost to 0.6 MPa. Notably, an electron transfer between the oxidatively quenched 2H1NA-TiO2 and TEMPO is established, offering a new pathway for environmental applications. This work presents a strategy in designing cutting-edge visible light photocatalysts via altering semiconductors with surface ligands.
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Affiliation(s)
- Xia Li
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaoming Ma
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Xianjun Lang
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
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Wang Y, Zhou J, Ma X, Li X, Lang X. Cooperative Photocatalysis with 4-Amino-TEMPO for Selective Aerobic Oxidation of Amines over TiO 2 Nanotubes. Chem Asian J 2021; 16:2659-2668. [PMID: 34302305 DOI: 10.1002/asia.202100682] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/20/2021] [Indexed: 12/17/2022]
Abstract
Attaching π-conjugated molecules onto TiO2 can form surface complexes that could capture visible light. However, to make these TiO2 surface complexes durable, integrating 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) or its analogues as a redox mediator with photocatalysis is the key to constructing selective chemical transformations. Herein, sodium 6,7-dihydroxynaphthalene-2-sulfonate (DHNS) was obtained by extending the π-conjugated system of catechol by adding a benzene ring and a substituent sodium sulfonate (-SO3 - Na+ ). The DHNS-TiO2 showed the best photocatalytic activity towards the blue light-induced selective aerobic oxidation of benzylamine. Compared to TEMPO, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4-amino-TEMPO) could rise above 70% in conversion of benzylamine over the DHNS-TiO2 photocatalyst. Eventually, a wide range of amines could be selectively oxidized into imines with atmospheric O2 by cooperative photocatalysis of DHNS-TiO2 with 4-amino-TEMPO. Notably, superoxide (O2 •- ) is crucial in coupling the photocatalytic cycle of DHNS-TiO2 and the redox cycle of 4-amino-TEMPO. This work underscores the design of surface ligands for semiconductors and the selection of a redox mediator in visible light photocatalysis for selective chemical transformations.
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Affiliation(s)
- Yuexin Wang
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Jun Zhou
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Xiaoming Ma
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Xia Li
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Xianjun Lang
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
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Nguyen TB, Ho TBC, Huang CP, Chen CW, Hsieh SL, Tsai WP, Dong CD. Adsorption characteristics of tetracycline onto particulate polyethylene in dilute aqueous solutions. Environ Pollut 2021; 285:117398. [PMID: 34082368 DOI: 10.1016/j.envpol.2021.117398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 04/28/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
The presence of ultrafine plastics particles and its potential to concentrate and transport organic contaminants in aquatic environments have become a major concern in recent years. Specifically, the uptake of hazardous chemicals by plastics particles may affect the distribution and bioavailability of the chemicals. In this study, the adsorption of tetracycline (TC), an antibiotic frequently found in aquatic environments, on high-density polyethylene (PE) particles with the average size of 45 μm, was investigated. The PE particles were characterized for surface acidity for the first time. Results showed that pH controls the surface charge of PE particles. TC adsorption onto PE particles was rapid as expected following the pseudo-second-order rate law (r2 > 0.99). Polar forces in addition to specific chemical interactions, such as hydrogen bonding and hydrophophilicity controlled TC adsorption onto PE particles. Parameters, including pH, dissolved organic matter, ionic strength, major cations and anions affected TC adsorption onto PE micro-particles. Results indicated that PE particles can function as a carrier of antibiotics in the aquatic environment, which potentially imposes ecosystem and human health risks.
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Affiliation(s)
- Thanh-Binh Nguyen
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Thi-Bao-Chau Ho
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Chin-Pao Huang
- Department of Civil and Environmental Engineering, University of Delaware, Newark, 19716, DE, USA
| | - Chiu-Wen Chen
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Shu-Ling Hsieh
- Department of Seafood Science, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Wen-Pei Tsai
- Department of Fisheries Production and Management, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Cheng-Di Dong
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan.
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7
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Barraqué F, Montes ML, Fernández MA, Candal R, Torres Sánchez RM, Marco-Brown JL. Arsenate removal from aqueous solution by montmorillonite and organo-montmorillonite magnetic materials. Environ Res 2021; 192:110247. [PMID: 32980304 DOI: 10.1016/j.envres.2020.110247] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 09/10/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
Magnetic-clay (MtMag) and magnetic-organoclay (O100MtMag) nanocomposites were synthesized, characterized and evaluated for arsenic adsorption. Batch arsenic adsorption experiments were performed varying pH conditions and initial As(V) concentration, while successive adsorption cycles were made in order to evaluate the materials reuse. The highest As(V) removal efficiency (9 ± 1 mg g-1 and 7.8 ± 0.8 mg g-1 for MtMag and O100MtMag, respectively) was found at pH 4.0, decreasing at neutral and alkaline conditions. From As(V) adsorption isotherm, two adsorption processes or two different surface sites were distinguished. Nanocomposites resulted composed by montmorillonite or organo-montmorillonite and magnetite as the principal iron oxide, with saturation magnetization of 8.5 ± 0.5 Am2 Kg-1 (MtMag) and 20.3 ± 0.5 Am2 Kg-1 (O100MtMag). Thus, both materials could be separated and recovered from aqueous solutions using external magnetic fields. Both materials allowed achieving arsenic concentrations lower than the World Health Organization (WHO) recommended concentration limit after two consecutive adsorption cycles (2.25 and 4.5 μg L-1 for MtMag and O100MtMag, respectively).
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Affiliation(s)
- Facundo Barraqué
- CETMIC, CICPBA, CONICET CCT-La Plata, Camino Centenario y 506, B1897ZCA, M. B. Gonnet, Argentina
| | - María L Montes
- IFLP, Instituto de Física La Plata, CONICET CCT-La Plata, Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Mariela A Fernández
- CETMIC, CICPBA, CONICET CCT-La Plata, Camino Centenario y 506, B1897ZCA, M. B. Gonnet, Argentina
| | - Roberto Candal
- Instituto de Investigación e Ingeniería Ambiental IIIA, Universidad Nacional de San Martín, CONICET, UNSAM, Av. 25 de Mayo y Francia, San Martín, Buenos Aires, Argentina
| | - Rosa M Torres Sánchez
- CETMIC, CICPBA, CONICET CCT-La Plata, Camino Centenario y 506, B1897ZCA, M. B. Gonnet, Argentina
| | - Jose L Marco-Brown
- Instituto de Investigación e Ingeniería Ambiental IIIA, Universidad Nacional de San Martín, CONICET, UNSAM, Av. 25 de Mayo y Francia, San Martín, Buenos Aires, Argentina.
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8
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Arroyave JM, Puccia V, Zanini GP, Avena MJ. Surface speciation of phosphate on goethite as seen by InfraRed Surface Titrations (IRST). Spectrochim Acta A Mol Biomol Spectrosc 2018; 199:57-64. [PMID: 29567523 DOI: 10.1016/j.saa.2018.03.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/06/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Phosphate adsorption at the metal oxide-water interface has been intensely studied, and the system phosphate-goethite in aqueous media is normally used as a model system with abundant information regarding adsorption-desorption under very different conditions. In spite of this, there is still discussion on whether the main inner-sphere surface complexes that phosphate forms on goethite are monodentate or bidentate. A new spectroscopic technique, InfraRed Surface Titration (IRST), is presented here and used to systematically explore the surface speciation of phosphate on goethite in the pH range 4.5-9.5 at different surface coverages. IRST enabled to construct distribution curves of surface species and distribution curves of dissolved phosphate species. In combination with the CD-MUSIC surface complexation model it was possible to conclude that surface complexes are monodentate. Very accurate distribution curves were obtained, showing a crossing point at pH5.5 at a surface coverage of 2.0μmolm-2, with a mononuclear monoprotonated species predominating at pH>5.5 and a mononuclear diprotonated species prevailing at pH<5.5. On the contrary, at the low surface coverage of 0.7μmolm-2 there is no crossing point, with the mononuclear monoprotonated species prevailing at all pH. IRST can become a powerful technique to investigate structure, properties and reactions of any IR-active surface complex at the solid-water interface.
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Affiliation(s)
- Jeison Manuel Arroyave
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Virginia Puccia
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Graciela P Zanini
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Marcelo J Avena
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina.
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9
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Wang RH, Zhu XF, Qian W, Yu YC, Xu RK. Effect of pectin on adsorption of Cu(II) by two variable-charge soils from southern China. Environ Sci Pollut Res Int 2015; 22:19687-19694. [PMID: 26278899 DOI: 10.1007/s11356-015-5150-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/03/2015] [Indexed: 06/04/2023]
Abstract
The influence of pectin on Cu(II) adsorption by two variable-charge soils (an Oxisol and an Ultisol) was investigated. Pectin increased the adsorption, and the extent of adsorption increased linearly with the dose of pectin, being greater in the Oxisol than that in the Ultisol because the adsorption of pectin by the Oxisol was greater. Both Langmuir and Freundlich equations fitted the adsorption isotherms of Cu(II) for both soils well. The fitting parameters of both equations indicated that pectin increased not only the adsorption capacity of the soils for Cu(II) but also the adsorption strength of Cu(II). The effect of pectin decreased with rising pH in the pH range 3.5-6.0, although the extent of electrostatic adsorption of Cu(II) by both soils was markedly greater over the pH range. Fourier-transformed infrared spectroscopy analysis and zeta potential measurement of soil colloids indicated that adsorption of pectin by the soils made the negative charge on both soils more negative, which was responsible for the increase in the electrostatic adsorption of Cu(II) induced by the addition of pectin. In conclusion, pectin-enhanced adsorption of Cu(II) especially at low pH would be beneficial to the soils as it would decrease the activity and mobility of Cu(II) in acidic variable-charge soils.
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Affiliation(s)
- Ru-hai Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
- College of Forest Resources and Environment, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
| | - Xiao-fang Zhu
- College of Forest Resources and Environment, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
- Nanjing Institute of Supervision & Testing on Product Quality, Nanjing, 210028, People's Republic of China
| | - Wei Qian
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Yuan-chun Yu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
- College of Forest Resources and Environment, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
| | - Ren-kou Xu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China.
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Abstract
Geochemical fate of antimony (Sb) - a similar oxyanion as arsenic (As) - in a variety of environment is largely unexplored. Kaolinite is an important, naturally occurring clay mineral in soils and aquifers and is known to control the fate of several contaminants via a multitude of geochemical processes, primarily adsorption. Here we report adsorption of antimony on kaolinite as a function of solution chemistry: initial antimony concentration, pH, ionic strength, and a competing anion. A surface complexation modeling (SCM) approach was undertaken to understand the potential mechanistic implications of sorption envelope data. In the SCM, a multicomponent additive approach, in which kaolinite is assumed to be a (1:1) mixture of quartz (≡SiOH) and gibbsite (≡AlOH), was tested. Results indicated that ionic strength has a minimal effect on antimony adsorption. For the lower initial antimony concentration (4.11 μM), the additive model with binuclear surface complexes on quartz and gibbsite showed a better fit at pH<6, but somewhat under predicted the experimental data above pH 6. At the higher initial antimony concentration (41.1 μM), the sorption envelope was of different shape than the lower load. The additive model, which considered binuclear surface complexes for quartz and gibbsite, resulted in over prediction of the adsorption data at pH>3.5. However, the additive model with binuclear surface complex on quartz and mononuclear surface complex on gibbsite showed an excellent fit of the data. Phosphate greatly influenced antimony adsorption on kaolinite at both low and high antimony loadings, indicating competition for available surface sites.
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Affiliation(s)
- Sudipta Rakshit
- Department of Agricultural and Environmental Sciences, Tennessee State University, 3500 John A. Merritt Blvd., Nashville, TN 37209-1561, USA.
| | - Dibyendu Sarkar
- Earth and Environmental Studies Department, Montclair State University, Montclair, NJ, USA
| | - Rupali Datta
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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Grabias E, Gładysz-Płaska A, Książek A, Majdan M. Efficient uranium immobilization on red clay with phosphates. Environ Chem Lett 2013; 12:297-301. [PMID: 24817839 PMCID: PMC4010658 DOI: 10.1007/s10311-013-0442-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/22/2013] [Indexed: 05/26/2023]
Abstract
Uranium is a very toxic and radioactive element. Removal of uranium from wastewaters requires remediation technologies. Actual methods are costly and ineffective when uranium concentration is very low. Little is known about the enhancement of sorption of uranyl ions by phosphate ions on aluminosilicates. Here, we studied sorption of uranyl acetate on red clay in the presence of phosphates. The concentration of U(VI) ranged 0.0001-0.001 mol/L, whereas the concentration of PO43- was constant at 0.0001 mol/L. We designed a new method for the analysis of ternary surface complexes. We observed for the first time a remarkable improvement of U(VI) sorption on red clay under the influence of phosphates. We also found that at least two different ternary surface complexes U(VI)-phosphate-clay are formed in the sorbent phase. The complexation of UO22+ cations by phosphate ligands in the sorbent phase was confirmed by the X-ray photoelectron spectra of U 4f electrons.
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Affiliation(s)
- Ewelina Grabias
- Faculty of Chemistry, Maria Curie-Skłodowska University, PL MC Skłodowskiej 2, 20-031 Lublin, Poland
| | - Agnieszka Gładysz-Płaska
- Faculty of Chemistry, Maria Curie-Skłodowska University, PL MC Skłodowskiej 2, 20-031 Lublin, Poland
| | - Anna Książek
- Faculty of Chemistry, Maria Curie-Skłodowska University, PL MC Skłodowskiej 2, 20-031 Lublin, Poland
| | - Marek Majdan
- Faculty of Chemistry, Maria Curie-Skłodowska University, PL MC Skłodowskiej 2, 20-031 Lublin, Poland
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