Abstract
The photochemical role of Fe(III)-citrate complex is significant in natural waters due to its ubiquitous existence and excellent photoreactivity at near neutral pH. Although there are many reports on the photoinduced degradation of pollutants in the Fe(III)-citrate system, the optimum pH for its photoreactivity is yet not clearly understood. Here, for the first time, we demonstrated that the optimum pH was 5.5 for the photoproduction of •OH in the Fe(III)-citrate system via kinetics modeling based on the steady-state approximation. According to the experimental results, the •OH photoproduction increased with increasing pH until 5.5 and then decreased in Fe(III)-citrate solution, which agreed well with the prediction trend of kinetic modeling. The effect of the common ligand oxalate on the photoreactivity of Fe(III)-citrate system was also investigated. The addition of oxalate promoted the photoproduction of •OH in Fe(III)-citrate solutions, and the measured [•OH]ss increased with oxalate concentration under a fixed Fe(III)-to-citrate ratio. Little synergistic effect exists in Fe(III)-citrate-oxalate system at pH 4.0–5.5. In contrast, an appreciable synergistic effect was observed at near neutral pH (6.0–8.0). Higher oxalate-to-citrate ratio facilitated the synergistic effect. Furthermore, antifungal drug fluconazole could be removed efficiently in the Fe(III)-citrate-oxalate system. The photodegradation kinetics also verified the optimum pH of Fe(III)-citrate system and synergistic effect of oxalate. By LC-ESI-MS/MS analyses, the photoproducts of fluconazole in the Fe(III)-citrate-oxalate system were identified and the reaction mechanism involving hydroxylation substitution and subsequent cleavage of heterocyclic amine was proposed. These findings suggest that Fe(III)-citrate exhibits best photoreactivity at pH 5.5, and the coexistence of reactive ligands will enhance its photoreactivity at circumneutral pH, indicating potential application in wastewater treatment via addition of appropriate citrate and co-ligands.
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References
Abida O, Kolar M, Jirkovsky J, Mailhot G (2012) Degradation of 4-chlorophenol in aqueous solution photoinduced by Fe (iii)–citrate complex. Photochem Photobiol Sci 11:794–802. https://doi.org/10.1039/c2pp05358f
Balmer ME, Sulzberger B (1999) Atrazine degradation in irradiated iron/oxalate systems: effects of pH and oxalate. Environ Sci Technol 33:2418–2424. https://doi.org/10.1021/es9808705
Behra P, Sigg L (1990) Evidence for redox cycling of iron in atmospheric water droplets. Nature 344:419–421. https://doi.org/10.1038/344419a0
Chen Y, Wu F, Lin Y, Deng N, Bazhin N, Glebov E (2007) Photodegradation of glyphosate in the ferrioxalate system. J Hazard Mater 148:360–365. https://doi.org/10.1016/j.jhazmat.2007.02.044
Chen Y, Liu Z, Wang Z, Xue M, Zhu X, Tao T (2011) Photodegradation of propranolol by Fe (III)-citrate complexes: kinetics, mechanism and effect of environmental media. J Hazard Mater 194:202–208. https://doi.org/10.1016/j.jhazmat.2011.07.081
Chen Y, Zhang K, Zuo Y (2013a) Direct and indirect photodegradation of estriol in the presence of humic acid, nitrate and iron complexes in water solutions. Sci Total Environ 463-464:802–809. https://doi.org/10.1016/j.scitotenv.2013.06.026
Chen ZF, Ying GG, Ma YB, Lai HJ, Chen F, Pan CG (2013b) Typical azole biocides in biosolid-amended soils and plants following biosolid applications. J Agric Food Chem 61:6198–6206. https://doi.org/10.1021/jf4013949
Chen ZF, Ying GG, Jiang YX, Yang B, Lai HJ, Liu YS, Pan CG, Peng FQ (2014) Photodegradation of the azole fungicide fluconazole in aqueous solution under UV-254: kinetics, mechanistic investigations and toxicity evaluation. Water Res 52:83–91. https://doi.org/10.1016/j.watres.2013.12.039
Chen M, Yao J, Huang Y, Gong H, Chu W (2018) Enhanced photocatalytic degradation of ciprofloxacin over Bi2O3/(BiO)2CO3 heterojunctions: efficiency, kinetics, pathways, mechanisms and toxicity evaluation. Chem Eng J 334:453–461. https://doi.org/10.1016/j.cej.2017.10.064
Cieśla P, Kocot P, Mytych P, Stasicka Z (2004) Homogeneous photocatalysis by transition metal complexes in the environment. J Mol Catal A Chem 224:17–33. https://doi.org/10.1016/j.molcata.2004.08.043
Clarizia L, Russo D, Di Somma I et al (2017) Homogeneous photo-Fenton processes at near neutral pH: a review. Appl Catal B Environ 209:358–371. https://doi.org/10.1016/j.apcatb.2017.03.011
Deng N, Wu F, Luo F, Zan L (1997) Photodegradation of dyes in aqueous solutions containing Fe (III)-oxalato complexes. Chemosphere 35:2697–2706. https://doi.org/10.1016/S0045-6535(97)00327-5
Faust BC, Zepp RG (1993) Photochemistry of aqueous iron (III)-polycarboxylate complexes: roles in the chemistry of atmospheric and surface waters. Environ Sci Technol 27:2517–2522. https://doi.org/10.1021/es00048a032
Feng X, Wang Z, Chen Y, Tao T, Wu F, Zuo Y (2012a) Effect of Fe (III)/citrate concentrations and ratio on the photoproduction of hydroxyl radicals: application on the degradation of diphenhydramine. Ind Eng Chem Res 51:7007–7012. https://doi.org/10.1021/ie300360p
Feng X, Wang Z, Chen Y, Tao T, Wu F (2012b) Multivariate-parameter optimization for photodegradation of tetracycline by Fe (III)-citrate complexes at near-neutral pH. J Environ Eng 138:873–879. https://doi.org/10.1061/(ASCE)EE.1943-7870.0000530
Feng X, Chen Y, Fang Y, Wang X, Wang Z, Tao T, Zuo Y (2014) Photodegradation of parabens by Fe (III)-citrate complexes at circumneutral pH: matrix effect and reaction mechanism. Sci Total Environ 472:130–136. https://doi.org/10.1016/j.scitotenv.2013.11.005
González-Ortegón E, Blasco J, Le Vay L, Giménez L (2013) A multiple stressor approach to study the toxicity and sub-lethal effects of pharmaceutical compounds on the larval development of a marine invertebrate. J Hazard Mater 263:233–238. https://doi.org/10.1016/j.jhazmat.2013.09.041
Guo J, Du Y, Lan Y, Mao J (2011) Photodegradation mechanism and kinetics of methyl orange catalyzed by Fe (III) and citric acid. J Hazard Mater 186:2083–2088. https://doi.org/10.1016/j.jhazmat.2010.12.112
Huang YH, Tsai ST, Huang YF, Chen CY (2007) Degradation of commercial azo dye reactive black B in photo/ferrioxalate system. J Hazard Mater 140:382–388. https://doi.org/10.1016/j.jhazmat.2006.10.083
Huang Q, Wang Z, Wang C, Peng X (2013) Chiral profiling of azole antifungals in municipal wastewater and recipient rivers of the Pearl River Delta, China. Environ Sci Pollut Res 20:8890–8899. https://doi.org/10.1007/s11356-013-1862-z
Kahle M, Buerge IJ, Hauser A, Müller MD, Poiger T (2008) Azole fungicides : occurrence and fate in wastewater and surface waters Azole Fungicides : Occurrence and Fate in Wastewater and Surface Waters. Environ Sci Technol 42:7193–7200. https://doi.org/10.1021/es8009309
Lee BD, Iso M, Hosomi M (2001) Prediction of Fenton oxidation positions in polycyclic aromatic hydrocarbons by frontier electron density. Chemosphere 42:431–435. https://doi.org/10.1016/S0045-6535(00)00061-8
Linxiang L, Abe Y, Nagasawa Y, Kudo R, Usui N, Imai K, Mashino T, Mochizuki M, Miyata N (2004) An HPLC assay of hydroxyl radicals by the hydroxylation reaction of terephthalic acid. Biomed Chromatogr 18:470–474. https://doi.org/10.1002/bmc.339
Mark G, Tauber A, Laupert R, Schuchmann HP, Schulz D, Mues A, von Sonntag C (1998) OH-radical formation by ultrasound in aqueous solution—part II: terephthalate and Fricke dosimetry and the influence of various conditions on the sonolytic yield. Ultrason Sonochem 5:41–52. https://doi.org/10.1016/S1350-4177(98)00012-1
Moreira FC, Boaventura RAR, Brillas E, Vilar VJP (2015) Degradation of trimethoprim antibiotic by UVA photoelectro-Fenton process mediated by Fe (III)-carboxylate complexes. Appl Catal B Environ 162:34–44. https://doi.org/10.1016/j.apcatb.2014.06.008
Ou X, Quan X, Chen S, Zhang F, Zhao Y (2008) Photocatalytic reaction by Fe (III)-citrate complex and its effect on the photodegradation of atrazine in aqueous solution. J Photochem Photobiol A Chem 197:382–388. https://doi.org/10.1016/j.jphotochem.2008.02.001
Page SE, Arnold WA, McNeill K (2010) Terephthalate as a probe for photochemically generated hydroxyl radical. J Environ Monit 12:1658–1665. https://doi.org/10.1039/c0em00160k
Peschka M, Roberts PH, Knepper TP (2007) Analysis, fate studies and monitoring of the antifungal agent clotrimazole in the aquatic environment. Anal Bioanal Chem 389:959–968. https://doi.org/10.1007/s00216-007-1480-z
Pozdnyakov I, Sherin P, Bazhin N, Plyusnin V (2018) [Fe (ox)3]3− complex as a photodegradation agent at neutral pH: advances and limitations. Chemosphere 195:839–846. https://doi.org/10.1016/j.chemosphere.2017.12.096
Qu X, Kirschenbaum LJ, Borish ET (2000) Hydroxyterephthalate as a fluorescent probe for hydroxyl radicals: application to hair melanin. Photochem Photobiol 71:307–313. https://doi.org/10.1562/0031-8655(2000)0710307HAAFPF2.0.CO2
Stumm W, Morgan JJ (1996) Aquatic chemistry: chemical equilibria and rates in natural waters. Wiley, New York
Weller C, Horn S, Herrmann H (2013) Effects of Fe (III)-concentration, speciation, excitation-wavelength and light intensity on the quantum yield of iron (III)-oxalato complex photolysis. J Photochem Photobiol A Chem 255:41–49. https://doi.org/10.1016/j.jphotochem.2013.01.014
Westerhoff P, Yoon Y, Snyder S, Wert E (2005) Fate of endocrine-disruptor, pharmaceutical, and personal care product chemicals during simulated drinking water treatment processes. Environ Sci Technol 39:6649–6663. https://doi.org/10.1021/es0484799
Wu F, Deng N (2000) Photochemistry of hydrolytic iron (III) species and photoinduced degradation of organic compounds. A minireview. Chemosphere 41:1137–1147. https://doi.org/10.1016/S0045-6535(00)00024-2
Wu F, Deng N, Zuo Y (1999) Discoloration of dye solutions induced by solar photolysis of ferrioxalate in aqueous solutions. Chemosphere 39:2079–2085. https://doi.org/10.1016/S0045-6535(99)00097-1
Yang JF, Yang LM, Zhang SB, Ou LH, Liu CB, Zheng LY, Yang YF, Ying GG, Luo SL (2017) Degradation of azole fungicide fluconazole in aqueous solution by thermally activated persulfate. Chem Eng J 321:113–122. https://doi.org/10.1016/j.cej.2017.03.103
Zhou D, Wu F, Deng N (2004a) Fe (III)-oxalate complexes induced photooxidation of diethylstilbestrol in water. Chemosphere 57:283–291. https://doi.org/10.1016/j.chemosphere.2004.05.043
Zhou D, Wu F, Deng N, **ang W (2004b) Photooxidation of bisphenol a (BPA) in water in the presence of ferric and carboxylate salts. Water Res 38:4107–4116. https://doi.org/10.1016/j.watres.2004.07.021
Zhou D, Wu Y, Feng X, Chen Y, Wang Z, Tao T, Wei D (2014) Photodegradation of hexabromocyclododecane (HBCD) by Fe (III) complexes/H2O2 under simulated sunlight. Environ Sci Pollut Res 21:6228–6233. https://doi.org/10.1007/s11356-014-2553-0
Zuo Y, Hoigné J (1994) Photochemical decomposition of oxalic glyoxylic and pyruvic acid catalysed by iron in atmsopheric waters. Atmos Environ 28:1231–1239. https://doi.org/10.1016/1352-2310(94)90270-4
Zuo Y, Holgne J (1992) Formation of hydrogen peroxide and depletion of oxalic acid in atmospheric water by photolysis of Iron (III)-oxalato complexes. Environ Sci Technol 26:1014–1022. https://doi.org/10.1021/es00029a022
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This work was financially supported by the National Natural Science Foundation of China (Nos. 21677054 and 21377043) and project funded by China Postdoctoral Science Foundation (No. 2018 M630865).
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Wan, D., Zhang, G., Chen, Y. et al. Photogeneration of hydroxyl radical in Fe(III)-citrate-oxalate system for the degradation of fluconazole: mechanism and products. Environ Sci Pollut Res 26, 8640–8649 (2019). https://doi.org/10.1007/s11356-019-04348-2
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DOI: https://doi.org/10.1007/s11356-019-04348-2