紫外光强化铁离子循环活化PS氧化苯胺
Enhanced oxidation of aniline by persulfate via cycling of ferrous ions in the presence of UV irradiation
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摘要: 研究了草酸铁离子(Fe (C2O4)33-)在UV光照条件下的铁离子循环转化过程及其强化过硫酸钠(PS)活化氧化苯胺的机理,考察了Fe (C2O4)33-浓度和初始pH对PS活化及苯胺氧化效果的影响.研究表明,在UV光照条件下,0.75 mmol·L-1的Fe (C2O4)33-溶液在初始pH值为3时,Fe2+的转化率最高可达到96%,远高于柠檬酸铁铵和氯化铁体系,但反应过程中草酸根离子(C2O42-)会发生分解并引起pH升高,导致Fe2+转化率急剧下降;Fe2+循环转化过程对UV/Fe (C2O4)33-体系强化PS活化的作用远大于UV光照直接活化PS过程,对PS活化分解率的贡献达到79%;初始Fe (C2O4)33-浓度决定了Fe2+循环转化的最大浓度并显著影响PS的活化效果,当Fe (C2O4)33-初始浓度从0.25 mmol·L-1逐渐提高到0.50、0.75、1.00 mmol·L-1时,PS活化分解速率不断增大,但当浓度高于0.75 mmol·L-1时,C2O42-对硫酸根自由基(SO4·-)的竞争作用显著增强,导致苯胺的氧化效果出现降低;中碱性条件不利于UV/Fe (C2O4)33-体系发生光化学反应生成Fe2+,但在其活化PS过程中,由于PS分解引起pH下降,在初始pH为7和9时PS仍可被有效活化,PS分解率可分别达到86%和68%.Abstract: The mechanisms of ferrous ion cycling and its performance in promoting the oxidative degradation of aniline by sodium persulfate (PS) in the presence of UV irradiation and ferric oxalate (Fe(C2O4)33-) were studied. The effects of initial Fe(C2O4)33- concentration and pH on PS activation and degradation of aniline were also investigated. It was indicated that the conversion efficiency of Fe2+ was as high as 96% in the solution with initial pH of 3 and Fe(C2O4)33- concentration of 0.75 mmol·L-1 under UV irradiation, which was much higher than those of ammonium ferric citrate and ferric chloride solution under identical conditions. However, the decomposition of oxalate ion and the induced pH increase led to the sharp decrease of Fe2+ conversion efficiency. The process of Fe2+ conversion played a much more significant role on promoting the PS activation than direct activation process via UV irradiation in UV/Fe(C2O4)33- systems, contributing up to 79% of the PS activation. The initial Fe(C2O4)33- concentration determined the maximum concentrations of generated Fe2+ and affected the PS activation significantly. When the concentration increased from 0.25 mmol·L-1 to 0.50, 0.75 and 1.00 mmol·L-1, the efficiency of PS activation increased accordingly. But when the ferric oxalate concentration was higher than 0.75 mmol·L-1, the enhanced competition of C2O42- for sulfate radicals led to a lower oxidation efficiency of aniline. Neutral and alkaline environments were not conducive to the Fe2+ generation via photochemical reaction in the UV/Fe(C2O4)33- systems. However, PS activation efficiency could reach as high as 86% and 68% at pH 7 and pH 9, respectively, which was due to the induced pH decline along with the PS decomposition.
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Key words:
- UV irradiation /
- ferric oxalate /
- ferrous ions cycling /
- persulfate /
- oxidation
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[1] MEDINA R, DAVID GARA P M, FERN NDEZ-GONZ LEZ A J, et al. Remediation of a soil chronically contaminated with hydrocarbons through persulfate oxidation and bioremediation[J]. Science of the Total Environment, 2018, 618:518-530. [2] DEVI P, DAS UDALAI A K. In-situ chemical oxidation:Principle and applications of peroxide and persulfate treatments in wastewater systems[J]. Science of the Total Environment, 2016, 571:643-657. [3] LIANG C J, BRUELL C J, MARLEY M C, et al. Persulfate oxidation for in situ remediation of TCE. I. Activated by ferrous ion with and without a persulfate-thiosulfate redox couple[J]. Chemosphere, 2004, 55(9):1213-1223. [4] HUANG K C, COUTTENYE R AHOAG G E. Kinetics of heat-assisted persulfate oxidation of methyl tert-butyl ether (MTBE)[J]. Chemosphere, 2002, 49(4):413-420. [5] YANG S, WANG P, YANG X, et al. Degradation efficiencies of azo dye acid orange 7 by the interaction of heat, UV and anions with common oxidants:Persulfate, peroxymonosulfate and hydrogen peroxide[J]. Journal of Hazardous Materials, 2010, 179(1-3):552-558. [6] FURMAN O S, TEEL A LWATTS R J. Mechanism of base activation of persulfate[J]. Environmental Science & Technology, 2010, 44(16):6423-6428. [7] TAN C Q, GAO N Y, CHU W H, et al. Degradation of diuron by persulfate activated with ferrous ion[J]. Separation and Purification Technology, 2012, 95:44-48. [8] JIANG X X, WU Y L, WANG P, et al. Degradation of bisphenol A in aqueous solution by persulfate activated with ferrous ion[J]. Environmental Science and Pollution Research, 2013, 20(7):4947-4953. [9] ZHU L L, AI Z H, HO W K, et al. Core-shell Fe-Fe2O3 nanostructures as effective persulfate activator for degradation of methyl orange[J]. Separation and Purification Technology, 2013, 108:159-165. [10] OH S Y, KANG S G, KIM D W, et al. Degradation of 2,4-dinitrotoluene by persulfate activated with iron sulfides[J]. Chemical Engineering Journal, 2011, 172(2-3):641-646. [11] OH S Y, KANG S GCHIU P C. Degradation of 2,4-dinitrotoluene by persulfate activated with zero-valent iron[J]. Science of the Total Environment, 2010, 408(16):3464-3468. [12] PU M, GUAN Z, MA Y, et al. Synthesis of iron-based metal-organic framework MIL-53 as an efficient catalyst to activate persulfate for the degradation of Orange G in aqueous solution[J]. Applied Catalysis A:General, 2018, 549:82-92. [13] 张金凤, 杨曦, 郑伟, 等. 水体系中Fe(Ⅱ)/K2S2O8降解敌草隆的研究[J]. 环境化学, 2008, 27(1):15-18. ZHANG J F, YANG X, ZHENG W, et al. Degradation of diuron by persulfate oxidation activated by ferrous ion in aqueous solution system[J]. Environmental Chemictry, 2008, 27(1):15-18(in Chinese).
[14] ZOU J, MA J, CHEN L W, et al. Rapid acceleration of ferrous iron/peroxymonosulfate oxidation of organic pollutants by promoting Fe(Ⅲ)/Fe(Ⅱ) Cycle with hydroxylamine[J]. Environmental Science & Technology, 2013, 47(20):11685-11691. [15] ZHANG H, WANG Z, LIU C C, et al. Removal of COD from landfill leachate by an electro/Fe2+/peroxydisulfate process[J]. Chemical Engineering Journal, 2014, 250:76-82. [16] KWAN C YCHU W. The role of organic ligands in ferrous-induced photochemical degradation of 2,4-dichlorophenoxyacetic acid[J]. Chemosphere, 2007, 67(8):1601-1611. [17] LIANG C J, HUANG C F, MOHANTY N, et al. A rapid spectrophotometric determination of persulfate anion in ISCO[J]. Chemosphere, 2008, 73(9):1540-1543. [18] TAMURA H, GOTO K, YOTSUYANAGI T, et al. Spectrophotometric determination of iron(Ⅱ) with 1,10-phenanthroline in the presence of large amounts of iron(Ⅲ)[J]. Talanta, 1974, 21(4):314-318. [19] ZHOU T, LIM T T, WU X H. Sonophotolytic degradation of azo dye reactive black 5 in an ultrasound/UV/ferric system and the roles of different organic ligands[J]. Water Research, 2011, 45(9):2915-2924. [20] ZHAO D, LIAO X Y, YAN X L, et al. Effect and mechanism of persulfate activated by different methods for PAHs removal in soil[J]. Journal of Hazardous Materials, 2013, 254:228-235. [21] SUN Y F, PIGNATELLO J J. Photochemical reactions involved in the total mineralization of 2,4-D by iron(3+)/hydrogen peroxide/UV[J]. Environmental Science & Technology, 1993, 27(2):304-310. [22] SHIH Y J, SU H T, HUANG Y H. Photoelectro-Fenton mineralization of phenol through optimization of ferrous regeneration[J]. Environmental Science and Pollution Research, 2013, 20(9):6184-6190. [23] SHAWAQFEH A T, AL MOMANI F A. Photocatalytic treatment of water soluble pesticide by advanced oxidation technologies using UV light and solar energy[J]. Solar Energy, 2010, 84(7):1157-1165. [24] BALMER M E, SULZBERGER B. Atrazine degradation in irradiated iron oxalate systems:Effects of pH and oxalate[J]. Environmental Science & Technology, 1999, 33(14):2418-2424. [25] ZUO Y, HOIGNE J. Formation of hydrogen peroxide and depletion of oxalic acid in atmospheric water by photolysis of iron(Ⅲ)-oxalato complexes[J]. Environmental Science & Technology, 1992, 26(5):1014-1022. [26] HAN D, WAN J, MA Y, et al. New insights into the role of organic chelating agents in Fe(Ⅱ) activated persulfate processes[J]. Chemical Engineering Journal, 2015, 269:425-433. [27] DENG J, SHAO Y, GAO N, et al. Zero-valent iron/persulfate(Fe0/PS) oxidation acetaminophen in water[J]. International Journal of Environmental Science and Technology, 2014, 11(4):881-890. [28] RAO Y F, QU L, YANG H, et al. Degradation of carbamazepine by Fe(Ⅱ)-activated persulfate process[J]. Journal of Hazardous Materials, 2014, 268:23-32. [29] 王婷, 吴乾元, 王文龙, 等. 紫外线/氯高级氧化降解甲基异噻唑啉酮[J]. 环境工程学报, 2017, 11(1):21-26. WANG T, WU W Y, WANG W L, et al. Degradation of methylisothiazolinone by UV/chlorine advanced oxidation process[J]. Chinese Journal of Environmental Engineering, 2017, 11(1):21-26(in Chinese).
[30] ORGE C A, FARIA J L, PEREIRA M F R. Removal of oxalic acid, oxamic acid and aniline by a combined photolysis and ozonation process[J]. Environ Technol, 2015, 36(9):1075-1083. [31] KUSIC H, PETERNEL I, UKIC S, et al. Modeling of iron activated persulfate oxidation treating reactive azo dye in water matrix[J]. Chemical Engineering Journal, 2011, 172(1):109-121. [32] LIN C C, WU M S. Degradation of ciprofloxacin by UV/S2O82- process in a large photoreactor[J]. Journal of Photochemistry and Photobiology A:Chemistry, 2014, 285:1-6. -

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