-
2,4-二氯苯氧乙酸(2,4-D)是一种含有苯氧乙酸基团的选择性除草剂,由于其具有廉价易得、高选择性等优点广泛用于去除农业和林业中的阔叶杂草[1]. 但是由于其具有急性神经毒性和慢性毒性,对皮肤和眼睛有刺激作用;慢性毒性表现为对血液、肝、肾的毒性及抑制某些酶的活力,抑制某些蛋白质的合成[2]. 并且其在环境中难以降解、具有生物累积性,会对人体和自然环境造成潜在危害.
因此2,4-D及其衍生物被世界卫生组织(WHO)定义为中度毒物,并且规定饮用水当中的2,4-D浓度不得超过100 mg·L−1 [3],因此探究高效安全的技术去除环境中残留的2,4-D是十分必要的.
高级氧化技术是一种使用强氧化物质与水中溶解性污染物反应的方法,目前高级氧化技术主要包括芬顿法和类芬顿法、臭氧类高级氧化法、光催化氧化技术、电化学氧化技术和基于硫酸根自由基(
${\rm{SO}}_4^{\cdot- } $ )的新型高级氧化技术等[4].由于传统的芬顿技术存在Fe2+利用率低、反应pH要求严格、易产生二次污染等缺点,基于硫酸根自由基的高级氧化技术能够解决传统芬顿技术的诸多问题[5]. 氧化剂过一硫酸盐(PMS)具有不对称结构,更容易被活化产生更多的活性物质,同时其标准氧化电位E0=2.5—3.1V,高于常用氧化剂的氧化性,在反应中pH适用范围更广并且硫酸根自由基比羟基自由基稳定时间更长[6],因此基于硫酸根自由基的高级氧化技术成为近年来处理有机污染物的研究热点.
本文采用一步水热法合成了NPF-FeCo2O4催化剂,该催化剂能够高效活化PMS产生硫酸根自由基降解2,4-D. 此外,分别采用了TEM、XPS等对材料进行表征分析,同时研究了不同pH、不同阴离子等条件下对2,4-D的去除效率,最后通过淬灭试验和EPR测试对反应机理进行探究.
改性FeCo2O4活化PMS降解水中2,4-二氯苯氧乙酸
Modified FeCo2O4 to activate PMS to degrade 2,4-dichlorophenoxyacetic acid in water
-
摘要: 以离子液体为氮源、磷源和氟源,采用一步水热法将N、P、F的3种元素掺杂到FeCo2O4中合成了NPF-FeCo2O4催化剂,用于活化过一硫酸氢钾(PMS)降解水中2,4-二氯苯氧乙酸(2,4-D). 分别采用透射电子显微镜(TEM)、X射线光电子能谱(XPS)、傅立叶红外光谱(FTIR)、X射线衍射(XRD)对催化剂进行表征. 实验结果表明,当催化剂投加量为0.1 g·L−1、PMS浓度为1 mmol·L−1时,反应30 min后2,4-D的去除率可达100%;初始pH值在3到9的范围内,体系对2,4-D的去除效果不受影响,水中低浓度的Cl−、
${\rm{HCO}}_3^{-} $ 和腐殖酸对反应有轻微的抑制. 通过电子自旋共振波谱(EPR)测试结果显示,相较于FeCo2O4和NP-FeCo2O4催化剂,NPF-FeCo2O4/PMS体系能产生更多的∙OH、${\rm{SO}}_4^{\cdot- } $ 和1O2. 淬灭试验结果显示${\rm{SO}}_4^{\cdot- } $ 为2, 4-D降解过程中的主要活性氧物种.Abstract: The N, P and F co-doped FeCo2O4 (NPF-FeCo2O4) catalyst was prepared via the one-step hydrothermal method using ionic liquid as nitrogen, phosphorus and fluorine sources. The catalyst was applied to activate potassium hydrogen persulfate (PMS) for the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) in water. Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) were employed to characterize the catalyst. The results showed that the removal rate of 2,4-D reached 100% after reaction for 30 min with 0.1 g·L−1 of catalyst and 1 mmol·L−1 of PMS. The removal of 2,4-D was not affected within pH 3—9, and the reaction was slightly inhibited by low concentrations of Cl−,${\rm{HCO}}_3^{-} $ and humic acid. Electron paramagnetic resonance (EPR) results exhibited that the NPF-FeCo2O4/PMS system produced more ∙OH,${\rm{SO}}_4^{\cdot- } $ and 1O2 than the FeCo2O4 and NP-FeCo2O4 counterparts, and the predomination of${\rm{SO}}_4^{\cdot- } $ was clarified by the quenching test during the 2,4-D degradation.-
Key words:
- ferric cobaltate catalyst /
- PMS /
- advanced oxidation /
- sulfate radical /
- 2,4-D
-
-
[1] 金党琴, 龚爱琴, 王元有, 等. 石墨烯-钙钛矿纳米复合材料分子印迹光电化学传感器的构建及测定蔬果中2, 4-D残留 [J]. 化学研究与应用, 2021, 33(8): 1433-1439. JIN D Q, GONG A Q, WANG Y Y, et al. Construction of Gr/CH3NH3PbI3 nanocomposite molecularly imprinted photoelectrochemical sensor and determination of 2, 4-D in vegetables and fruits [J]. Chemical Research and Application, 2021, 33(8): 1433-1439(in Chinese).
[2] 徐爱东. 我国蔬菜中常用植物生长调节剂的毒性及残留问题研究进展 [J]. 中国蔬菜, 2009(8): 1-6. XU A D. Research advance in the toxicity and residue of plant growth regulator in vegetables in China [J]. China Vegetables, 2009(8): 1-6(in Chinese).
[3] SUN C, BAIG S A, LOU Z M, et al. Electrocatalytic dechlorination of 2, 4-dichlorophenoxyacetic acid using nanosized titanium nitride doped palladium/nickel foam electrodes in aqueous solutions [J]. Applied Catalysis B:Environmental, 2014, 158/159: 38-47. doi: 10.1016/j.apcatb.2014.04.004 [4] 杨梖, 刘颢, 俞映倞, 等. 高级氧化技术去除水体中抗性基因污染的研究进展 [J]. 环境化学, 2021, 40(4): 1263-1273. YANG B, LIU H, YU Y L, et al. A review: Elimination of antibiotic resistance genes in water by advanced oxidation progress [J]. Environmental Chemistry, 2021, 40(4): 1263-1273(in Chinese).
[5] 刘萌, 胡莉敏, 张广山, 等. Co/Zn双金属氧化物活化过一硫酸盐降解双酚A的性能研究 [J]. 环境化学, 2018, 37(4): 753-760. LIU M, HU L M, ZHANG G S, et al. Activation of peroxymonosulfate by the Co/Zn bimetallic oxide for the degradation of bisphenol A [J]. Environmental Chemistry, 2018, 37(4): 753-760(in Chinese).
[6] 韩爽, 肖鹏飞. 过硫酸盐活化技术在四环素类抗生素降解中的应用进展 [J]. 环境化学, 2021, 40(9): 2873-2883. HAN S, XIAO P F. Application progress of persulfate activation technology in degradation of tetracycline antibiotics [J]. Environmental Chemistry, 2021, 40(9): 2873-2883(in Chinese).
[7] SUN J, GUO N K, SHAO Z Y, et al. Electrocatalysts: A facile strategy to construct amorphous spinel-based electrocatalysts with massive oxygen vacancies using ionic liquid dopant [J]. Advanced Energy Materials, 2018, 8(27): 1870121. doi: 10.1002/aenm.201870121 [8] LOBO L S, KALAINATHAN S, KUMAR A R. Investigation of electrical studies of spinel FeCo2O4 synthesized by Sol-gel method [J]. Superlattices and Microstructures, 2015, 88: 116-126. doi: 10.1016/j.spmi.2015.09.010 [9] SHAHEEN N, AADIL M, ZULFIQAR S, et al. Fabrication of different conductive matrix supported binary metal oxides for supercapacitors applications [J]. Ceramics International, 2021, 47(4): 5273-5285. doi: 10.1016/j.ceramint.2020.10.108 [10] XU M J, LI J, YAN Y, et al. Catalytic degradation of sulfamethoxazole through peroxymonosulfate activated with expanded graphite loaded CoFe2O4 particles [J]. Chemical Engineering Journal, 2019, 369: 403-413. doi: 10.1016/j.cej.2019.03.075 [11] HU M Z, ZHU J Y, ZHOU W J. Synthesis of oxygen vacancy-enriched N/P co-doped CoFe2O4 for high-efficient degradation of organic pollutant: Mechanistic insight into radical and nonradical evolution [J]. Environmental Pollution, 2021, 270: 116092. doi: 10.1016/j.envpol.2020.116092 [12] YAN Y, XIA B Y, GE X M, et al. A flexible electrode based on iron phosphide nanotubes for overall water splitting [J]. Chemistry (Weinheim an Der Bergstrasse, Germany), 2015, 21(50): 18062-18067. [13] WANG J L, WANG S Z. Effect of inorganic anions on the performance of advanced oxidation processes for degradation of organic contaminants [J]. Chemical Engineering Journal, 2021, 411: 128392. doi: 10.1016/j.cej.2020.128392 [14] WANG J L, WANG S Z. Activation of persulfate (PS) and peroxymonosulfate (PMS) and application for the degradation of emerging contaminants [J]. Chemical Engineering Journal, 2018, 334: 1502-1517. doi: 10.1016/j.cej.2017.11.059 [15] ZHOU H Y, LAI L D, WAN Y J, et al. Molybdenum disulfide (MoS2): A versatile activator of both peroxymonosulfate and persulfate for the degradation of carbamazepine [J]. Chemical Engineering Journal, 2020, 384: 123264. doi: 10.1016/j.cej.2019.123264 [16] MA W J, WANG N, FAN Y N, et al. Non-radical-dominated catalytic degradation of bisphenol A by ZIF-67 derived nitrogen-doped carbon nanotubes frameworks in the presence of peroxymonosulfate [J]. Chemical Engineering Journal, 2018, 336: 721-731. doi: 10.1016/j.cej.2017.11.164 [17] FANG G D, DIONYSIOU D D, WANG Y, et al. Sulfate radical-based degradation of polychlorinated biphenyls: Effects of chloride ion and reaction kinetics [J]. Journal of Hazardous Materials, 2012, 227/228: 394-401. doi: 10.1016/j.jhazmat.2012.05.074 [18] CUI X L, LIU X T, LIN C Y, et al. Activation of peroxymonosulfate using drinking water treatment residuals modified by hydrothermal treatment for imidacloprid degradation [J]. Chemosphere, 2020, 254: 126820. doi: 10.1016/j.chemosphere.2020.126820 [19] ZHOU X Q, LUO M Y, XIE C Y, et al. Tunable S doping from Co3O4 to Co9S8 for peroxymonosulfate activation: Distinguished Radical/Nonradical species and generation pathways [J]. Applied Catalysis B:Environmental, 2021, 282: 119605. doi: 10.1016/j.apcatb.2020.119605 [20] LATIFOGLU A, GUROL M D. The effect of humic acids on nitrobenzene oxidation by ozonation and O3/UV processes [J]. Water Research, 2003, 37(8): 1879-1889. doi: 10.1016/S0043-1354(02)00583-3