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目前,由于在医疗、畜牧和水产养殖等领域的广泛应用[1],过量的抗生素以原型或代谢产物形式被排入水体中,对水生生态系统和人类健康造成了不可估量的危害。目前,抗生素废水处理方法主要有高级氧化法(advanced oxidation processes, AOPs)[2-3]、吸附法[4]、生物法[5]等。其中,作为高级氧化法之一的光催化氧化法因其处理成本低,降解效率高和无二次污染等优点,具有很好的应用前景。
研发高效稳定且成本低廉的光催化剂是目前光催化技术应用的关键。近年来,非金属半导体石墨相氮化碳(g-C3N4)因其原料廉价易得、物理化学性质稳定、能带结构合适与可见光响应活性强等特点[6-7],被认为是最具潜力的新型光催化剂。然而,块体g-C3N4的表面积小、电荷重组快、可见光利用率低,使其在实际应用中受到极大限制。目前,通过耦合其他半导体构建异质结是提高g-C3N4光催化活性的有效方法,2个半导体间密切接触可以形成较大的界面面积,并产生激子解离界面和空间带电载流子迁移通道,加速光生载流子分离,从而提升g-C3N4的光催化活性[8]。例如,SUN等[9]通过静电自组装制备了SnO2/g-C3N4异质结,在可见光照射50 min后,对罗丹明B的降解率达到96.9%;ZHANG等[8]采用聚合偶联共沉淀方法制备了增强分子氧活化的FeOOH QDs/CQDs/g-C3N4异质结,在可见光照射下可以降解85.5%的土霉素。以上结果表明,通过构建异质结可以增强g-C3N4的催化活性,但仍有巨大的提升空间。
基于SO4·−的AOPs因其氧化性能强、氧化剂稳定性好、环保无害等优点被广泛应用于降解有机污染物[10-11]。SO4·−通常可以通过光、微波、超声波、加热、过渡金属离子、金属和无金属催化剂等活化过一硫酸盐(Peroxymonosulfate, PMS, HSO5−)和过二硫酸盐(Peroxodisulfate, PS, S2O82−)产生[12-15]。其中,过渡金属离子易活化,无需额外能量输入,已被广泛研究[16]。而在基于过渡金属的体系中,铁基催化剂/过硫酸盐由于铁的化学状态不同(Fe0、Fe2+、Fe3+),是一个高度灵活的体系。因此,将铁基催化剂/过硫酸盐体系与光催化耦合,构建多反应耦合型高级氧化体系用于高效降解水中有机污染物是目前研究的热点。
在铁基催化剂中,FeOOH由于环境友好性、自然丰度、相对稳定性、可见光响应、耐腐蚀性强和低成本而引起广泛关注。因此,本研究采用原位沉淀法将FeOOH与g-C3N4复合,成功制备出FeOOH/g-C3N4异质光催化剂,并通过耦合过一硫酸盐(PMS)构建多反应耦合型高级氧化体系(光催化+PMS活化),研究了其降解环丙沙星(Ciprofloxacin, CIP)的性能,考察了各影响因素对CIP催化降解效果的影响,评价了体系的稳定性并提出了可能的催化降解机理。
FeOOH/g-C3N4异质光催化剂耦合过硫酸盐降解环丙沙星
Catalytic degradation of ciprofloxacin by FeOOH/g-C3N4 heterogeneous photocatalyst activating peroxymonosulfate system
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摘要: 采用原位沉淀法制备了FeOOH/g-C3N4异质光催化剂,并通过耦合过一硫酸盐(PMS)建立了多反应耦合型高级氧化体系,在此体系下考察了其对环丙沙星(CIP)的去除性能。在催化剂/可见光/PMS反应体系下,相对于g-C3N4,FeOOH/g-C3N4的催化性能明显提高,其中5% FeOOH/g-C3N4表现出最优异的催化性能,表明FeOOH的耦合提高了g-C3N4的光催化活性,且光催化+PMS活化体系加速了污染物的降解。此外,分别考察了FeOOH负载量、催化剂投加量、pH等因素对CIP降解性能的影响。结果表明:在催化剂投加量为0.4 g·L−1、pH为9.0时,5% FeOOH/g-C3N4对CIP的降解率达到72.34%。使用XRD、TEM、XPS、UV-vis DRS等分析方法对催化剂进行了表征, FeOOH的复合显著增强了g-C3N4的光吸收能力,提高了其光催化活性。最后,基于实验数据与活性物种捕获实验,初步提出了FeOOH/g-C3N4对CIP催化降解的可能机理。
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关键词:
- FeOOH/g-C3N4 /
- 光催化 /
- 过一硫酸盐 /
- 环丙沙星
Abstract: The FeOOH/g-C3N4 heterogeneous photocatalyst was prepared by in-situ precipitation method, and the multi-reaction coupling advanced oxidation technology was further established by coupling the photocatalysis with peroxymonosulfate (PMS) activation, and its removal performance for ciprofloxacin (CIP) was investigated. Under vis/PMS conditions, the photocatalytic activity of FeOOH/g-C3N4 significantly increased compared to that of g-C3N4. Among them, 5% FeOOH/g-C3N4 showed the most excellent photocatalytic performance, indicating that FeOOH coupling could improve the photocatalytic activity of g-C3N4, and photocatalysis + PMS activation system accelerated the degradation of pollutants. The effects of various factors (i.e., FeOOH loading, photocatalyst dosage and initial pH) on CIP degradation efficiency were studied. The results showed that when the photocatalyst dosage was 0.4 g·L−1, and pH was 9.0, the best degradation efficiency of 5% FeOOH/g-C3N4 for CIP was 72.34%. The photocatalysts were characterized by XRD, TEM, XPS, and DRS, and the results indicated FeOOH coupling could greatly enhance the light absorption capacity of g-C3N4 and further improve its photocatalytic activity. Based on experimental data and active species capture experiment, CIP possible degradation mechanism by FeOOH/g-C3N4 photocatalyst was proposed.-
Key words:
- FeOOH/g-C3N4 /
- photocatalysis /
- peroxymonosulfate /
- ciprofloxacin
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[1] SHI Y, WAN D, HUANG J, et al. Stable LBL self-assembly coating porous membrane with 3D heterostructure for enhanced water treatment under visible light irradiation[J]. Chemosphere, 2020, 252: 126581. doi: 10.1016/j.chemosphere.2020.126581 [2] 杨婷婷, 陈星, 陈长斌, 等. CeO2/g-C3N4光催化-芬顿高效降解盐酸强力霉素[J]. 环境工程学报, 2021, 15(8): 2576-2587. [3] WANG H, YE Z, LIU C, et al. Visible light driven Ag/Ag3PO4/AC photocatalyst with highly enhanced photodegradation of tetracycline antibiotics[J]. Applied Surface Science, 2015, 353: 391-399. doi: 10.1016/j.apsusc.2015.06.125 [4] LI R, WANG Z, ZHAO X, et al. Magnetic biochar-based manganese oxide composite for enhanced fluoroquinolone antibiotic removal from water[J]. Environmental Science and Pollution Research, 2018, 25(31): 31136-31148. doi: 10.1007/s11356-018-3064-1 [5] 陈小洁, 李凤玉, 郝雅宾. 两种水生植物对抗生素污染水体的修复作用[J]. 亚热带植物科学, 2012, 41(4): 1-7. [6] AN X, WU S, TANG Q, et al. Strongly coupled polyoxometalates/oxygen doped g-C3N4 nanocomposites as Fenton-like catalysts for efficient photodegradation of sulfosalicylic acid[J]. Catalysis Communications, 2018, 112: 63-67. doi: 10.1016/j.catcom.2018.03.013 [7] HU J, ZHANG P, AN W, et al. In-situ Fe-doped g-C3N4 heterogeneous catalyst via photocatalysis-Fenton reaction with enriched photocatalytic performance for removal of complex wastewater[J]. Applied Catalysis B:Environmental, 2019, 245: 130-142. doi: 10.1016/j.apcatb.2018.12.029 [8] ZHANG M M, LAI C, LI B S, et al. Unravelling the role of dual quantum dots cocatalyst in 0D/2D heterojunction photocatalyst for promoting photocatalytic organic pollutant degradation[J]. Chemical Engineering Journal, 2020, 396: 1-13. [9] SUN C Y, YANG J K, ZHU Y, et al. Synthesis of 0D SnO2 nanoparticles/2D g-C3N4 nanosheets heterojunction: improved charge transfer and separation for visible-light photocatalytic performance[J]. Journal of Alloys and Compounds, 2021,871: 1-14. [10] LIN K Y A, ZHANG Z Y. Degradation of bisphenol a using peroxymonosulfate activated by one-step prepared sulfur-doped carbon nitride as a metal-free heterogeneous catalyst[J]. Chemical Engineering Journal, 2017, 313: 1320-1327. doi: 10.1016/j.cej.2016.11.025 [11] LIU J, ZHOU J, DING Z, et al. Ultrasound irritation enhanced heterogeneous activation of peroxymonosulfate with Fe3O4 for degradation of azo dye[J]. Ultrasonics Sonochemistry, 2017, 34: 953-959. doi: 10.1016/j.ultsonch.2016.08.005 [12] GUAN Y H, MA J, LI X C, et al. Influence of pH on the formation of sulfate and hydroxyl radicals in the UV/peroxymonosulfate system[J]. Environmental Science & Technology, 2011, 45(21): 9308-9314. [13] CAI C, ZHANG H, ZHONG X, et al. Ultrasound enhanced heterogeneous activation of peroxymonosulfate by a bimetallic Fe–Co/SBA-15 catalyst for the degradation of orange II in water[J]. Journal of Hazardous Materials, 2015, 283: 70-79. doi: 10.1016/j.jhazmat.2014.08.053 [14] JI Y, DONG C, KONG D, et al. Heat-activated persulfate oxidation of atrazine: Implications for remediation of groundwater contaminated by herbicides[J]. Chemical Engineering Journal, 2015, 263: 45-54. doi: 10.1016/j.cej.2014.10.097 [15] WACŁAWEK S, LUTZE H V, GRüBEL K, et al. Chemistry of persulfates in water and wastewater treatment: A review[J]. Chemical Engineering Journal, 2017, 330: 44-62. doi: 10.1016/j.cej.2017.07.132 [16] ZOU, CHEN, LW, 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. [17] YANG H, ZHANG S, CAO R, et al. Constructing the novel ultrafine amorphous iron oxyhydroxide/g-C3N4 nanosheets heterojunctions for highly improved photocatalytic performance[J]. Scientific Reports, 2017, 7(1): 8686. doi: 10.1038/s41598-017-09283-1 [18] WU Y Z, WARD-BOND J, LI D L, et al. g-C3N4@alpha-Fe2O3/C photocatalysts: Synergistically intensified charge generation and charge transfer for NADH regeneration[J]. ACS Catalysis, 2018, 8(7): 5664-5674. doi: 10.1021/acscatal.8b00070 [19] LI C, DU Y, WANG D, et al. Unique P—Co—N surface bonding states constructed on g-C3N4 nanosheets for drastically enhanced photocatalytic activity of H2 evolution[J]. Advanced Functional Materials, 2017, 27(4): 1604328. doi: 10.1002/adfm.201604328 [20] WANG K, LI Y, LI J, et al. Boosting interfacial charge separation of Ba5Nb4O15/g-C3N4 photocatalysts by 2D/2D nanojunction towards efficient visible-light driven H2 generation[J]. Applied Catalysis B:Environmental, 2020, 263: 1-10. [21] BICALHO H A, RIOS R D F, BINATTI I, et al. Efficient activation of peroxymonosulfate by composites containing iron mining waste and graphitic carbon nitride for the degradation of acetaminophen[J]. Journal of Hazardous Materials, 2020, 400: 1-10. [22] GUO T, WANG K, ZHANG G K, et al. A novel alpha-Fe2O3@g-C3N4 catalyst: Synthesis derived from Fe-based MOF and its superior photo-Fenton performance[J]. Applied Surface Science, 2019, 469: 331-339. doi: 10.1016/j.apsusc.2018.10.183 [23] KATSUMATA H, SAKAI T, SUZUKI T, et al. Highly efficient photocatalytic activity of g-C3N4/Ag3PO4 hybrid photocatalysts through Z-scheme photocatalytic mechanism under visible light[J]. Industrial & Engineering Chemistry Research, 2014, 53(19): 8018-8025. [24] ZHAO H, TIAN C, MEI J, et al. Synergistic effect and mechanism of catalytic degradation toward antibiotic contaminants by amorphous goethite nanoparticles decorated graphitic carbon nitride[J]. Chemical Engineering Journal, 2020, 390: 1-12. [25] BANIC N, ABRAMOVIC B, KRSTIC J, et al. Photodegradation of thiacloprid using Fe/TiO2 as a heterogeneous photo-Fenton catalyst[J]. Applied Catalysis B:Environmental, 2011, 107(3/4): 363-371. doi: 10.1016/j.apcatb.2011.07.037 [26] DANGWANG DIKDIM J M, GONG Y, NOUMI G B, et al. Peroxymonosulfate improved photocatalytic degradation of atrazine by activated carbon/graphitic carbon nitride composite under visible light irradiation[J]. Chemosphere, 2019, 217: 833-842. doi: 10.1016/j.chemosphere.2018.10.177 [27] REN H T, JIA S Y, WU Y, et al. Improved photochemical reactivities of Ag2O/g-C3N4 in phenol degradation under UV and visible light[J]. Industrial & Engineering Chemistry Research, 2014, 53(45): 17645-17653. [28] SHI Y H, LI J S, WAN D J, et al. Peroxymonosulfate-enhanced photocatalysis by carbonyl-modified g-C3N4 for effective degradation of the tetracycline hydrochloride[J]. Science of the Total Environment, 2020, 749: 1-14.