改性碳毡电极构建杂化膜电容去离子去除阴离子型染料的性能及机理

谷佳蓉; 陈瑞程; 杨晨旭; 马俊俊; 牛建瑞; 李耘科; 刘春

doi:10.7524/j.issn.0254-6108.2023070604

河北科技大学环境科学与工程学院，石家庄，050018

河北省污染防治生物技术实验室，石家庄，050018

通讯作者: E-mail：majj16@163.com;

基金项目:

国家重点实验室专项基金课题(22K05ESPCT)和河北省高等学校科学技术研究项目(QN2022038) 资助

Removal of anionic dyes by modified carbon felt electrodes to construct hybrid the membrane capacitive deionization

Academy of Environmental Science, Hebei University of Science and Technology, Shijiazhuang, 050018, China

Biotechnology Laboratory for Pollution Control in Hebei Province, Shijiazhuang, 050018, China

Corresponding author: MA Junjun, majj16@163.com ;

Fund Project: State Key Joint Laboratory of Environment Simulation and Pollution Control (22K05ESPCT); Science and Technology Project of Hebei Education Department (QN2022038).

摘要: 根据染料不过膜的特点，构建了新型杂化半膜膜电容去离子（MCDI）装置，首次利用MCDI对阴离子型染料进行去除. 将铁氧化物以不同铁碳质量比掺杂在碳毡(CF)中制备复合电极，通过扫描电子显微镜（SEM）、X射线衍射（XRD）和X射线光电子能谱（XPS）等多重手段表征电极材料的形貌、结构和化学组成等，表明铁氧化物的成功掺杂. 并根据循环伏安（CV）和电化学阻抗谱（EIS）证明铁氧化物掺杂比例为25%的改性材料CF-Fe(25%)具有最优的电化学性能. 对比CFs对阴离子型染料刚果红（congo red，CR）的去除效果，并探究电压、染料浓度和pH等参数对CR去除性能的影响，验证最佳条件下对其他阴离子型染料的去除效果. 结合自由基捕获实验阐述MCDI对阴离子型染料的降解机理. 得到在1.2 V电压，流速3 mL·min⁻¹下，pH 7的进水环境中，对100 mg·L⁻¹的CR、新胭脂红染料（new carmine，NC）和日落黄染料（sunset yellow FCF，SY FCF）在15 min内分别达到66.3%、61.6%和60.7%的去除率，且酸性环境有利于染料的去除. 新型杂化半膜MCDI装置可直接将离子型染料富集，后经阳极产生的高活性自由基（·OH）氧化降解、去除，铁氧化物的掺杂可增加电极反应活性位点，利于染料的吸附，并促进·OH的生成. ·OH是降解染料的主要作用力. 该方法去除效率高，同时避免了膜污染，为MCDI去除阴离子型染料方面提供科学依据.

Abstract: A novel hybrid half-membrane membrane capacitive deionization (MCDI) device was constructed for the removal of anionic dyes using MCDI for the first time, based on the characteristic that dyes do not pass through the membrane. The composite electrodes were prepared by doping iron oxides in carbon felt (CF) with different iron-to-carbon mass ratios. The morphology, structure and chemical composition of the electrode materials were characterized by multiple means such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), indicating the successful doping of iron oxides. It was also demonstrated that the modified material CF-Fe(25%) with 25% Fe oxide doping has the best electrochemical performance based on cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The effect of CFs on the removal of the anionic dye congo red (CR) was compared and the effect of parameters such as voltage, dye concentration and pH on the removal performance of CR was investigated to verify the removal of other anionic dyes under optimal conditions. The mechanism of degradation of anionic dyes by MCDI was investigated in conjunction with free radical capture experiments. The removal rates of CR, new carmine (NC) and sundown yellow FCF (SY FCF) at 100 mg·L⁻¹ were 66.3%, 61.6% and 60.7%, respectively, within 15 min at 1.2 V, a flow rate of 3 mL·min⁻¹ and pH 7 in the feed water, and the acidic environment was favorable to the removal of dyes. The new hybrid half-membrane MCDI device can directly enrich ionic dyes, which are later degraded and removed by the oxidation of highly reactive radicals (·OH) generated by the anode. The doping of iron oxides increases the active site of the electrode reaction, which facilitates the adsorption of dyes and promotes the production of ·OH. ·OH is the main force for the degradation of dyes. The method is highly efficient in removal, while avoiding membrane contamination, and provides a scientific basis for MCDI in the removal of anionic dyes.

Key words:

hybrid membrane capacitive deionization /
composite electrode materials /
carbon felt /
iron oxides /
anionic dyes.

改性碳毡电极构建杂化膜电容去离子去除阴离子型染料的性能及机理

通讯作者: E-mail：majj16@163.com;

1. 河北科技大学环境科学与工程学院，石家庄，050018

2. 河北省污染防治生物技术实验室，石家庄，050018

收稿日期: 2023-07-06

录用日期: 2023-09-28

网络出版日期: 2024-02-28

基金项目:

国家重点实验室专项基金课题(22K05ESPCT)和河北省高等学校科学技术研究项目(QN2022038) 资助

关键词:

Removal of anionic dyes by modified carbon felt electrodes to construct hybrid the membrane capacitive deionization

Corresponding author: MA Junjun, majj16@163.com ;

1. Academy of Environmental Science, Hebei University of Science and Technology, Shijiazhuang, 050018, China

2. Biotechnology Laboratory for Pollution Control in Hebei Province, Shijiazhuang, 050018, China

Received Date: 2023-07-06

Accepted Date: 2023-09-28

Available Online: 2024-02-28

Fund Project: State Key Joint Laboratory of Environment Simulation and Pollution Control (22K05ESPCT); Science and Technology Project of Hebei Education Department (QN2022038).

Keywords:

hybrid membrane capacitive deionization /
composite electrode materials /
carbon felt /
iron oxides /
anionic dyes.

全文HTML

我国作为世界印染和纺织大国，有机染料废水的排放成为一个普遍问题. 有机染料分子中大多含显色基团，还原后易形成有毒的胺，不仅会破坏生态系统，也会对人类身体健康带来健康风险^[1]. 因此，有机染料废水的处理具有重要意义.

目前，许多技术被应用于有机染料废水的处理，如复合纳米纤维材料吸附^[2]、光催化^[3]、膜吸附^[4]、电凝吸附^[5]、超分子包合技术^[6]等，但这些技术或多或少存在处理时间长、操作成本高、二次污染等弊端. 因此，开发高效、便捷、环境友好且价格低廉的染料废水处理技术至关重要. 传统技术对于染料的去除为物理转移，存在不能将染料彻底氧化降解，或降解效率极低等问题. 因此将废水中的染料富集后再氧化降解可有效提升染料废水的处理效率.

电容去离子（capacitive deionization, CDI）是基于双电层（electric double layer, EDL）或法拉第电容（faradic capacitor）基本原理^[7]，实现淡化水质的一种新型脱盐技术，具有装置操作简单、能耗低等优势，除了应用在海水淡化，也逐渐应用在去除有机污染物方面. Bayram等^[8]利用CDI去除废水中的芳香醇有机酸，Senoussi等^[9]采用CDI（BM CDI）首次去除并回收纺织废水中的阳离子型染料，Tang等^[10]利用流动电极电容去离子同时分馏、脱盐和去除染料，都证明CDI可以有效处理废水中的有机物. 但CDI在解吸过程中的同离子效应降低了系统的电荷效率. Kim等^[11]在CDI装置两电极表面加入厚度约为20 μm的阴、阳离子交换膜，形成了膜电容去离子（membrane capacitive deionization，MCDI）. MCDI利用离子交换膜对离子的选择性可大大提高系统的电荷效率^[12].

然而，目前并没有膜电容去离子应用于染料去除的相关研究. 其原因可能是染料属于大分子有机物，经离子交换过膜困难，处理效率低. 因此可通过只加阳离子交换膜（cation exchange membrane, CEM），组建半膜MCDI装置. 碳毡（carbon felt, CF）是一种由聚丙烯腈基（PAN）碳纤维^[13]经预氧化、低温碳化、高温碳化后形成的稳定致密碳纤维材料，高纯无污染，具有优异的电化学性能^[14]，其表面丰富的介孔/大孔结构，突破了微孔材料的扩散限值，更有利于实现对大分子有机物的充分吸附，是较好的电极材料^[15]. 研究表明碳毡电极作为电极材料时，在电场作用下，可原位产生H₂O₂^[16]，但需经活化后才能产生具有直接氧化作用的羟基自由基，而铁氧化物是活化H₂O₂产生活性自由基的常用催化剂. 此外，铁的掺杂不仅扩大CF内部缺陷，增加活性位点，提供更多反应空间，而且促进羟基自由基的产生^[17]，实现染料废水中有机物的氧化降解. 同时，优化MCDI装置结构，构建更适合去除阴离子型染料的半膜MCDI装置，可显著提高对染料的富集、降解速率.

本研究制备并详细表征了碳毡-铁氧化物复合电极，并构建了半膜MCDI装置. 考察了铁碳掺杂比、电压、染料浓度、pH等运行参数对去除染料的影响，确定了在一定范围内最佳去除条件，为MCDI去除废水中的有机染料提供参考依据，为其在有机染料盐废水中有机物和离子的同时去除建立基础.

3. 结论（Conclusion）

1）本论文根据阴离子型染料特点，设计了新型杂化半膜MCDI装置，对CR、NC、SY FCF三种阴离子型染料进行去除，阐明铁氧化物掺杂CF作为电极材料的优势.

2）系统地研究了铁碳掺杂比对电极材料电化学性能和去除阴离子型染料性能的影响，得到最佳电极材料为CF-Fe（25%），并根据五次吸附-解吸实验证明材料的循环稳定性.

3）在此基础上进一步探究pH、电压和染料浓度等运行参数对染料去除的影响，结果表明在1.2 V电压，流速3 mL·min⁻¹中性环境下，对100 mg·L⁻¹的CR、NC、SY FCF在15 min内可达66.3%、61.6%和60.7%，并且酸性环境更有利于对染料的去除. 同时，总有机碳（TOC）去除率达69.4%，证明有机物得到彻底降解.

4）EPR试验中检测出DMPO-·OH的特异信号，证明起降解作用的主要氧化性物质为·OH. 本研究将对MCDI处理染料废水方向具有重要指导意义.

参考文献 (32)

[1]	CAI Z Q, SUN Y M, LIU W, et al. An overview of nanomaterials applied for removing dyes from wastewater[J]. Environmental Science and Pollution Research, 2017, 24(19): 15882-15904. doi: 10.1007/s11356-017-9003-8
[2]	AHMADIJOKANI F, MOLAVI H, BAHI A, et al. Electrospun nanofibers of chitosan/polyvinyl alcohol/UiO-66/nanodiamond: Versatile adsorbents for wastewater remediation and organic dye removal[J]. Chemical Engineering Journal, 2023, 457: 141176. doi: 10.1016/j.cej.2022.141176
[3]	SAAD I, RALHA N, ABUKHADRA M R, et al. Recent advances in photocatalytic oxidation techniques for decontamination of water[J]. Journal of Water Process Engineering, 2023, 52: 103572. doi: 10.1016/j.jwpe.2023.103572
[4]	MOKHTARI N, DINARI M, FASHANDI H. Developing polysulfone-based mixed matrix membrane containing hydrazone-linked covalent organic frameworks towards dye wastewater purification[J]. Chemical Engineering Journal, 2022, 446: 137456. doi: 10.1016/j.cej.2022.137456
[5]	CASTAÑEDA-DÍAZ J, PAVÓN-SILVA T, GUTIÉRREZ-SEGURA E, et al. Electrocoagulation-adsorption to remove anionic and cationic dyes from aqueous solution by PV-energy[J]. Journal of Chemistry, 2017, 2017: 1-14.
[6]	DUAN Z B, LI Y L, ZHANG M, et al. Towards cleaner wastewater treatment for special removal of cationic organic dye pollutants: A case study on application of supramolecular inclusion technology with β-cyclodextrin derivatives[J]. Journal of Cleaner Production, 2020, 256: 120308. doi: 10.1016/j.jclepro.2020.120308
[7]	JIA B P, ZHANG W. Preparation and application of electrodes in capacitive deionization (CDI): A state-of-art review[J]. Nanoscale Research Letters, 2016, 11(1): 64. doi: 10.1186/s11671-016-1284-1
[8]	BAYRAM E, AYRANCI E. Structural effects on electrosorptive behavior of aromatic organic acids from aqueous solutions onto activated carbon cloth electrode of a flow-through electrolytic cell[J]. Journal of Electroanalytical Chemistry, 2012, 683: 14-20. doi: 10.1016/j.jelechem.2012.07.028
[9]	SENOUSSI H, BOUHIDEL K E. Feasibility and optimisation of a batch mode capacitive deionization (BM CDI) process for textile cationic dyes (TCD) removal and recovery from industrial wastewaters[J]. Journal of Cleaner Production, 2018, 205: 721-727. doi: 10.1016/j.jclepro.2018.09.026
[10]	TANG K X, ZHENG H, DU P H, et al. Simultaneous fractionation, desalination, and dye removal of dye/salt mixtures by carbon cloth-modified flow-electrode capacitive deionization[J]. Environmental Science & Technology, 2022, 56(12): 8885-8896.
[11]	KIM Y J, CHOI J H. Improvement of desalination efficiency in capacitive deionization using a carbon electrode coated with an ion-exchange polymer[J]. Water Research, 2010, 44(3): 990-996. doi: 10.1016/j.watres.2009.10.017
[12]	PORADA S, ZHAO R, van der WAL A, et al. Review on the science and technology of water desalination by capacitive deionization[J]. Progress in Materials Science, 2013, 58(8): 1388-1442. doi: 10.1016/j.pmatsci.2013.03.005
[13]	MINKE C, KUNZ U, TUREK T. Carbon felt and carbon fiber - A techno-economic assessment of felt electrodes for redox flow battery applications[J]. Journal of Power Sources, 2017, 342: 116-124. doi: 10.1016/j.jpowsour.2016.12.039
[14]	PIGNOL G, BASSIL P, FONTMORIN J M, et al. Electrochemical properties of carbon fibers from felts[J]. Molecules, 2022, 27(19): 6584. doi: 10.3390/molecules27196584
[15]	SARDINHA A F, ALMEIDA D A L, VERNASQUI L G, et al. Electrochemical response enhancement of CF and GO/CF composites using a promising CF etching[J]. Diamond and Related Materials, 2020, 108: 107997. doi: 10.1016/j.diamond.2020.107997
[16]	TANG W W, HE D, ZHANG C Y, et al. Comparison of Faradaic reactions in capacitive deionization (CDI) and membrane capacitive deionization (MCDI) water treatment processes[J]. Water Research, 2017, 120: 229-237. doi: 10.1016/j.watres.2017.05.009
[17]	BAI X Y, SUN H C, SUN J, et al. Efficient removal of sixteen priority polycyclic aromatic hydrocarbons from textile dyeing sludge using electrochemical Fe²⁺-activated peroxymonosulfate oxidation-a green pretreatment strategy for textile dyeing sludge toxicity reduction[J]. Journal of Hazardous Materials, 2022, 435: 129087. doi: 10.1016/j.jhazmat.2022.129087
[18]	LU J S, LI W W, KANG H L, et al. Microstructure and properties of polyacrylonitrile based carbon fibers[J]. Polymer Testing, 2020, 81: 106267. doi: 10.1016/j.polymertesting.2019.106267
[19]	WANG Y, LIN Y, YANG C P, et al. Calcination temperature regulates non-radical pathways of peroxymonosulfate activation via carbon catalysts doped by iron and nitrogen[J]. Chemical Engineering Journal, 2023, 451: 138468. doi: 10.1016/j.cej.2022.138468
[20]	ZHAO C, MENG L H, CHU H Y, et al. Ultrafast degradation of emerging organic pollutants via activation of peroxymonosulfate over Fe₃C/Fe@N-C-x: Singlet oxygen evolution and electron-transfer mechanisms[J]. Applied Catalysis B:Environmental, 2023, 321: 122034. doi: 10.1016/j.apcatb.2022.122034
[21]	ZHANG Q L, CHENG Y L, FANG C Q, et al. Electrochemically enhanced adsorption of organic dyes from aqueous using a freestanding metal-organic frameworks/cellulose-derived porous monolithic carbon foam[J]. Bioresource Technology, 2022, 347: 126424. doi: 10.1016/j.biortech.2021.126424
[22]	SHEN G, MA J J, NIU J R, et al. Mechanism of ball milled activated carbon in improving the desalination performance of flow- and fixed-electrode in capacitive deionization desalination[J]. Frontiers of Environmental Science & Engineering, 2023, 17(5): 64.
[23]	QIU S Y, WANG Y, WAN J Q, et al. Enhanced electro-Fenton catalytic performance with in situ grown Ce/Fe@NPC-GF as self-standing cathode: Fabrication, influence factors and mechanism[J]. Chemosphere, 2021, 273: 130269. doi: 10.1016/j.chemosphere.2021.130269
[24]	XIE F S, SHI Q Y, BAI H L, et al. An anode fabricated by co electrodeposition on ZIF-8/CNTs/CF for peroxymonosulfate (PMS) activation[J]. Chemosphere, 2023, 313: 137384. doi: 10.1016/j.chemosphere.2022.137384
[25]	SUN N, ZHOU H J, ZHANG H M, et al. Synchronous removal of tetracycline and water hardness ions by capacitive deionization[J]. Journal of Cleaner Production, 2021, 316: 128251. doi: 10.1016/j.jclepro.2021.128251
[26]	ARAB C, EL KURDI R, PATRA D. Effect of pH on the removal of anionic and cationic dyes using zinc curcumin oxide nanoparticles as adsorbent[J]. Materials Chemistry and Physics, 2022, 277: 125504. doi: 10.1016/j.matchemphys.2021.125504
[27]	ZHAO C H, SHAO B B, YAN M, et al. Activation of peroxymonosulfate by biochar-based catalysts and applications in the degradation of organic contaminants: A review[J]. Chemical Engineering Journal, 2021, 416: 128829. doi: 10.1016/j.cej.2021.128829
[28]	XIA C, XIA Y, ZHU P, et al. Direct electrosynthesis of pure aqueous H₂O₂ solutions up to 20% by weight using a solid electrolyte[J]. Science, 2019, 366(6462): 226-231. doi: 10.1126/science.aay1844
[29]	DUAN L S, LIU X H, ZHANG H D, et al. A novel way for hydroxyl radicals generation: Biochar-supported zero-valent iron composite activates oxygen to generate hydroxyl radicals[J]. Journal of Environmental Chemical Engineering, 2022, 10(4): 108132. doi: 10.1016/j.jece.2022.108132
[30]	ZHANG J, LV S Y, YU Q, et al. Degradation of sulfamethoxazole in microbubble ozonation process: Performance, reaction mechanism and toxicity assessment[J]. Separation and Purification Technology, 2023, 311: 123262. doi: 10.1016/j.seppur.2023.123262
[31]	JO W K, KUMAR S, ISAACS M A, et al. Cobalt promoted TiO₂/GO for the photocatalytic degradation of oxytetracycline and Congo Red[J]. Applied Catalysis B:Environmental, 2017, 201: 159-168. doi: 10.1016/j.apcatb.2016.08.022
[32]	ASSES N, AYED L, HKIRI N, et al. Congo red decolorization and detoxification by Aspergillus niger: Removal mechanisms and dye degradation pathway[J]. BioMed Research International, 2018, 2018: 3049686.