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全氟辛烷磺酸(perfluorooctane sulfonate,PFOS)具有大量的C—F键,极性高、稳定性强,因其链端具有亲水性磺酸基(—SO3H)而能部分溶解于水。PFOS具有较低的水表面张力和优异的化学稳定性,通常被用作铬雾抑制剂广泛用于硬铬电镀中[1]。然而,PFOS具有持久性、生物累积性和生物放大性,会引发许多毒性作用[2-4]。因而,PFOS被列为持久性有机污染物(persistent organic pollutants, POPs),在环境水体中检出的质量浓度可达10~50 ng·L−1 [5]。全氟烷基醚磺酸盐(F-53B)是PFOS的一种替代品,在中国电镀行业使用了30多年,一直未受管控[5],导致大量F-53B释放到自然水体中,检出水平与PFOS接近,达到10~50 ng·L−1。虽然F-53B在自然水体中检出的质量浓度较低,但考虑到F-53B具有环境持久性和生物累积性[5],低浓度的F-53B可能造成的健康危害也需引起足够的重视。有研究表明,F-53B的毒性竟然相当于甚至高于PFOS[6-7]。赵楠等[8]的研究也表明大鼠暴露于F-53B后可能会影响血清的氧化应激反应,引发炎症、心血管疾病、糖尿病和高血压,引起神经毒性且抑制大脑发育。因此,消除F-53B对水环境污染势在必行。
对水中F-53B的去除技术主要有吸附、电化学氧化、光降解和机械化学降解等[9-12]。由于F-53B的稳定性较强,电化学氧化、光降解和机械化学降解等技术的脱氟率较低,并不能完全降解F-53B,而吸附法则被认为是去除水中F-53B的最有效策略之一。目前关于活性炭和离子交换树脂吸附F-53B的研究报道较多,这2种吸附剂均能有效吸附去除水中的F-53B [9, 13-14],但在实际应用过程中还存在运行成本较高和易受阴离子影响等问题。近年来研究表明金属-有机骨架(metal-organic frameworks, MOFs)是一种有潜力的环境处理材料[15-17],可用于污染修复和环境监测等场景。这种由金属离子或金属簇与有机配体进行配位组装而成的多孔晶体材料[18]具有高比表面积、高孔隙率及结构/功能可调等作为吸附剂的优势。有研究[19-23]表明,MOFs可高效去除水中的重金属、染料和抗生素等,在PFOS捕获方面也表现出优异性能[24-26],这主要归因于MOFs材料的比表面积大、活性反应位点多及孔隙结构的限域作用。
MOFs材料的金属中心是重要的活性反应位点,先前的研究主要集中在过渡金属(如Cr、Fe、Co、Zn、Zr等)和镧系/锕系金属作为MOFs材料的金属中心[24-25, 27],所需成本较高。采用Ni作为MOFs材料的金属中心具有价格低廉、反应活性高等优点[28],但目前对于Ni-MOFs材料吸附F-53B的研究还鲜有报道。此外,研究发现,较大的分子尺寸限制了大分子有机物在三维MOFs材料孔道中的传输,吸附受限于表面。二维MOFs材料具有更为发达的孔隙结构,可以有效降低分子尺寸对有机物传输的限制,加上二维MOFs片层结构的限域作用,可以很好地解决该问题[29-30]。因此,尝试制备二维Ni-MOFs有望提高水中F-53B的吸附效能。
本研究采用溶剂热法通过控制合成温度制备二维和三维Ni-MOFs材料,利用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、N2吸/脱附实验和热重分析(TG)对材料的结构形貌和热稳定性进行了表征分析,采用动力学和热力学实验以及对比分析,开展了对水中F-53B的吸附研究,并进一步结合理论计算探究了可能的吸附机理。
Ni-MOFs对水中全氟烷基醚磺酸盐的吸附性能及机理
Adsorption performance and mechanisms of Ni-MOFs towards chlorinated polyfluoroalkyl ether sulfonic acid in aqueous phase
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摘要: 为有效去除水中的全氟烷基醚磺酸盐(F-53B),采用溶剂热法合成二维Ni-MOFs和三维Ni-MOFs材料。采用XRD、FTIR、SEM、N2吸/脱附实验和热重分析对材料的结构形貌和热稳定性进行了表征,采用动力学和热力学实验以及对比分析,考察了Ni-MOFs对水中F-53B的吸附性能,并进一步结合理论计算探究了可能的吸附机理。结果表明,2种材料均具有明显的晶型,其中Ni是以双齿配位模式与有机骨架进行结合,二维Ni-MOFs呈现分散片层结构,三维Ni-MOFs则呈现出块状结构,二维Ni-MOFs比三维Ni-MOFs具有更高的比表面积、孔隙率和热稳定性。2种材料对F-53B的吸附均符合准二级动力学方程和Freundlich等温方程,二维Ni-MOFs的吸附速率常数和吸附容量分别达到0.002 4 g·(min·mg)−1和451.2 mg·g−1,比三维Ni-MOFs分别高出20%和16%,吸附过程以非均质多层吸附为主,受共存阴离子的影响较小。对F-53B的吸附性能与2种材料的构效有关,活性吸附位点和限域作用决定了二维Ni-MOFs比三维Ni-MOFs更优的吸附特性,吸附过程主要受静电作用控制。以上研究结果表明二维Ni-MOFs对F-53B的吸附性能较好,具有良好的应用前景。Abstract: To effectively remove chlorinated polyfluoroalkyl ether sulfonic acid (F-53B) in aqueous phase, two metal-organic framework materials (2D Ni-MOFs and 3D Ni-MOFs) were prepared via solvothermal method. Multiple technologies, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), N2 adsorption/desorption, and thermogravimetry (TG), were used to characterize the structure, morphology, and thermal stability of Ni-MOFs samples. The kinetic and thermodynamic experiments and comparative analysis were used to investigate the performance of Ni-MOFs towards of F-53B in aqueous phase. Moreover, the theoretical calculation was combined to further investigate the adsorption mechanism. Results showed that 2D and 3D Ni-MOFs were crystal materials, of which Ni bonded the organic framework with the bidentate complex form. 2D Ni-MOFs presented a lamellar structure, and 3D Ni-MOFs exhibited a massive structure. 2D Ni-MOFs had a higher specific surface area, porosity and thermal stability than those of 3D Ni-MOFs. The adsorption kinetics and isotherms of F-53B were in line with the pseudo-second-order model and Freundlich model, respectively. The adsorption rate constant and adsorption capacity of 2D Ni-MOFs reached 0.002 4 g·(min·mg)−1 and 451.2 mg·g−1, respectively, which were 20% and 16% higher than those of 3D Ni-MOFs. Moreover, the adsorption process was dominated by the heterogeneous multilayer adsorption, and the co-existing anions had negligible impacts on the adsorption of F-53B on 2D Ni-MOFs. The adsorption performance of Ni-MOFs to F-53B was dependent on their structure-effect. The abundant active adsorption sites and confinement effect determined the better adsorption performance of 2D Ni-MOFs than 3D Ni-MOFs, and the adsorption process was mainly controlled by electrostatic interaction. The results of this study showed that 2D Ni-MOFs is an excellent adsorbent for F-53B and has a good application prospect.
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表 1 二维和三维Ni-MOFs的比表面积、孔容和孔径
Table 1. Specific surface area, pore volume and pore size of 2D Ni-MOFs and 3D Ni-MOFs
样品 BET比表面积/(m2·g−1) 总孔容/(cm3·g−1) 平均孔径/nm 二维Ni-MOFs 58.38 0.336 23.01 三维Ni-MOFs 21.12 0.037 6.98 表 2 2种Ni-MOFs材料吸附F-53B的动力学参数
Table 2. Kinetic parameters for F-53B adsorption on two Ni-MOFs samples
Ni-MOFs q实/(mg·g−1) 准一级动力学 准二级动力学 qecal/(mg·g−1) k1/min−1 R2 qecal/(mg·g−1) k2/(g·(min·mg)−1) R2 二维Ni-MOFs 224.6 26.7 0.004 7 0.714 5 224.2 0.002 4 0.999 9 三维Ni-MOFs 195.6 28.5 0.004 4 0.647 5 195.7 0.002 0 0.999 9 表 3 2种Ni-MOFs材料吸附F-53B的等温线拟合参数
Table 3. Adsorption isotherm parameters for F-53B by two Ni-MOFs samples
Ni-MOFs Langmuir模型 Freundlich模型 qm/(mg·g−1) KL/(L·mg−1) R2 n-1 KF/(L·mg−1) R2 二维Ni-MOFs 448.4 0.35 0.976 6 0.269 148.1 0.989 6 三维Ni-MOFs 401.6 0.17 0.969 7 0.345 90.0 0.995 6 -
[1] PILAT M J, PEGNAM R C. Particle emissions from chrome plating[J]. Aerosol Science and Technology, 2006, 40(8): 639-648. doi: 10.1080/02786820600763020 [2] 陆宏, 周锦阳, 杨帆, 等. 基于Meta分析的全氟化合物对鱼类生态毒性效应[J]. 环境科学,DOI:10.13227/j.hjkx.202209239. [3] FUJII S, POLPRASERT C, TANAKA S, et al. New POPs in the water environment: distribution, bioaccumulation and treatment of perfluorinated compounds: A review paper[J]. Journal of Water Supply:Research and Technology-Aqua, 2007, 56(5): 313-326. doi: 10.2166/aqua.2007.005 [4] MUNOZ G, LIU J, VO DUY S, et al. Analysis of F-53B, Gen-X, ADONA, and emerging fluoroalkylether substances in environmental and biomonitoring samples: A review[J]. Trends in Environmental Analytical Chemistry, 2019, 23: e00066. doi: 10.1016/j.teac.2019.e00066 [5] WANG S, HUANG J, YANG Y, et al. First report of a Chinese PFOS alternative overlooked for 30 years: Its toxicity, persistence and presence in the environment[J]. Environmental Science & Technology, 2013, 47(18): 10163-10170. [6] LI C H, REN X M, RUAN T, et al. Chlorinated polyfluorinated ether sulfonates exhibit higher activity toward peroxisome proliferator-activated receptors signaling pathways than perfluorooctanesulfonate[J]. Environmental Science & Technology, 2018, 52(5): 3232-9. [7] XIN Y, REN X M, RUAN T, et al. Chlorinated polyfluoroalkylether sulfonates exhibit similar binding potency and activity to thyroid hormone transport proteins and nuclear receptors as perfluorooctanesulfonate[J]. Environmental Science & Technology, 2018, 52(16): 9412-9418. [8] 赵楠, 孔媛, 张莹莹, 等. 基于1H NMR的代谢组学方法研究F-53B暴露对大鼠血清代谢表型的影响[J]. 环境化学, 2023, 42(1): 11-19. [9] GAO Y, DENG S, DU Z, et al. Adsorptive removal of emerging polyfluoroalky substances F-53B and PFOS by anion-exchange resin: A comparative study[J]. Journal of Hazardous Materials, 2017, 323: 550-557. doi: 10.1016/j.jhazmat.2016.04.069 [10] ZHUO Q, WANG J, NIU J, et al. Electrochemical oxidation of perfluorooctane sulfonate (PFOS) substitute by modified boron doped diamond (BDD) anodes[J]. Chemical Engineering Journal, 2020, 379: 122280. doi: 10.1016/j.cej.2019.122280 [11] CAO H, ZHANG W, WANG C, et al. Photodegradation of F-53B in aqueous solutions through an UV/Iodide system[J]. Chemosphere, 2022, 292: 133436. doi: 10.1016/j.chemosphere.2021.133436 [12] ZHANG K, CAO Z, HUANG J, et al. Mechanochemical destruction of Chinese PFOS alternative F-53B[J]. Chemical Engineering Journal, 2016, 286: 387-393. doi: 10.1016/j.cej.2015.10.103 [13] ATEIA M, ARIFUZZAMAN M, PELLIZZERI S, et al. Cationic polymer for selective removal of GenX and short-chain PFAS from surface waters and wastewaters at ng/L levels[J]. Water Research, 2019, 163: 114874. doi: 10.1016/j.watres.2019.114874 [14] DU Z, DENG S, LIU D, et al. Efficient adsorption of PFOS and F53B from chrome plating wastewater and their subsequent degradation in the regeneration process[J]. Chemical Engineering Journal, 2016, 290: 405-413. doi: 10.1016/j.cej.2016.01.077 [15] 兰馨, 高生军, 樊佳铜, 等. 氨修饰NiMg-MOF-74材料共吸附硫硝碳效能及其机理[J]. 环境工程学报, 2023, 17(1): 142-155. [16] HE Y, WANG Z, WANG H, et al. Metal-organic framework-derived nanomaterials in environment related fields: Fundamentals, properties and applications[J]. Coordination Chemistry Reviews, 2021, 429: 213618. doi: 10.1016/j.ccr.2020.213618 [17] DUAN C, YU Y, XIAO J, et al. Recent advancements in metal-organic frameworks for green applications[J]. Green Energy & Environment, 2021, 6(1): 33-49. [18] FURUKAWA H, MüLLER U, YAGHI O M. “Heterogeneity within Order” in Metal-Organic Frameworks[J]. Angewandte Chemie International Edition, 2015, 54(11): 3417-3430. doi: 10.1002/anie.201410252 [19] 岳琳, 张迎, 张文丽, 等. Sn-MOF对染料废水中酸性大红3R的吸附特性[J]. 环境工程学报, 2019, 13(11): 2553-2561. doi: 10.12030/j.cjee.201812100 [20] 万红友, 阎靖炜, 郭丛, 等. Cu/Fe-MOF复合材料在水处理过程应用研究进展[J]. 水处理技术, 2022, 48(11): 1-7. [21] XU G-R, AN Z-H, XU K, et al. Metal organic framework (MOF)-based micro/nanoscaled materials for heavy metal ions removal: The cutting-edge study on designs, synthesis and applications[J]. Coordination Chemistry Reviews, 2021, 427: 213554. doi: 10.1016/j.ccr.2020.213554 [22] KALAJ M, BENTZ K C, AYALA S, JR. , et al. MOF-polymer hybrid materials: From simple composites to tailored architectures[J]. Chemical Reviews, 2020, 120(16): 8267-8302. doi: 10.1021/acs.chemrev.9b00575 [23] WANG B, LV X-L, FENG D, et al. Highly stable Zr(IV)-based metal–organic frameworks for the detection and removal of antibiotics and organic explosives in water[J]. Journal of the American Chemical Society, 2016, 138(19): 6204-6216. doi: 10.1021/jacs.6b01663 [24] LI Y, YANG Z, WANG Y, et al. A mesoporous cationic thorium-organic framework that rapidly traps anionic persistent organic pollutants[J]. Nature Communication, 2017, 8(1): 1354. doi: 10.1038/s41467-017-01208-w [25] BARPAGA D, ZHENG J, HAN K S, et al. Probing the sorption of perfluorooctanesulfonate using mesoporous metal–organic frameworks from aqueous solutions[J]. Inorganic Chemistry, 2019, 58(13): 8339-8346. doi: 10.1021/acs.inorgchem.9b00380 [26] LI X, WANG B, CAO Y, et al. Water contaminant elimination based on metal-organic frameworks and perspective on their industrial applications[J]. ACS Sustainable Chemistry & Engineering, 2019, 7(5): 4548-4563. [27] CHANG P-H, CHEN C-Y, MUKHOPADHYAY R. et al. Novel MOF-808 metal–organic framework as highly efficient adsorbent of perfluorooctane sulfonate in water[J]. Journal of Colloid and Interface Science, 2022, 623: 627-636. doi: 10.1016/j.jcis.2022.05.050 [28] VENTURA K, ARRIETA R, MARCOS-HERNANDEZ M. et al. Superparamagnetic MOF@GO Ni and Co based hybrid nanocomposites as efficient water pollutant adsorbents[J]. Science of the Total Environment, 2020, 738: 139213. doi: 10.1016/j.scitotenv.2020.139213 [29] CHAKRABORTY G, PARK I-H, MEDISHETTY R, et al. Two-dimensional metal-organic framework materials: Synthesis, structures, properties and applications[J]. Chemical Reviews, 2021, 121(7): 3751-3891. doi: 10.1021/acs.chemrev.0c01049 [30] ZHAO M, HUANG Y, PENG Y, et al. Two-dimensional metal-organic framework nanosheets: Synthesis and applications[J]. Chemical Society Reviews, 2018, 47(16): 6267-6295. doi: 10.1039/C8CS00268A [31] XUE F, KUMAR P, XU, W, et al. , Direct synthesis of 7 nm-thick zinc(ii)-benzimidazole-acetate metal-organic framework nanosheets[J]. Chemistry of Materials, 2018, 30(1): 69-73. doi: 10.1021/acs.chemmater.7b04083 [32] TI B, LI L, LIU J. , et al. Global distribution potential and regional environmental risk of F-53B[J]. Science of the Total Environment, 2018, 640-641, 1365-1371. [33] 柳泽伟. 金属-有机骨架材料吸附分离性能的功能化改性计算化学研究及高通量筛选[D]. 广州: 华南理工大学, 2019. [34] ALLEN F H, BELLARD S, BRICE M, et al. The Cambridge Crystallographic Data Centre: computer-based search, retrieval, analysis and display of information[J]. Acta Crystallographica Section B:Structural Crystallography and Crystal Chemistry, 1979, 35(10): 2331-2339. doi: 10.1107/S0567740879009249 [35] RAPPé A K, CASEWIT C J, COLWELL K, et al. UFF, a full periodic table force field for molecular mechanics and molecular dynamics simulations[J]. Journal of American Chemical Society, 1992, 114(25): 10024-10035. doi: 10.1021/ja00051a040 [36] LI X, HOU M, QU X, et al. Electric‐field assisted hydrolysis-oxidation of MOFs: Hierarchical ternary (oxy) hydroxide micro-flowers for efficient electrocatalytic oxygen evolution[J]. Small, 2022, 18(6): 2104863. doi: 10.1002/smll.202104863 [37] 惠远峰. 新型金属有机骨架材料的合成及吸附染料废水的性能研究[J]. 功能材料, 2018, 49(7): 7188-7191. [38] ZHAO S, LIU S, WANG F, et al. Sorption behavior of 6: 2 chlorinated polyfluorinated ether sulfonate (F-53B) on four kinds of nano-materials[J]. Science of the Total Environment, 2021, 757: 144064. doi: 10.1016/j.scitotenv.2020.144064 [39] QIAN J, SHEN M, WANG P, et al. Perfluorooctane sulfonate adsorption on powder activated carbon: Effect of phosphate (P) competition, pH, and temperature[J]. Chemosphere, 2017, 182: 215-222. doi: 10.1016/j.chemosphere.2017.05.033