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有机染料是水体中最常见的污染物之一,主要包含胺、芳香化合物、部分重金属等[1]。而高浓度的有机染料污染对环境和人体健康造成极大的危害[2]。生物炭对多种有机物具有高亲和性[3-5],且来源广泛、费用较低[6-7],因此采用生物炭吸附有机染料受到了广泛重视,如YIN等制备的槟榔叶生物炭[3]、ABD-ELHAMID研磨改性的水稻秸秆生物炭[8]、高等制得城镇垃圾生物炭[9]、张等合成的辣椒秸秆生物炭[10]等,均对有机染料吸附表现良好。
此前的研究主要聚焦于生物炭改性及对单一污染物的吸附效能,而对多种污染物的吸附容量差别关注较少。研究生物炭吸附多种污染物的效能差别,能明确污染物影响吸附过程的具体因素,便于预测生物炭对未知污染物的吸附效果。根据过往研究,氢键作用是解释多种污染物在生物炭上吸附的重要机制[11],生物炭上氢键位点的增加能提高对污染物的吸附容量,同时污染物自身的氢键位点对吸附容量也有影响。YANG等以竹生物炭吸附多种典型芳香污染物的研究结果表明,具有氢键受体的污染物更容易被吸附[12]。SONG等选择了5种典型保健品作为污染物,发现污染物的吸附容量随其含有氢键受体数量上升而增加[13]。很多基于线性溶解能关系模型的研究认为污染物氢键供体对其吸附容量没有显著影响[14-16];但有研究[17]表明,污染物氢键供体能与碳基吸附剂的氢键受体形成氢键,从而影响吸附容量。因此,有必要探讨污染物氢键供体对生物炭吸附容量的影响与作用机理。
为了确定污染物氢键供体能否影响生物炭对污染物的吸附容量,本研究制备了以KHCO3和尿素协同活化的玉米秸秆生物炭,并选择了亚甲基蓝与天青B作为目标污染物,通过一系列的吸附实验与计算模拟考察了污染物氢键供体对吸附容量的影响及相关的作用机理,以期为生物炭对不同污染物吸附的实际应用提供参考。
生物炭对含氢键供体染料的吸附性能及机理
Adsorption performance and mechanism of biochar to dyes with H-donor
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摘要: 为确定染料有无氢键供体对生物炭吸附容量的影响及作用机理,制备了尿素/碳酸氢钾联合活化的玉米秸秆生物炭(KN-BC),考察其对于结构相似的亚甲基蓝(MB)与天青B(AB)的吸附容量差别及具体机制。对KN-BC的表征结果表明,经处理后的生物炭疏松多孔,表面含氧官能团含量显著增加。吸附实验结果表明,Langmuir模型拟合的KN-BC对MB和AB的最大吸附量为2 268.7 mg·g−1和4 368.5 mg·g−1,KN-BC对含有氢键供体的AB吸附性能更好。DFT计算与机理分析结果表明,氢键供体的存在使得单个污染物分子与生物炭可以同时形成氢键和π-π相互作用,两者的协同效应增强了π电子密度,显著提高了吸附效能。以上研究结果为预测生物炭对混合染料污水的吸附提供参考。Abstract: To determine whether the H-donors on dyes affect the adsorption capacity of biochar, the corn straw biochar was prepared by the combined activation of potassium bicarbonate and urea (named KN-BC), and KN-BC was used to adsorb the similar structure dyes of methylene blue (MB) and azure B (AB) to investigate the difference in adsorption capacities and underlying mechanisms. The characterizations revealed that KN-BC was highly porous, and the content of oxygen-containing functional groups increased significantly after activation. The batch experiments indicated that the maximum adsorption capacities to MB and AB in the Langmuir model reached 2 268.7 mg·g−1 and 4 368.5 mg·g−1, respectively. And higher adsorption capacity of KN-BC to AB with the H-donors occurred. DFT computation and analysis implied that the H-donor on dyes allows the co-existence of hydrogen bonding and π-π interaction between single dye molecular and KN-BC. The synergistic effect increased the π-electron density and improved the adsorption capacity. This work can provide a reference for estimating mixed dye adsorption on biochar.
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Key words:
- biochar /
- adsorption /
- H-donor /
- hydrogen bond /
- π-π interaction /
- synergistic effect
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表 1 生物炭的比表面积与孔径结构
Table 1. Specific surface area and pore structure of biochar
生物炭类型 SBET/(m2·g−1) VPore/(cm3·g−1) Vmic/(cm3·g−1) DP/nm BC 432.53 0.189 0.139 1.74 N-BC 145.11 0.065 0.055 1.80 K-BC 1 898.21 0.905 0.603 1.91 吸附前KN-BC 2 387.79 1.520 0.548 2.55 吸附后KN-BC 687.47 0.448 0.085 2.61 表 2 生物炭对MB与AB吸附的动力学模型拟合参数
Table 2. Kinetics parameters for MB and AB adsorption on biochar
吸附剂 吸附质 准一级动力学 准二级动力学 qe/(mg·g−1) k1/min−1 R2 qe/(mg·g−1) k2/(g·(mg·min)−1) R2 KN-BC MB 2 261.4 0.215 0.666 2 308.9 2.89×10-4 0.956 AB 3 105.5 0.270 0.615 3 148.3 3.56×10-4 0.958 K-BC MB 1 487.3 0.058 0.888 1 599.2 5.77×10-5 0.988 AB 2 577.9 0.050 0.946 2 792.6 2.66×10-5 0.995 N-BC MB 51.7 0.052 0.977 56.0 1.35×10-3 0.980 AB 72.9 0.064 0.976 77.7 1.34×10-3 0.981 BC MB 99.4 0.028 0.949 111.7 3.13×10-4 0.955 AB 181.2 0.097 0.938 190.0 9.54×10-4 0.978 表 3 KN-BC对MB与AB吸附等温线拟合参数
Table 3. Isotherms parameters for MB and AB adsorption on KN-BC
吸附质 Langmuir模型 Freundlich模型 Redlich-Peterson模型 Dubinin-Radushkevich模型 Qmax KL R2 KF n R2 KRP aRP g R2 qDR KDR R2 MB 2 268.7 0.737 0.891 1 411.4 10.07 0.984 5 653.6 3.59 0.92 0.994 2 209.0 5.18×10−7 0.788 AB 4 368.5 0.071 0.992 1 111.7 3.67 0.963 396.8 0.13 0.92 0.996 3 454.9 1.36×10−5 0.780 -
[1] 孙宇. 辣椒秸秆生物炭的制备、改性及对有机染料的吸附性能研究[D]. 邯郸: 河北工程大学, 2021. [2] ANWER H, MAHMOOD A, LEE J, et al. Photocatalysts for degradation of dyes in industrial effluents: Opportunities and challenges[J]. Nano Research, 2019, 12(5): 955-72. doi: 10.1007/s12274-019-2287-0 [3] YIN Z B, LIU N, BIAN S Y, et al. Enhancing the adsorption capability of areca leaf biochar for methylene blue by K2FeO4-catalyzed oxidative pyrolysis at low temperature[J]. RSC Advances, 2019, 9(72): 42343-50. doi: 10.1039/C9RA06592J [4] JIN Z H, WANG B D, MA L, et al. Air pre-oxidation induced high yield N-doped porous biochar for improving toluene adsorption[J]. Chemical Engineering Journal, 2020, 385: 123843. doi: 10.1016/j.cej.2019.123843 [5] ZHOU X H, ZHOU J J, LIU Y C, et al. Preparation of magnetic biochar derived from cyclosorus interruptus for the removal of phenolic compounds: Characterization and mechanism[J]. Separation Science and Technology, 2018, 53(9): 1307-18. doi: 10.1080/01496395.2018.1444056 [6] YU Y, AN Q, JIN L, et al. Unraveling sorption of Cr (VI) from aqueous solution by FeCl3 and ZnCl2-modified corn stalks biochar: Implicit mechanism and application[J]. Bioresource Technology, 2020, 297: 122466. doi: 10.1016/j.biortech.2019.122466 [7] OLIVEIRA F R, PATEL A K, JAISI D P, et al. Environmental application of biochar: Current status and perspectives[J]. Bioresource Technology, 2017, 246: 110-22. doi: 10.1016/j.biortech.2017.08.122 [8] ABD-ELHAMID A I, EMRAN M, EL-SADEK M H, et al. Enhanced removal of cationic dye by eco-friendly activated biochar derived from rice straw[J]. Applied Water Science, 2020, 10(1): 45. doi: 10.1007/s13201-019-1128-0 [9] 高豆豆, 郭敏辉, 王侃, 等. 城镇有机垃圾热解生物炭对水中亚甲基蓝的吸附[J]. 环境工程学报, 2019, 13(05): 1165-74. doi: 10.12030/j.cjee.201810129 [10] 张娟, 孙宇, 黄贵琦, 等. 辣椒秸秆生物炭对考马斯亮蓝染料的吸附性能研究[J]. 工业水处理, 2022, 42(02): 118-23. doi: 10.19965/j.cnki.iwt.2021-0582 [11] FANG Q L, CHEN B L, LIN Y J, et al. Aromatic and hydrophobic surfaces of wood-derived biochar enhance perchlorate adsorption via hydrogen bonding to oxygen-containing organic groups[J]. Environmental Science and Technology, 2014, 48(1): 279-88. doi: 10.1021/es403711y [12] YANG K, YANG J J, JIANG Y, et al. Correlations and adsorption mechanisms of aromatic compounds on a high heat temperature treated bamboo biochar[J]. Environmental Pollution, 2016, 210: 57-64. doi: 10.1016/j.envpol.2015.12.004 [13] SONG J Y, JHUNG S H. Adsorption of pharmaceuticals and personal care products over metal-organic frameworks functionalized with hydroxyl groups: Quantitative analyses of H-bonding in adsorption[J]. Chemical Engineering Journal, 2017, 322: 366-74. doi: 10.1016/j.cej.2017.04.036 [14] ZHAO Y F, LIN S, CHOI J W, et al. Prediction of adsorption properties for ionic and neutral pharmaceuticals and pharmaceutical intermediates on activated charcoal from aqueous solution via LFER model[J]. Chemical Engineering Journal, 2019, 362: 199-206. doi: 10.1016/j.cej.2019.01.031 [15] YU X Q, SUN W L, NI J R. LSER model for organic compounds adsorption by single-walled carbon nanotubes: Comparison with multi-walled carbon nanotubes and activated carbon[J]. Environmental Pollution, 2015, 206: 652-60. doi: 10.1016/j.envpol.2015.08.031 [16] PLATA D L, HEMINGWAY J D, GSCHWEND P M. Polyparameter linear free energy relationship for wood char-water sorption coefficients of organic sorbates[J]. Environmental Toxicology and Chemistry, 2015, 34(7): 1464-71. doi: 10.1002/etc.2951 [17] BHADRA B N, YOO D K, JHUNG S H. Carbon-derived from metal-organic framework MOF-74: A remarkable adsorbent to remove a wide range of contaminants of emerging concern from water[J]. Applied Surface Science, 2020, 504: 144348. doi: 10.1016/j.apsusc.2019.144348 [18] LAGERGREN S K. About the theory of so-called adsorption of soluble substances[J]. Kungliga Svenska Vetenskapsakademiens Handlingar, 1898, 24: 1-39. [19] BLANCHARD G, MAUNAYE M, MARTIN G. Removal of heavy metals from waters by means of natural zeolites[J]. Water Research, 1984, 18(12): 1501-7. doi: 10.1016/0043-1354(84)90124-6 [20] LANGMUIR I. The adsorption of gases on plane surfaces of glass, mica and platinum[J]. Journal of the American Chemical Society, 1918, 40(9): 1361-403. doi: 10.1021/ja02242a004 [21] FREUNDLICH H. Über die adsorption in lösungen[J]. Zeitschrift für Physikalische Chemie, 1907, 57(1): 385-470. [22] DUBININ M I. Physical adsorption of gases and vapors in micropores[J]. Amsterdam:Elsevier, 1975: 1-70. [23] REDLICH O, PETERSON D L. A useful adsorption isotherm[J]. The Journal of Physical Chemistry, 1959, 63(6): 1024. doi: 10.1021/j150576a611 [24] FRISCH M J, TRUCKS G W, SCHLEGEL H B, et al. Gaussian 16, Revision C. 01[CP/DK]. Wallingford CT: Gaussian Inc. , 2019. [25] LEE C, YANG W, PARR R G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density[J]. Physical Review B, 1988, 37(2): 785-9. doi: 10.1103/PhysRevB.37.785 [26] BECKE A D. Density-functional thermochemistry. III. The role of exact exchange[J]. The Journal of Physical Chemistry, 1993, 98(7): 5648-52. doi: 10.1063/1.464913 [27] GRIMME S, EHRLICH S, GOERIGK L. Effect of the damping function in dispersion corrected density functional theory[J]. Journal of Computational Chemistry, 2011, 32(7): 1456-65. doi: 10.1002/jcc.21759 [28] TREUTLER O, AHLRICHS R. Efficient molecular numerical integration schemes[J]. Journal of Chemical Physics, 1995, 102(1): 346-54. doi: 10.1063/1.469408 [29] WEIGEND F, AHLRICHS R. Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: Design and assessment of accuracy[J]. Physical Chemistry Chemical Physics, 2005, 7(18): 3297-305. doi: 10.1039/b508541a [30] ZHENG J J, XU X F, TRUHLAR D G. Minimally augmented Karlsruhe basis sets[J]. Theoretical Chemistry Accounts, 2011, 128(3): 295-305. doi: 10.1007/s00214-010-0846-z [31] LU T, CHEN F W. Multiwfn: A multifunctional wavefunction analyzer[J]. Journal of Computational Chemistry, 2012, 33(5): 580-92. doi: 10.1002/jcc.22885 [32] WANG H Z, GUO W Q, LIU B H, et al. Edge-nitrogenated biochar for efficient peroxydisulfate activation: An electron transfer mechanism[J]. Water Research, 2019, 160: 405-14. doi: 10.1016/j.watres.2019.05.059 [33] TIAN W J, ZHANG H Y, SUN H Q, et al. Heteroatom (N or N-S)-doping induced layered and honeycomb microstructures of porous carbons for CO2 capture and energy applications[J]. Advanced Functional Materials, 2016, 26(47): 8651-61. doi: 10.1002/adfm.201603937 [34] XIAO X, CHEN B L, ZHU L Z. Transformation, morphology, and dissolution of silicon and carbon in rice straw-derived biochars under different pyrolytic temperatures[J]. Environmental Science and Technology, 2014, 48(6): 3411-9. doi: 10.1021/es405676h [35] LENG L J, XU S Y, LIU R F, et al. Nitrogen containing functional groups of biochar: An overview[J]. Bioresource Technology, 2020, 298: 122286. doi: 10.1016/j.biortech.2019.122286 [36] CHEN B L, ZHOU D D, ZHU L Z. Transitional adsorption and partition of nonpolar and polar aromatic contaminants by biochars of pine needles with different pyrolytic temperatures[J]. Environmental Science and Technology, 2008, 42(14): 5137-43. doi: 10.1021/es8002684 [37] SHAFEEYAN M S, DAUD W W, HOUSHMAND A, et al. Ammonia modification of activated carbon to enhance carbon dioxide adsorption: Effect of pre-oxidation[J]. Applied Surface Science, 2011, 257(9): 3936-42. doi: 10.1016/j.apsusc.2010.11.127 [38] RAMESHA G K, VIJAYA K A, MURALIDHARA H B, et al. Graphene and graphene oxide as effective adsorbents toward anionic and cationic dyes[J]. Journal of Colloid and Interface Science, 2011, 361(1): 270-7. doi: 10.1016/j.jcis.2011.05.050 [39] VOGGU R, ROUT C S, FRANKLIN A D, et al. Extraordinary sensitivity of the electronic structure and properties of single-walled carbon nanotubes to molecular charge-transfer[J]. Journal of Physical Chemistry C, 2008, 112(34): 13053-6. doi: 10.1021/jp805136e [40] KIM S J, SONG Y J, WRIGHT J, et al. Graphene bi- and trilayers produced by a novel aqueous arc discharge process[J]. Carbon, 2016, 102: 339-45. doi: 10.1016/j.carbon.2016.02.049 [41] PEREIRA R C, ARBESTAIN M C, SUEIRO M V, et al. Assessment of the surface chemistry of wood-derived biochars using wet chemistry, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy[J]. Soil Research, 2015, 53(7): 753-62. doi: 10.1071/SR14194 [42] TIAN S Q, WANG L, LIU Y L, et al. Enhanced permanganate oxidation of sulfamethoxazole and removal of dissolved organics with biochar: Formation of highly oxidative manganese intermediate species and in situ activation of biochar[J]. Environmental Science and Technology, 2019, 53(9): 5282-91. doi: 10.1021/acs.est.9b00180 [43] LI Y C, XING B, WANG X L, et al. Nitrogen-doped hierarchical porous biochar derived from corn stalks for phenol-enhanced adsorption[J]. Energy & Fuels, 2019, 33(12): 12459-68. [44] GAO F, XU Z X, DAI Y J. Removal of tetracycline from wastewater using magnetic biochar: A comparative study of performance based on the preparation method[J]. Environmental Technology & Innovation, 2021, 24: 101916. [45] YU J F, FENG H P, TANG L, et al. Insight into the key factors in fast adsorption of organic pollutants by hierarchical porous biochar[J]. Journal of Hazardous Materials, 2021, 403: 123610. doi: 10.1016/j.jhazmat.2020.123610 [46] WANG H L, TANG H Q, LIU Z T, et al. Removal of cobalt(II) ion from aqueous solution by chitosan–montmorillonite[J]. Journal of Environmental Sciences, 2014, 26(9): 1879-84. doi: 10.1016/j.jes.2014.06.021 [47] TONG D S, WU C W, ADEBAJO M O, et al. Adsorption of methylene blue from aqueous solution onto porous cellulose-derived carbon/montmorillonite nanocomposites[J]. Applied Clay Science, 2018, 161: 256-64. doi: 10.1016/j.clay.2018.02.017 [48] ZHOU N, GUO X X, YE C Q, et al. Enhanced fluoride removal from drinking water in wide pH range using La/Fe/Al oxides loaded rice straw biochar[J]. Water Supply, 2021, 22(1): 779-94. [49] LIU S J, PAN M D, FENG Z M, et al. Ultra-high adsorption of tetracycline antibiotics on garlic skin-derived porous biomass carbon with high surface area[J]. New Journal of Chemistry, 2020, 44(3): 1097-106. doi: 10.1039/C9NJ05396D [50] CHENG N, WANG B, WU P, et al. Adsorption of emerging contaminants from water and wastewater by modified biochar: A review[J]. Environmental Pollution, 2021, 273: 116448. doi: 10.1016/j.envpol.2021.116448 [51] WU J, YANG J W, FENG P, et al. High-efficiency removal of dyes from wastewater by fully recycling litchi peel biochar[J]. Chemosphere, 2020, 246: 125734. doi: 10.1016/j.chemosphere.2019.125734 [52] XU C H, NIE J D, WU W C, et al. Self-healable, recyclable, and strengthened epoxidized natural rubber/carboxymethyl chitosan biobased composites with hydrogen bonding supramolecular hybrid networks[J]. ACS Sustainable Chemistry and Engineering, 2019, 7(18): 15778-89. doi: 10.1021/acssuschemeng.9b04324