Correlation between pore-size distribution of carbonaceous sorbent and the separation of organic components in coking wastewater

doi:10.16085/j.issn.1000-6613.2017-2476

Abstract

Abstract: Four kinds of carbonaceous sorbents including wood (A₁), coconut shell (A₂), coal (A₃) and coke (H), with different pore structures were selected for the static adsorption of total organic carbon (TOC) in coking wastewater. The influences of adsorption capacity, molecular weight and other factors on the adsorption performance were investigated. For the purpose of fully understand the correlation between surface chemical properties and pore size distribution of carbonaceous sorbents and its adsorption performance toward coking wastewater, the adsorbents were characterized by Fourier transform infrared spectrometer(FTIR), Brunauer-Emmett-Teller (BET) and other analysis means. The results showed that the above four adsorbents had similar surface characteristics. Pore structures of adsorbents were the main factors that affected the adsorption performance. BET surface areas:A₁(1723.59m²/g) > H(1716.19m²/g) > A₂(911.55m²/g) > A₃(505.23m²/g), average pore diameter:A₁(5.14nm) > H(5.02nm) > A₃(3.81nm) > A₂(3.45nm). The adsorption behavior could be well described by Redlich-Peterson adsorption isotherm equation. The investigation about the molecular weight distribution, UV₂₅₄, SUVA, and EEMs indicated that A₁ and A₂ with large micropore area preferentially adsorbed low molecular weight organics, while A₃ and H could refractory high molecular weight organics, reducing aromatic structure degree of coking wastewater; 94.29% organic matter in the TOC of coking wastewater was less than 10000. Carbonaceous sorbent with micropores(< 2nm)and small mesopores(2-10nm)were more suitable for the treatment of coking wastewater. All these findings indicated that correlation was existed in the pore structure, pore size of the sorbent material and properties of coking wastewater as well as the molecular structure of organic matter. Therefore, adsorption and separation process with optimization of wastewater pretreatment can be achieved by matching the properties of sorbent and wastewater.

Key words: coking wastewater, carbonaceous sorbent, pore-size distribution, adsorption capacity, selectivity

摘要： 选取4种孔隙结构不同的炭质吸附剂木质（A₁）、椰壳（A₂）、煤质（A₃）和焦炭（H）吸附焦化废水中的总有机碳（TOC）成分，考察吸附性能、分子量大小等因素对吸附效果的影响，同时利用傅里叶红外光谱、比表面积及介孔/微孔分析仪对吸附剂进行表征，探究吸附剂表面化学性质和孔径分布对焦化废水吸附差异相关性。结果表明：4种吸附剂表面性质相近，孔隙结构不同是其吸附性能差异的主要因素。比表面积：A₁（1723.59m²/g） > H（1716.19m²/g） > A₂（911.55m²/g） > A₃（505.23m²/g），平均孔径：A₁（5.14nm） > H（5.02nm） > A₃（3.81nm） > A₂（3.45nm）。Redlich-Peterson吸附等温线方程能更好地拟合吸附数据。分子量分布、UV₂₅₄、SUVA和EEMs说明微孔面积较大的A₁和A₂优先吸附低分子量（< 1000）有机物，A₃和H能够回收高分子量（1000～0.45μm）有机物，降低废水芳香构造化程度。焦化废水TOC中94.29%的有机物分子量小于10000，微孔（< 2nm）和较小中孔（2～10nm）更适合用焦化废水吸附处理。上述研究指出，吸附材料、孔结构与孔径分布、焦化废水性质、有机物分子结构之间存在相关性，通过性质的匹配来实现废水预处理优化的吸附分离工艺。

关键词: 焦化废水, 炭质吸附剂, 孔径分布, 吸附性能, 选择性

CLC Number:

X703

WANG Feng, KONG Qiaoping, ZHOU Hongtao, FU Bingbing, WU Haizhen, REN Yuan, WEI Chaohai. Correlation between pore-size distribution of carbonaceous sorbent and the separation of organic components in coking wastewater[J]. Chemical Industry and Engineering Progress, 2018, 37(08): 3252-3259.

王丰, 孔巧平, 周红桃, 付炳炳, 吴海珍, 任源, 韦朝海. 炭质吸附剂孔径分布与焦化废水有机组分分离的相关性[J]. 化工进展, 2018, 37(08): 3252-3259.

References

[1] MELANIE K, GABRIEL S, FENG X, et al. Sorption of ionizable and ionic organic compounds to biochar, activated carbon and other carbonaceous materials[J]. Water Research, 2017, 127(11):673-692.
[2] PATRICI A Q, LEI L, DETLEF R U K. Effects of activated carbon characteristics on the simultaneous adsorption of aqueous organic micropollutants and natural organic matter[J]. Water Research, 2005, 39(03):1663-1673.
[3] LEI L, PATRICIA A Q, DETLEF R U K. Effects of activated carbon surface chemistry and pore structure on the adsorption of organic contaminants from aqueous solution[J]. Carbon, 2003, 40(08):2085-2100.
[4] 韦朝海, 廖建波, 胡芸. 煤的基本化工过程与污染特征分析[J]. 化工进展, 2016, 35(6):1875-1883. WEI Chaohai, LIAO Jianbo, HU Yu. Basic coal chemical processes and their pollution characteristics[J]. Chemical Industry and Engineering Progress, 2016, 35(6):1875-1883.
[5] LV J T, ZHANG S Z, WANG S S, et al. Molecular-scale investigation with ESI-FT-ICR-MS on fractionation of dissolved organic matter induced by adsorption on iron oxyhydroxides[J]. Environmental Science and Technology, 2016, 2(4):2328-2336.
[6] YAN M Q, KORSHIN G, WANG D S, et al. Characterization of freshwater natural dissolved organic matter using high-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with a multiple wavelength absorbent detector[J]. Chemosphere, 2012, 87:879-885.
[7] SANTOS D, SILVA L, ALBUQUERQUE A, et al. Biodegradability enhancement and detoxification of cork processing wastewater molecular size fractions by ozone[J]. Bioresource Technology, 2013, 147(10):143-151.
[8] NEWCOMBE G, DRIKAS M, HAYES R. Influence of characterized natural organic material on activated carbon adsorption:effect on pore volume distribution and adsorption of 2-methylisoborneol[J]. Water Research, 1997, 31(5):1065-1073.
[9] ZHANG S J, SHAO T, KOSE H S, et al. Adsorption of aromatic compounds by carbonaceous adsorbents:a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes[J]. Environmental Science & Technology, 2010, 44(16):6377-6383.
[10] 刘立恒, 辜敏, 鲜学福. 孔结构和表面化学性质对活性炭吸附性能的影响[J]. 环境工程学报, 2012, 6(4):1299-1304. LIU Liheng, GU Min, XIAN Xuefu. Effect of pore structure and surface chemical properties on adsorption properties of activated carbons[J]. Chinese Journal of Environmental Engineering, 2012, 6(4):1299-1304.
[11] 魏晓币, 王光华, 李文兵, 等. 磁性Fe₃O₄/改性焦炭的制备及其降解性能[J]. 化工进展, 2017, 36(7):2577-2583. WEI Xiaobi, WANG Guanghua, LI Wenbing, et al. Preparation and degradation properties of magnetic Fe₃O₄/modified coke[J]. Chemical Industry and Engineering Progress, 2017, 36(7):2577-2583.
[12] 曾会会, 仪桂云, 邢宝林, 等. 煤基石墨烯/TiO₂复合材料的制备及光催化性能[J]. 化工进展, 2017, 36(7):2568-2575. ZENG Huihui, YI Guiyun, XING Baolin, et al. Preparation of coal-based graphene/TiO₂ composites and their photocatalytic activity[J]. Chemical Industry and Engineering Progress, 2017, 36(7):2568-2575.
[13] GAO X M, DAI Y, ZHANG Y, et al. Effective adsorption of phenolic compound from aqueous on activated semi coke[J]. Journal of Physics and Chemistry of Solids, 2017, 102(11):142-150.
[14] 刘苗茹, 席宏波, 周岳溪, 等. 水解酸化+ A/O工艺对石化废水不同分子量有机物去除效果评价[J]. 环境工程学报, 2014, 8(7):2665-2671. LIU Miaoru, XI Hongbo, ZHOU Yuexi, et al. Treatment effect of hydrolysis-acidification + A/O process on organics with different molecular weight in petrochemical wastewater[J]. Chinese Journal of Environmental Engineering, 2014, 8(7):2665-2671.
[15] JAMES L W, GEORGE R A, BRIAN A B, et al. Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon[J]. Environmental Science &Technology, 2003, 37(20):4702-4708.
[16] EDZWAL J K. Coagulation in drinking water treatment:Particles, organics and coagulants[J]. Water Science and Technology, 1993, 27(11):21-35.
[17] LI P, NUERLA J, CAO X X, et al. Pretreatment of coal gasification wastewater by adsorption using activated carbons and activated coke[J]. Colloids and Surfaces A:Physicochemical and Engineering Aspects, 2015, 482(5):177-183.
[18] OU H S, WEI C H, MO C H, et al. Novel insights into anoxie/aerobic1/aerobic2 biological fluidized-bed system for coke wastewater treatment by fluorescence excitation-emission matrix spectra coupled with parallel factor analysis[J]. Chemosphere, 2014, 52(6):997-1005.
[19] CHEN W, WESTERHOFF P, LEENHEER J A, et al. Fluorescence excitation-emission matrix regional integration to quantify spectra for dissolved organic matter[J]. Environmental Science & Technology, 2003, 37(24):5701-5710.
[20] 徐荣华, 武恒平, 贺润生, 等. 焦化废水中不同极性组分的光谱分析及可生物降解特性[J]. 环境科学学报, 2016, 36(3):900-906. XU Ronghua, WU Hengping, HE Runsheng, et al. Spectral analysis and biodegradation characteristics of different polar fractions in coking wastewater[J]. Acta Scientiae Cirumstantiae, 2016, 36(3):900-906.
[21] EWA L G, MARIA A D, et al. Influence of pore size distribution on adsorption of phenol on PET-based activated carbons[J]. Journal of Colloid and Interface Science, 2016, 39(2):205-212.
[22] ZHANG W, CHANG Q G, LIU W D, et al. Selecting activated carbon for water and wastewater treatability studies[J]. Environmental Porgress, 2007, 26(3):289-298.