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为了保障钻井液的性能稳定,以实现在高温、高压、高盐的地层环境进行快速钻井及后续作业,通常在钻井过程中会大量使用具有高色度、难降解的磺化聚合物泥浆体系[1],从而导致钻井废水具备高色度、高COD、难降解的特点[2-3]。上述钻井废水若直接排放,会严重污染土壤和地下水。因此,钻井废水的达标处理对油气田环境保护具有重大意义。
近年来,三维电解法在废水处理中特别是难降解有机污染物的处理领域备受关注[4-8]。三维电极系统中常规粒子电极主要通过羟基自由基等强氧化性中间物质降解有机物,而钻井废水中的氯离子对羟基自由基具有较强抑制作用[9-10]。钻井废水电解过程中生成的活性氯(Cl2、ClO−、HClO)具有强氧化性,能进一步促进有机物的降解[11]。杨蕴哲等[12]研究发现活性氯能有效降解活性艳蓝KN-R。吉庆华[13]研究证明活性氯可强化溶解性有机碳、三氯甲烷和氯酸烷等的混凝去除作用。刘咏等[14]研究发现Cl−含量越大,苯酚被完全氧化所需的时间越短。基于二氧化锰对电解活性氯具有良好催化活性的特点,而软锰矿的主要成分为MnO2且在我国分布广泛,因而采用软锰矿、石墨为主要成分制备新型粒子电极。将自制软锰矿粒子电极应用于三维电极系统中处理高含氯的钻井废水,通过软锰矿的催化活性和石墨良好的导电性,可有效提高电解过程中活性氯生成量和COD去除率。
磺化聚合物泥浆体系以磺化酚醛树脂(SMP)为主[15],其相对分子质量10 kDa左右[16]。本研究以SMP为目标污染物,通过自制软锰矿粒子电极催化电解产生更多的活性氯,进一步提高SMP的处理效率。以活性氯浓度、COD为主要检测指标,研究并优化了软锰矿粒子电极的制备过程参数;并与常规活性炭粒子电极进行了对比研究,采用电化学分析及紫外分光光度等方法,初步探索软锰矿粒子电极对SMP的电催化降解机理。
软锰矿粒子电极的制备及其对SMP的催化降解
Preparation of pyrolusite particle electrode and its catalytic degradation of SMP
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摘要: 针对二氧化锰对废水中氯离子电解生成活性氯具有较好催化活性的特点,以软锰矿为原料制备一种新型粒子电极,将其用于三维电极系统处理油气田高含氯废水,利用活性氯的强氧化性进一步强化废水中难降解有机物SMP的处理;并考察软锰矿粒子电极制备条件对电极性能和电解效果的影响。结果表明:软锰矿与石墨质量比6∶4、PTFE分散液加入量10%、330 °C下灼烧2 h为软锰矿粒子电极最优制备条件;与常规活性炭粒子电极相比,软锰矿粒子电极电解活性氯的产生量、COD去除率均显著优于活性炭粒子电极;且软锰矿粒子电极在重复使用多次后,活性组分流失量较小,对SMP的降解效率仍较高,保持了稳定的电催化性能。Abstract: The electrolysis of chloride ions in wastewater by manganese dioxide can produce active chlorine with a good catalytic activity. Thus, a new type of particle electrode was prepared with pyrolusite, which was used in a three-dimensional electrode system to treat high-chlorine wastewater in oil and gas fields. Then the active chlorine with strong oxidation ability was produced to strengthen the treatment of refractory organic matter SMP in wastewater. The effects of preparation conditions of pyrolusite particle electrode on electrode properties and electrolysis performance were investigated. The particle electrode was characterized by specific surface area analyzer and X-ray diffraction. The results show that the optimal preparation conditions of pyrolusite electrode were determined as follows: mass ratio of pyrolusite to graphite of 6∶4, PTFE dispersion dosage of 10%, and 2 h sintering at 330 ℃. Compared with the conventional activated carbon particle electrode, the production of activated chlorine and COD removal rate of the pyrolusite particle electrode were significantly higher. Moreover, after several recycling of the pyrolusite particle electrode, its active component loss was low, the recycled pyrolusite particle electrode still showed high SMP degradation efficiency and maintained a stable electro-catalysis performance accordingly.
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表 1 PTFE加入量对粒子电极比表面积和孔容的影响
Table 1. Effect of PTFE addition on the specific surface area and the pore volume of particle electrode
PTFE加入量/% BET比表面积/(m3·g−1) 孔容/(cm3·g−1) 平均孔径/nm 10 13.885 4 0.057 2 16.489 7 20 11.365 9 0.050 5 17.819 4 30 9.924 2 0.055 2 21.169 3 40 8.249 1 0.051 5 24.679 4 -
[1] 蒋学彬. 川渝地区油气田钻井废水处理研究[D]. 成都: 西南交通大学, 2008. [2] 彭娟华, 莫正平, 李旭东. Fenton试剂预处理提高钻井废水可生化性[J]. 应用与环境生物学报, 2008, 14(2): 265-269. doi: 10.3321/j.issn:1006-687X.2008.02.025 [3] 张红岩, 吕荣湖, 郭绍辉. 混凝-臭氧氧化法处理三磺泥浆体系钻井废水[J]. 过程工程学报, 2007, 7(4): 718-722. doi: 10.3321/j.issn:1009-606x.2007.04.016 [4] HUSSAIN S N, DE LAS HERAS N, ASGHAR H M A, et al. Disinfection of water by adsorption combined with electrochemical treatment[J]. Water Research, 2014, 54: 170-178. doi: 10.1016/j.watres.2014.01.043 [5] CAN W, YAO-KUN H, QING Z, et al. Treatment of secondary effluent using a three-dimensional electrode system: COD removal, biotoxicity assessment, and disinfection effects[J]. Chemical Engineering Journal, 2014, 243: 1-6. doi: 10.1016/j.cej.2013.12.044 [6] YAVUZ Y, KOPARAL A S, ÖĞÜTVEREN Ü B. Treatment of petroleum refinery wastewater by electrochemical methods[J]. Desalination, 2010, 258(1/2/3): 201-205. [7] GEDAM N, NETI N R. Carbon attrition during continuous electrolysis in carbon bed based three-phase three-dimensional electrode reactor: Treatment of recalcitrant chemical industry wastewater[J]. Journal of Environmental Chemical Engineering, 2014, 2(3): 1527-1532. doi: 10.1016/j.jece.2014.06.025 [8] 梁宏, 任阳民, 邱阳, 等. 三维电极法处理含氯废水过程中电解活性氯的研究[J]. 工业水处理, 2017, 37(9): 37-40. [9] LAAT J D, LE T G. Effects of chloride ions on the iron(III)-catalyzed decomposition of hydrogen peroxide and on the efficiency of the Fenton-like oxidation process[J]. Applied Catalysis B: Environmental, 2006, 66(1/2): 137-146. [10] LÓPEZ-GÁLVEZ, F, et al. Electrochemical disinfection: An efficient treatment to inactivate Escherichia coli O157∶H7 in process wash water containing organic matter[J]. Food Microbiology, 2012, 30(1): 146-156. doi: 10.1016/j.fm.2011.09.010 [11] CHEN S, ZHENG Y, WANG S, et al. Ti/RuO2-Sb2O5-SnO2 electrodes for chlorine evolution from seawater[J]. Chemical Engineering Journal, 2011, 172(1): 47-51. doi: 10.1016/j.cej.2011.05.059 [12] 杨蕴哲, 杨卫身. 恒电流下原位电生成活性氯氧化降解蒽醌染料[J]. 大连理工大学学报, 2006, 46(6): 813-818. doi: 10.3321/j.issn:1000-8608.2006.06.007 [13] 吉庆华. 活性氯强化混凝对消毒副产物生成势的控制研究[D]. 北京: 中国科学院研究生院, 2008. [14] 刘咏, 赵仕林, 李启彬, 等. 苯酚在氯离子体系中的电化学氧化研究[J]. 环境科学与技术, 2006, 29(11): 21-22. doi: 10.3969/j.issn.1003-6504.2006.11.009 [15] 王平全, 余冰洋, 王波, 等. 常用磺化酚醛树脂性能评价及分析[J]. 钻井液与完井液, 2015, 32(2): 29-33. doi: 10.3969/j.issn.1001-5620.2015.02.008 [16] 樊世忠, 鄢捷年, 周大晨. 钻井液完井液及保护油气层技术[M]. 东营: 石油大学出版社, 1996: 122. [17] 中华人民共和国环境保护部. 环境保护行业标准: HJ 586-2010[S]. 北京: 中国环境科学出版社, 2012. [18] 陈集, 尹忠, 冯英, 等. 油气田高Cl−废水的COD测定[J]. 西南石油学院学报, 1992, 14(4): 94-101. [19] DONG H, YU H, WANG X, et al. A novel structure of scalable air-cathode without nafion and Pt by rolling activated carbon and PTFE as catalyst layer in microbial fuel cells[J]. Water Research, 2012, 46(17): 5777-5787. doi: 10.1016/j.watres.2012.08.005 [20] 肖惠文, 梁宏, 庞凯, 等. 软锰矿粒子电极处理SMP模拟废水实验研究[J]. 四川理工学院学报, 2016, 29(1): 12-16. [21] CHENG S A, WU J C. Air-cathode preparation with activated carbon as catalyst, PTFE as binder and nickel foam as current collector for microbial fuel cells[J]. Bioelectrochemistry, 2013, 92(2): 22-26. [22] CHEN J Y, LI N, ZHAO L. Three-dimensional electrode microbial fuel cell for hydrogen peroxide synthesis coupled to wastewater treatment[J]. Journal of Power Sources, 2014, 254: 316-322. doi: 10.1016/j.jpowsour.2013.12.114 [23] 柏栋予, 白红伟, 傅强. 高分子材料烧结成型研究进展[J]. 高分子通报, 2017(10): 13-22. [24] LIANG S, TENG F, BULGAN G, et al. Effect of phase structure of MnO2 nanorod catalyst on the activity for CO oxidation[J]. Journal of Physical Chemistry C, 2010, 112(14): 5307-5315. [25] 芦佳. α-MnO2纳米颗粒的可控制备及催化性能研究[D]. 石家庄: 河北师范大学, 2010. [26] SELVAKUMAR K, KUMAR S M S, THANGAMUTHU R, et al. Development of shape-engineered α-MnO2, materials as bi-functional catalysts for oxygen evolution reaction and oxygen reduction reaction in alkaline medium[J]. International Journal of Hydrogen Energy, 2014, 39(36): 21024-21036. doi: 10.1016/j.ijhydene.2014.10.088 [27] NI Y L, MENG H M, CHEN D, et al. Preparation of IrO2+MnO2 coating anodes and their application in NaClO production[J]. Journal of University of Science & Technology Beijing, 2008, 15(4): 461-467. [28] LI X, WU Y, ZHU W, et al. Enhanced electrochemical oxidation of synthetic dyeing wastewater using SnO2-Sb-doped TiO2-coated granular activated carbon electrodes with high hydroxyl radical yields[J]. Electrochimica Acta, 2016, 220: 276-284. doi: 10.1016/j.electacta.2016.09.109 [29] ALAOUI A, KACEMI K E, ASS K E, et al. Activity of Pt/MnO2 electrode in the electrochemical degradation of methylene blue in aqueous solution[J]. Separation & Purification Technology, 2015, 154: 281-289. [30] KUAN W H, CHAN Y C. pH-dependent mechanisms of methylene blue reacting with tunneled manganese oxide pyrolusite[J]. Journal of Hazardous Materials, 2012, 239-240: 152-159. doi: 10.1016/j.jhazmat.2012.08.051 [31] SZPYRKOWIC L, RADAELI M, DANIEL S. Electrocatalysis of chlorine evolution on different materials and its influence on the performance of an electrochemical reactor for indirect oxidation of pollutants[J]. Catalysis Today, 2005, 100(3/4): 425-429. [32] ABBAR A H, SALMAN R H, ABBAS A S. Electrochemical incineration of oxalic acid at manganese dioxide rotating cylinder anode: Role of operative parameters in the presence of NaCl[J]. Journal of the Electrochemical Society, 2016, 163(13): E333-E340. doi: 10.1149/2.0551613jes [33] SZPYRKOWICZ L, JUZZOLINO C, KAUL S N. A comparative study on oxidation of disperse dyes by electrochemical process, ozone, hypochlorite and fenton reagent[J]. Water Research, 2001, 35(9): 2129-2136. doi: 10.1016/S0043-1354(00)00487-5 [34] HUANG T, CHEN J, WANG Z, et al. Excellent performance of cobalt-impregnated activated carbon in peroxymonosulfate activation for acid orange 7 oxidation[J]. Environmental Science and Pollution Research, 2017, 24(10): 9651-9661. doi: 10.1007/s11356-017-8648-7 [35] LIANG H, QIU Y, ZHAO L Y, et al. Investigation of a novel pyrolusite particle electrode effects in the chlorine-containing wastewater[J]. Water Science and Technology, 2018, 78(7): 1427-1437. [36] TIAN S H, TU Y T, CHEN D S, et al. Degradation of acid orange II at neutral pH using Fe2(MoO4)3, as a heterogeneous Fenton-like catalyst[J]. Chemical Engineering Journal, 2011, 169(1): 31-37.