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石油是由碳氢化合物组成的混合物, 包括多种有毒有害物质, 疏水性强[1]。进入饱和层中的石油以吸附态、溶解态以及非水相液体(NAPL相)形式存在。由于石油中各组分土水分配系数较高, 饱和层中的石油大部分以吸附态存在。以吸附态及NAPL相存在的石油会随着地下水中石油浓度的降低持续释放, 成为污染源[2-3]。因此, 降低吸附态石油的浓度是石油污染地下水修复的关键。
石油污染修复技术主要包含物理修复技术、化学修复技术、生物修复技术和物理化学修复技术等[4-5]。其中, 地下水抽出-处理(P & T)技术由于工艺流程简单、设备容易获取、适用范围广等优点, 在污染地下水修复技术发展初期成为主导技术[6]。美国环保署发布的《超级基金修复报告(第14版)》[7]显示, P & T技术应用比例最高时超过90%。然而, 到了2011年P & T技术应用比例下降至20%。其主要原因是P & T技术对有机污染地下水, 尤其是疏水性强的有机物污染地下水修复效率低, 修复后期容易出现“拖尾效应”, 修复停止后污染物浓度反弹严重[8]。表面活性剂强化脱附净化技术作为一种可以避免“拖尾效应”及污染物浓度反弹的技术, 利用表面活性剂在高于其临界胶束浓度(critical micelle concentration, CMC)时对有机物的增溶作用[9-10]以及低于其CMC时对有机物的卷缩作用[11], 提高吸附态有机污染物在地下水中的溶解度及迁移性, 实现地下水中有机污染物的快速去除, 在有机污染土壤及地下水修复中得到较多的研究[12-15]。马浩等[10]研究证实, 添加羧甲基纤维素钠表面活性剂能促进石油污染土壤中石油的脱附, 最优条件下石油脱附率达到60%。URUM等[16]以实验室模拟石油污染土壤研究了鼠李糖脂、皂苷以及SDS等3种表面活性剂的脱附净化效率, 结果表明SDS脱附净化效率优于鼠李糖脂及皂苷。
现有表面活性剂脱附净化的研究[17-21]大多以人工配制单一污染物的均匀介质为研究对象, 鲜见以实际场地中污染物经过长时间老化的复杂不均匀介质作为研究对象, 但人工配制污染土壤在污染组分复杂性、污染物赋存形态、介质均一性等方面均与实际污染介质存在较大的差异, 人工配制污染土壤实验所得结果能否为实际修复工程提供参考是需要关注的问题。本研究以某石化企业污染场地中受石油污染的含水层介质为研究对象, 采用振荡及溶出模拟实验筛选适宜的表面活性剂, 研究脱附时间、表面活性剂浓度、脱附净化流程等参数对石油污染含水层净化效果的影响, 并分析脱附净化过程石油中不同碳原子数组分的去除规律, 以期为石油污染含水层修复提供技术支撑。
石油污染含水层介质表面活性剂脱附净化效应
Surfactant desorption and purification effect on petroleum contaminated aquifer medium
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摘要: 通过批式振荡及溶出模拟实验研究了十二烷基硫酸钠(SDS)、吐温80(TW80)及脂肪醇聚氧乙烯醚硫酸钠(AES)对石油污染含水层介质的脱附净化效果, 考察了振荡时间、SDS浓度、脱附净化流程等对污染物净化效率的影响。结果表明: SDS对石油污染的脱附净化效果优于TW80及AES, 适宜的振荡时间为3 h, 适宜的SDS浓度为4.0 g·L-1; 脱附净化流程实验证实, 按照流程3(首先采用去离子水脱附, 然后采用4.0 g·L-1的SDS溶液进行脱附, 最后采用去离子水脱附)进行脱附净化后, 污染物溶出浓度最低, 推荐流程3作为适宜的脱附净化流程。经上述推荐的实验条件处理后, 含水层介质溶出模拟实验中TPH浓度降低了99%以上, 接近地下水质量标准Ⅳ类限值; 苯浓度降低超过了87%, 低于地下水质量标准Ⅳ类限值, 污染含水层环境及人体健康风险大大降低。基于SDS的脱附净化技术是一种有工程应用前景的石油污染含水层介质修复技术。Abstract: The desorption and purification effects of sodium dodecyl sulfate (SDS), Tween 80 (TW80) and sodium alcohol ether sulphate(AES) on petroleum-contaminated aquifer were investigated by batch test and dissolution simulation test, and the influences of oscillation time, SDS concentration and desorption process on pollutant purification efficiency were investigated. Results showed that SDS was more efficient than TW80 and AES in removing petroleum pollutants. The appropriate oscillation time and SDS concentration were 3 h and 4.0 g·L-1, respectively. The desorption and purification process experiment confirmed that concentration of pollutants in the dissolution was the lowest when the process 3(desorption with deionized water at first, then desorption with 4.0 g·L-1 SDS solution, and finally desorption with deionized water) was used for desorption and purification. So the process 3 was recommended as an appropriate desorption and purification process. After treatment with the above recommended experimental conditions, TPH concentration in simulated dissolution test of contaminated aquifer medium decreased by over 99%, which approached the requirements of the standard for groundwater quality(Ⅳ) in China. And the reduction of benzene concentration exceeded 87%, which was lower than the standard for groundwater quality(Ⅳ) in China. After desorbing and purifying, the environment and human health risks caused by the contaminated aquifer were reduced dramatically. Therefore, the desorption and purification technology based on SDS could be a promising remediation technology for petroleum contaminated aquifer medium.
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表 1 实验用含水层介质粒径分布
Table 1. Particle distribution of aquifer medium used in experiment
粒径范围/mm 质量分数/% > 9.5 36.5±4.7 2~9.5 42.2±4.8 0.075~2 13.3±0.5 ≤0.075 8±1.1 表 2 SDS强化脱附TPH脱附效果对比
Table 2. Comparison of SDS enhanced TPH desorption effect
表 3 SDS脱附净化后模拟溶出实验中污染物浓度对比
Table 3. Concentrations of pollutants in the simulated dissolution test after SDS desorption
mg·L-1 实验流程 第1次模拟溶出实验 第2次模拟溶出实验 TPH 苯 TPH 苯 原始样 1 750.32±844.96 0.5±0.38 — — 流程1 15.8±4.55 0.18±0.03 11.47±7.45 0.14±0.03 流程2 13.97±12.99 0.07±0.02 8.57±4.00 0.09±0.01 流程3 10.19±14.48 0.07±0.04 1.1±0.40 0.06±0.01 -
[1] 吕晓立, 孙继朝, 刘景涛, 等.地下水石油烃污染修复技术研究进展[J].安徽农业科学, 2014, 42(17): 5567-5571. doi: 10.3969/j.issn.0517-6611.2014.17.083 [2] 李永霞.含水介质中石油污染物迁移与残留特征[D].青岛: 中国海洋大学, 2011. http://cdmd.cnki.com.cn/Article/CDMD-10423-1011229208.htm [3] 苏小四, 袁文真, 宋绵, 等.含水层介质对石油类污染质的吸附特征研究[J].科技导报, 2012, 30(24): 28-32. doi: 10.3981/j.issn.1000-7857.2012.24.003 [4] 王博.加油站石油污染修复技术研究[D].北京: 清华大学, 2010. http://cdmd.cnki.com.cn/Article/CDMD-10003-1011280831.htm [5] 王业耀, 孟凡生.石油烃污染地下水原位修复技术研究进展[J].化工环保, 2005, 25(2): 117-120. doi: 10.3969/j.issn.1006-1878.2005.02.010 [6] 杨宾.饱和多孔介质中典型DNAPLs污染物的表面活性剂强化抽出处理特征[D].北京: 中国环境科学研究院, 2013. http://cdmd.cnki.com.cn/Article/CDMD-82405-1013315528.htm [7] USEPA. Superfund remedy report(fourteenth edition)[EB/OL]. [2018-08-21]. https://clu-in.org/download/remed/asr/14/SRR_14th_2013Nov.pdf, 2013. [8] 李隋.表面活性剂强化抽取处理修复DNAPL污染含水层的实验研究[D].长春: 吉林大学, 2008. http://cdmd.cnki.com.cn/article/cdmd-10183-2008126658.htm [9] UNDSTEN G, BACKLUND S. The isotropic oil surfactant-rich phase in systems of aromatic oils, nonionic surfactants, and water[J]. Journal of Colloid and Interface Science, 1995, 169(2): 408-413. doi: 10.1006/jcis.1995.1050 [10] 马浩, 刘元元, 肖文燕, 等.表面活性剂CMC对石油烃污染土壤的增溶[J].环境工程学报, 2016, 10(12): 7333-7338. doi: 10.12030/j.cjee.201507133 [11] BORKOVEC M. From micelles to microemulsion droplets-size distributions, shape fluctuations, and interfacial-tensions[J]. Journal of Chemical Physics, 1989, 91(10): 6268-6281. doi: 10.1063/1.457393 [12] FOUNTAIN J C, KLIMEK A, BEIKIRCH M G, et al. The use of surfactants for in situ extraction of organic pollutants from a contaminated aquifer[J]. Journal of Hazardous Materials, 1991, 28(3): 295-311. doi: 10.1016/0304-3894(91)87081-C [13] ZHU K, HART W, YANG J T. Remediation of petroleum-contaminated loess soil by surfactant-enhanced flushing technique[J]. Journal of Environmental Science and Health Part A: Toxic/Hazardous Substances & Environmental Engineering, 2005, 40(10): 1877-1893. [14] MOUSSET E, OTURAN M A, VAN HULLEBUSCH E D, et al. Soil washing/flushing treatments of organic pollutants enhanced by cyclodextrins and integrated treatments: state of the art[J]. Critical Reviews in Environmental Science and Technology, 2014, 44(7): 705-795. doi: 10.1080/10643389.2012.741307 [15] 卢媛, 马小东, 孙红文, 等.表面活性剂清洗处理重度石油污染土壤[J].环境工程学报, 2009, 3(8): 1483-1487. [16] URUM K, GRIGSON S, PEKDEMIR T, et al. A comparison of the efficiency of different surfactants for removal of crude oil from contaminated soils[J]. Chemosphere, 2006, 62(9): 1403-1410. doi: 10.1016/j.chemosphere.2005.05.016 [17] ZHAO B W, ZHU L Z, LI W, et al. Solubilization and biodegradation of phenanthrene in mixed anionic-nonionic surfactant solutions[J]. Chemosphere, 2005, 58(1): 33-40. doi: 10.1016/j.chemosphere.2004.08.067 [18] AMANI H. Evaluation of biosurfactants and surfactants for crude oil contaminated sand washing[J]. Petroleum Science and Technology, 2015, 33(5): 510-519. doi: 10.1080/10916466.2014.999941 [19] 毕璐莎.表面活性剂淋洗修复石油类污染土壤实验研究[D].北京: 中国地质大学(北京), 2016. [20] SHI Z, CHEN J, LIU J, et al. Anionic-nonionic mixed-surfactant-enhanced remediation of PAH-contaminated soil[J]. Environmental Science and Pollution Research, 2015, 22(16): 12769-12774. doi: 10.1007/s11356-015-4568-6 [21] LOPEZ J, ITURBE R, TORRES L G. Washing of soil contaminated with PAHs and heavy petroleum fractions using two anionic and one ionic surfactant: Effect of salt addition[J]. Journal of Environmental Science and Health Part A: Toxic/Hazardous Substances & Environmental Engineering, 2004, 39(9): 2293-2306. [22] 中华人民共和国建设部, 中华人民共和国国家质量监督检验检疫总局.岩土工程勘察规范: GB 50021-2001[S].北京: 中国建筑工业出版社, 2001. [23] USEPA. Nonhalogenated organics using GC/FID[EB/OL].[2018-08-21]. https://www.epa.gov/sites/production/files/2015-12/documents/8015d_r4.pdf, 2003. [24] USEPA. Volatile organic compounds by gas chromatography/mass spectrometry (GC/MS)[EB/OL]. [2018-08-21]. https://www.epa.gov/sites/production/files/2017-04/documents/method_8260d_update_vi_final_03-13-2017_0.pdf, 2018. [25] 杨娟娟, 楼林洁, 周文军.皂角苷对芘的增溶作用及影响因素[J].环境科学学报, 2011, 31(1): 172-176. [26] JING Q F, YI Z L, LIN D H, et al. Enhanced sorption of naphthalene and p-nitrophenol by nano-SiO2 modified with a cationic surfactant[J]. Water Research, 2013, 47(12): 4006-4012. doi: 10.1016/j.watres.2012.09.057 [27] LU L, ZHU L Z. Effect of soil components on the surfactant-enhanced soil sorption of PAHs[J]. Journal of Soils and Sediments, 2012, 12(2): 161-168. doi: 10.1007/s11368-011-0432-6 [28] 毕璐莎, 张焕祯, 罗成成, 等.表面活性剂淋洗修复石油类污染土壤的研究[J].中国人口·资源与环境, 2015, 25(S1): 195-198. [29] 陈刚.表面活性剂修复石油污染土壤研究[D].济南: 山东科技大学, 2008. http://cdmd.cnki.com.cn/Article/CDMD-10424-2009022254.htm [30] 李佳斌.土壤中石油烃的芬顿氧化实验研究[D].北京: 轻工业环境保护研究所, 2016. http://cdmd.cnki.com.cn/Article/CDMD-83702-1016049564.htm