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An industrial coating site in activity located on a chalky plateau, contaminated by BTEX (mainly xylenes, no benzene), is currently remediated by in situ chemical oxidation (ISCO). We present the bench scale study that was conducted to select the most appropriate oxidant. Ozone and catalyzed hydrogen peroxide (Fenton’s reaction) were discarded since they were incompatible with plant activity. Permanganate, activated percarbonate and activated persulfate were tested. Batch experiments were run with groundwater and groundwater-chalk slurries with these three oxidants. Total BTEX degradation in groundwater was reached with all the oxidants. The molar ratios [oxidant]:[Fe2+]:[BTEX] were 100:0:1 with permanganate, 100:100:1 with persulfate and 25:100:1 with percarbonate. Precipitation of either manganese dioxide or iron carbonate (siderite) occurred. The best results with chalk slurries were obtained with permanganate at the molar ratio 110:0:1 and activated persulfate at the molar ratio 110:110:1. To avoid precipitation, persulfate was also used without activation at the molar ratio 140:1. Natural Oxidant Demand measured with both oxidants was lower than 5% of initial oxidant contents. Activated percarbonate was not appropriate because of radical scavenging by carbonated media. Permanganate and persulfate were both effective at oxidant concentrations of ca 1 g kg−1 with permanganate and 1.8 g kg−1 with persulfate and adapted to site conditions. Activation of persulfate was not mandatory. This bench scale study proved that ISCO remediation of a chalky aquifer contaminated by mainly xylenes was possible with permanganate and activated or unactivated persulfate. 相似文献
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Quantification of potassium permanganate consumption and PCE oxidation in subsurface materials 总被引:1,自引:0,他引:1
A series of laboratory scale batch slurry experiments were conducted in order to establish a data set for oxidant demand by sandy and clayey subsurface materials as well as to identify the reaction kinetic rates of permanganate (MnO(4)(-)) consumption and PCE oxidation as a function of the MnO(4)(-) concentration. The laboratory experiments were carried out with 31 sandy and clayey subsurface sediments from 12 Danish sites. The results show that the consumption of MnO(4)(-) by reaction with the sediment, termed the natural oxidant demand (NOD), is the primary reaction with regards to quantification of MnO(4)(-) consumption. Dissolved PCE in concentrations up to 100 mg/l in the sediments investigated is not a significant factor in the total MnO(4)(-) consumption. Consumption of MnO(4)(-) increases with an increasing initial MnO(4)(-) concentration. The sediment type is also important as NOD is (generally) higher in clayey than in sandy sediments for a given MnO(4)(-) concentration. For the different sediment types the typical NOD values are 0.5-2 g MnO(4)(-)/kg dry weight (dw) for glacial meltwater sand, 1-8 g MnO(4)(-)/kg dw for sandy till and 5-20 g MnO(4)(-)/kg dw for clayey till. The long term consumption of MnO(4)(-) and oxidation of PCE can not be described with a single rate constant, as the total MnO(4)(-) reduction is comprised of several different reactions with individual rates. During the initial hours of reaction, first order kinetics can be applied, where the short term first order rate constants for consumption of MnO(4)(-) and oxidation of PCE are 0.05-0.5 h(-1) and 0.5-4.5 h(-1), respectively. The sediment does not act as an instantaneous sink for MnO(4)(-). The consumption of MnO(4)(-) by reaction with the reactive species in the sediment is the result of several parallel reactions, during which the reaction between the contaminant and MnO(4)(-) also takes place. Hence, application of low MnO(4)(-) concentrations can cause partly oxidation of PCE, as the oxidant demand of the sediment does not need to be met fully before PCE is oxidised. 相似文献
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为了提高高锰酸盐指数项目测定的准确性,通过实验分析,从高锰酸钾的校正系数、蒸馏水空白值、水浴的温度、加热的时间、样品酸度、滴定的过程、滴定终点的判断等因素加以分析,找出其影响测定结果的原因。实验操作中,应注重上述因素的质量控制,以提高测试的准确性。 相似文献
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高锰酸盐指数测定方法的探讨 总被引:1,自引:0,他引:1
本文对高锰酸盐指数的测定,用直火加热法和水浴加热法两种方法同时进行了对比测定.结果表明,两种方法的精密度和准确度基本一致. 相似文献
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Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)
Lei Dong Pin Xie Xin Zhang Junlian Qiao Dandan Rao Yuankui Sun Xiaohong Guan 《Frontiers of Environmental Science & Engineering》2022,16(8):109
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鸭绿江丹东段水体TOC与高锰酸盐指数相关性及应用探讨 总被引:1,自引:0,他引:1
通过对2007年~2009年鸭绿江丹东段地表水中TOC和高锰酸盐指数进行枯、丰、平三个水期109组数据同步监测的结果表明,两者之间存在密切的相关关系,经一元线性回归得出三个水期的回归方程。经相关系数显著水平检验,表明在99.9%的置信水平下,TOC和高锰酸盐指数线性相关非常显著。 相似文献
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SERES高锰酸盐指数分析仪的空白参数V0、V2,以及校准系数K等对仪器的测量的准确性非常重要.本文采用格拉布斯检验法(Gnubbs检验法)对几台不同SERES高锰酸盐指数分析仪的空白参数进行检验,以判断仪器的V0、V2,校准系数K是否在正常的范围内波动,是否为异常值,并以此来指导我们以后对仪器的校准工作. 相似文献
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Chemical oxidation of cable insulating oil contaminated soil 总被引:2,自引:0,他引:2
Leaking cable insulating oil is a common source of soil contamination of high-voltage underground electricity cables in many European countries. In situ remediation of these contaminations is very difficult, due to the nature of the contamination and the high concentrations present. Chemical oxidation leads to partial removal of highly contaminated soil, therefore chemical oxidation was investigated and optimized aiming at a subsequent bioremediation treatment. Chemical oxidation of cable oil was studied with liquid H2O2 and solid CaO2 as well as permanganate at pH 1.8, 3.0 and 7.5. Liquid H2O2 most effectively removed cable oil at pH 7.5 (24%). At pH 7.5 poor oil removal of below 5% was observed with solid CaO2 and permanganate within 2 d contact time, whereas 18% and 29% was removed at pH 1.8, respectively. A prolonged contact time of 7 d showed an increased oil removal for permanganate to 19%, such improvement was not observed for CaO2.Liquid H2O2 treatment at pH 7.5 was most effective with a low acid use and was best fit to a subsequent bioremediation treatment. To further optimize in situ chemical oxidation with subsequent bioremediation the effect of the addition of the iron catalyst and a stepwise liquid H2O2 addition was performed. Optimization led to a maximum of 46% cable oil removal with 1469 mM of H2O2, and 6.98 mM Fe(II) chelated with citric acid (H2O2:FeSO4 = 210:1 (mol mol−1). The optimum delivery method was a one step addition of the iron catalyst followed by step wise addition of H2O2. 相似文献