摘要
本文研究了不同pH条件下高锰酸钾/亚硫酸氢钠(PM/BS)对农药嗪草酮(MET)的氧化降解,预氧化后续氯化过程中消毒副产物(DBPs)的变化和毒性评估,同时高锰酸钾(PM)氧化作为对照组.研究表明,PM/BS预氧化较PM预氧化能加大污染物质MET的降解效率,两种预氧化过程中MET的降解率在酸性条件下最大且随着pH的升高而降低,DBPs的生成量和毒性都随着pH的升高而增大.碱性条件下降解率低却生成了大量的二氯乙腈,导致DBPs的生成量和毒性大幅增加,值得引起重视和注意,本文对此种现象产生的原因进行了详细探讨.PM/BS系统降解污染物需要控制在酸性条件下进行,既能增大降解效率,又能降低DBPs的毒性.
This paper investigated the effects of potassium permanganate/sodium bisulfite(PM/BS) on the degradation of pesticide metribuzin(MET) under different pH conditions, and the changes and toxicity evaluation of disinfection by-products(DBPs) during oxidation and subsequent chlorination. At the same time, potassium permanganate(PM) was used as a control group. Results showed that PM/BS pre-oxidation increased the degradation efficiency of MET compared with PM pre-oxidation. In the two pre-oxidation processes, the degradation efficiency of MET was the largest under acidic conditions and decreased with the increase of pH, while the formation potential and toxicity of DBPs increased with the increase of pH. It is worth noting that the degradation efficiency under alkaline conditions was low, and a large amount of dichloroacetonitrile was formed, which leads to a large increase in the formation potential and toxicity of DBPs. The reasons for this phenomenon were discussed in detail. Finally, it was concluded that the degradation of pollutants in the PM/BS system needs to be controlled under acidic conditions, which can increase the degradation efficiency and reduce the toxicity of DBPs.
引文
[1] BOUCHONNET S,BOURCIER S,SOUISSI Y,et al.GC-MSn and LC-MS/MS couplings for the identification of degradation products resulting from the ozonation treatment of Acetochlor[J].Journal of Mass Spectrometry,2012,47(4):439-452.
[2] HENRIKSEN T,SVENSMARK B,JUHLER R K.Analysis of metribuzin and transformation products in soil by pressurized liquid extraction and liquid chromatographic-tandem mass spectrometry[J].Journal of Chromatography A,2002,957(1):79-87.
[3] MALOSCHIK E,ERNST A,HEGEDUS G,et al.Monitoring water-polluting pesticides in Hungary[J].Microchemical Journal,2007,85(1):88-97.
[4] PETRI B G,THOMSON N R,URNOWICZ M A.Fundamentals of ISCO using permanganate[M]//In Situ Chemical Oxidation for Groundwater Remediation[M].New York:Springer,2011:89-146.
[5] GUAN X,HE D,MA J,et al.Application of permanganate in the oxidation of micro-pollutants:A mini review[J].Frontiers of Environmental Science & Engineering in China,2010,4(4):405-413.
[6] 孙波.NaHSO3活化KMnO4快速氧化水中微量有机污染物的效能与机理[D].哈尔滨:哈尔滨工业大学,2017.SUN B.Kinetics and mechanisms on the fast degradation of Micro-Organic contaminants by bisulfite activated permanganate[D].Harbin:Harbin Institute of Technology,2017 (in Chinese).
[7] SUN B,GUAN X H,FANG J Y,et al.Activation of manganese oxidants with bisulfite for enhanced oxidation of organic contaminants:The involvement of Mn(Ⅲ) [J].Environmental Science Technology 2015,49:12414-12421.
[8] GAO Y,JIANG J,ZHOU Y,et al.Does soluble Mn (Ⅲ) oxidant formed in situ account for enhanced transformation of triclosan by Mn (Ⅶ) in the presence of ligands[J].Environmental Science & Technology,2018,52(8):4785-4793.
[9] GAO Y,JIANG J,ZHOU Y,et al.Unrecognized role of bisulfite as Mn (Ⅲ) stabilizing agent in activating permanganate (Mn (Ⅶ)) for enhanced degradation of organic contaminants [J].Chemical Engineering Journal,2017,327:418-422.
[10] TARTAR H V,GARRETSON H H.The thermodynamic ionization constants of sulfurous acid at 25 ℃[J].Journal of the American Chemical Society,1941,63(3):808-816.
[11] LIU C,ZHAO M,HE S,et al.Activation of permanganate with hydrogen sulfite for enhanced oxidation of a typical amino acid[J].Environmental Technology,doi:10.1080/09593330.2018.1426644.
[12] WANG A Q,LIN Y L,XU B,et al.Degradation of acrylamide during chlorination as a precursor of haloacetonitriles and haloacetamides[J].Science of the Total Environment,2018,615:38-46.
[13] FANG J,MA J,YANG X,et al.Formation of carbonaceous and nitrogenous disinfection by-products from the chlorination of Microcystis aeruginosa[J].Water Research,2010,44(6):1934-1940.
[14] DING S,CHU W,BOND T,et al.Formation and estimated toxicity of trihalomethanes,haloacetonitriles,and haloacetamides from the chlor (am) ination of acetaminophen [J].Journal of Hazardous Materials,2018,341:112-119.
[15] YU Y,RECKHOW D A.Kinetic analysis of haloacetonitrile stability in drinking waters [J].Environmental Science & Technology,2015,49(18):11028-11036.
[16] ANTONOPOULOU M.,KONSTANTINOU I.Photocatalytic treatment of metribuzin herbicide over TiO2aqueoussuspensions:Removal efficiency,identification of transformation products,reaction pathways and ecotoxicity evaluation [J].Journal of Photochemistry and Photobiology A:Chemistry ,2014,294:110-120.
[17] KRASNER S W,WEINBERG H S,RICHARDSON S D,et al.Occurrence of a new generation of disinfection byproducts[J].Environmental Science & Technology,2006,40(23):7175-7185.
[18] PLEWA M J.Charting a new path to resolve the adverse health effects of DBPs//Abstracts of papers of the american chemical society[C].1155 16TH ST,NW,WASHINGTON,DC 20036 USA:AMER CHEMICAL SOC,2014,248.
[19] PLEWA M J,WAGNER E D,MUELLNER M G,et al.Comparative mammalian cell toxicity of N-DBPs and C-DBPs[J].Urbana,2008,51:36-50.
[20] HU J,CHU W,SUI M,et al.Comparison of drinking water treatment processes combinations for the minimization of subsequent disinfection by-products formation during chlorination and chloramination[J].Chemical Engineering Journal,2018,335:352-361.