Abstract:Using the three oxidation systems including Fenton (Fe2+/H2O2), ferrous ion activated sodium persulfate (Fe2+/PS) and alkali activated sodium persulfate (NaOH/PS) to treat the typical pollutant chlorobenzene (CB), we found there were big differences in the amount of p-chlorophenol intermediate (4-CP) produced during the oxidation of CB by the three oxidation systems. The effect of the oxidant dosage on the degradation of CB and its intermediate 4-CP by three oxidation systems was studied, and CB mineralization was characterized by the changes of the total organic carbon and free chloride concentration. The results showed that lots of stable 4-CP intermediates were produced in the oxidation systems of Fe2+/H2O2 or Fe2+/PS when the concentrations of H2O2 or PS were less than 1 mmol·L?1 and 5 mmol·L?1, respectively. While at the overdoses of H2O2 or PS, 4-CP could be further oxidized and decomposed. Being different from Fe2+/H2O2 and Fe2+/PS systems, NaOH/PS system oxidation did not lead to the yield of 4-CP intermediate. Being different from the oxidation process of Fe2+/PS system, the dechlorination reaction occurred during CB oxidation by NaOH/PS and Fe2+/H2O2 systems. In addition, the verification experiment of groundwater in the actual contaminated site showed that NaOH/PS was suitable for CB removal in the remediation process, and PS addition in batches for stepwise oxidation CB could achieve a high degradation efficiency of CB pollutants and avoid the generation of harmful intermediate of 4-CP. Key words:groundwater in contaminated sites/ advanced oxidation/ chlorobenzene/ p-chlorophenol.
图13种氧化体系降解CB前后中间体产物的GC-MS谱图 Figure1.GC-MS spectra of intermediates before and after CB degradation by three oxidation systems
图3Fe2+/H2O2、Fe2+/PS体系中氧化剂与CB不同摩尔比下4-CP的浓度变化 Figure3.Concentration changes of 4-CP at different mole ratios of oxidant to CB in Fe2+/PS and Fe2+/H2O2 system
图10一步法与分批次添加NaOH、PS对实际污染地下水中CB降解率的影响 Figure10.Effects of one step method and batch addition of NaOH and PS on CB degradation in polluted underground water
SONG, WANG F, BIAN Y, et al. Chlorobenzenes and organochlorinated pesticides in vegetable soils from an industrial site, China[J]. Journal of Environmental Science, 2012, 24(3): 362-368. doi: 10.1016/S1001-0742(11)60720-1
HICHAM Z, NIHAL O, MUTLU S, et al. Mineralization of chlorobenzene in aqueous medium by anodic oxidation and electro-Fenton processes using Pt or BDD anode and carbon felt cathode[J]. Journal of Electroanalytical Chemistry, 2016, 774: 22-30. doi: 10.1016/j.jelechem.2016.04.051
[8]
JIANG F C, LI Y L, ZHOU W, et al. Enhanced degradation of monochlorobenzene in groundwater by ferrous iron/persulfate process with cysteine[J]. Chemical Engineering Journal, 2020, 387: 124048.
[9]
OUYANG Y, XU Q, XIANG Y, et al. Degradation of simulated organic wastewater by advanced oxidation with oxidants generated from oxygen reduction[J]. Chinese Journal of Chemical Engineering, 2019, 27: 850-856. doi: 10.1016/j.cjche.2018.07.004
[10]
ZHANG S, HU X B, LI L, et al. Activation of sodium percarbonate with ferrous ions for degradation of chlorobenzene in aqueous solution: Mechanism, pathway and comparison with hydrogen peroxide[J]. Environmental Chemistry, 2018, 14(8): 486-494.
[11]
SEDLAK D L, ANDREN A W. Oxidation of chlorobenzene with Fenton’s reagent[J]. Environmental Science & Technology, 1991, 25(4): 777-782.
[12]
SAI Z, XUEBIN H, LI L, et al. Activation of sodium percarbonate with ferrous ions for degradation of chlorobenzene in aqueous solution: Mechanism, pathway and comparison with hydrogen peroxide[J]. Environmental Chemistry, 2018, 14(8): 486-494.
[13]
CARMEN S, YIM B, VINATORU M, et al. Sonolysis of chlorobenzene in Fenton-type aqueous systems[J]. Ultrasonics Sonochemistry, 2002, 9(6): 291-296. doi: 10.1016/S1350-4177(02)00088-3
[14]
WU Y, ZHANG Y C, ZHAO Y Y, et al. A DFT study on the degradation of chlorobenzene to p-chlorophenol via stable hydroxo intermediate promoted by iron and manganese monoxides[J]. Journal of Physical Chemistry & Biophysics, 2015, 5: 6.
[15]
HIGGINS B, THOMSON M J, LUCAS D, et al. An experimental and numerical study of the thermal oxidation of chlorobenzene[J]. Chemosphere, 2001, 42(5/6/7): 703-717. doi: 10.1016/S0045-6535(00)00245-9
[16]
HOFMANN J, FREIER U, WECKS M, et al. Degradation of halogenated organic compounds in ground water by heterogeneous catalytic oxidation with hydrogen peroxide[J]. Topics in Catalysis, 2005, 33(1/2/3/4): 243-247. doi: 10.1007/s11244-005-2538-9
YAN J, LEI M, ZHU L, et al. Degradation of sulfamonomethoxine with Fe3O4 magnetic nanoparticles as heterogeneous activator of persulfate[J]. Journal of Hazardous Materials, 2011, 186(2/3): 1398-1404.
[21]
FURMAN O S, TEEL A L, WATTS R J. Mechanism of base activation of persulfate[J]. Environmental Science & Technology, 2010, 44(16): 6423-6428.
[22]
TANG L, LIU Y, WANG J, et al. Enhanced activation process of persulfate by mesoporous carbon for degradation of aqueous organic pollutants: electron transfer mechanism[J]. Applied Catalysis B: Environmental, 2018, 231: 1-10. doi: 10.1016/j.apcatb.2018.02.059
LIU B, LIU Z, YU P, et al. Enhanced removal of tris(2-chloroethyl) phosphate using a resin-based nanocomposite hydrated iron oxide through a Fenton-like process: Capacity evaluation and pathways[J]. Water Research, 2020, 175: 115655. doi: 10.1016/j.watres.2020.115655
[25]
SERPONE N, TERZIAN R, HIDAKA H, et al. Ultrasonic induced dehalogenation and oxidation of 2-, 3-, and 4-chlorophenol in air-equilibrated aqueous media. Similarities with irradiated semiconductor particulates[J]. Journal of Physical Chemistry, 1994, 98(10): 2634-2640. doi: 10.1021/j100061a021
[26]
DRIJVERS D, LANGENHOVE H V, VERVAET K. Sonolysis of chlorobenzene in aqueous solution: Organic intermediates[J]. Ultrasonics Sonochemistry, 1998, 5(1): 13-19. doi: 10.1016/S1350-4177(98)00006-6
[27]
CAO J, ZHANG W X, BROWN D G, et al. Oxidation of lindane with Fe(II)-activated sodium persulfate[J]. Environmental Engineering Science, 2008, 25(2): 221-228. doi: 10.1089/ees.2006.0244
[28]
LIANG C, WANG Z S, BRUELL C J. Influence of pH on persulfate oxidation of TCE at ambient temperatures[J]. Chemosphere, 2007, 66(1): 106-113. doi: 10.1016/j.chemosphere.2006.05.026
[29]
FURMAN O S, TEEL A L, WATTS R J. Mechanism of base activation of persulfate[J]. Environmental Science & Technology, 2010, 44(16): 6423-6428.
[30]
MUNOZ M, PEDRO Z M D, CASAS J A, et al. Assessment of the generation of chlorinated byproducts upon Fenton-like oxidation of chlorophenols at different conditions[J]. Journal of Hazardous Materials, 2011, 190(1/2/3): 993-1000.
Everbright Environmental Remediation(Jiangsu)Limited, Nanjing 211100, China Received Date: 2020-08-11 Accepted Date: 2020-11-06 Available Online: 2021-03-24 Keywords:groundwater in contaminated sites/ advanced oxidation/ chlorobenzene/ p-chlorophenol Abstract:Using the three oxidation systems including Fenton (Fe2+/H2O2), ferrous ion activated sodium persulfate (Fe2+/PS) and alkali activated sodium persulfate (NaOH/PS) to treat the typical pollutant chlorobenzene (CB), we found there were big differences in the amount of p-chlorophenol intermediate (4-CP) produced during the oxidation of CB by the three oxidation systems. The effect of the oxidant dosage on the degradation of CB and its intermediate 4-CP by three oxidation systems was studied, and CB mineralization was characterized by the changes of the total organic carbon and free chloride concentration. The results showed that lots of stable 4-CP intermediates were produced in the oxidation systems of Fe2+/H2O2 or Fe2+/PS when the concentrations of H2O2 or PS were less than 1 mmol·L?1 and 5 mmol·L?1, respectively. While at the overdoses of H2O2 or PS, 4-CP could be further oxidized and decomposed. Being different from Fe2+/H2O2 and Fe2+/PS systems, NaOH/PS system oxidation did not lead to the yield of 4-CP intermediate. Being different from the oxidation process of Fe2+/PS system, the dechlorination reaction occurred during CB oxidation by NaOH/PS and Fe2+/H2O2 systems. In addition, the verification experiment of groundwater in the actual contaminated site showed that NaOH/PS was suitable for CB removal in the remediation process, and PS addition in batches for stepwise oxidation CB could achieve a high degradation efficiency of CB pollutants and avoid the generation of harmful intermediate of 4-CP.