过硫酸盐缓释材料降解水溶液中四氯乙烯的效果
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摘要
为提高过硫酸盐原位氧化工艺中使用的氧化剂的传输效率,制备基于水泥的过硫酸盐缓释材料,利用其降解水溶液中的四氯乙烯(PCE),考察缓释材料的氧化剂释放能力、地下水水质对PCE降解的影响以及缓释材料的循环利用效果。结果表明,试验条件下过硫酸盐缓释材料在水溶液中能够释放42.5~57.6 g/L的过硫酸盐,且溶液p H值维持在13左右,保证了碱活化过硫酸盐的反应条件。水溶液中PCE降解符合准一级动力学方程,24 h内PCE基本完全降解,反应液中加入阴离子或腐植酸均会产生抑制作用,其中阴离子抑制程度为Cl~->HCO_3~->SO_4~(2-)>NO_3~-。缓释材料循环利用3次仍能够有效降解溶液中的PCE。
In order to improve transport efficiency of oxidant during in-situ persuflate oxidation process, slow-releasing persulfate material based on cement was prepared and used for perchloroethylene(PCE) degradation. In this study, performance of persulfate release and PCE degradation, effect of solution matrix, and recycling performance of the material were investigated. The results showed that released persulfate concentration was 42.5~57.6 g/L under experimental conditions, and solution p H value was kept around 13, which was beneficial for alkaline activation of persulfate. Degradation performance of PCE was fitted with a pseudo-first-order kinetic model,and PCE could be completely removed during 24 h. Anions and humic acid had negative effects on PCE degradation, and inhibition order was Cl~-> HCO_3~->SO_4~(2-)>NO_3~-. In addition, PCE could be efficiently degraded during 3 times' recycle of slow-releasing material.
In order to improve transport efficiency of oxidant during in-situ persuflate oxidation process, slow-releasing persulfate material based on cement was prepared and used for perchloroethylene(PCE) degradation. In this study, performance of persulfate release and PCE degradation, effect of solution matrix, and recycling performance of the material were investigated. The results showed that released persulfate concentration was 42.5~57.6 g/L under experimental conditions, and solution p H value was kept around 13, which was beneficial for alkaline activation of persulfate. Degradation performance of PCE was fitted with a pseudo-first-order kinetic model,and PCE could be completely removed during 24 h. Anions and humic acid had negative effects on PCE degradation, and inhibition order was Cl~-> HCO_3~->SO_4~(2-)>NO_3~-. In addition, PCE could be efficiently degraded during 3 times' recycle of slow-releasing material.
引文
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[8]LIANG C,SU H W.Identification of sulfate and hydroxyl radicals in thermally activated persulfate[J].Industrial&Engineering Chemistry Research,2009,48(11):5558-5562.
[2]于颖,周启星.污染土壤化学修复技术研究与进展[J].环境污染治理技术与设备,2005,6(7):1-7.
[3]龙安华,雷洋,张晖.活化过硫酸盐原位化学氧化修复有机污染土壤和地下水[J].化学进展,2014,26(5):898-908.
[4]TSITONAKI A,PETRI B,CRIMI M,et al.In situ chemical oxidation of contaminated soil and groundwater using persulfate:A review[J].Critical Reviews in Environmental Science and Technology,2010,40(1):55-91.
[5]FURMAN O S,TEEL A L,WATTS R J.Mechanism of base activation of persulfate[J].Environmental Science&Technology,2010,44(16):6423-6428.
[6]KAMBHU A,COMFORT S,CHOKEJAROENRAT C,et al.Developing slow-release persulfate candles to treat btex contaminated groundwater[J].Chemosphere,2012,89(6):656-664.
[7]陈方义,安达,杨昱,等.过硫酸盐缓释材料释放过程模型构建[J].环境工程学报,2015(1):7-13.
[8]LIANG C,SU H W.Identification of sulfate and hydroxyl radicals in thermally activated persulfate[J].Industrial&Engineering Chemistry Research,2009,48(11):5558-5562.