苯胺污染土壤的固化稳定化快速处置技术研究

发布时间：2017-12-28 09:24

本文关键词：苯胺污染土壤的固化稳定化快速处置技术研究　出处：《中国海洋大学》2015年硕士论文　论文类型：学位论文

【摘要】：突发性化学污染事故频率高、影响大,所涉及的污染物浓度高、毒性强,对环境安全和人体健康都存在严重威胁。苯胺是一种重要的有机化工原料和化工产品,具有致癌、致畸、致突变性。由于固化稳定化能够有效处理污染土壤,但在有机污染土壤领域的应用仍存在一定局限性,因此本课题将氧化降解与固化稳定化技术相结合,针对突发性化学污染事故造成的高浓度苯胺污染土壤开展了快速、高效的处置技术研究。本课题采用水泥为固化剂,过硫酸钾为氧化剂,活性炭为吸附剂,对苯胺污染土壤的固化稳定化处理进行试验研究,并对固化产物的特性进行观察分析,探讨不同的药剂添加配比对苯胺固定效果的影响,以及对固化体的微观形貌的影响。试验首先研究了不同的反应温度、氧化剂浓度、初始pH条件下,过硫酸钾氧化降解苯胺的效果。结果表明,随温度升高、过硫酸钾浓度增加,苯胺的降解率也相应提高,当反应温度为40℃,过硫酸钾与苯胺的摩尔比为100,初始pH为5～11时,水中苯胺的降解效果最佳,150 min后降解率可达94.1%。试验进一步研究了过硫酸钾对于土壤中苯胺污染物降解去除的适用性。结果表明,过硫酸钾能够有效降解土壤中的苯胺,在40℃条件下,过硫酸钾与苯胺的摩尔比为100时,苯胺的降解率达到98.6%,反应过程较水溶液中进行得更快,且适用于不同pH的土壤环境中。研究了基于过硫酸钾的高级氧化技术、基于活性炭的吸附作用以及水泥基固化稳定化技术相结合条件下对苯胺污染土壤的处理效果。探索了不同的水泥添加量对污染物固定效果的影响,随着水泥添加量的增大,固定率越来越高,水泥的添加量为30%(占污染土壤的质量比)是固化苯胺污染土壤的最佳配比,对于较低浓度(以50 mg/kg为代表)的苯胺污染土壤,仅使用水泥进行固化处置即可达到环境要求。探索了土壤中污染物浓度对固化效果的影响,在水泥的添加量一定时,随着苯胺浓度的增加,固定效果越来越差。通过向其中添加活性炭可降低浸出液中苯胺的含量,固定率随活性炭添加量的增大而提高,对于2000 mg/kg苯胺污染土壤,添加5.0%活性炭(占污染土壤的质量比)和30%水泥,则可满足固定率达到90%以上的要求。对于高浓度苯胺污染物,需要向其中同时添加过硫酸钾和活性炭方可达到较好的固定效果。实验配制苯胺浓度为10000 mg/kg的模拟污染土壤,当添加剂投加量分别为水泥30%,活性炭5.O%,过硫酸钾14.5%时,对于目标污染物的处置效果较好,固定率达到94.07%。观察分析了固化体的微观形貌,固化体中发生了明显的水化反应,且污染土壤与干净土壤在不同的添加剂配比条件下化学成分基本一致;虽然有机物苯胺的存在不利于水泥的水化反应过程,固化体中颗粒细小而分散,但通过添加活性炭和过硫酸钾减小了这种影响,养护完成后的固化体表面基本无裂缝,结构致密。
[Abstract]:The sudden chemical pollution accidents have high frequency and great influence, and the concentration of pollutants is high and the toxicity is strong, and there are serious threats to environmental safety and human health. Aniline is an important organic chemical raw material and chemical product. It has carcinogenic, teratogenic and mutagenicity. Because of solidification and stabilization can effectively deal with the pollution of soil, but the application in the field of organic contaminated soil still has some limitations, so this issue will be oxidative degradation and solidification and stabilization technology combined with high concentration of aniline polluted soil resulting in sudden chemical accident to carry out the research of fast and efficient disposal technology. This paper uses cement as curing agent and potassium persulfate as oxidant, activated carbon as adsorbent, solidification and stabilization of aniline polluted soil were studied, and the properties of the cured product were analyzed, to explore the different effects of reagent addition ratio of aniline fixed effect, and the influence of microstructure on the solidified body the. The effect of oxidation degradation of aniline by potassium persulfate under different reaction temperature, oxidant concentration and initial pH condition was first studied. The results showed that the degradation rate of aniline increased with the increase of temperature and the concentration of potassium persulfate. When the reaction temperature was 40 degrees, the molar ratio of potassium persulfate to aniline was 100, and the initial pH was 5~11, the degradation effect of aniline in water was the best, and the degradation rate after 150 min could reach 94.1%. The applicability of potassium persulfate for degradation of aniline pollutants in soil was further studied. The results show that potassium persulfate can effectively degrade aniline in soil. When the molar ratio of potassium persulfate to aniline is 100 at 40 degree, the degradation rate of aniline is 98.6%, the reaction process is faster than that in aqueous solution, and it is suitable for different pH soil environments. The effects of advanced oxidation technology based on potassium persulfate, adsorption based on activated carbon and cement based solidification stabilization technology on aniline contaminated soil were studied. To explore the different cement additives on the pollutant fixed effect, with the increase of amount of cement, the fixed rate is more and more high, add the amount of cement is 30% (the quality of contaminated soil than) is the best curing ratio of aniline polluted soil, for low concentration (50 mg/kg) aniline pollution the soil solidified disposal can reach environmental requirements using only cement. The effect of the concentration of pollutants in the soil on the curing effect was explored. With the increase of the content of the cement, the fixing effect was worse and worse with the increase of the concentration of aniline. By adding activated carbon into which can reduce the content of aniline in the leaching solution, the amount of fixed rate increases with the addition of activated carbon for 2000 mg/kg aniline contaminated soil, adding 5% activated carbon (the quality of contaminated soil and cement ratio) 30%, can meet the requirements of the fixed rate reached more than 90%. For high concentration of aniline, potassium persulfate and activated carbon should be added to the high concentration of aniline at the same time. The simulated contaminated soil with aniline concentration of 10000 mg/kg was prepared. When the dosage of additives was cement 30%, activated carbon 5.O% and potassium persulfate 14.5%, the disposal effect of target pollutants was good, and the fixation rate reached 94.07%. To observe and analyze the microstructure of solidified body, the hydration reaction was solidified, and the chemical components of polluted soil and clean soil additive ratio in different conditions are basically the same; although organic aniline is not conducive to the existence of the hydration process of cement, fine particles solidified and dispersed, but by adding activated carbon and potassium persulfate to reduce this effect, the solidified surface maintenance after the completion of the basic crack free and dense structure.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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