【作者】 单良；

【导师】 杨世迎；

【作者基本信息】 中国海洋大学 ， 环境工程， 2011， 硕士

【摘要】 过硫酸盐氧化是新型高级氧化技术（AOPs）,在难降解废水处理方面具有良好的发展前景。印染废水是典型难生化有机废水,且常含有大量氯离子（Cl^-）。Cl^-对AOPs的影响,受到学者们广泛的关注。一般认为,Cl^-在AOPs反应中是一种有效的自由基捕获剂,不利于有机污染物的降解。与基于羟基自由基·OH的AOPs相比,很少有学者关注Cl^-对过硫酸盐高级氧化技术的影响。本文以水中典型的难降解有机物金橙Ⅱ（AO7）和罗丹明B（RhB）为模型污染物,研究了三种过氧化物（过二硫酸盐（PS）、过一硫酸盐（PMS）与过氧化氢（H₂O₂））在紫外光（UV）、热（25 70℃）、金属离子(Fe²⁺)活化条件下降解含Cl^-体系中有机物,并对降解动力学、影响因素进行了研究,同时初步探讨了其反应机理。此外,本文还探讨了含铬盐（Cr（Ⅵ））水中,两步法去除AO7与Cr（Ⅵ）。具体研究内容与结果如下:（1）以PS、PMS、H₂O₂三种常见的过氧化物为氧化剂,以海水作为Cl^-来源,以偶氮染料AO7为模型污染物,对UV活化条件下海水体系中AO7的降解进行了研究,并讨论了海水体系中的起主要降解作用的活性物种。结果表明:在海水体系中,254 nm波长的紫外光可以活化PS、PMS、H₂O₂降解AO7;自由基捕获实验表明PMS可直接被Cl^-活化。254 nm紫外光作用下,AO7在可见区和紫外区的官能团均都被破坏;AO7的降解速率随氧化物浓度增加而加快;海水中常见阴离子(Cl^-、SO₄^2-、HCO₃^-)对AO7的降解过程没有太大的影响。（2）以AO7为目标污染物,对热活化PS降解含Cl^-盐体系中AO7做了初步研究,并探讨了该过程中的起主要降解作用的活性物种。结果表明:在海水体系中,温度高于50℃可活化PS降解AO7,且AO7的降解速率随氧化物浓度增加而加快;自由基俘获实验证明,对AO7降解起主要作用的为SO4-·。（3）以PS、H₂O₂为氧化剂,研究了Fe²⁺活化法,即传统的Fenton法、类Fenton法为技术手段,研究了三种体系（蒸馏水DW、海水NSW、模拟海水SSW）中AO7的降解情况。结果表明:NSW体系中,Fe²⁺对PS几乎没有活化作用;而传统的Fenton法均可降解三种体系中的AO7,AO7降解效果顺序为DW > SSW > NSW;自由基实验表明,在NSW体系中,·OH是类Fenton氧化体系(Fe²⁺活化H₂O₂体系,柠檬酸为螯合剂)的主要活性物质,对AO7的降解起到主导作用。（4）由（1）的研究结果知,Cl^-可直接活化PMS降解AO7。通过比较NaClO、Cl^-/PMS两个氧化体系对阴离子染料AO7和阳离子染料RhB的降解,进一步探讨了Cl^-活化PMS降解有机物的机理。结果表明Cl^-是一种高效活化PMS的方法,可以快速降解AO7及RhB。且Cl^-的浓度对Cl^-活化PMS有影响,其浓度越高,对有机物的降解效果就越好。通过俘获剂实验可知,HClO是Cl^-活化PMS的产物,对有机物的降解起主要作用。（5）有些印染废水中含有Cr（Ⅵ）。以AO7为目标污染物,以PMS及H₂O₂为氧化剂,分两步依次去除水中AO7和Cr（Ⅵ）,即在第一步过程中利用Cr（Ⅵ）活化PMS降解AO7,并使体系的pH降低,从而以H₂O₂为氧化剂进行第二步反应,去除Cr（Ⅵ）。结果发现,Cr（Ⅵ）活化PMS可较快地降解高浓度的AO7（200 500 mg/L）;且随着氧化剂浓度的增大,AO7的降解速率也随之增大。第二步过程中H₂O₂的加入可迅速降低Cr（Ⅵ）的浓度,H₂O₂浓度越大,Cr（Ⅵ）的还原速率也就越快。且H₂O₂的加入可增加AO7在紫外区的降解。更多还原

【Abstract】 Advanced oxidation technologies, in which peroxydisulfate （PS） or peroxymonosulfate （PMS） is used as oxidant, came forth recently for the degradation of non-biodegradable contaminants. In other side, the high saline condition makes printing and dyeing wastewater more difficult to decontaminate. In this study, azo dye Acid Orange 7 （AO7） was chosen as a model contamination to study its degradation rate by heat, UV, or metal activated peroxide oxidation （PS, PMS and H₂O₂） in the solutions containing Cl^-. The influential factor and radical mechanism were also studied. Specific studies are as follows:1) The AO7 degradation rate of UV activated peroxide （PS, PMS and H₂O₂） oxidation in seawater （NSW） was studed. The results indicated that PS, PMS and H₂O₂ can be activated by UV （254 nm） in NSW, but can not be activated under UV （365 nm） except PMS. Moreover, UV activated PS could not only decolorize AO7 in visible spectrum but also in the ultraviolet spectrum.2) High-temperature wastewater constitutes one of the largest groups of organic compounds that represent an increasing environmental danger. The goal of this section is to use the high-temperature wastewater as heat resource to activate PS to degrade contamination in wastewater containing Cl^-. The result indicated that high-temperature can activate PS to degrade AO7. The presence of Cl^- has little effect on the degradation of AO7.3) The aim of this experiment is to study the degradation of AO7 by PS and H₂O₂ under Fe²⁺ activated method. The results showed that AO7 can be degraded in the three systems （distilled water: DW; simulated seawater: SSW; seawater: NSW） by H₂O₂, but can’t be removed by PS in NSW. In Fe²⁺ activated H₂O₂ system, the degradation order is DW > SSW > NSW. The radical quenching experiments demonstrate that·OH plays a dominant role in the Fe²⁺ activated method.4) In this section, the PMS and NaClO were used as oxidants to compare the degradation of AO7 and Rhodamine B （RhB） by Cl^-/PMS and that by NaClO. The results show that Cl^- is an effective activation method. Cl^- activated PS could degrade AO7 rapidly. As the increasing of concentration of Cl^-, the degradation rate increases. The radical quenching experiments demonstrate that HClO plays a dominant role in the degradation of AO7 in Cl^-/PMS system.5) In this section, we have studied the oxidation capacity of the PMS/Cr（Ⅵ） redox system and the removal of Cr（Ⅵ） by 2st-stage which involves the reaction between H₂O₂ and Cr（Ⅵ）. PMS was expected to be activated by Cr（Ⅵ） to degrade AO7 and used to low down the pH value of the solution in the oxidation process since it can dinegative H+. Afterwards, H₂O₂ was then used as a reductant to completely remove Cr（Ⅵ） from solution in the acid entironment benefitting from the 1st-stage. The result indicated that Cr（Ⅵ） can activate PMS and then degrade AO7. The use the acid condition making from the 1st-stage can completely removal Cr（Ⅵ） by H₂O₂ instead of adding other acid.更多还原