【作者】 刘玥；

【导师】 陈忠林；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2011， 博士

【摘要】 常规的饮用水处理工艺对水体中有机污染物的去除效果甚微。目前国内外虽然已经采取一些强化去除技术去除水体中的有机污染物,如吸附技术、膜分离技术、生物强化技术和零价金属还原技术等,这些技术的去除能力通常比较弱、工艺造价比较高。因此寻找一种新型的处理技术去除水体中的有机污染物是十分必要的。论文以实验室制备的四种金属硅酸盐作为催化剂,分别对它们的物理性质和表面性质进行了表征。在实验室静态实验和连续流实验等不同工艺条件下,分别考察了四种催化剂催化臭氧氧化去除模拟水体中痕量氯代硝基苯（Chloronitrobenzenes）的催化活性,筛选出催化活性最高的催化剂,并对其在不同工艺条件下催化臭氧氧化水体中痕量氯代硝基苯的活性进行了详细的研究;并考察了该催化剂催化臭氧氧化的机理。实验室成功的制备了硅酸铁、硅酸锰、硅酸铜和硅酸锌四种金属硅酸盐。四种硅酸盐材料结构中包含了很多纳米级的氧化物颗粒。通过检测发现四种催化剂对气体均具有一定的吸附能力和容量,其中硅酸锌的吸附能力最大,依次为硅酸铁、硅酸锰和硅酸铜。四种催化剂表面均含有大量的表面羟基和吸附水,其中硅酸锌表面羟基密度最大,四种催化剂的零电荷电位均在中性范围内。无论在去离子水模拟配水的静态实验中,还是在自来水模拟配水的连续流实验中,硅酸铁、硅酸锰、硅酸铜和硅酸锌均具有良好的催化活性,其中硅酸锌的催化活性最高,反应1min可以使CNBs的去除率达到90%以上。四种催化剂对氯代硝基苯的吸附去除能力均较差,吸附24 h后,硅酸锰和硅酸铜对氯代硝基苯没有任何去除效果,硅酸铁对氯代硝基苯的去除效果为9%,硅酸锌的吸附去除效果为15%。四种催化剂的酸碱稳定性均较好。分别研究了硅酸锌在静态实验（去离子水模拟配水）和连续流实验（自来水模拟配水）中催化臭氧氧化水中氯代硝基苯的效能和反应过程的影响因素。结果表明,无论在静态实验或者连续流实验中,氯代硝基苯的去除率均随着臭氧浓度和催化剂投加量的增加而增大;在静态实验中,在臭氧投加量为0.8 mg/L时、硅酸锌投加量为300 mg/L时,反应体系对初始浓度为200μg/L的氯代硝基苯的去除率最高,反应15min后,硝基氯苯的去除率达到99%以上;而在连续流实验中,在臭氧化气体浓度为3.2 mg/L、气体流速0.4 L/min时,硅酸锌催化臭氧氧化对初始浓度50μg/L的氯代硝基苯的去除率最高,在水力停留时间为20 min时,可以使硝基氯苯的去除率达到85%以上;随着水体背景趋于复杂,催化剂促进氯代硝基苯降解的能力均显著下降;水体中Ca²⁺、Mg²⁺、Na⁺、K⁺和NO3-对硅酸锌催化臭氧氧化去除氯代硝基苯有微弱的影响,能够使硝基氯苯的去除率降低10%左右;水中无机阴离子对硅酸锌催化臭氧氧化降解氯代硝基苯的效果有不同程度的影响,其中,氯离子和磷酸根离子对硅酸锌臭氧氧化去除氯代硝基苯的抑制作用明显,可以使硝基氯苯的去除率降低60%左右;HCO₃^-离子浓度和腐植酸含量对催化臭氧氧化去除氯代硝基苯均有影响,但与静态实验（去离子水模拟配水）相比,连续流实验（自来水模拟配水）中氯代硝基苯的去除率受HCO₃^-和腐植酸浓度的影响较小可以忽略不计;随着硅酸锌烘制温度的升高,催化剂的催化活性不断下降;硅酸锌在多次连续使用后仍可保持较高的催化活性。通过自由基抑制实验和电子自旋共振（ESR）分析,证明羟基自由基是硅酸锌催化臭氧氧化氯代硝基苯过程中产生的重要活性物种。溶液pH值对硅酸锌催化臭氧氧化过程的影响证明,硅酸锌表面的羟基能够加速臭氧分解产生羟基自由基。络合性无机阴离子对硅酸锌催化臭氧氧化过程的影响进一步证明,在硅酸锌催化臭氧氧化过程中表面羟基起着非常重要的作用。对硅酸锌中主要成分的催化性能进行了对比研究,认为硅酸锌中的ZnO和Zn-O-Si络合体在催化臭氧氧化去除氯代硝基苯的过程中起着重要的作用。更多还原

【Abstract】 In the traditional water treatment process, the trace organic pollutants in aqueous solution is difficult to be removed. Many strategies such as, adsorption, membrane seperation, bioaugmentation, zero-valent metal reduction and so on, have been carried out to solve the pollutants problem in aqueous solution. However, many drawbacks of these strategies such as low removal efficiency, high cost, make them difficult to be utilized in the practical water treatment. So, exploring new strategy in drinking water treatment to resolve trace organic pollutants problem in aqueous solution is necessary.Four kinds of common transitional metal silicate, prepared in laboratory, were used in the paper as ozone catalyst. Physical structure and surface properties of the four kinds of catalysts were characterized in the study. Static experiments and continuous flow experiments were conduct to study the catalytic activity of the four kinds of catalysts for ozonation of chloronitrobenzenes （CNBs）. Then, the highest catalytic activity catalyst was used to study the catalytic properties in the catalytic oxidation of CNBs in aqueous solution.The catalysts prepared in the laboratory were iron silicate, manganese silicate, copper silicate and zinc silicate. TEM analysis shown that all of them contain many nano-sized oxide. Most materials have certain ability and capacity for the adsorption of gas, moreover, zinc silicate have the maximum adsorption capacity, followed by iron silicate, manganese silicate and copper silicate. FTIR analysis results shown that, hydroxyl groups was the mainly functional groups on the surface of the four catalysts. Zinc silicate has the maximum hydroxyl density. In addition, the zero charge of four catalysts are in the neutral range.Iron silicate, manganese silicate, zinc silicate, copper silicate exhibited good catalytic activity in the continuous flow experiments and static experiments. However, no matter in what process, the zinc silicate also exhibited highest catalytic activity. The adsorption capacity of four catalysts were very poor. After 24h adsorption, the CNBs removal efficiency were less than 5%. The pH stability of the four catalysts was well.The efficiency and affecting factors of zinc silicate catalytic ozonation of CNBs were studied in the preocesses of static experiments and continuous flow experiments, respectively. Experiment results showed that no matter in what process, the removal of CNBs increased with the increasing of initial concentration of ozone, catalyst dosage, water purity. In the static experiments, under the condition of ozone dosage 0.8mg/L, zinc silicate dosage 300mg/L, the initial concentration of CNBs was 200μg/L, the removal efficiency of CNBs in deionized water was best. However, in the continuous flow experiments, when the initial concentration of CNBs was 50μg/L, the removal efficiency of CNBs in tap water was best.Effect of Ca²⁺、Mg²⁺、Na⁺、K⁺ and NO3-on the catalytic ozonation of CNBs were very less. The removal efficiency of CNBs was decreased with the increase of the Cl- and PO43-. The ozonation of CNBs were slightly inhibited by the SO42-. For the HCO₃^- was the hydroxyl inhibitors, so in aqueous solution, it could inhibit the zinc silicate catalytic ozonation of CNBs. The ramoval efficiency of CNBs increased with the decrease concentration of humic acid, moreover, compared the process of static experiments in deionized water, the effect of HCO₃^- and humic acid were much less in the process of continuous flow experiments in tap water. With the increasing of the calcinated temperature, the catalytic activity of zinc silicate get weaker. After successive recycles, the catalytic activity of the zinc silicate kept stable.The mechanism of zinc silicate catalyzed ozonation of CNBs were carried out. Based on the tert-butanol inhibition test and ESR analysis, we conclused that in the process of zinc silicate catalytic oznation ,·OH was the activity species . The effect of anions concentration and solution pH on the catalytic ozonation confirmed that in the zinc silicate catalyzed ozonation of CNBs, hydroxyal groups which were on the surface of zinc silicate were the activity site.更多还原