非均相臭氧—光催化氧化高盐含氰废水的工艺研究

发布时间：2018-01-06 13:15

  本文关键词：非均相臭氧—光催化氧化高盐含氰废水的工艺研究　出处：《天津大学》2016年博士论文　论文类型：学位论文

  更多相关文章： 氰根 氨氮 臭氧 活性炭 光催化 三相流反应器 氯化钠

【摘要】：含氰、氨氮废水广泛存在于制造业、采矿业和日常生活,排放到水体,会对环境安全和生物生存造成极大危害。本课题以氰化钠-氯气法合成三聚氯氰工艺废水为研究模型,本着 没有不能利用的垃圾,只有放错位置的资源‖的理念,提出了 三聚氯氰-废水处理-氯碱化工‖区域经济耦合构想,使含氰、氨氮的高盐废水经处理后直接用于氯碱化工,氯碱工业的产品又可用作三聚氯氰的原料,实现系统的能量降低和废水零排放。根据实验研究探讨了废弃物的原位处理法,提出氰化物与氨氮分步处理的理念,采用非均相臭氧氧化氰根、非均相光催化降解氨氮及产生的硝酸氮的综合处理方法,对过程的反应器设计、流程设计、操作参数优化、废水处理效果及反应模型展开研究,主要研究成果和结论如下:采用非均相催化臭氧化对废水中CN~-、NH_4~+进行处理,设计了适于过程的三相流反应器,考察了活性炭粒径、活性炭浓度、臭氧浓度、pH值等因素对CN~-、NH_4~+的降解影响,发现活性炭与臭氧有明显的协同效应,协同因子为1.36,当活性炭用量为10g/L,pH=10,混合气体(臭氧/氧气)流量为3.2L/min,臭氧加入量为30mg/min,此时臭氧浓度为9.4mg/L,控制温度30℃时,氰根去除率为99.8%,处理过的水中残余氰含量为0.3mg/L。研究了非均相光催化氧化-还原体系对废水体系的处理效果,为了提高过程还原能力,设计了连续三相流化床光催化反应器,以活性炭为载体,制备了负载型颗粒状AC/TiO_2催化剂,在pH=11,紫外灯功率为12W,空床流速40mL/s,反应温度60℃,停留时间120min时,总氮的去除率达98.02%,剩余总氮量只有0.7mg/L,优于氯碱行业4mg/L的上限。为提高光催化速率及非均相臭氧化过程与光催化过程的相互耦合,在连续三相流化床光催化反应器中,研究了光催化与臭氧的协同效应,协同因子为1.58,当紫外灯功率为12W,AC/TiO_2催化剂投加量10g/L(w(TiO_2)=1.92%),臭氧流量20mg/min,pH值为11,水力停留时间50min时,总氮脱除率在90%以上,残留总氮在2.6~3.3mg/L之间。研究了非均相臭氧-光催化过程的反应机理,明确了活性炭富集体系中的底物,为反应过程提供场所的作用,本文的光催化臭氧化过程是AC/TiO_2吸附臭氧、臭氧直接氧化与紫外光催化臭氧产生·OH自由基和AC/TiO_2激发·OH自由基间接氧化、AC/TiO_2的导带电子还原过氧化产物共同作用的结果。
[Abstract]:Wastewater containing cyanide and ammonia nitrogen is widely used in manufacturing, mining and daily life, and is discharged into water body. It will do great harm to environmental safety and biological survival. This project takes sodium cyanide-chlorine gas synthesis process wastewater as the research model, and there is no waste that can not be used. The concept of regional economic coupling of melamine cyanide-wastewater treatment and chlor-alkali chemical industry is put forward, so that the high-salt wastewater containing cyanide and ammonia nitrogen can be directly used in chlor-alkali chemical industry after treatment. The products of chlor-alkali industry can also be used as raw materials of cyanuric chloride to reduce the energy of the system and zero discharge of waste water. Based on the experimental study, the in-situ treatment method of waste materials is discussed, and the idea of treating cyanide and ammonia nitrogen step by step is put forward. The process reactor design, process design and operation parameters optimization were adopted in this paper, including heterogeneous ozone oxidation, heterogeneous photocatalytic degradation of ammonia nitrogen and nitrate nitrogen. The effect of wastewater treatment and the reaction model were studied. The main results and conclusions were as follows: heterogeneous catalytic ozonation was used to treat CNG-NH _ 4 ~ in wastewater. A three-phase flow reactor suitable for the process was designed. The effects of the particle size of activated carbon, the concentration of activated carbon and the pH value of ozone concentration on the degradation of NH _ 4N _ 4 ~ were investigated. It was found that the synergistic effect of activated carbon and ozone was 1.36. When the amount of activated carbon was 10 g / L ~ (-1) pH ~ (10), the flow rate of mixed gas (ozone / oxygen) was 3.2 L / min. The amount of ozone added is 30 mg / min, and the ozone concentration is 9.4 mg / L, and the removal rate of cyanide is 99.8% when the temperature is 30 鈩，

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