常压下吹脱法与气相氨催化氧化法串联处理高浓度氨氮废水的研究

【作者】 李晟；

【导师】 陈建中；

【作者基本信息】 昆明理工大学 ， 环境工程， 2004， 硕士

【摘要】 氨氮是水体中的重要耗氧污染物，是造成富营养化的重要原因之一。随着工农业的迅速发展，氨氮的来源越来越广泛，排放量越来越大，除了生活污水、动物排泄物外，还有大量的工业废水，如氨加工废水、合金废水、炼油废水，以及垃圾渗滤液。工业对高浓度氨氮废水排放的贡献最大，而工业高浓度氨氮废水的治理是目前国内水处理领域的难题。因此，寻找经济有效的治理高浓度氨氮废水的技术成为环境工作者的重大研究课题。 本文研究以吹脱法为基础，采用了气相氨催化氧化法作为后序处理方法，将吹脱出的氨加以氧化。实验方法为常压下将废水中的NH₃从液相吹脱至气相，以空气为载气及氧化剂，在催化剂作用下和一定的温度范围内将NH₃氧化，可能生成的氧化产物有NO_x、N₂、H₂O、肼等，通过温度控制使氧化产物主要为N₂和H₂O。实验的氨氮废水浓度为人工调配的1024mg／L。所用的四种催化剂按混合法和沉淀法制成，活性组分和助剂负载量分别为30％和50％。 通过实验发现：①在空气流量≤2L／min、pH=14、水温98℃条件下，从1024mg／L的氨氮废水中吹脱出的NH₃的体积和浓度可视为定量。②沉淀法制备的负载量为50％的催化剂活性最高、反应温度最低、N₂生成选择性较好。其最佳反应温度是500℃，填装量10ml时的最佳空速为6000h^-1。③以该催化剂在最佳反应条件下处理1024mg／L的氨氮废水，经120min反应后废水中的NH₃-N浓度降为34mg／L，去除率为96.7％；气相NH₃转化率为95.7％，残余NH₃浓度为139ppm，产生的NO的浓度为360ppm，推算出N₂的生成率约为88.4％。④气相氨催化氧化反应遵循SCR机理，符合一级反应的特征，受化学动力学的控制。 本论文研究的目的在于尝试一种新方法用于处理高浓度工业氨氮废水，探讨其可行性、反应机理和反应动力学，为今后更深入的研究奠定基础。更多还原

【Abstract】 Ammonia nitrogen is one of the important oxide consumable pollutants in water, and one of the key reasons of eutrophication. With the agriculture and industry development, the pollution sources of wastewater containing ammonia nitrogen become more and more comprehensive, and does the amount of discharge, which are from all types of industrial wastewaters, such as, ammonia machining plant, metallurgical plant and petroleum refinery plant wastewater and landfill leachate, besides domestic wastewater and animal excrement. The most important source of wastewater with high concentration of ammonia nitrogen is the industry. However, how to deal with this wastewater is a puzzle in China’s wastewater-control field. Therefore, seeking the effective and economical method to dispose it is an important task for environment researchers.In this thesis, based on the stripping method, the author adopts gaseous catalytic oxidation to remove ammonia as the following process. Firstly, in this experiment, ammonia is snipped from water to air under the atmospheric press, while air is carrier and oxidant. Secondly, in the range of reaction temperature, ammonia is oxidized to NOx, N2, H2O and NxHy etc. By controlling temperature, the chief oxide are N2 and H2O. The concentration of ammonia nitrogen in wastewater is 1024mg/L. The four kinds of catalysts, laden amount of active and secondary components being about 30% and 50%, are cranked out by mixing and deposition method apart.Though the experiment, it can be found mat:(1)the volume and concentration of ammonia stripped from wastewater could be regarded as ration, by the conditions of air flow<2L/min, pH=14, water temperature=98C; (2)the activity of the catalyst which contains 50% active and secondary components made by deposition method is highest, while its reaction temperature is lowest and its selectivity of producing N2 is comparatively well, under the optimal conditions of reaction temperature=500C and airspeed=6000h-1, when backfill volume of this catalyst is 10ml;(3)when the aforementioned catalyst is used under the optimal conditions, the concentration of NHs-N in wastewater can be cut down from 1024mg/L to 34mg/L after 120min, while the elimination quotiety of it is about 96.7%, and the transformation quotiety of NH3 is about 95.7%, with the concentration of remnant NH3 andNO being 139ppm and 360ppm respectively, and the producing quotiety of N2 is about 88.4%; (4)the reaction of ammonia catalytic oxidation abides by the mechanism of SCR, and it is controlled by chemistry kinetics.The aim of this study is to attempt a new method to dispose the wastewater with high concentration of ammonia nitrogen, and to discuss its feasibility, reaction mechanism and chemistry kinetics. Based on that, the study can proceed further in future.更多还原