【作者】 雷萍；

【导师】 聂麦茜； 葛碧洲；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2011， 硕士

【摘要】 DMAC是一种具有良好溶解能力的溶剂,已被广泛应用于膜生产工艺,产生了大量的DMAC生产废水。因此,如何降解消除DMAC造成的污染废水,一直受到社会各界的关注。本文针对膜生产过程中产生的大量DAMC溶剂废水,研究了光催化氧化降解DMAC的条件优化及其机理,寻找HPLC的色谱分离条件,运用HPLC对降解效果进行检测及对降解过程中微观行为的研究。取得以下成果:（1）通过条件摸索,HPLC分离DMAC及其降解产物的最佳色谱分离条件为:流动相用8:92的甲醇:水（0.4%乙酸）溶液,流速为1.0mL/min,采用二极管矩阵全谱扫描的最大紫外吸收谱图;（2）DMAC的光催化降解过程中,DMAC中间氧化产物按照生成顺序共有4种产物1、产物2、产物3和产物4,除产物4外,其余的氧化产物在氧化过程均有从生成→积累→消失的规律;DMAC的分子式为CH₃CON（CH₃）₂,含有C、H、O、N四种元素,其中N含量为16 %;光催化氧化使其最终矿化,生成CO₂、H₂O和无机盐。最终产物4是N的转化生成物,运用盐酸萘乙二胺比色法,证明了DMAC中N转化的最后生成物不是NO₂^-,利用多维色谱进一步鉴定了N的最终存在形态为NO₃^-,这一结果为解释降解机理提供了依据。（3）光催化氧化法降解DMAC时,UV-C为最佳光源,DMAC浓度为500mg/L、催化剂用量为3g/l、水样酸碱度为中性时,降解效率最高。（4）根据DMAC及其降解产物的HPLC追踪测定结果,在最佳降解条件下,描述DMAC降解产物生成→积累→消失规律的方程式分别为:产物1:C = - 0.2147t² + 0.5775t - 0.0047产物2:C = 0.0727t² + 0.0095t - 0.0085产物3: C = 0.0014t² + 0.0043t - 0.0045及降解终产物NO₃^-的方程式为:C = 0.0259t-0.0479其为DMAC废水降解过程中各个产物间的转化提供了一定的动力学参考。（5）根据DMAC降解过程酸碱度变化趋势,结合相关报道,产物1、产物3的生成伴随着酸性物质,使得降解体系pH值降低;产物4的产生伴随着碱性物质的生成,导致体系pH增加;降解14h后体系酸碱度达到稳定,此时,DMAC彻底矿化产生NO₃^-。（6）以通透膜制造产生的溶剂废水为对象,通过测定废水的水质参数,根据光催化氧化DMAC过程中对不同DMAC模拟废水降解的优化降解,实验对制膜废水进行了最优化条件下的降解,结果表明,在3g/l催化剂下光催化氧化500g制膜废水需36h～42h。更多还原

【Abstract】 DMAC ,which is a solvent with good solubility, is widely used in film production process, resulting in a large number of DMAC waste water. Therefore, how to eliminate the wastewater caused by pollution of DMAC , has always been concerns of the community. In view of the large number of DAMC solvent waste generated in the film production process, the optimal conditions and photocatalytic degradation mechanism for DMAC had been studied in this paper. We searched for the chromatographic separation conditions of HPLC, used the HPLC to detect degradation and researched the micro-behavior in the degradation process. The conclusions are as follows:（1）Through the exploration, we got that the best chromatographic conditions of separation of DMAC and its degradation products by HPLC were as follows: the methanol to water （0.4% acetic acid） in chromatographic mobile phase is 8:92; the flow rate was 1.0mL/min; the samples was detected by the diode array of whole spectrum scanning of the ultraviolet absorption spectra;（2）In the process of photocatalytic degradation of DMAC , there were a total of four intermediate oxidation products generated in accordance with the order: product I、II、III and IV. Besides product IV, the other oxidation products all followed the same law in the oxidation process :from generation to accumulation, then to disappearance; The Molecular Formula of DMAC is CH3CON （CH3） 2, containing four element of C、H、O and N , of which the content of N is 16%; The DMAC was final mineralized into CO₂, H2O and inorganic salts by photocatalytic oxidation. The final product IV was the resultant converted from the element of N. Using the Colorimetric method of hydrochloric acid naphthylethylenediamine, we proved the final generation product converting from N was not NO₂^-. By the multidimensional chromatography , we further identified the final existing form of N is NO₃^-.Those results provide a basis to explain the degradation mechanism of DMAC.（3）The highest degradation efficiency happened on those conditions when using the method of Photocatalytic oxidation to degrade DMAC:UV-C as the light source, DMAC’s concentration of 500mg/L, the amount of catalyst of 3g/L and the neutral samples.（4）According to the HPLC trace determination results of DMAC and its degradation products , on the best conditions, the equations respectively describing the law of the degradation products of DMAC are: Product 1: C = - 0.2147t² + 0.5775t - 0.0047 Product 2: C = 0.0727t² + 0.0095t - 0.0085 Product 3: C = 0.0014t² + 0.0043t - 0.0045 And the formula of final degradation product （NO₃^-） is: y = C = 0.0259t-0.0479 Those formulas provide some dynamic reference for the conversion among products in the process of degradation of DMAC.（5）Through the trend of pH in the process of DMAC’s degradation, combined with the related news, 2, there were acid material generated along with the formation of product 1 and product 3, making the pH value of degradation system decreased; There were alkaline substances generated along with the formation of product 4, resulting in the increasing of pH value of degradation system; With the degradation for 14h, the system’s pH became stable. At this time, the system produced NO₃^-which was the end product of mineralization of DMAC.（6）We mainly researched the solvent wastewater generated by film production. By measuring the water quality parameters of wastewater, we degraded the film wastewater experimental on the optimized conditions, combining with the optimized degradation of simulated wastewater in the process of photocatalytic oxidation of DMAC. The result showed that we need 36h 42h to oxide the film wastewater of 500g with the catalyst of 3g/L.更多还原