固态多相催化法制备高纯度二氧化氯及其在自来水中消除有机污染物的研究

发布时间：2018-05-09 07:21

  本文选题：二氧化氯 + 固相多相催化法　； 参考：《华东师范大学》2017年硕士论文

【摘要】：二氧化氯作为消毒剂,在消毒过程中不会产生三卤甲烷(THMs)等对人体健康危害巨大的"三致"物质,且具有良好的杀菌能力,已逐渐取代液氯消毒剂。许多发达国家已采用二氧化氯对饮用水消毒。我国二氧化氯生产技术落后,多采用氯酸盐和亚氯酸盐为原料,液相合成,生产成本较高,产品纯度不够高。因此,寻找以低成本投入,制备高纯度、稳定性好的二氧化氯的方法,显得尤为重要,这将极大改善人们的饮水安全问题。为了解决这一问题,本论文在前人研究的基础上,以廉价的氯酸钾和草酸为原料,以ZSM-5负载过渡金属为催化剂,采用固态多相催化加热的方法,制备出高纯度的二氧化氯。该方法采用固态方法,不同于其他方法,避免了液相法的强酸对设备的腐蚀,工艺简单,反应时间短,且不产生氯气等其他杂质。探究了反应的最佳实验条件:氯酸钾与草酸摩尔比为1:1.2,适量催化剂;反应温度:75℃;反应物粒度大小:200-250目。制备出的二氧化氯纯度可达99.9%以上。本论文采用国标—五步碘量法对二氧化氯的纯度进行了分析,并考察了储存在不同温度、pH条件下的二氧化氯溶液、以及亚氯酸根、氯酸根溶液的稳定性。实验结果表明,二氧化氯溶液(1g/L)在储存过程中二氧化氯气体会挥发,但在存储过程中不发生变化。二氧化氯溶液在25 ℃能稳定保存,在碱性条件下发生歧化反应转变为亚氯酸根、氯酸根。亚氯酸根和氯酸根在水溶液中稳定存在。本论文还用自制的二氧化氯溶液对自来水中苯、苯酚、苯醌及苯胺类有机污染物进行了氧化处理,探讨了在不同反应时间、反应物摩尔比、pH和温度下的氧化产物。研究表明,二氧化氯可将苯氧化为二氧化碳,将苯酚氧化为苯醌,而苯醌不能被二氧化氯进一步氧化;将苯胺氧化为偶氮苯,将邻甲基苯胺氧化为邻甲基对氨基酚,N-甲基苯胺氧化为N-甲基对苯酚,N-甲基对苯酚可被二氧化氯进一步氧化为对苯醌。
[Abstract]:Chlorine dioxide, as a disinfectant, will not produce trihalomethane (THMs) and other "trihalomethane" substances, which are harmful to human health, and have good bactericidal ability, which has gradually replaced the liquid chlorine disinfectant. Chlorine dioxide has been used to sterilize drinking water in many developed countries. The production technology of chlorine dioxide in China is backward. Chlorate and chlorite are mostly used as raw materials. The production cost is high and the purity of the product is not high enough. Therefore, it is very important to find a method to prepare chlorine dioxide with high purity and good stability at low cost, which will greatly improve the drinking water safety of people. In order to solve this problem, a high purity chlorine dioxide was prepared from cheap potassium chlorate and oxalic acid, ZSM-5 supported transition metal catalyst and solid heterogeneous catalytic heating method. The solid state method is different from other methods. It avoids the corrosion of the strong acid in liquid phase, the process is simple, the reaction time is short, and other impurities such as chlorine are not produced. The optimum experimental conditions are as follows: molar ratio of potassium chlorate to oxalic acid is 1: 1.2, appropriate amount of catalyst; reaction temperature: 75 鈩，

本文编号：1865098