二氧化氯的制备及其在废水处理中的应用研究

【作者】 彭清静；

【导师】 王继徽； 张新民；

【作者基本信息】 湖南大学 ， 环境工程， 2002， 硕士

【摘要】 二氧化氯是一个活性极强的氧化剂，它不仅能破坏有机色素，而且也能够氧化破坏许多污染物，还有很强的杀菌消毒作用。因而它在废水处理中的强大能力引起了人们的极大兴趣。它的制备、应用等方面的研究已取得了许多成果。但因在制备上所用还原剂较贵，从而使二氧化氯的价格很高，这在很大程度上限制了它的应用与发展。 为了解决上述问题，本论文选择廉价易得的硫磺、硫铁矿和闪锌矿进行二氧化氯的制备研究。研究结果表明，用它们作还原剂，不仅能大大降低二氧化氯的生产成本，同时还具有产品质量好、工艺简单、适应性强的优点。反应的最佳条件分别是：用硫磺作还原剂时：温度为60～70℃，氯酸钠浓度为4～5mol／L，氯酸钠与硫磺的摩尔比为6：1，反应液中维持硫酸浓度为1mol／L以上。用硫铁矿作还原剂时：硫铁矿过量6～9％左右，温度为60℃左右，氯酸钠初始浓度为4～5mol／L，需维持硫酸浓度在1mol／L以上。用闪锌矿作还原剂时：闪锌矿过量2～4％左右，温度为60℃左右，氯酸钠初始浓度为4～5mol／L，硫酸浓度要求在2.5mol／L以上。 对硫还原氯酸钠的动力学研究表明，反应动力学方程为r_C=kC_AC_B，表观活化能：61.352KJ／mol，指前因子为1.3601×10^-7L／（m²．min．mol）。 对用二氧化氯处理黄磷废水研究显示，二氧化氯能很好地氧化废水中的元素磷及氰化物，处理可在常温下进行，当二氧化氯过量40％以上时，元素磷的氧化率达100％，氰化物的氧化率达90％以上。再经石灰脱氟后完全可达到GB8978—1996中有关废水一级排放标准。 本论文还用铁氰化钾模拟含铁氰化物的废水，用二氧化氯进行处理，重点考察了各处理条件对处理效果的影响。实验结果表明，在焦磷酸钠存在下，二氧化氯能很好地氧化废水中的铁氰化物，处理后水中的总氰含量在0.3mg／L以下。处理可在常温下进行，焦磷酸钠加入量为铁氰化物量的120％（摩尔比）以上，处理时间为60分钟左右，二氧化氯与总氰化物的摩尔比为2.5左右。更多还原

【Abstract】 Chlorine dioxide is a very activated oxidant. It can destroy organic pigment as well as much polluter in the water. These characteristics have attracted the interest of many groups during last decade. In the meantime, the people has recognized that chlorine dioxide is too costly to confine its application.A scheme that should overcome the problem is to use cheaper reducing agent. In this paper, we investigated preparation of chlorine dioxide by sodium chlorate being reduced with sulfur and pyrite and blende. The experimental results showed that these methods have much virtue. For example, the reaction is easily controlled, less sulfuric acid is consumed, the cost is cheap and purity of product is higher. When use sulfur, the best reaction condition is that temperature is 60-70 ℃,sodium chlorate density is 4 ~ 5 mol / L , and sulfuric acid density is over 1 mol / L in the reaction liquid. When use pyrite, it is that require amount of pyrite is 6-9 % over theoretical require amount, temperature is about 60 ℃, sodium chlorate density is 4?mol/L, and the concentration of sulfuric acid is over 1 mol/L. When use blende , it is that require amount of blende is 2 - 4 % over theoretical require amount, temperature is about 60 "C , sodium chlorate density is 4~5mol/L, and the concentration of sulfuric acid is over 2.5 mol/L.The kinetics research that sodium chlorate was reduced with sulfur to form chlorine dioxide showed that the equation of reaction rate is re = k CxCs, the apparent activation energy is 61.352KJ/mol, and the frequency factor is 1.3601 X 107L2/(m2min mol).The experimental results showed that chlorine dioxide could oxidize phosphor and cyanide in wastewater. Under proper reaction condition, the oxidation yield of phosphor was 100%, the oxidation yield of cyanide was over 90 %. It could attain the first standard in GB4283-84 after wastewater was treated with chlorine dioxide and lime. The results of research showed there is sodium pyrophosphate that chlorine dioxide could oxidize ferricyamide.更多还原