Preparation Of Chlorine Dioxide And Its Application In Wastewater Treatment

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.