Study On The Treatment Of Cyanide Wastewater By Catalytic Oxidation

The paper adopts pressurized hydrolysis, catalysis and oxidation, activated carbonadsorption and the combination to treat the cyanide wastewater.Study on the reaction condition and kinetics by pressurized hydrolysis. In result，thehydrolysis temperature has the most remarkable effect，followed by the reaction time. ThepH、milling speed and initial concentration are less remarkable. The experiment proves thathydrolysis of KCN follows the first-order reaction kinetics.k=A·exp(-73.6×10~3/RT)And the activation energy in this condition is73.6kJ/mol. A mathematical model forrelationship of the hydrolysis rate to the hydrolysis temperature and time is established.H2O2、ClO2are regarded as oxidant at catalysis and oxidation. The effect of the H2O2dosage and oxidation time, the ClO2dosage, temperature, pH and reaction time is reviewed inthe definite concentration range. Metal ions are chose as activators.The Cu2+catalysis is best.The Cu2++Ni2+、Cu2++Co2+、Na2SO3+Cu2+、Na2S·9H2O+Cu2+can remove the KCN at thecombination systems.At the activated carbon adsorption, when the activated carbon quantity is10g/L, pH=6~9,the adsorb time is150min, it has a better adsorption impact. The results show that theadsorption of KCN onto activated carbon can be well described by Freundlich and Langmuirmodels. The relation of the reaction speed constant and temperature accords with the formulaof the Arrhenius, and the activation energy in this experiment condition is28.57kJ/mol.Peroxide oxidation and activated carbon adsorption are combined to remove KCN, andconfirms the best experiment condition. The copper-impregnated charcoal enhances theadsorption capability further. The metal Cu2+has the most remarkable effect. The loaded Cu2+is considered research object. The different load capabilities of activator, pH of adsorptionsolution, initial concentration have an effect to adsorption capability.