Technology Study On Electric Fenton Process On Folic Acid Wastewater Treatment

Folic acid wastewater,which is a kind of pharmaceutical wastewater with high concentration of organic matter,high salinity,high chroma,and poor biochemical pharmaceutical wastewater,is generated from the process of producing folic acid.The effect of conventional methods for its treatment is not ideal.This paper used in-situ production of hydrogen peroxide method for the folic acid wastewater treatment,optimized the process conditions,studied the degradation kinetics of the folic acid,and designed a small experiment device to simulate the whole process which is used in the disposal of folic acid wastewater.The results of this study provided some reference for the disposal of folic acid wastewater.First of all,with the same concentration of hydroxyl radicals,we compared the COD removal efficiency between in-situ production of hydrogen peroxide method and sacrificial anode method.Results showed that after 90 minutes,the COD removal efficiency of in-situ production of hydrogen peroxide method is higher than sacrificial anode method.At the same time,cost of in-situ production of hydrogen peroxide method is relatively low,so we decided to adopt in-situ production of hydrogen peroxide method for the following study.We conducted powder activated carbon adsorption experiments,and studied the influence of the powder activated carbon additive amount to the degradation effect of folic acid wastewater in electricity and non electricity situation.The results verified the necessary of adding powder activated carbon to form the three-dimensional electrode,at the same time determined that the quantity of adding powder activated carbon is 1.5 g/L.We studied the influence of ventilation,current density,initial solution pH,and reaction time on folic acid wastewater COD degradation.Meanwhile,through the four factors and four levels orthogonal test,we determined the optimal conditions is the ventilation of 0.75 mL/min,the current density of 10.26 mA/cm~2,pH of 5,the reaction time of 90 min.Under this condition,COD removal rate of folic acid wastewater can reach 94.87%.Through the analysis,we could got the influence order of four factors is ventilation>time>current density>p H.Using folic acid simulated wastewater as raw material,we curved fitting of folic acid concentration with the time change.As a result,we confirmed that folic acid wastewater COD degradation is in line with the secondary reaction kinetics,at the same time,we found that the smaller folic acid initial concentration,the faster the degradation rate is.We designed a small experiment device to simulate the whole process which is used in the disposal of folic acid wastewater.The results show that the Electro-Fenton-A/O process treatment effect is good.In this process,COD removal rate can reach85.81%,the total nitrogen removal rate can reach 88.44%,ammonia nitrogen removal rate can reach 53.73%.Through the calculation of the electric energy consumption of electro-fenton pretreatment,we found that,the consumption of folic acid wastewater pretreatment cost is 19.44 yuan/m~3.We need further study to reduce costs for the large-scale application of this process.