Application Of Iron-based Compounds And Electrocoagulation(EC) In Wastewater Treatment

The principles of Fenton’s reagent and electrocoagulation(EC) and their application in water treatment are reviewed. And then methods for treatment of acid wastewater are also discussed. The emphasis of this thesis lies in the influencing factors of Fenton’s reagent and electrocoagulation(EC), and prospects of their practical application.In the third chapter, the degradation efficiencies of wastewater with low COD concentration by ferrous coagulant, Fenton’s reagent and class Fenton’s reagent were investigated. The results indicated that Fenton’s reagent had the highest degradation rate under similar conditions. The optimized experimentation indicated that when the ratio of n(H2O2) to n(Fe2+) was 1.5, the degradation rate could reach 47.8% under pH 3-4. After reaction of 120min, the degradation rate almost kept constant.. On this basis of above results, we tried to fossilize the Fe2+ to avoid generation of sludge, then two catalysts (noted as W1 and W2) were prepared in this word. Considering the the activity of Iron Phthalocyanine (FePc) in some oxidative reactions, we also tested its catalytic activity in treatment of wasterwater by H2O2. The result of preliminary trial indicated that no matter Wi,W2 or Iron Phthalocyanine(FePc), they can’t catalyze the decomposition of H2O2, a unique mix of class Fenton’s reagent had less effective on wastewater treatment.In the forth chapter, the removal rate and influencing factor of electrocoagulation(EC) were investigated. The results showed that the removal rate reached 58.0% at current density of 60mA/cm2 under optimized conditions, compared with simple coagulation, (take the same amount of Fe2+ as electrolysis in 90min), EC had higher the removal rate of COD. Owing to the cost, electrocoagulation(EC) was better than coagulation. Besides, the results of biological treatment indicated that the BOD5/COD of the disposed wastewater was increased from 0.139 to 0.463, showing that the biodegradability of the wasterwater improved greatly. Thus, the wastewater could be directly treated by biological method after EC pretreatment.At last, I also had six months of experience on Electro-sorb Technology for desalination at Shaoxing wastewaterwater treatment factory. It was found that it not only had a better efficiency on reducing conductivity, but also it had efficiency on the removal of COD. Owing to the lower cost compared with membrane treatment, one may infer the Electro-sorb Technology has good application prospect.