Treatment Of Dye And Dye Intermediate Wastewater By Fenton Process

Dye is used extensively in textile,papermaking,food industries and the treatment of effluents containing synthetic dye has attracted great attention.Generally speaking,dye wastewater with higher strength of organic load which is recalcitrant to biological treatment.As one of the largest country to use dye,our country is quite disturbing by the pollution of dye wastewater.The release of dye wastewater without pretreatment into the ecological environment is undesirable due to the serious environmrnt problem.Traditional treatment methods such as biological method,membrance method,adsorption method are no longer meeting the treatment requirement.Fenton process is one of the classic advanced oxidation processes.The principle of it is to produce reactive redical with strong oxidizing ability after the reaction between peroxides and iron ions.In recent years,this process was efficiently utilized in wasterwater treatment process.In this paper,homogeneous and heterogeneous Fenton process was chosen to treat dye modal wastewater.The key factors including initial pH,H₂O₂dosage,catalyst dosage,temperature and substrate concentration were investigated during the homogeneous and heterogeneous Fenton process.Finally,two processes were used to treat the high concentrated dye intermediate industrial wastewater.The main results fall into following parts:（1）The results of the degradation of RBR X-3B by homogeneous process shown that the optimal pH was between 2.5 and 3.0.The highest degradation efficiency of RBR X-3B can be achieved under this condition.The over dosed H₂O₂ and Fe²⁺can increase side reactions thus affact the dye degradation efficiency.The high temperature applied can not only accelerate the reaction rate but also can promote the self-decomposition of preoxides into O₂ and H₂O.The kinetic of homogeneous Fenton degradation of RBR X-3B were complying with the pseudo-first-order equation.（2）A novel heterogeneous catalyst（MS-Fe）based on FeSO₄·7H₂O,H₂C₂O₄·2H₂O,Na₂S₂O₃·5H₂O was also prepared,and analyst by various techniques such as BET,XRD,FTIR and so on.Under the optimal conditions with pH value of 3.0,temperature of 60°C,catalyst dosage of0.02 g,H₂O₂ concentration of 6.0 mmol/L,initial concentration of 200mg/L,reacting time of 10 min,the degradation efficiency of reactive brilliant red X-3B can reach up to 77%after the treatment by the heterogeneous-Fenton process.Meanwhile,the response surface methodology was used to found the optimization of the RBR X-3B by heterogeneous Fenton system.（3）The effects of different parameters on the degradation of COD by homogeneous Fenton and heterogeneous Fenton were detected.Both of these two systems have a good mineralization on organic matters.As the reaction going by,the effluent color dilution deceases from 800 to 4.Via operating under the base conditions,it is shown that the degradation of RBR X-3B during the beginning of the reaction is complied with the pseudo-first order kinetics by homogeneous Fenton process and complied with the pseudo-second order kinetics by heterogeneous Fenton process.