Study On The Treatment Of Phenol Wastewater By Three-dimensional Electrode-Fenton Reagent Method

Three-dimensional electrode-Fenton reagent method was put forward basing on the three-dimensional electrode method and electro-Fenton method.Aa a new type of electrochemistry water treatment technologies, it has begun to take shape in the field of environmental pollution control applications.So it has the important theoretical and practical significance to in-depth study about this mothod.In this paper,a self-made electrochemistry reactor was used to treat phenol simulation wastewater,using three-dimensional electrode-Fenton reagent method to treat it,mainly content as follows:The paper studies the influence of the three kinds of anode materials which are iron,graphite and Ti/RuO2-IrO2 and the three kinds of cathode materials which are porous graphite, activated carbon fiber and stainless steel on the effect of phenol wastewater treatment.. The results showed that the removal rate of phenol reached the tiptop in electrolysis system When using the Ti/RuO2-IrO2 as anode and the activated carbon fiber as cathode. At the same time,the paper studies the influence of the different paddings as particle electrode on the removal rate of phenol.The results showed that granule carbon was not suitable as particle electrode,and it had better treatment effect using quartz sand and active carbon as mixed padding than using single active carbon padding.It could improve the reactivity worth and enhance the removal rate of phenol obviously if proportional dosing of the active carbon doped membrane and the active carbon non-doped membrane.The removal rate of phenol was 95.9% when the volume ratio of active carbon doped membrane and active carbon non-doped membrane was 1:2.The paper studies the main factors of producing of the H2O2 by three-dimensional electric-Fenton method under the conditions of rinsing.The yield of H2O2 was 248.6mg/L in the reaction temperature was 20℃,the reaction time was 60min,the pH value was 3,the current density was 10mA/cm2,using pass into the air for aeration and other experiment contions.It establishes theory and experiment foundation for the dosing of Fe2+ for the next step.The paper studies the influence of the dosage concentration of Na2SO4 electrolyte,the sample concentration of phenol,the pH value,the reaction time, the electrolyte voltage, the dosage concentration of Fe2+, the pole distance and the aeration intensity on the effect of phenol wastewater treatment by three-dimensional electrode-Fenton reagent method,and analyses the mechanism of their effects. The orthogonal experiment was carried on basing on the single factor experiment. The results show that the primary and secondary sequence of influencing factor of phenol removal rate of the water sample was that pH value> electrolyte voltage> dosage concentration of Fe+2> pole distance> dosage concentration of electrolyte.According to the results of the orthogonal experiment to determine the optimal reaction conditions,the average removal rate of phenol is 97.27% under this condition.The paper studies the influence of several kinds of inorganic anion and cation on the effect of reaction system,and educes the effect of Fe3+ in the reaction depending on its concentration in solution.Appropriate concentration of Fe3+ has a synergetic effect with Fe2+,and promotes the ability of catalytic oxidation of Fenton reagent.But the high concentration of Fe3+ has a inhibitional effect.There is a different degrees of inhibitional effect of CO32-、H2PO4- and Cl-,and the capacity is CO32->H2PO4->Cl-.The effect of these ions on the reaction system is that the clear action of free radical,participating complexation of iron ion,or inefficacy decompose of H2O2. NO3-can hardly affect the ability of catalytic oxidation which to treatment phenol wastewater.The paper studies the different influences of the major single factor on the two kinds of E-Fenton methods,and educes the request of pH value of three-dimensional electrode-Fenton reagent method was lower than the two-dimensional,and it could be processed the high concentration of phenol wastewater.The reaction voltage,the electrolyte time and the addition quantity of electrolyte and other factors were all under the twe-dimensional E-Fenton method.The removal rate of phenol by three-dimensional E-Fenton method was higher than the two-dimensional E-Fenton nearly 20%.The paper establishes the energy consumption ratio model of three-dimensional E-Fenton reactor and two-dimensional E-Fenton reactor: Through the energy consumption model,we could educe that the three-dimensional E-Fenton method is more saving the energy than the two-dimensional E-Fenton method,and it is worth promoting in practical engineering applications.The paper establish a dynamic model of phenol wastewater oxidative degradation by three-dimensional electrode-Fenton reagent method and educes that it can be described with first order dynamic model.At a certain reaction conditions,the order of factors which affecting the reaction speed from strong to weak is voltage, the addition quantity of Fe2+, the pole distance, the addition quantity of electrolyte, the aeration speed.The fitting equation of overall reaction is Ct=C0exp (-1.05×10-12 U1.7784D1.2289M0.9941Q0.9210F1.46.3t) The degradation mechanism of phenol was analysed,and obtained that the removal of phenol is mainly result of joint action of hydroxyl radical,the direct oxidation of electrode and other active species in system.The hydroxyl radical in the system made the greatest contribution to the phenol degradation. Through the analysis of UV-VIS and GC-MS of phenol sample,the paper educes that the main intermediate product of phenol oxidative degradation are hydroquinone,quinones and carboxylic acid,etc.The degradation process could be that phenol was first oxidized to aromaticring hydroquinone and quinones by·OH,and then opened into a carboxylic acid compounds,until the last mineralized to carbon dioxide and water.