Degradation Of Dyeingwaster By Co/PMS System

The Co/PMS?cobalt/peroxymonosulfate?system is one of the important branches in the field of high-new oxidation technology because of its high efficiency,high speed,and low secondary pollution.The principle is that the Co/PMS system produces highly activeSO₄^-that degrade organic pollutants in the water.Based on the homogeneous Co²⁺/PMS system,a very rapid degradation effect was exhibited during the treatment of printing and dyeing wastewater.The optimal experimental conditions can be controlled in 1 min.The reaction can be completed completely.This rapid degradation process makes sampling analysis difficult,especially for 1 min.Within the dye degradation process.In this work,online spectrophotometry was used to monitor the instantaneous degradation of dyes in the Co²⁺/PMS system.Ultraviolet light?UV?was used to enhance the degradation process,and the anion and cation effects on the degradation process of the dyes.In addition,taking into account the environmental harm caused by the introduction of cobalt ions,a cobalt-containing alumina pellet water purifying agent was prepared and coupled with PMS to degrade the organic pollutants in the water.Specifically obtained the following phase results:At the research of degradation of Rhodamine B and Acid Yellow G by homogeneous Co²⁺/PMS,acid dye Rhodamine B under the condition of optimization that[Co²⁺]=2.5771×10^-2 mmol/L,[PMS]=2.6026×10^-1 mmol/L,pH=7,the degradation rate is 100%within 60 s;and azo dye Acid Yellow G under the condition of optimization that[Co²⁺]=1.7180×10^-2 mmol/L,[PMS]=2.6026×10^-1 mmol/L,p H=9,the degradation rate is 93.4%within 80 s.Further study of homogeneous Co²⁺/PMS system is needed.The use of ultraviolet light to assist Co²⁺/PMS system for catalytic oxidation and degradation of acid red dyes,under the optimal conditions,that is,[Co²⁺]=2.1475×10^-2 mmol/L,[PMS]=2.2773×10^-1 mmol/L,pH=7,T=298 K,the reaction can achieve removal rates of more than 96.9%within 40s.In addition,in the study of UV-assisted degradation of Acid Red 6B by Co²⁺/PMS,it is found that as the intensity of UV light increases,the degradation rate of the dye increases first and then decreases.Without UV irradiation,the removal rate was 89%.And when the UV power is 18 W,the removal rate of Acid Red 6B is the highest,as high as 91.3%.In the experimental study on the effect of anions,the degradation of Rhodamine B according to the Co²⁺/PMS system which based on coexisting anions,shows that it has a dual effect on the degradation of Rhodamine B by advanced oxidation.The anion of the strong acid salt(SO₄^2-)has little effect on the degradation reaction of the dye Rhodamine B,and the anions(HPO₄^2-,CO₃^2-)carried by the weak acid salt have a certain inhibitory effect on the degradation reaction of Rhodamine B.In the experimental study on the influence of cations,according to the experimental research on the degradation of dye rhodamine B by the cationic Mⁿ⁺+PMS system,it is known that Co²⁺is the most suitable catalyst for the degradation of dye Rhodamine B by sulfate radical.In order to avoid secondary pollution,development and research of heterogeneous Co/PMS system is very important.The catalyst Co/Al₂O₃ pellets were prepared by mechanical coating technology.The evolution model of cobalt coating formation process is inferred,which includs nucleation,formation and coalescence of discrete islands,formation of continuous coatings and exfoliation.Cobalt loading on the surface of Al₂O₃ balls increased first and then decreased with the increase of MCT rotation time.Among them,the load of cobalt is the largest when the MCT time was20 h,that is to say,the best MCT time was 20 h.The catalyst Co/Al₂O₃ is degraded by dye wastewater with persulfate radical.When the optimum amount of catalyst and oxidant is m?Co/Al₂O₃?=0.100 g,[PMS]=6.5066×10^-1 mmol/L,the degradation rate of Acid Yellow G is as high as 93.10%.In addition,as the reaction temperature increases,the dye degradation rate increases first and then decreases,but the magnitude of them is smaller.When the reaction temperature is 308 K,the degradation rate of the dye Acid Yellow G reaches a maximum of 95.65%.The reaction process of degradation of Acid Yellow G dye wastewater based on sulfate radical in the Co/Al₂O₃ system is consistent with the first-order kinetics.For the repeated use of the catalyst Co/Al₂O₃pellets,five repetitions are performed,and the final dye degradation rate is not low,both higher than 76.65%and as high as 93.43%.In general,the cobalt-supported Al₂O₃ pellet catalyst system has a strong catalytic performance for repeated use.