Removal Of Dye Contaminants In Aqueous Solution By Peroxymonosulfate Activated With Differernt Chemical Reagents

Rhodamine B（RhB）,Methylene Blue（MB）and Acid Orange 7（AO7）in printing and dyeing wastewater are difficult to be degraded by microorganisms,which are seriously harmful to the ecological environment,it is great significance to explore the economic,efficient and feasible removal technology.In this paper,peroxymonosulfate（PMS）system activated by ferrous and hydroxylamine hydrochloride（NH₂OH）(Fe²⁺/NH₂OH/PMS)and peroxymonosulfate system activated by phosphate buffered saline（PBS/PMS）were used to degrade three target dyes.The kinetic study of the degradation three kinds of dyes,and the effects of initial concentration of PMS,Fe²⁺,NH₂OH,PBS,target dyes,the pH value and temperature of the system on the degradation efficiency were investigated,respectively.Furthermore,the free radical analysis and application exploration of two systems were carried out.The results of kinetic study indicated that the degradation of target dyes in the Fe²⁺/NH₂OH/PMS system was found to follow the pseudo-second-order kinetics model.The reaction rate constants were 0.0528,0.0572,0.0513,respectively and the removal rate were76.16%,81.82%and 86.87%,respectively.The degradation of the three kinds of dyes in the PBS/PMS system could be described by the pseudo-first-order kinetics model.The reaction rate constants were 0.0916,0.0422,0.0677,respectively and the removal rate were 94.45%,96.59%,86.11%,respectively.The results of influence factors study indicated that removal rates of RhB,MB and AO7in the system of Fe²⁺/NH₂OH/PMS gradually were increased with the increase of PMS concentration.With the increasing of Fe²⁺concentration,the removal rates of RhB and MB were first increased and then decreased;the removal rate of AO7 was significantly increased with the Fe²⁺concentration increased.The trends of removal rates of RhB and MB were first increased and then decreased with the increase of NH2OH concentration;but the removal rate of AO7 was increased with NH2OH concentration increasing in the system.However,the increase of target concentration decreased the removal efficiency of target dyes.Solution temperature rise would increase the degradation rates of RhB and MB.With the rise of pH vaule,the removal rates of targets were first increased and then decreased.In the system of PBS/PMS,the targets removal rates indicated an increasing trend with the increase of PMS and PBS concentration,system temperature.Increasing the target concentration,their removal efficiency would be decreased.With the increase of solution pH the removal rate of RhB was first increased and then decreased;the effect of solution pH on the removal rate and reaction rate of MB and AO7showed a trend of continuously increased.Analysis of the radicals in the system of Fe²⁺/NH₂OH/PMS and PBS/PMS indicated that SO4^·-and·OH contributed the main degradation of target dyes.And exploration of the application of two oxidation systems showed the performance characteristics of economic efficiency and environmental friendly,however,the former has less reagent dosage and wider range of applicability,the latter has an advantage to treat the target dyes in phosphate-rich and eutrophic water.