Degradation Of 2,4-DNT By Persulfate Activated With Fe~0-C In Groundwater

With the development of Industry,the water environmental pollutant caused by huaman beings is more and more serious.2,4- dinitrotoluene is a typical organic matter pollution,and the degradation of 2,4-DNT by persulfate activated with Fe⁰-C is an ideal way.The operation is not only simple,but also efficient.Persulafate activated with Fe⁰-C can convert 2,4-DNT to less toxic substances,which enhanced biodegradability,and it wouldn’t produce secondary pollution,so it gets good repair effect.In this paper,based on groundwater, the author studied the mechanism and influence of groundwater environment factors to 2,4-DNT degradation of Fe⁰-C, the effect of groundwater environment fators to 2,4-DNT degradation by persulfate activated with Fe⁰-C,and the discipline of 2,4-DNT degradation by persulfate activated with Fe⁰-C under dynamic environment.（1） To study the degradation of 2,4-DNT by Fe⁰-C,batch experiments were applied to study the influence that initial pH,dissolved oxygen（DO） and common cations/anions on removal of 2,4-DNT in groundwater.Products attained from the process of removal were also clearly identified.The study indicates that under condition pH=7 and DO=0.23mg/L, Fe⁰-C can remove 2,4-DNT in solution in an efficient manner.The removal efficiency achieve 81% after 330 min since reaction takes place.The higher the pH,the less efficient the degradation of 2,4-DNT is.The removal rate of 2,4-DNT reached as high as 99.05% when pH=2. The removal rate jumped 9.5% when DO increasesd from 0.23mg/L to 9.26mg/l. Common cations and anions found in groundwater had very limited influence on removing 2,4-DNT by Fe0.The nitro groups from 2,4-DNT are converted to amino groups during the reaction where the intermediate products are 2A4 NT and 4A2 NT and final product is 2,4-DAT.This report is written in a hope to provide theoretical evidence and experimental support for the practical application of removing 2,4-DNT in groundwater using Fe⁰-C.（2） To grasp the degrading discipline of 2,4-DNT in groundwater by persulfate activated with Fe⁰-C, and in this study, batch experiments were conducted for the purpose of understanding the degrading mechanism and pattern and the influence of common influencing factors（pH, DO） and common anions（Cl^-, HCO₃^-） in groundwater.The results show that under condition where pH=7, T=15℃, t=340min,persulfate activated with Fe⁰-C can effectively remove 2,4-DNT from the solution;Degradation rate could reach to 93.7%.Fe0/C/persulfate is much more capable than other material（ Fe⁰/K₂S₂O₈ 、 Fe⁰/C 、 C/K₂S₂O₈ �'� K₂S₂O₈） in such circumstance.Degradation of 2,4-DNT could be more efficient when solution gets more acidic.Degradation rate is 99.84% when initial pH=5 whereas degradation rate is 83.25% when initial pH =9.Anaerobic condition has adverse effect on degradation.Degradation rate is 62.4% when DO=0.3mg/L whereas degradation rate is 94.3% when DO =9.26mg/L. Common anions（Cl^-, HCO₃^-） in groundwater inhibit the process of degradation.When Cland HCO₃^- is present and their concentration equal to 200mg/L,degradation rate are 59.49% and 65.53% respectively.（3） To study the displine of degradation of 2,4-DNT by persulfate activated by Fe⁰-C,column experiment in groundwater was conducted for the purpose of understanding the degrading effects of 2,4-DNT by persulfate activated by Fe⁰-C.On the basis of Fe⁰-C micro electrolysis, through persulfate reaction colum,2,4-DNT and its intermediate and the final products was further degraded, so 2,4-DNT was almost nonexistence.The reaction products in dynamic systems is very complexm, and after reaction in persulfate reaction column,there are more products and the response in the system is more th thoroughly; Degradation by Fe0 reduction, Fe⁰- C micro electrolysis and persulfate activated will affect pH、ORP and TOC in the system.