Degradation Of 1,2, 3-trichloropropane By Activated Sodium Persulfate Using Nano Iron Suspension Synthesized By Green Tea

1,2,3-Trichloropropane?TCP?is a new emerging synthetic chlorinated hydrocarbon organic pollutants,which can cause soil and groundwater pollution.And that threatens human health?In recent years,persulfate?PS?advanced oxidation technology based on sulfate radical has been widely applied to the degradation of refractory organic compounds in wastewater.Compared,But the choice of activation method is crucial.This study uses green tea nanometer iron suspension?GN-NIS?to activate PS,which is applied to the degradation of organic pollutants TCP,and the degradation efficiency of TCP is improved by optimizing conditions.?1?GT-NIS was produced by reacting green tea extract with ferrous sulfate.SEM/EDX and TEM results showed that the shape of iron nanoparticles was relatively round and spherical,the particle size was about 20-100 nm,and the dispersion was good.The main elements in gt-nis particles were C,O,S and Fe,with atomic percentages of 69.91%,28.25%,0.45%and 1.38%,respectively.XPS results showed that ferric iron and ferric iron existed in GT-NIS.FT-IR results confirmed that GT-NIS contained-OH,-CH3?C=O?-CH2-?C-O?C-H?-OCH and other organic groups as well as iron and iron oxides.?2?In this paper,the effect of PS concentration,TCP concentration,GN-NIS concentration and temperature on the activation Persulfate to degradation of TCP by GT-NIS was studied.The results showed that the degradation of TCP could well fit the first-order reaction kinetics model?R²>0.9?.The degradation rate of TCP increases with the increase of temperature.In the range of PS concentration of 5-25 mM,the degradation rate of TCP increases with the increase of PS concentration.After optimization of PS concentration,TCP concentration,GT-NIS concentration and temperature,For 100 mg/L TCP,the degradation rate of TCP finally reached 77%after 48 hours in PS 25 mM,GT-NIS 0.05mM?used Fe as measure unit?and at the temperature of 25?.The overall performance of anion on the degradation of TCP is inhibition.The degradation rate of TCP is in the following order:NO^3-?58%?>Cl^-?57%?>SO₄^2-?53%?>PO₄^3-?18%???3?Neither green tea extract nor green tea iron nanoparticles could effectively reduce TCP?12%?.Persulfates that were inactive or green tea extract activated were also less efficient at oxidative degradation of TCP?16%and 1%?.Fe²⁺and Fe³⁺activated persulfate oxidation degradation of TCP efficiency up to 34%and 25%,Can effectively degrade TCP.However,it was significantly lower than that of green tea?77%?.This fully shows that green tea nanometer iron suspension activated persulfate has a significant advantage in improving the degradation efficiency of pollutants.?4?The presence of SO₄^-·and·OH in the reaction system was determined by free radical capture of nitrobenzene,phenyl ether and hexachloroethane.Compared with SO₄^-·,·OH contributes more to the degradation of TCP.During the oxidative degradation of TCP under the action of GT-NIS/PS,the sulfur element in persulfate was completely converted to sulfate radical,and the chlorine element in TCP was mostly converted to chloride ion,and the organic by-products were also relatively few,and the total chemical oxygen demand of the system was significantly reduced.This indicates that for the whole system,the reaction is more thorough,and the unreacted part is more and more easy to be oxidized and degraded.On the whole,green tea nanometer iron suspension is a new type of persulfate activator,which can effectively reduce the cost of repairing agent,reduce the secondary pollution of Fe,improve the repairing efficiency,and degrade TCP more thoroughly and efficiently.