Polyacrylic Acid-b-Aolyptyrene Covered Ni/Fe Nanoparticles To Remove 1,1,1-trichloroethane And Tetracycline From Groundwater

Chlorinated aliphatic hydrocarbons and Cr(?)are two common types of pollutants in groundwater,which have had a serious impact on human life safety.In this study,a polyacrylic acid-b-polystyrene-embedded nano-Ni/Fe bimetallic material(PAA-b-PS-Fe/Ni)was prepared by microemulsion reduction method and atom transfer radical method.The migration and oxidation resistance of nanomaterials were investigated by exposure experiments and quartz sand packed column experiments.And the removal effect of nano-bimetallic materials on 1,1,1-trichloroethane(1,1,1-TCA)and Cr(?)was investigated under the presence of potentially interfering substances..The results show:Since PAA-b-PS can prevent zero-valent iron agglomeration,the average size of PAA-b-PS embedded nano-Fe/Ni bimetallic particles is about 50 nm;The optimal dose for PAA-b-PS-Fe/Ni degrades 1,1,1-TCA is:Ni/Fe=2 wt%and 0.5 g/L PAA-b-PS embedding concentration.The pseudo first order rate constant(Kobs)of 1 mg/L PAA-b-PS-Fe/Ni removed 200 mg/L 1,1,1-TCA was 0.61 h"1 in 240 minutes.However,the Kobs of 1,1,1-TCA removed by other materials(Fe,pure bimetallic Ni/Fe,PAA-b-PS-Fe)were only 0.13,0.23 and 0.42 h-1,respectively.The removal efficiency of 1,1,1-TCA by PAA-b-PS-Fe/Ni(about 88%)is independent of various concentrations of various common inorganic anions(NO3-,HCO3-and SO42-).However,humic acid(HA)has a great influence on the degradation of 1,1,1-TCA.In the removal of Cr(?)from groundwater in low-permeability formation by PAA-b-PS-Fe/Ni,it was found that the nZVI after PAA-b-PS embedding has superior mobility and oxidation resistance.When the temperature is 25? and the initial concentration of Cr(?)is C0=30 mg/L,the dosage of PAA-b-PS-Fe/Ni is 0.4 g/L,which has the best removal effect on Cr(VI).The rate reaches 99.8%;the acidic environment is favorable for the reduction reaction,and the carboxylic acid radical('COOH)of PAA-b-PS creates an acidic environment,which accelerates the removal of Cr(VI).