摘要
The removal of iodide(I^(−))from source waters is an effective strategy to minimize the formation of iodinated disinfection by-products(DBPs),which are more toxic than their brominated and chlorinated analogues.In this work,a nanocomposite Ag-D201 was synthesized by multiple in situ reduction of Ag-complex in D201 polymer matrix,to achieve highly efficient removal of iodide from water.Scanning electron microscope/energy dispersive spectrometer characterization showed that uniform cubic silver nanoparticles(AgNPs)evenly dispersed in the D201 pores.The equilibrium isotherms data for iodide adsorption onto Ag-D201 was well fitted with Langmuir isotherm with the adsorption capacity of 533 mg/g at neutral pH.The adsorption capacity of Ag-D201 increased with the decrease of pH in acidic aqueous solution,and reached themaximum value of 802 mg/g at pH 2.This was attributed to the oxidization of I^(−),by dissolved oxygen under the catalysis of AgNPs,to I2 which was finally adsorbed as AgI3.However,the aqueous solutions at pH 7–11 could hardly affect the iodide adsorption.The adsorption of I^(−)was barely affected by real water matrixes such as competitive anions(SO_(4)^(2−),NO_(3)^(−),HCO3−,Cl^(−))and natural organic matter,of which interference of NOM was offset by the presence of Ca^(2+).The proposed synergistic mechanism for the excellent performance of iodide adsorption by the absorbent was ascribed to the Donnan membrane effect caused by the D201 resin,the chemisorption of I^(−)by AgNPs,and the catalytic effect of AgNPs.
基金
This work was kindly supported by the National Natural Science Foundation of China(Nos.42192571 and 21827815).
