High iodine groundwater potentially causes high iodine intake and thyroid disorders in many areas of China.In order to remove iodide from groundwater,two bismuth-based materials,i.e.,(BiO)x(OH)1(NO3)m(CO3)n(BIN)and(BiO)2CO3,were synthesized by the solvothermal method and further investiga-ted to identify the removal efficiency and adsorption stability for iodide ions under complex aqueous envi-ronments(different pH,coexisting anions and simulated groundwater).The microstructure and adsorption mechanism of the bismuth-based materials were analyzed using BET,SEM,XRD,FTIR,Raman and XPS.The results are as follows:BIN and(BiO)2CO3 have rapid rates of iodide removal,which are in accordance with the pseudo-second-order dynamics,and the rapid deiodination are completed by chemical reaction with iodide ions to form BiOI,with the adsorption rates of 93.81％and 95.11％,respectively;the Langmuir model can better describe the adsorption isotherms of both and the maximum adsorption capacities of BIN and(BiO)2CO3 are 129.37 mg/g and 113.76 mg/g,respectively.Under the pH of 3 to 7,the adsorption rates of BIN and(BiO)2CO3 on iodide are favorable,and decrease significantly when pH＞9;the results of coexisting anion and ionic strength experiments show that NO3 has almost no effect on the adsorption of i-odide by the two bismuth-based materials,while CO23-has the greatest effect,and the ionic competition or-der is CO32-＞SO42-＞Cl-＞NO3-.In the solution with 0～10 mol/L CO3-2/SO42-/Cl-,the iodide adsorption rates are inhibited with increasing ionic strength;the results of desorption tests show that the desorption rates of the adsorption products in pure water are all less than 0.76％,and below 50％under four anions(10 mol/L).The two prepared bismuth-based materials have good iodine removal efficiencies and applica-tion prospects for the removal of iodine from water in specific water types whose anions are dominated by SO42-,NO3-and Cl-,which are of great practical importance for ensuring the safety of water supply.
维普
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