Improved Pb(II) removal by D001 resin with a facile nanoscale α-FeOOH modification

Macroporous strong acidic resin (D001) is restricted in Pb(II) removal from water due to the interference of common environmental cations. A novel modified D001 (nFeOOH@D001) was developed by loading nanoscale α-FeOOH (nFeOOH) with a facile ethanol-dispersion-impregnation method to improve Pb(II) removal from aqueous solution. Solid-phase analysis showed that α-FeOOH of 10-100nm was evenly loaded onto D001. The nFeOOH@D001 maintained the electrostatic adsorption ability of D001, and obtained the complexation adsorption capacity of nFeOOH. The nFeOOH@D001 therefore achieved a 20.2% higher Pb(II) removal rate of 74.5% as compared to the D001 of 54.3%. Under the competition of Ca2+ and Mg2+ ions, the nFeOOH@D001 showed better selectivity for Pb(II) through the complexation of hydroxyl and ferrite groups on nFeOOH. The pseudo-first order kinetics and Langmuir-adsorption models well fitted the Pb(II) removal data, indicating a chemistry and monolayer adsorption process. This process depended on pH and achieved a Pb(II) removal over 65% within a pH range of 3-7. During cyclic test, used nFeOOH@D001 could be refreshed with acetic acid as eluent. Spent nFeOOH@D001 could be remodified with nFeOOH by the above impregnation method after stripping iron oxides with hydrochloric acid. The regenerated nFeOOH@D001 obtained a regeneration rate of 97.6% as compared to virginal nFeOOH@D001. The results demonstrated that the introduction of nFeOOH could effectively improve the performance of D001 for Pb(II) removal from water.