Removal of cadmium and lead from aqueous solutions using iron phosphate-modified pollen microspheres as adsorbents
Xiaoxing Zhang, Hui Liu, Jin Yang, Li Zhang, Binxia Cao, Libo Liu, Weimin Gong
Abstract
Abstract Iron phosphate-modified pollen microspheres (pollen@FePO 4 ) were prepared and applied as sorbents for the removal of heavy metals (Cd 2+ and Pb 2+ ) from the aqueous solution. Batch sorption studies were conducted to investigate the effects of solution pH, contact time, sorbent dosage, and metal concentration on the adsorption process. The sorption of Cd 2+ and Pb 2+ ions on pollen@FePO 4 corresponds to the pseudo-second-order model and Langmuir isotherm, which is similar to the unmodified pollen. At pH 5.92, pollen@FePO 4 offers maximum adsorption capacities of 4.623 and 61.35 mg·g −1 for Cd 2+ and Pb 2+ , respectively. The faster sorption kinetics and higher adsorption capacities of Cd 2+ and Pb 2+ ions onto pollen@FePO 4 than pollen indicates that it might be a promising material for the removal of heavy metal ions in aqueous solutions. The possible adsorption mechanism involves electrostatic and chemisorption for Cd 2+ and mainly complexion for Pb 2+ .