Efficient and simultaneous immobilization of fluoride and lead in water and tea garden soil by bayberry tannin foam loaded zirconium

Human activities have led to various pollution in the environment, and the combined pollution of fluoride and lead in acidic tea garden soil has received much attention. The key to eliminating this combined pollution is to immobilize pollutants simultaneously, thus preventing their migration from tea garden soil to tea trees. In this paper, the natural product bayberry tannin was employed as raw material to fabricate functional materials (TF-Zr) for simultaneous adsorption of fluorine (F) and lead (Pb) in water and soil by the reactivity of tannin with Pb 2+ and the affinity of Zr with F. The characterization techniques such as SEM-Mapping, EDS, FT-IR, XPS were utilized to probe the adsorption mechanism. The results showed that TF-Zr could simultaneously and efficiently adsorb F − and Pb 2+ with the adsorption capacity of 5.02 mg/g (Pb) and 4.55 mg/g (F), and the adsorption processes were both in accordance with the proposed secondary kinetic adsorption model. Besides, the presence of F − promoted the adsorption of Pb 2+ by TF-Zr. The materials were applied into the tea garden soil to explore its effect on the variation of F and Pb forms in tea garden soil. It was found that the proportion of water-soluble fluorine, exchangeable fluorine and exchangeable lead in the tea garden soil decreased significantly, while the proportion of residual fluorine and residual lead increased evidently, illustrating TF-Zr possessed eximious fixation effect on the highly reactive fluorine and lead in the soil and facilitated their conversion to the more stable residue state. Therefore, TF-Zr can be used for the efficient and simultaneous immobilization of fluorine and lead in water and tea garden soil.