In-site interface growth of bismuth-based hydrothermal carbon using collagen fiber for selective removal of iodide ion from wastewater

The effective adsorption and removal of iodide ion from pharmaceutical wastewater is of great importance. In this paper, a novel adsorbent BT@ACF-Bi for iodide ion recognition adsorption was successfully constructed by chelating Bi3+ at the interface of activated collagen fiber (ACF) coated with plant polyphenols (bayberry tannin, BT). The results showed that BT@ACF-Bi(0.5) reached an adsorption capacity of 55 mg/g at pH 4.0, temperature 25 °C and an initial concentration of 150 mg/L. The iodide ion removal rate reached 90.04% when the adsorbent mass was 160 mg. Meanwhile, the kinetic model and isothermal adsorption fitting for the adsorption process of iodide ion by BT@ACF-Bi(0.5) showed that the process was more consistent with the pseudo-second-order kinetic model and the Freundlich isotherm model. In addition, Bi2O3 generated from the solid loading of Bi3+ on the adsorbent surface is an effective grip for iodide ion, which eventually form stable compounds with the adsorbent in the form of Bi4O5I2. Therefore, the prepared BT@ACF-Bi(0.5) is expected to play an important role in the removal of iodine-containing pharmaceutical wastewater in complex systems due to its high removal rate, ability to be prepared on a large scale and environmental friendliness.