Behavior and mechanism of the adsorption of lead by an eco-friendly porous double-network hydrogel derived from keratin. (February 2022)

• Record Type: Journal Article
• Authors: Cao, Hui; Ma, Xiuna; Wei, Ziqi; Tan, Yang; Chen, Siwei; Ye, Tai; Yuan, Min; Yu, Jinsong; Wu, Xiuxiu; Yin, Fengqin; Xu, Fei
• Is Part Of: Chemosphere. Volume 289(2022)
• Publication Date: 2022-02
• Subjects: Keratin -- Porous double-network hydrogel -- Lead ions removal -- Recognition mechanism; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.133086
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In this study, a novel eco-friendly porous double-network keratin/polyacrylic acid (keratin-PAA) hydrogel was prepared using the one-pot method to improve the adsorption performance of the hydrogel toward Pb(II). The obtained porous keratin-PAA hydrogel was then characterized using nitrogen adsorption–desorption isotherms, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The interaction mechanism of Pb(II) and the keratin-PAA hydrogel was further investigated using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The results showed that keratin-PAA hydrogel was successfully synthesized, with a specific surface area of 49.35 m 2 /g and a uniform pore distribution of 6.20 nm. The synthesized keratin-PAA hydrogel only took 6 min to adsorb nearly 70% of Pb(II) from the solution because of the interconnected porous network. The keratin-PAA hydrogel also showed a maximal adsorption amount of 234.6 mg/g, and satisfactory selectivity toward Pb(II). The adsorption kinetics of the keratin-PAA hydrogel binding to Pb(II) could be better described by the pseudo-second-order model, whereas the adsorption isotherms could be fitted using the Langmuir equation; this suggested that chemisorption was the main rate-limiting step. The XPS and FT-IR analysis results indicated that the sulfur-, nitrogen- and oxygen-containing groups in the keratin-PAA hydrogel were the main binding sites for Pb(II). In real aqueous samples, the keratin-PAA hydrogel could remove 93–104% of Pb(II). It is clear that the keratin-PAA hydrogel is an outstanding adsorbent material for the removal of Pb(II) from aqueous samples. Graphical abstract: Image 1 Highlights: A novel eco-friendly porous keratin-PAA double-network hydrogel was synthesized herein. The hydrogel had a maximal adsorption capacity (234.6 mg/g) for Pb(II) owing to large surface area. The hydrogel only took 6 min to adsorb nearly 70% of Pb(II) owing to its porous structure. The S- and N-containing groups in the hydrogel are the main binding sites for Pb(II). The hydrogel can remove 93–104% of the Pb(II) in aqueous samples.