Adsorption of Ag~+ by persimmon tannins immobilized on collagen fiber

摘要

In the present work, a novel adsorbent to effectively adsorb Ag~+ from an aqueous solution has been prepared by immobilizing persimmon tannin (PT) on collagen fiber. The adsorption capacity of Ag~+ on the immobilized PT were evaluated under various treatment conditions, including the initial solution pH, solid-liquid ratio, temperature, and initial concentration of Ag~+. The results showed that the effect of initial solution pH, solid-liquid ratio, and initial concentration of Ag~+ on the adsorption capacity were remarkable, while the influence of temperature was insignificant. The adsorption capacity reached 1947 mg/g at 303 K and pH 7.0 when the initial concentration of Ag~+ was 800 mg/L and solid-liquid ratio was 0.4. Adsorption equilibrium isotherms of Ag~+ on the surface of the adsorbent fibers were studied using Freundlich and Langmuir isotherms. The experimental data fitted best to the Freund-lich models. Also, the immobilized PT before and after adsorption of Ag~+ was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction, and scanning electron microscopy. All these results indicated that the immobilized PT adsorbed efficiently and could be used as a low-cost alternative for the adsorption of Ag~+ in wastewater treatment.