Facile preparation of tannin-coated waste silk fabric as an effective heavy metal adsorbent

Abstract

Recently, environmental issues caused by industrial wastewater containing toxic heavy metal ions become have severe owing to rapid industrialization. In particular, heavy metal ions that cause water pollution accumulate in living organisms, endangering life. To remove large amounts of heavy metals from industrial effluents, cost-effective and eco-friendly adsorbents are required. In particular, Pb ion is a representative harmful heavy metal ion. Tannic acid (TA) contains a large amount of polyphenol groups, such as gallol and catechol groups, and TA can effectively remove heavy metal ions owing to its superior metal coordination performance. Herein, we prepared a heavy metal adsorbent using waste silk fibroin (SF) fabric by a simple dip-coating process. The intermolecular reactions involving in the process of coating TA on the SF fabric were analyzed by ATR-IR, DRUV, XPS in detail. In addition, the heavy metal adsorption behavior and applicability of the SF/TA adsorbent was investigated using Pb ion as a representative harmful heavy metal ion. Furthermore, the experimental data for heavy metal adsorption was analyzed using adsorption kinetics and adsorption isotherm. Overall, the SF/TA adsorbent showed excellent adsorption and reusability for Pb ion.