Wool Keratin Mineralization and Functionalization: Silver Nanoparticles Synthesis and Rare Earth Elements Binding

Abstract

This paper reports a facile synthesis approach of wool keratin (WK) -templated ultrasmall(≈2nm) Ag nanoparticles. WK molecules are introduced as the template protein because of the high content of the thiol group (−SH) and unique macro molecular network structure. The optimal conditions for the formation of luminescent WK@AgNPs is established by several controlled experiments. TEM, AFM, and Photoluminescent (PL) are used for investigation of morphology and confirmation of wool keratin functionality. The structure of WK@AgNPs can be clearly observed that one or more AgNPs are bridged by keratin chain to form high molecular weight species. Take a step futher, the success of silver nanoparticle synthesis provides us with an idea to make use of the thiol group for the functionalization of wool keratin. By linking the group HOPO-Malamide to the thiol group in the WK, it is possible to apply this modified WK for rare earth recovery. The CD, FTIR and XPS results confirmed that the success of modification. But the efficiency of recovery of rare earth elements need to be further studied.