Investigation of a Bioflotation Interface with Infrared Spectroscopy

In this paper we report an approach for the structural analysis of mineral-collector interfaces of (bio) flotation systems by means of attenuated total reflection Fourier-transform infrared spectroscopy (ATR FT-IR). The extraction of rare earth metals from electronic waste materials is an important challenge for the recycling industry. In a current project bacteriophage are used as biocollectors to develop a bioflotation model system for the separation of lanthanum phosphate doped with cerium and terbium (LaPO₄:Ce³⁺,Tb³⁺) from mixed fluorescent phosphors. As an initial analytical concept fluorescence microscopy was successfully applied to investigate particles of spent fluorescent lamp powders and to visualize the bacteriophage on the surface of the waste material. However, due to the restrictions of this technique we are not able to identify the molecular interactions of the bacteriophage with the recycled material. ATR FT-IR was found to be an effective tool to detect the major coat protein of the bacteriophage biocollectors on the surface of the LaPO₄:Ce³⁺,Tb³⁺ and sense their specific bonding interaction opening the gates for the high level chemical characterization of the interface.