Simultaneous removal of toxic cyanide and Cu(II) ions from wastewater by a bi-functional raspberry-like TiO₂@yeast microspheres

A novel strategy for simultaneous removal of cyanide anions and copper cations was proposed. Firstly, TiO₂@yeast hybrid microspheres with raspberry-like structure were fabricated by a facile hydrolysis method using titanium tetrachloride as Ti precursor. The physicochemical properties of the as-prepared samples were fully characterized. The bi-functional composites were then employed for the simultaneous removal of a typical mixture of cyanide and copper metal ions via bio-adsorption in dark and photo-catalysis under UV irradiation. The results showed that the satellitic TiO₂ nanoparticles within the TiO₂@yeast raspberry-like structure functioned as the photocatalytic active sites providing the electron/hole pairs, while the yeast cores worked as the adsorbent to capture the cyanide and copper ions onto the photocatalytic active sites. The synergistic effects of the bio-adsorption by yeast and photo-catalysis by the TiO₂ nanoparticles over the bi-functional composites were demonstrated. Our results are expected to be of significant value for various environmental friendly applications.