Enhanced fluoride uptake by bimetallic hydroxides anchored in cotton cellulose/graphene oxide composites

A novel hybrid nanomaterial was synthesized by embedding the bimetallic Zr and La (hydro)xides onto the cotton cellulose/graphene oxide composites (CC/GO composites), forming the Zr-La-CC/GO nanocomposites. Selective uptake of fluoride onto the Zr-La /GO hybrids in multiple competitive environments were evaluated. Morphological characteristics of Zr-La-CC/GO nanocomposites reflected the well distributions of embedded Zr and La hydroxides in the nanocomposites. Results also indicated that the encapsulated bimetallic hydroxides in Zr-La-CC/GO hybrids exhibited extremely high fluoride adsorption capacity and stability. XPS investigation exhibited the strong Zr-F and La-F bonds in spent Zr-La-CC/GO nanocomposites, and the bonds were weakened at higher pH, which was consistent with the adsorption results. In addition, CC/GO composites using as the host could also exert the strong shielding effect to improve the stability of embedded La and Zr species so as only a low La dissolution (< 4.2%) and almost no Zr leaching (0.1%) were observed in high HA concentration. What's more, the Zr-La-CC/GO nanocomposites have also shown great potential application for defluoridation in field.