Effective remediation of fluoride from drinking water using cerium-silver oxide composite incorporated with reduced graphene oxide

The adsorption capacity of adsorbents towards fluoride removal depends on the component of the adsorption system, such as optimizing parameters, matrix of the adsorbent, and entrapped metal oxides. In the present study, we have developed reduced graphene oxide (rGO)-incorporated cerium‑silver mixed oxide composite (rGO-Ce/Ag) and Ce/Ag bimetallic oxide, for removal of fluoride effectively from the sample solution as well as real water samples. Our aim of this study is to study the effect of rGO matrix on the adsorption capacity of the bimetallic oxide. Both these adsorbents were characterized by FTIR, XRD, TGA/DTA, FESEM, EDX, TEM and BET to understand the physiochemical which had been engaged for defluoridation from aqueous solutions. The results of surface analysis give the surface area of rGO-Ce/Ag and Ce/Ag are 375 and 174 m2/g, respectively which clearly shows that the surface area of rGO-Ce/Ag composite is much higher as compared to the Ce/Ag oxide and hence its adsorption capacity. The adsorption capacity of rGO-Ce/Ag and Ce/Ag are 434.78 and 294.11 mg/g with 99.5 and 95.7% removal, respectively which is consistent with the surface analysis results. Both the adsorbents shows similar adsorption kinetics follows pseudo-second order model and followed Freundlich adsorption isotherm i.e. multilayer type of adsorption mechanism on heterogeneous surface of adsorbent, might be due to same entrapping metals, the matrix only plays the role of enhancing adsorption sites and surface area.