Fluoride removal performance of a new hybrid sorbent of Zr(IV)–ethylenediamine

A novel zirconium(IV)-ethylenediamine (ZrEDA) hybrid material was prepared by mixing aqueous solution of zirconium oxychloride (0.1 M) and aqueous solution of ethylenediamine (0.1 M) following an environmental friendly sol–gel method. The material was characterized by FTIR, XRD and SEM combined with energy dispersive spectrum technique. The hybrid material was tested for removal of fluoride with variation of solution parameters. The extent of fluoride removal was more than 99% and fluoride adsorption equilibrium was attained in a 14 min time period. The adsorption follows a pseudo second order kinetics with theoretical adsorption capacity (qe,cal) and experimental adsorption capacity (qe,exp) close to each other. The value of thermodynamic parameter ΔH indicated an endothermic adsorption process. A negative value of ΔG shows the feasibility and spontaneity of material-anion interaction. The adsorbed fluoride could easily be desorbed from the material by using 0.1 M NaOH solution. Further, the regenerated material was tested up to 10th consecutive cycles of operation without significance loss of adsorption efficiency.

The proton shifting mechanism in the formation of ZrEDA.Figure optionsDownload as PowerPoint slideHighlights
► Zirconium–ethylenediamine (ZrEDA) is prepared using environmental friendly sol–gel method.
► EDS spectrum shows elemental composition as Zr, C, O and F.
► Fluoride adsorption on ZrEDA follows pseudo second order kinetics.
► No effect of nitrate, chloride and sulphate on adsorption properties.
► Adsorption capacity (qm) at pH 7.0 is 37.03.