Development of zirconium (IV)-metalloporphyrin grafted Fe3O4 nanoparticles for efficient fluoride removal

Fluoride contamination of the industrial wastewaters is one of the major problems worldwide imposing a serious threat to human health. Among several treatment technologies applied for fluoride removal, adsorption process has been explored widely and magnetic nanoparticles has provided unique advantages in due course. We report here the synthesis of a new sorbent consisting of 3-aminopropyl triethoxysilane (APTES) coated magnetic nanoparticles functionalized with a zirconium (IV) porphyrin complex Zr(TCPP)Cl2 [TCPP: tetrakis(4-carboxyphenyl) porphyrin]. Fe3O4 nanoparticles were synthesized by co-precipitation of Fe2+ and Fe3+ in an ammonia solution, and then their surface was modified with APTES and Zr(TCPP). The morphology and properties of the nanoparticles were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental analysis, Fourier transform infrared spectroscopy (FT-IR), and Thermo-gravimetric analysis (TGA). The batch experiments showed that modified nanoparticles can effectively be used to remove fluoride from water. Under optimal conditions for a fluoride concentration of 10 mg L−1, contact time: 20 min, pH: 5.5, and nanosorbents dosage: 100 mg, the percentage of the extracted fluoride ions was 92.0 ± 1.7%. The regeneration studies also showed that nanoadsorbents could be re-used for fluoride removal from aqueous solutions without any significant changes in the sorption capacity. The synthesized sorbent was successfully applied for treating a wastewater sample from glass industry.

► This work aims at fluoride removal in batch experiments.
► The major advantage of this work is the application of magnetic nanoadsorbents.
► This method applies the anion selectivity of metalloporphyrins.
► We have synthesized a new compound which could effectively and selectively remove fluoride ions which are harmful in excessive amounts.
► As far as we examined the proposed method is without any major interference.