Magnesium ferrite-reinforced polypyrrole hybrids as an effective adsorbent for the removal of toxic ions from aqueous solutions: Preparation, characterization, and adsorption experiments

Contaminated waters with high contents of toxic anions are detrimental to the human health and wildlife. Thus, the quality of drinking water should be carefully monitored. Adsorption technique has been determined to be a reasonable strategy out of several methods used to remove toxic anions from water. Novel MgFe₂O₄-reinforced polypyrrole (Ppy@x%MgFe₂O₄) (x = 1%, 2%, and 5% of MgFe₂O₄) hybrids were synthesized from a pyrrole monomer and MgFe₂O₄ using a simple chemical oxidation method. The fabricated hybrids were studied for their capability to remove PO₄^3–, NO₃^–, and Cr(VI) from aqueous solutions. The results showed that PO₄^3–, NO₃^–, and Cr(VI) removal was highly pH-dependent. The adsorption isotherms of hybrids were fitted well by the Langmuir model, with the maximum adsorption efficiency of 116.90, 76.14, and 138.60 mg/g for PO₄^3–, NO₃^–, and Cr(VI), respectively. In addition, the above-mentioned toxic anions could be efficiently desorbed from spent Ppy@x%MgFe₂O₄ using a 0.1 M NaOH solution, and the hybrids exhibited good regenerability. The prepared materials are promising candidates for PO₄^3–, NO₃^–, and Cr(VI) removal and exhibit high adsorption efficiency, rapid adsorption–desorption behavior, and appropriate recovery from the aqueous medium under external magnetic field.