Engineered ZnFe2O4/C nanocomposite for efficient hexavalent chromium removal

Abstract

This study investigates the synthesis, characterization, and application of a carbonaceous zinc ferrite (ZnFe₂O₄/C) nanocomposite as an efficient adsorbent for hexavalent chromium removal from aqueous solutions. The synthesized composite material was characterized using X-ray diffraction, which revealed a crystallite size of 46 nm. Brunauer-Emmett-Teller (BET) analysis confirmed its mesoporous nature, with a specific surface area of 56.925 m²/g, a pore volume of 0.085 cc/g, and an average pore diameter of 3.726 nm. Batch adsorption studies demonstrated excellent Cr (VI) removal efficiency of 83 % under optimal conditions. The adsorption process exhibited pH dependency, with a maximum removal of 86 % achieved at pH 4. This is attributed to the electrostatic attraction between the positively charged adsorbent surface and negatively charged chromate species. Isotherm studies revealed that the adsorption process best fits the Langmuir model, indicating monolayer adsorption with a maximum capacity of 39.37 mg/g with kinetic studies revealing the rapid initial uptake followed by gradual equilibration. The adsorbent demonstrated remarkable stability during reusability tests, with removal efficiency reported at 78.76 % even after six consecutive adsorption-desorption cycles. The study establishes ZnFe₂O₄/C as a promising adsorbent for chromium removal in an effort to establish sustainable water remediation technologies.