A novel FeTiZn ternary oxide nanocomposite for spontaneous and efficient adsorptive removal of hexavalent chromium from polluted water.

This study investigates the adsorption performance of a FeTiZn oxide nanocomposite for the efficient removal of toxic hexavalent chromium [Cr(VI)] from aqueous media. The nanocomposite was synthesized via a simple aqueous co-precipitation route and characterized using XRD, FTIR, SEM, TEM, and EDX techniques, confirming its crystalline structure and uniform nanostructured morphology. Batch adsorption studies were conducted to evaluate the effects of pH, contact time, adsorbent dosage, and temperature on Cr(VI) removal. The maximum adsorption capacity (qmax) determined from the Langmuir model was 256.41 mg g⁻¹ at 298 K, indicating a high affinity toward Cr(VI) ions. Kinetic modeling revealed that adsorption followed a pseudo-second-order model (R² = 0.998), suggesting chemisorption as the rate-determining mechanism. Thermodynamic analysis yielded ΔG° = - 4.35 kJ mol⁻¹ and ΔH° = +24.18 kJ mol⁻¹, confirming that the adsorption process is spontaneous and endothermic in nature. The FeTiZn oxide nanocomposite exhibited excellent stability, maintaining 84.6% of its initial adsorption efficiency after five regeneration cycles. Statistical analyses, including ANOVA and t-tests, validated the reliability of the experimental results and model predictions. Overall, the findings demonstrate that the FeTiZn oxide nanocomposite is a promising and reusable adsorbent for Cr(VI) removal, offering a sustainable approach for water purification and environmental remediation.