Nanoceria-loaded tea waste as bio-sorbent for Cr(VI) removal

In this work, tea waste/CeO₂ bio-composite was synthesized by using tea waste as the carbon matrix in a simple co-precipitation method and assessed for Cr(VI) remediation from contaminated water environment. The formed cerium oxide in bio-composite was crystalline, round in shape, 3–7 nm in size and the surface area of tea waste/CeO₂ bio-composite was 47.3 m²/g respectively. The bio-composite was able to remove 96% of Cr(VI) in the optimized condition of 0.8 g of adsorbent dose, pH 3, temperature 60 °C and initial concentration of 10 mg/L. Langmuir isotherm model and pseudo-second-order rate equation were fitted to the experimental conditions of this adsorption study. The bio-composite has an uptake capacity of 32.15 mg/g at pH 3. The material was effectively able to remove 85% of Cr(VI) in the fourth consecutive cycle. The FT-IR and Zeta potential analysis revealed that hydroxyl functional groups were responsible for Cr(VI) adsorption on the bio-composite surface. The principal mechanisms for this Cr(VI) removal study was mainly due to electrostatic attraction. Overall, the tea waste/CeO₂ bio-composite can be a safe, promising, and novel adsorbent for real wastewater applications.