Green synthesized Fe/Pd and in-situ Bentonite-Fe/Pd composite for efficient tetracycline removal

Abstract

The residual TC in the aquatic system is a major threat to human and animal lives. In this study, green synthesized bimetallic Fe/Pd and in-situ clay supported Fe/Pd was used for the efficient removal of tetracycline antibiotics from the aqueous system. Green synthesized bimetallic Fe/Pd nanocomposite and in-situ clay supported Fe/Pd (B-Fe/Pd) were characterized by SEM-EDX, FTIR, and XRD to confirm their size and surface functional groups. The batch removal processes were performed to examine the effect of operational parameters such as dopant Pd concentration (5−20 mM), sorbents: Fe/Pd (100−1000 mg/L) and B-Fe/Pd (100−300 mg/L), pollutant TC (20−60 mg/L) and pH (3–9) on the TC removal. At the optimized conditions, Fe/Pd (sorbent dosage 1000 mg/L, pH 7, TC conc. 20 mg/L), and B-Fe/Pd (sorbent dosage 300 mg/L, pH 7, TC conc. 20 mg/L) nanocomposite can remove 81 % and 97 % of TC from aqueous sample. Higher surface area and prolonged shelf-life of B-Fe/Pd with highest removal percentage make it more effective and efficient material for TC removal; further, the statistical optimization of TC removal by B-Fe/Pd was carried out by response surface methodology, and 95 % of TC could be eliminated from the aqueous solution. Reusability studies of B-Fe/Pd showed that the TC removal efficiency up to 3rd cycle with above 60 % TC removal and the validation on real water sample confirmed with above 75 % TC removal. Residual toxicity of B-Fe/Pd interacted TC solution on freshwater chlorella sp. showed less toxicity, which indicates the environmentally friendly and hazardous free nature of B-Fe/Pd.