In-situ coating of Fe/Pd nanoparticles on sand and its application for removal of tetracycline from aqueous solution

Abstract The current work investigated the potential of Tetracycline (TC) removal from aqueous solutions using Fe/Pd nanoparticles coated over sand by in situ process (IS-Fe/Pd). The developed IS-Fe/Pd was then characterized using XRD, SEM, and EDAX. In batch studies, optimum TC removal (99.78 ± 0.05 %) was attained by initial TC concentration: 20 μg/mL; IS-Fe/Pd weight: 1000 mg; and interaction time: 180 min. The underlying TC removal mechanism was studied by performing a thorough characterization of IS-Fe/Pd and TC solution during the removal process. The structural modifications in IS-Fe/Pd were characterized using XRD, FTIR, SEM, and EDAX, while the chemical variations of the TC solution were studied through TOC, ORP, and LCMS measurements. A combination of degradation and adsorption by IS-Fe/Pd nanoparticle-coated sand was responsible for TC removal from aqueous medium. Also, the cell viability assessment using the bacteria, Bacillus and Pseudomonas, and algae Chlorella sp. revealed that the toxicity of TC has substantially reduced after treatment with IS-Fe/Pd nanoparticle-coated sand. Further, the column study evaluated the impacts of varying bed height, flow rate, and initial TC concentration. At the optimized condition (bed height: 10 cm; flow rate: 1 mL/min; initial TC concentration: 20 μg/mL), the removal capacity was 433 ± 13 μg/mg in column reactors. In the case of TC-spiked natural water systems, 350 ± 18 μg/mg and 395 ± 15 μg/mg capacity was noted for lake and tap water, respectively.