Silica-Magnetite Composite as an Eco-friendly Adsorbent for Aqueous Tetracycline Removal: Kinetic and Isotherm Studies

Abstract

Silica and magnetite have been recognized as emerging and effective environmentally-friendly pollutant removers. In this study, the effectiveness of silica/magnetite (SM) composites derived from local beach sand were developed and evaluated as an environmentally friendly adsorbent for taking up tetracycline from water. The formation of SM composites was verified through characterization performed using Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and Scanning Electron Microscope (SEM) analysis. Two key parameters, kinetics and isotherms, were investigated to find the best condition for tetracycline adsorption using SM composites. In the kinetic adsorption studies, the pseudo-first-order, with correlation coefficients (R 2 > 0.99) higher than those of the pseudo-second-order and Elovich models, was performed to be the best-fitting model due to the close alignment between the experimental and theoretical data. The non-linear Langmuir isotherm model offered the most accurate fit (R 2 = 0.954, root-mean-square-errors = 1.505) compared to the Freundlich model, signifying that the adsorption process takes place on a uniform surface where the adsorbate is distributed in monolayers. In the present study, the maximum adsorption capacity of tetracycline onto SM composite reached 29.955±4.165 mg/g for 24-hour contact time with an adsorption rate constant of 0.415±0.050 min -1 . In conclusion, the developed environmentally conscious composite demonstrates the potential to be an effective adsorbent with remarkable tetracycline removal properties while also providing valuable insights for further research.

Aquatic assessment of the chelating ability of Silica-stabilized magnetite nanocomposite to lead nitrate toxicity with emphasis to their impact on hepatorenal, oxidative stress, genotoxicity, histopathological, and bioaccumulation parameters in Oreochromis niloticus and Clarias gariepinus

“…Silica can be safely applied in the food and aquaculture sectors [ 24 ]. Combining magnetite NPs with silica has been recognized as an emerging and effective approach to improve the adsorption efficiency of these nanoparticles by enhancing their chemical stability [ 25 , 26 ].…”