Application of CuFe2O4/CuS as a new green magnetic nanocomposite in adsorption of tetracycline from aqueous solutions: mathematical models of thermodynamics, isotherms, and kinetics

In current study, a novel adsorbent of CuFe₂O₄/CuS magnetic nanocomposite (MNC) was constructed via a green approach for tetracycline (TC) removal. The leaf extract of the Alhagi pseudalhagi plant was employed as a green reductant agent. The features of the nanocomposite were characterized using XRD, FTIR, FESEM, TEM, BET, and VSM. Batch studies were conducted to assess the impact of parameters, including pH (3.0–9.0), adsorbent dosage (0.025–2 g/L), TC concentration (5–100 mg/L), and temperature (5–50 °C) on the TC adsorption efficiency. The antibiotic was fully removed at pH 7.0, nanocomposite dose of 1.5 g/L, time of 200 min, and TC content of 5 mg/L. Based on the thermodynamic study, the TC adsorption onto the CuFe₂O₄/CuS MNC occurred spontaneously and was primarily driven by physical interactions (physisorption). Positive values of ∆H° (enthalpy change) and ∆S° (entropy change) demonstrated that the adsorption process is naturally endothermic, and the degree of dispersion improves with rising temperature. Adsorption kinetics was well fitted by the pseudo-second-order model. The isotherm studies showed that TC can be removed by the adsorbent at a maximum of 31 mg/g. Overall, CuFe₂O₄/CuS MNC exhibited notable efficacy and cost-effectiveness (reusability: 5 times) for the TC adsorption from water.