Abstract
Effectively eliminating residual antibiotics from wastewater produced by human activities continues to pose a considerable challenge. In response, a series of (MgCu)xFe-LDH (x = 2~5) adsorbents with well-defined layered structures and diverse (MgCu)/Fe ratios were prepared via a straightforward one-step hydrothermal approach in this work. The materials were characterized through multiple techniques, and their adsorption capacities were evaluated for tetracycline hydrochloride (TC) removal. Results indicated that while all synthesized (MgCu)xFe-LDHs possessed characteristic hydrotalcite-like structures, (MgCu)3Fe-LDH exhibited superior performance by removing 93.6% of TC under the conditions of 0.2 g·L‒1 adsorbent dose, 100 mg·L‒1 initial concentration, and 298 K. Thermodynamic and kinetic analyses revealed that the adsorption behavior conformed to the pseudo-second-order kinetic model and the Langmuir isotherm, indicating a spontaneous and exothermic reaction influenced by solution pH and coexisting ions. The adsorption process was driven by a synergy of mechanisms, such as electrostatic attraction, hydrophobic interaction, and minor metal complexation. Additionally, Magnesium–copper–iron layered double hydroxide (MgCu)3Fe-LDH) demonstrated excellent recyclability and structural stability, maintaining over 90% removal efficiency after five consecutive cycles. This work represents a dual contribution: it proposes a promising adsorbent for TC removal from wastewater and elucidates the associated adsorption thermodynamics, kinetics, and underlying mechanisms.