Mo-doped CuAl-layered double hydroxide for high-efficiency adsorption of tetracycline hydrochloride in wastewater

Effectively removing the residual antibiotics from wastewater generated in daily human production and life remains a significant challenge. To address this issue, a molybdenum-doped CuAl layered double hydroxide (Mo-CuAl-c LDH) was prepared through a one-pot hydrothermal method. Comprehensive characterization techniques were employed to examine the effects of Mo doping on the adsorbent's structural properties and surface chemistry. The efficacy of Mo-CuAl-c for removing tetracycline hydrochloride (TC) from wastewater was quantitatively assessed via adsorption capacity measurements. Analytical results verified the successful integration of Mo into the CuAl framework, confirming the formation of a modified LDH material. Moreover, Mo doping induced structural reorganization of the layered matrix and augmented the density of active sites on its lamellar surfaces. Consequently, the maximum TC uptake capacity of Mo-CuAl-c at 298 K reached 2317.6 mg g^-1, representing a significant enhancement over the undoped CuAl-c analogue. Thermodynamic and kinetic studies confirmed that this adsorption process adhered to the pseudo-second-order kinetics and Langmuir isotherm model, with ion exchange and electrostatic interactions identified as the dominant mechanisms. This work not only presents a alternative adsorbent for TC from wastewater but also provides deeper insights into the adsorption process (including its thermodynamics and kinetics) and the underlying mechanisms.