Mg/Al LDO microspheres with high surface area for efficient tetracycline hydrochloride removal from water

Abstract

Mg/Al layered double oxide (Mg/Al LDO) microspheres with a high specific surface area (221.69 m² g⁻¹) were synthesized via a hydrothermal–calcination method based on Ostwald ripening, exhibiting exceptional adsorption performance for tetracycline hydrochloride (TCH). The experimental results indicate that the material calcined at 500 °C for 3 hours exhibits the best adsorption performance. Kinetic studies of TCH adsorption revealed that the adsorption phenomenon conforms to the pseudo-second-order kinetic model, confirming that the process is dominated by chemical adsorption. Isothermal adsorption experiments showed that the Langmuir model can most accurately describe the adsorption characteristics of TCH, confirming that it is monolayer adsorption. According to this model, the maximum adsorption capacity of the material for TCH reaches 187.17 mg g⁻¹ at 318 K. Further mechanistic analysis indicates that the adsorption of TCH by Mg/Al LDO microspheres is primarily achieved through a combination of electrostatic attraction, hydrogen bonding, and surface complexation. This study demonstrates that Mg/Al LDO microspheres, as an efficient and stable adsorbent material, hold significant practical application value and broad development prospects in the field of antibiotic wastewater treatment.