Boron nitride modified CuZn-calcinated layered double hydroxides as efficient adsorbents for tetracycline removal

The design and synthesis of derived composite materials based on calcined layered double hydroxides (CLDH) and other materials are essential for tackling antibiotic contamination in aquatic environments through adsorption methods. Herein, the novel CuZn-CLDH modified with non-metallic graphene-like analog of boron nitride (BN) composites (BN@CuZn-CLDH) were fabricated via in situ co-precipitation and calcination method, and then characterized by XRD, FESEM, FT -IR, Raman and XPS in detail. The assembled nanoparticle-sized BN@CuZn-CLDH exhibited exceptional structural stability due to the well-coupled BN and CuZn-CLDH in the composites. The removal efficiency for tetracycline (TC) was up to 7.1 and 2.3 times by BN@CuZn-CLDH over the pure BN and CuZn-CLDH, respectively, and the maximum adsorption capacity, estimated to be 5000 mg/g, was calculated using the Langmuir model fitted under conditions of an adsorbent dosage of 0.1 g/L and a temperature of 303 K. Systematic study of adsorption isotherms, thermodynamics and kinetics revealed that the remarkable improvement of the adsorption performance of BN@CuZn-CLDH was mainly attributed to the enhanced affinity forces such as electrostatic attraction, hydrogen bond, 7c -7c interaction as well as metal complexation between the adsorbent and the adsorbate TC. More importantly, BN@CuZn-CLDH showed good stability and reusability, manifested by the fact that it maintained a consistent removal ratio of 99 % for TC even after undergoing 20 cycles.