Adsorption performance of tetracycline on NiFe layered double hydroxide hollow microspheres synthesized with silica as the template

Tetracycline (TC) has poor degradability and hepatotoxicity which will increase the burden on the aquatic environment when discharged into lakes in large quantities. LDH materials are often used as adsorbents because of their superior surface area and controllability of morphology. Herein, NiFe LDH hollow microspheres (NFHMS) were synthesized by a facile hydrothermal method. The removal of tetracycline by the as-prepared material in an aquatic environment was systematically investigated through comprehensive characterizations. The NFHMS sample presents a larger specific surface area than the two control samples, which contributes to its higher adsorption performance. The adsorption mechanisms of TC on NFHMS is mainly electrostatic adsorption. The fitting results of experimental data coincide well with pseudo-second-order and Weber-Morris models through kinetic simulation. Moreover, the Langmuir model is verified to be more suitable than the Freundlich model in elucidating molecular surface adsorption, and the maximum adsorption capacity of NFHMS obtained from the Langmuir model is 90.9 mg g-1. Higher temperature is beneficial to improve the adsorption performance, and the adsorption process is spontaneous and endothermic. The initial pH of the solution will affect the adsorption capacity, and the partial neutral condition is more favorable. In addition, NFHMS sample exhibits good stability in cyclic tests. Therefore, NFHMS material is expected to be a very promising adsorbent for treating tetracycline in wastewater.