Heat-Resistant Boron Carbonitride with Nitrogen-Vacancies and Oxygen-Doping for Efficient Tetracycline Removal: Adsorption Characteristics, Mechanism and Regeneration

Abstract

The increasing environmental risks associated with tetracycline (TC) have been of widespread interest in the development of adsorbents for the efficient treatment of TC. This work synthesized a high-performance boron carbonitride (BCNvO) with nitrogen-vacancies (Nv) and oxygen-doping (Od) via a hydrogen peroxide mediated strategy. The adsorption capacity of BCNvO-1 for TC (202.85 mg/g) is 1.79 times higher than that of BCN (113.08 mg/g). The adsorption process is well described by the pseudo-second-order kinetic and controlled by surface and intra-pore diffusion. Langmuir can well characterize isothermal adsorption with the fitted maximum adsorption up to 440.53 mg/g. Thermodynamics indicates a spontaneous and endothermic progress in BCNvO-1 adsorption. The abundant pore structures promote pore filling of TC by BCNvO-1. Nv and Od enhance BCNvO-1 proton capture, and the captured protons strengthen hydrogen bonding and electrostatic interactions during adsorption. The functional groups, aromatic regions, and B-N rings on BCNvO-1 are involved in hydrogen bonding and π-π stacking to TC. BCNvO-1 has high adsorption performance, great environmental appropriateness and thermal regeneration performance, suggesting good prospects for its potential application in environmental wastewater treatment.

Keywords: Boron carbonitride, Nitrogen-vacancies and Oxygen-doping, tetracycline, Adsorption, Thermal regeneration