One-step high-efficiency microwave synthesis of N-doped bamboo biochar for tetracycline degradation

Abstract

N-doped bamboo biochar (NBB) was successfully synthesized through one-step, rapid pyrolysis (e.g., 10 min) using urea and urea nitrate impregnated bamboo particles exposed to low power (e.g., 460 W) microwave radiation. NBB-460 exhibited high specific surface area of 876.1 m2/g and outstanding catalytic performance for tetracycline hydrochloride (TCH) degradation. The TCH degradation efficiency reached to 94.3 % with the optimized catalytic condition (i.e., 0.2 g/L NBB-460, 3 mM PMS, 50 mg/L TCH, 25 ℃, without pH regulation). The density functional theory calculation showed that the graphitic nitrogen and pyridinic nitrogen of NBB-460 served as active sites for peroxymonosulfate activation and TCH degradation. The quenching test, electron paramagnetic resonance spectra, and electrochemical measurements indicated that tetracycline hydrochloride underwent degradation via radical (O2•−), non-radical (1O2) pathways, and surface electron transfer. This study introduces an energy-efficient and time-effective method for converting biomass to N-doped biochar as highly efficient peroxymonosulfate activator for environmental applications.