Efficient degradation of tetracycline in wide pH range using MgNCN/MgO nanocomposites as novel H2O2 activator. (15th June 2021) - Ge, Lifa
Highlights: MgNCN/MgO nanocomposites were firstly prepared by a one-pot calcination method. MgNCN/MgO nanocomposites were firstly used as H2 O2 activator for TC degradation. The catalytic degradation of TC could be conducted in a wide pH range of 4-10. Singlet oxygen was main reactive oxygen species responding for TC degradation. The Mg-N coordination in composites played a key role in H2 O2 activation. Abstract: Currently existing Fenton-like catalysts were limited in wastewater treatment owing to their potential transition-metal poisoning, narrow applicable pH range and high dependence on external energy excitation. In this work, the MgNCN/MgO nanocomposites were firstly synthesized by a facile one-pot calcination of melamine and basic magnesium carbonate, and used as novel H2 O2 activator for antibiotic removal. It was found that the MgNCN/MgO composite calcined at 550°C with the mass ratio of melamine to basic magnesium carbonate at 2:1, exhibited an excellent catalytic ability to tetracycline (TC) degradation in a wide pH range of 4-10 without any external energy input. More than 90% of TC (100 mL, 50 mg/L) could be degraded within 30 min by 10 mg of the nanocomposite in the presence of 0.2 mL of 30 wt% H2 O2 . Based on the experimental results, it was concluded that the Mg-N coordination between MgNCN and MgO in MgNCN/MgO nanocomposites activated H2 O2 to produce primary singlet oxygen ( 1 O2 ) and minor hydroxyl radicals (·OH), responding for TC degradation. In addition, the degradation pathways of TC were deduced by determining the generated intermediates during the degradation process. This work provided a novel idea for designing transition-metal-free catalysts for nonradical activation of H2 O2 in the absence of external energy excitation. Graphical abstract: Image, graphical abstract