A novel boron-doped NiCo-LDH catalyst: Rapid activation of peroxymonosulfate for efficient tetracycline degradation

Medical and livestock effluents containing high concentrations of tetracycline (TC) from antibiotic overuse pose a serious threat to human health and ecological environment. Currently, advanced oxidation process (AOP) based on system of layered double hydroxide (LDH) with peroxymonosulfate (PMS) is considered as a promising strategy for treating antibiotic wastewater. However, the limited removal efficiency and difficulties in recovery of LDH restrict its wider practical application. Here, we innovatively synthesized boron-doped nickel-cobalt layer double oxides (B-NiCo-LDO) from NiCo-LDH as an efficient PMS activator. Under the optimum status ([B-NiCo-LDO] = 0.05 g/L, [PMS] = 0.2 g/L), the degradation efficiency of TC (20 mg/L) in the B-NiCo-LDO/PMS system (0.51/min) increased by a factor of 12.75 compared to that in the NiCo-LDH/PMS system (0.04/min) within 10 min reaction. Mechanism explorations revealed that abundant oxygen vacancy (O_vac) and reducibility transition metal on B-NiCo-LDO are the core factors for the enhancement in catalytic activity. Relevant radicals quenching experiments identified ¹O₂ as the key reactive oxygen species. Furthermore, the B-NiCo-LDO/PMS system with non-radical pathway not only exhibited stable performance in different water matrix factors (pH, organic matter, and anion), but was also broadly applicable to remove other refractory organic matter (dyes and ciprofloxacin). This work contributes to gain deeper understanding of the antibiotic removal mechanism by LDH-activated PMS, and supports its application and promotion in complex wastewater treatment.