Efficient degradation of organic dye using Ni-MOF derived NiCo-LDH as peroxymonosulfate activator

Nickel-based metal-organic framework (Ni-MOF) was employed as a sacrificial template for the preparation of nickel-cobalt layered double hydroxide (NiCo-LDH) under different hydrolysis time. The template etching rate varied at different hydrolysis time, resulting in variations of the structural and morphology of NiCo-LDHs. The NiCo-LDH/10 sample showed a large specific surface area and the well-oriented larger dimension of thinner sheets due to the sufficient in-situ etching of the Ni-MOF template. The NiCo-LDH/10 was an excellent heterogeneous catalyst to activate peroxymonosulfate (PMS) for highly efficient Reactive Red-120 dye degradation. The results exhibited that the degradation efficiency of the NiCo-LDH/10-PMS catalyst was 89% for RR-120 dye within 10 min in the presence of the PMS system, which is higher than other NiCo-LDHs. Moreover, the other influencing factors such as PMS concentration, catalyst dosage, initial pH were also investigated towards degradation. The radical quenching measurement proved that the sulfate (SO₄^•-) and hydroxyl (OH^•) had been indicated as the primary radicals. Besides, the NiCo-LDH/10-PMS catalyst showed excellent reusability even after five consecutive cycles (83.6% of the degradation efficiency). This work offer insight study on the construction of controlled morphology NiCo-LDH heterogeneous structure for high-efficiency PMS activation.