Deposition of dyes on Cobalt-based metal-organic framework (Co-MOF) composites with promoted achievement photocatalytic degradation of an anionic dye (EBT) under visible light irradiation

In this study, porous cobalt-based organic frameworks (Co-MOF) were facilely synthesised and functionalised with the amino group using 1, 4-diazabicyclo [2.2.2] octane (DABCO) as a linker. After that, Co-MOF was encapsulated with photosensitive dyes such as methylene blue (MB) and methyl orange (MO) to form MB@Co-MOF and MO@Co-MOF composites. The prepared photocatalysts were fully characterised to evaluate their crystal structure, catalytic properties and morphology. The prepared composites were evaluated towards the photodegradation of Erichrome Black-T dye (EBT) as an example of azo dyes under visible light compared with Co-MOF photocatalyst. The photocatalytic efficiency was 78.9%, 92.0% and 99.7% using 100 mg/L of EBT and photodegradation rate constants (K1) ranged from 0.02, 0.05 and 0.08 min−1at 240 min of visible light irradiation using Co-MOF, MO@Co-MOF and MB@Co-MOF, respectively. This indicates the importance of using photosensitive azo-dyes in this study (e.g. MB and MO) for enhanced the photodegradation of wastewater pollutants. The results demonstrate that MB@Co-MOF photocatalyst is the most prominent photocatalyst for in situ degradation of anionic dyes (e.g. EBT) from wastewater with the highest photostability up to five cycles.