Interfacial growth of metal-organic framework on carboxyl-functionalized carbon nanotubes for efficient dye adsorption and separation

Hybrid nanocomposites based on UiO-66-NH 2 and carboxyl-functionalized carbon nanotubes were developed in this study via different synthetic pathways. Combining them through interfacial in situ growth was beneficial for the better dispersity of UiO-66-NH 2 in the CNTs@UiO-66-NH 2 composite than physically mixing CNTs/UiO-66-NH 2 and chemically bonded CNTs-CONH-UiO-66. Coordination between carboxyl groups of CNTs and zirconium ions resulted in the interfacial growth of UiO-66-NH 2 on CNTs. Adsorption experiments showed that CNTs@UiO-66-NH 2 exhibited the highest adsorption efficiency towards methyl orange (MO). The adsorption capacity of CNTs@UiO-66-NH 2 was up to 392 mg g −1 , which was 77.45% and 201.5% higher than those of CNTs-CONH-UiO-66 and CNTs/UiO-66-NH 2 respectively. Moreover, CNTs@UiO-66-NH 2 could selectively adsorb MO from the MO/MB mixture. CNTs@UiO-66-NH 2 hybrids prepared through an interfacial in situ growth pathway exhibited a high adsorption capacity 392 mg g −1 towards MO and can effectively separate the MO/MB mixture.