Construction of novel HKUST-1 supported vermiculite composite for excellent enhancing of malachite green adsorption

Water-soluble organic dye removal has great importance for the management and protection of water resources. In our study, vermiculite (Ver) clay was evaluated for malachite green (MG) removal and enhanced with Cu metal-organic framework (HKUST-1) to increase adsorption potential. The structural properties of adsorbents were characterized by XRD, BET/N2, FT-IR and SEM-EDX. The MG adsorption capacity of Ver, 10HKUST-1/Ver and 25HKUST-1/Ver was obtained as 54.97, 296.74 and 213.22 mg g-1, respectively. The Langmuir isotherm and pseudo second order kinetic models were found to be compatible for all three adsorbents. Since both the adsorbent surfaces and the MG have a positive charge in the low pH medium, the adsorption capacity decreased. The MG adsorption processes showed thermodynamically endothermic and spontaneous nature. The adsorption capacities of MG in different water medium were investigated, furthermore, the adsorption behaviors were elucidated with solutions containing various anions and cations to support the effect of water content. In the reusability tests, the adsorbents uptake rates in the fifth cycle were 60.91%, 84.34% and 83.04% for Ver, 10HKUST-1/Ver and 25HKUST-1/Ver, respectively. Ver and composites also exhibited remarkable adsorption efficiencies against different types of organic pollutants. Finally, 10HKUST-1/Ver composite is efficient sorbent for MG removal treatments.