Adsorptive removal of 2,4-dinitrophenol from aqueous phase using amine functionalized metal organic framework (NH2-MIL-101(Cr))

This study reports the successful synthesis of an amine functionalized chromium based metal organic framework ((NH2-MIL-101(Cr)) by hydrothermal method. Characterization of the prepared MOF was carried out by several spectroscopic and analytical techniques in terms of structural, textural, morphological and thermal properties. Notably, a high surface area of 1321 m2/g was obtained for the synthesized NH2-MIL-101(Cr). Furthermore, the MOF showcased remarkable adsorption capacity for the removal of 2,4-dinitrophenol from aqueous medium. Detailed studies for optimizing several process conditions such as pH of 2,4-DNP solution, dosage of adsorbent, initial concentration and temperature were conducted. Results showed that 99% removal of 2,4-DNP was attained with NH2-MIL-101(Cr) at dose-0.5 g L-1 with pH 4 and initial phenol concentration-10 mg/L in 50 min. The adsorption mechanism followed pseudo second order kinetic model. The obtained adsorption data was modelled using different isotherm models and best fitting was attained with Langmuir isotherm. The attained high adsorption tendency could be ascribed to the hydrogen bonding interactions between the nitro group of 2,4-DNP and amino group of NH2-MIL-101(Cr).

Automated summary

This study successfully synthesized an amine functionalized chromium based metal organic framework (NH2-MIL-101(Cr)) using the hydrothermal method. The prepared MOF was characterized for its structural, textural, morphological, and thermal properties. The NH2-MIL-101(Cr) showed a high surface area of 1321 m2/g and exhibited remarkable adsorption capacity for 2,4-dinitrophenol removal. Optimization studies were conducted for various process conditions, and the adsorption mechanism and data were analyzed. The results suggest that the hydrogen bonding interactions between the nitro group of 2,4-dinitrophenol and the amino group of NH2-MIL-101(Cr) contribute to its high adsorption tendency.