MIL-53(Al)@HC nanohybrid for bicomponent adsorption of ibuprofen and metsulfuron-methyl: Application of macro- and microscopic models and competition between contaminants.

In this work, a hybrid was synthesized by hydrothermal treatment, metal-organic framework functionalized with hydrochar (MIL-53(Al)@HC) for the adsorption of two organic molecules Ibuprofen sodium salt and Metsulfuron-methyl, in binary system. The hybrid is composed of 71 wt% biomass and 29 wt% MOF. TGA, BET, FTIR, XRD and XPS characterization techniques were used to verify the hybridization of MIL-53(Al)@HC. The MIL-53(Al)@HC hybrid showed in situ MIL-53(Al) crystal growth capability. Batch adsorption experiments were carried out to study the effect of pH, adsorbent dosage, adsorbate concentration, contact time and temperature effect. The results obtained under extreme conditions demonstrate that MIL-53(Al)@HC is an adsorbent capable of removing >98% of IBU and MTM in mixture at a concentration of 0.3 mM (68 ppm IBU and 115 ppm MTM). The pseudo-second order model adequately described the adsorption kinetics and equilibrium using the Sips and Freundlich models. The physico-statistical microscopic model (2-layer) corroborated the hypothesis of a multilayer adsorption proposed by the macroscopic Freundlich model. In the competition study between IBU and MTM, both antagonistic and synergistic effects were observed. In the thermodynamic study, positive values of (ΔH°) indicate that adsorption is endothermic in nature and that the dominant mechanism is physisorption. A mechanism of adsorption by hydrogen bridging and non-covalent π*-π adsorbate-adsorbate and adsorbate-adsorbate-adsorbate interactions was proposed. The desorption study shows that in 5 washing cycles MIL-53(Al)@HC is a recoverable material.