Novel composite from chitosan and a metal-organic framework for removal of tartrazine dye from aqueous solutions; adsorption isotherm, kinetic, and optimization using Box-Benkhen design.

Cosmetics, textiles, foodstuffs, and medicines frequently contain the yellow dye tartrazine. It has carcinogenic properties and can trigger allergies. In this study, a unique NH-MIL-101(Cr)/chitosan composite (MIL/chitosan composite) was created using a hydrothermal process. The effectiveness of this composite in removing Tartrazine (TZ) from aqueous solutions was investigated. It was characterized via FT-IR, XPS, XRD, and BET analysis. The surface area of the MIL/chitosan nanoadsorbent sample was 1256.64 m/g, where after five times recycling, it was reduced to 1068.14 m/g. The study analyzed the impact of dye concentration, pH, temperature, and MIL/chitosan composite dosage. Experimental measurements were taken for the equilibrium isotherms of dye adsorption. The kinetic models and adsorption isotherm were used to analyze the results. The adsorption process was found to match Langmuir and pseudo-second-order kinetic models. Chemisorption was the mechanism of the adsorption process. Based on thermodynamic parameters, it was determined that the adsorption process was endothermic. The MIL/chitosan composite was recycled up to five cycles. Using the MIL/chitosan composite towards the adsorption of the tartrazine from the real sample has been checked. The interaction process between the MIL/chitosan nanoadsorbent and Tartrazine adsorbate has been investigated. The TZ electrical characteristics, reactivity, and shape were ascertained through the application of density functional theory (DFT). The placement of electrophilic and nucleophilic attack sites is in good agreement with the molecular orbitals (HOMO and LUMO) and MEP results, according to DFT. The optimization of adsorption results was accomplished using Box-Behnken design (BBD).