In this study, amine-functionalized of Fe-MIL-101 (NH2-Fe-MIL-101) was synthesized by the solvothermal method and applied for the removal of two food dyes amaranth (AM) and sunset yellow (SU). Due to the overlap of absorption peaks of these two dyes, it is impossible to measure and simultaneous monitor adsorption process of dyes. The principal component regression was assisted in overcoming this problem. To fnd signifcant parameters that can potentially infuence the adsorption process, a fractional factorial design (26-1) was applied. To optimize the signifcant factors, the response surface methodology was implemented based on Box–Behnken design. The independent variables of sorbent dose (8–20 mg), solution pH (2–10), initial concentration (20–40 mg L−1) of dyes, and contact time (10–30 min) were considered in this study. The optimal conditions for each variable were achieved by the desirability function approach. The conditions were obtained as follows: adsorbent dosages (14 mg), pH (2), initial concentration (40 mg L−1), and contact time (30 min). Isotherm models of Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich were also studied. Under optimal conditions, the maximum adsorption capacities obtained were 131 and 116 mg g−1 for AM and SU, respectively.
