Synthesize of Iron-Polyphenol Nanohydrogel from Melia Azedarach Fruit Extract and its Application as a Flocculant for Coagulation and Removal of Disperse Yellow 211

Melia azedarach fruit extract is used to synthesize iron-polyphenol nanohydrogel and its capability as a flocculant in coagulation and removal of Disperse Yellow 211 dye from the aqueous solution is examined. The structure of iron-polyphenol nanohydrogel is studied by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis, and zeta potential. The field emission scanning electron microscopy analysis indicates that in situ-cross-linking of polyphenols of Melia azedarach extract by ferric ions resulted in the formation of nanohydrogel containing particles in the range of 23-35 nm. Experiments confirmed that the prepared iron-polyphenol nanohydrogel has the excellent ability as the flocculant for coagulation and removal of the Disperse Yellow 211 dye in the pH range of 4.0-8.0, at room temperature. The required time for obtaining equilibrium at different concentrations of dye is ~ 50 min, and in this period, 200 mg l-1 of dye solution is 92% decolorized. The best-fitted model for experimental data is found to be the second-order kinetics and Langmuir thermodynamic indicating the sorption occurs in a monolayer and is governed by chemisorption. The maximum capacity of the sorbent is 1111.1 mg g-1.