A new type of porous Zn (II) metal-organic gel designed for effective adsorption to methyl orange dye

Metal-organic gels, which have attracted much attention and research due to their novel properties, were usually prepared with organic solution. In this paper, a new metal-organic gel was assembled by mixing proper amount of xanthine and zinc acetate in pure water with the assistance of triethylamine . The results of FTIR and XRD indicated that the hydrogel was self-assembled through coordination, hydrogen bond and π-π stacking. The hydrogel exhibited thixotropic property and good resistance to acid, alkali and heat. The xerogel obtained by freeze-drying had a porous structure with pore size ranging from several nanometers to several hundred nanometers as shown in the SEM images. The xerogel had the effectively adsorption properties for methyl orange in aqueous solution, and the adsorption efficiency is up to 80.63%. The model of adsorption kinetics and adsorptions isotherm show that the adsorption data were consistent with the Freundlich equation and the pseudo-second-order model, which mainly attribute to the chemisorption of methyl orange on multilayer heterogeneous surface of the xerogel . Prepared by a simple and mild method, the xerogel is a promising adsorbent for dye wastewater treatment .