Single step synthesis of a polyhydroxy ether and its optimization to adsorption of a textile dye

Abstract

An ion exchange resin was designed by combining different ratios of ethylene glycol diglycidyl ether (EGDE) and imidazole (IM). The aim of the research was to obtain in a single step a resin with permanent positive charges. The strategy was to use the IM in a dual way, first as a curing agent during the synthesis and as carrier of the permanentpositive charge in the final product. This novel procedure avoid further modification of the resin, reducing time and cost of production. The material with 1:0.3 EGDE:IM molar ratio achieved high adsorption capacity for the textile dye, Remazol Black B (qmax: 1.33 × 103 mg g-1) and good performance in a continuous adsorption system. The water uptake was 592% and pH independent. 1H-NMR confirmed the covalent binding of IM to the polyelectrolyte chain, and the FTIR results evidenced epoxy opening. The shielding of the positive charge resulting from the electrostatic interaction of this polyelectrolyte with Remazol Black B induced some degree of chain shrinkage, according to SEM images and to the visual inspection. In the attempt to optimize the performance of the fixed bed adsorption system an experimental design was carried out. The multilinear regression model allowed the acquisition of a deeper knowledge of the experimental space and opening the way to further improvement of the process.