Highly efficient 1,3,4- thiadiazole impregnated cross-linked hydrogel: water retention and adsorption of phenol red for sustainable environment

Abstract

In this study, free radical copolymer was used to prepare a hydrogel of acrylic acid poly (acrylic acid-co-2-amino-5-(2-chlorophenyl)-1,3,4-thiadiazole) (poly-OCTMAC). The poly-OCTMAC hydrogel was characterized using Fourier transform infrared spectroscopy FTIR, ¹H-NMR  was measured using (Bruker Ultra Shield), 500 MHz, using DMSO-d6 solvent and reference. thermogravimetric analysis (TGA), and field emission scanning electron microscopy (SEM). Phenol red (PhR) dye was removed from the aqueous medium using the poly-OCTMAC hydrogel. To determine the maximum adsorption, the effects of initial dye concentration, contact time, and adsorbent dosage were investigated. The poly-OCTMAC hydrogel had a high swelling ratio of 456%. The high water penetration rate of the poly-OCTMAC hydrogel coupled with the high swelling rate exposed the internal adsorption sites for the adsorption of PhR dye. The adsorption performance of the poly-OCTMAC gel was explained by quasi-first-order adsorption models. Moreover, after three different times, the poly-OCTMAC maintained 80% absorption efficiency. The high water holding capacity of Poly-OCTMAC improved the moisture holding limit of soil for irrigation up to 24 days. As a result, Poly-OCTMAC can be used in the removal of toxic dyes as well as in irrigation systems.