Water and dye sorption characteristics of acrylamide/sodium acrylate hydrogels containing guar gum and kaolin as an effective novel biosorbent composites

In this study, it was to investigate the swelling and sorption properties of novel biosorbent composite hydrogels composed of acrylamide with sodium acrylate as co-monomer, containing kaolin, a hydrocolloid such as guar gum and a multifunctional crosslinker such as poly (ethylene glycol) diacrylate, (PEGDA 1.0% of PEGDA). The hydrogels were prepared by free radical solution polymerization using ammonium persulfate, (APS 0.2 mL of APS (5.0 g APS/100 mL water))/N,N,N’,N’-tetramethylethylenediamine, (TEMED 0.25 mL of 1.0% of TEMED) as redox initiating pair at ambient temperature. Swelling experiments were performed gravimetrically in water at 25 ℃. The equilibrium percentage swelling factor ranges are 760%-4147%. Fourier Transform Infrared Spectroscopy (FT-IR) analysis was applied for structural characterization. Sorption of water-soluble cationic dye, union green B, into the hydrogels was studied with the batch sorption technique at 25 ℃. For equilibrium sorption studies, dye uptake performance, dye sorption percentage, and partition coefficient of the hydrogel systems were investigated. For equilibrium sorption studies, the dye uptake performance values of the hydrogels varied between 1.92 x 10 − 4–5.67 x 10 − 4 mol g-1. The values for dye sorption percentage of the hydrogels varied between 41.93% – 96.07%, and the values for partition coefficient 0.56–24.46.