Modification of glycidyl methacrylate based cryogels by cellulose nanocrystals and determination of dye adsorption performance

Cellulose nanocrystal (CNC) modified poly(2-hydroxy ethyl methacrylate- glycidyl methacrylate) [poly(HEMA-GMA)] cryogels were prepared by base-catalyzed CNC addition. Resultant cryogels were characterized via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and N 2 -adsorption methods. As expected, the CNC-modified cryogels’ ability to retain water (~ 600 mg/g cryogel) was high leading to increased diffusion of the analyte to the adsorbent flow channels. To increase the functionality of polymeric adsorbent towards anions, iron (II) metal cations were immobilized onto the polymeric adsorbent and quantified by an electrochemical method. Methyl orange was chosen as model anionic dye molecule and adsorption studies were conducted at different pH levels, target concentrations and times of binding. Advantages of CNC addition and Fe(II) cation immobilization were determined against unmodified poly(HEMA-GMA) cryogels. It was found that 455 mg/g of the Fe(II) immobilized polymer (25% removal) was optimal for adsorption resulting in the removal of approximately 55.75 mg/g (17.25%) for the methyl orange at a concentration of 100 mg/L.