Investigation of the Extraction of Hemoglobin by Adsorption onto Nanocellulose-Based Superabsorbent Composite Having Carboxylate Functional Groups from Aqueous Solutions: Kinetic, Equilibrium, and Thermodynamic Profiles

We have developed a superabsorbent composite based on cellulose, namely poly(acrylic acid)-modified poly(glycidylmethacrylate)-grafted nanocellulose (PAPGNC), via graft copolymerization technique, and it is well characterized. The adsorption of a globular protein, hemoglobin (Hb), onto PAPGNC was studied by batch-adsorption technique. The optimum pH for Hb adsorption was found to be 6.7, and the adsorption attained equilibrium within 3.0 h. The kinetic data were found to follow pseudo-second-order model, and the equilibrium data were found to agree with the Langmuir isotherm model. The maximum adsorption capacity of PAPGNC was found to be 119.92 mg/g at 30 degrees C. The adsorption capacity of PAPGNC toward Hb was found to increase with an increase in temperature. Spent adsorbent was effectively degenerated using 0.1 M KSCN solution without a loss in adsorption capacity, even after four cycles. The present investigation shows that PAPGNC can be developed as an efficient adsorbent for the extraction and recovery of Hb from aqueous solutions.