Selective adsorption of carboxymethylcellulose onto mesoporous silica derived from de-oiled mustard cake

Abstract

The mechanism of adsorption of carboxymethylcellulose (CMC) onto the solid–liquid interface has been a topic of long-standing debate. An attempt has, therefore, been made on selective adsorption aspects of CMC at the solid–liquid interface employing Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray powder diffraction (XRD) and Brunauer-Emmett-Teller (BET) surface area analyzer. The change in solution conditions such as concentration, dose, pH, contact time, temperature and presence of urea was found to have a significant influence on the adsorption of CMC onto mesoporous silica derived from de-oiled mustard cake (MSDOMC). The change in the infra-red spectra and the presence of urea during adsorption suggested that hydrogen bonding play a vital role. The presence of urea reduced considerably CMC adsorption onto MSDOMC, indicating that adsorption in this case was due to the presence of hydrogen bonding. All of the above results suggest that the adsorption of CMC on the surface of MSDOMC is a complex interplay of hydrogen bonding and electrostatic interaction rather than hydrophobic force. Thus, the current study providedsignificant proof that hydrogen bonding dominate fore rather than non-covalent interaction during CMC adsorption onto MSDOMC.