Preparation of Psyllium Mucilage and Acrylic Acid Based Hydrogels and their Application in Selective Absorption of Water from Different Oil/Water Emulsions

In the present study, psyllium mucilage which is obtained from Plantago ovata has been modified through graft copolymerization and network formation using acrylic acid (AA) as the monomer, potassium persulphate (KPS) as an initiator, and hexamethylene tetramine (HMTA) as a cross-linker. Initially, various reaction parameters such as initiator concentration, amount of solvent, reaction time, reaction temperature, pH, monomer concentration, and cross-linker concentration were optimized. The optimized cross-linked [Psy-g-poly(AA)] hydrogel was then investigated for its efficiency in removing water from petrol/water, diesel/water, kerosene/water and petroleum ether/water emulsions. The study was carried-out at various time, temperature, pH, and NaCl concentration of the swelling media. The cross-linked Psy-g-poly(AA) hydrogel has been found to act as a smart polymer. It has been found that the functionalized polymer can absorb water up to 6710% and it is effective in selective removal of water from different oil/water emulsions. The polymer has a high swelling affinity in aqueous medium, though it fails to swell in ethanol, acetone, iso-propanol, petrol, diesel, kerosene, and petroleum ether. Moreover, the polymer is pH-sensitive and can act as a suitable candidate for colon-specific drug delivery systems.