Synthesis of clay-based superabsorbent composite and its sorption capability

A novel superabsorbent composite was synthesized by copolymerization reaction of partially neutralized acrylic acid (AA) on bentonite micropowder using N,N′-methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator in aqueous solution. The superabsorbent composite (SAC) was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The water retention test of SAC was also performed. The water absorbency of SAC synthesized was found to be 352 and 110 g H 2O g −1 in distilled water and 0.2% NaCl, respectively. Sorption capacity of SAC was investigated for heavy metal ions (HMI) using Langmuir and Freundlich model of adsorption. The maximum adsorption capacity ( Q m) of HMI onto the bentonite-based SAC from their solution was 1666.67, 270.27, 416.67 and 222.22 mg g −1 for Pb(II), Ni(II), Cd(II) and Cu(II), respectively. All results suggested that SAC offers excellent potential for HMI removal from contaminated water.