Synthesis and adsorption study of acrylamide grafted soybean copolymer.

Copolymerization is a cooperative polymerization that involves two or more different monomers that are incorporated into the same polymer chain. It allows the development of unlimited range of polymers, tunable properties and surface modifications. In this study, the oil-free base treated soybean waste was used as a biomass precursor and it was copolymerized with acrylamide through the free radical polymerization with potassium persulfate as initiator. The adsorption characteristic of the newly prepared acrylamide-soybean copolymer towards Pb(II) was studied by the use of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA). The adsorption conditions were optimized in terms of pH, adsorbent dosage and contact time. The Freundlich isotherm model can fit well the adsorption data obtained towards Pb(II). In comparison, the pseudo-second-order is the better fit kinetic system that explained the adsorption mechanism of Pb(II) onto the acrylamide-soybean copolymer. The adsorption capacity of the acrylamide-soybean copolymer was determined to be 22.12 mg g, which is comparable with the absorption capacity of other grafted polymers.