A NOVEL RICE STRAW-BUTYL ACRYLATE GRAFT COPOLYMER: SYNTHESIS AND ADSORPTION STUDY FOR OIL SPILL CLEANUP FROM SEAWATER

For the first time, a potential material for oil spill cleanup has been successfully synthesized by the graft polymerization of butyl acrylate (BA) onto rice straw (RS) using 2,2'-azobisisobutyronitrile (AIBN) as initiator and divinyl benzene (DVB) as cross-linking agent. The copolymer synthesis was controlled by the concentration of monomer BA and AIBN, reaction time, and temperature. It was found that the optimal conditions for the highest graft yield of 41.50% were as follows: [AIBN] = 0.04 mol/L, [BA] = 1.50 mol/L, 180 min at 75 degrees C. The graft copolymer RS-g-BA was structurally analyzed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). In the presence of DVB (1.5%), the maximal adsorption capacity of the copolymer was 20.56 g/g. The reusability of the RS-g-BA copolymer was assessed during seven sorption/desorption cycles with 70% recovery. The experimental data were clearly more suitably fitted by the Langmuir monolayer adsorption model rather than by the Freundlich isotherm model. The kinetic study indicated that oil adsorption by RS-g-BA is likely to be a chemisorption process.