Radiation synthesis of polyacrylamide/functionalized multiwalled carbon nanotubes composites for the adsorption of Cu(II) metal ions from aqueous solution

Polyacrylamide/functionalized multiwalled carbon nanotubes (PAAm/FMWCNTs) composites were prepared by different polymerization techniques using gamma radiation as an initiator. These polymerization techniques were template polymerization of acrylic acid (AA) onto PAAm/FMWCNTs (N-1), template polymerization of acrylamide (AAm) onto PAAm/FMWCNTs (N-2), copolymerization of AA and AAm onto FMWCNTs (N-3), and in situ polymerization of AAm from FMWCNTs surface (N-4). The composites were analyzed by FTIR, SEM, and TGA. The composites were applied for the removal of Cu(II) metal ions by the batch adsorption method. The adsorption was investigated under various experimental conditions including initial pH, contact time, composites dosage, the concentration of Cu(II) metal ions, and temperature. The adsorption capacities of N-1, N-2,N- N-3,N- and N-4 composites were 385.44, 330.23, 351.95, and 320.29 mg/g, respectively, at a contact time: 90 min, initial concentration of Cu(II) metal ions: 0.8 g/L, the temperature: 25 degrees C, rpm: 150, pH: 5. and V/m: 1 L/g. The adsorption experimental results were closer to pseudo-second-order and Langmuir adsorption models. Thermodynamic data showed that the adsorption process was endothermic. The desorption studies have shown that PAAm/FMWCNTs composites adsorbents have a good adsorption/desorption performance for Cu(II) metal ions.