The monomer N-methacryloxyphthalimide (NMP) was prepared by the reaction of methacrylic acid (MA) with N-hydroxyphthalimide (NHP) in the presence of N, N-dicyclohexylcarbodiimide (DCCI). The copolymerization of NMP with Styrene (St) was carried out in dimethylformamide (DMF) using Benzoyl peroxide (BzO2) as initiator at 70°C.
The monomer reactivity ratios for the copolymerization of NMP with St were found to be r1= 0.6341 and r2=0.573 by the Kelen-Tudos methods. The adsorption of Cu (II) ions onto the copolymers was examined, and found that the (NMP/St) (0.5: 0.5) copolymer has the highest uptake capacity. For this target, the batch adsorption experiments were conducted to explore the kinetics and isotherms of the removal process onto resin with pH-value, initial concentration, temperature, and contact time as the controlling parameters. The kinetic and isotherm data could be well elucidated with pseudo second-order equation and Langmuir model respectively. Thermodynamic parameters, involving ΔHo, ΔSo and ΔGo were also calculated from graphical interpretation of the experimental data. The standard heat of adsorption (ΔHo) was found to be endothermic and the entropy change value (ΔSo) was calculated to be positive for the adsorption of Cu(II), ions onto the tested adsorbent. Negative value of ΔGo indicated that adsorption process for tested metal ions onto resin was spontaneous.