A radioactively durable melamine-styrene based polymer: Highly efficient removal of Sr.

Removal of strontium has a vital importance for radioactive waste management due to its long half-life. In this context, melamine-styrene based polymer (MSBP) was synthesized and characterized by different spectrophotometric methods. Sr ions were removed from the solution using MSBP sorbent. In this respect, adsorption of Sr onto melamine-based polymer was studied as a part of pH, amount of adsorbent, initial Sr concentration, contact time, temperature and particle size. Also, adsorption rate of radioactive strontium was investigated by using LSC (Liquid Scintillation Counter). The adsorption data were fitted to Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. MSBP sorbent reached maximum adsorption capacity for Sr as 142.9 mg.g. Thermodynamic parameters such as free energy (ΔG), entropy (ΔS) and enthalpy (ΔH) of Sr adsorption on MSBP were examined at five different temperatures of 293 K, 303 K, 313 K, 323 K and 333 K. 0 < ΔH values indicated that sorption mechanism presented endothermic feature. 0 > ΔG and 0 < ΔS revealed that Sr adsorption on MSBP occurred spontaneously and irreversible, respectively. Pseudo first and second orders were investigated as a part of kinetic parameters and seen that pseudo second order was much more convenient for adsorption of Sr onto MSBP.