A radioactively durable melamine-styrene based polymer: Highly efficient removal of Sr-90

Abstract

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. Sr2+ ions were removed from the solution using MSBP sorbent. In this respect, adsorption of Sr(2+)onto melamine-based polymer was studied as a part of pH, amount of adsorbent, initial Sr(2+)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 Sr2+ as 142.9 mg.g(-1). Thermodynamic parameters such as free energy (Delta G(0)), entropy (Delta S-0) and enthalpy (Delta H-0) of Sr2+ adsorption on MSBP were examined at five different temperatures of 293 K, 303 K, 313 K, 323 K and 333 K. 0 < Delta H-0 values indicated that sorption mechanism presented endothermic feature. 0 > Delta G(0) and 0 < Delta S-0 revealed that Sr2+ 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 Sr2+ onto MSBP.