Adsorption of Th 4+ from aqueous solution onto Poly( N,N -diethylacrylamide- co -acrylic acid) microgels

Poly( N,N -diethylacrylamide- co -acrylicacid) (P(DEA- co -AA)) was synthesized by Free-Radical polymerization. The effects of contact time, solid/liquid ratio, pH value, and initial concentration on the adsorption of Th 4+ ions onto P(DEA- co -AA) were investigated. The adsorption was highly dependent on the initial pH and initial metal ions concentration of the solvent. The adsorption kinetic data indicated that the chemical adsorption is a swiftness processes, the adsorption equilibrium could be achieved within 20 min. The adsorption isotherm of the microgels for Th 4+ is fitted to the Langmuir isotherm model. Gibbs free enthalpy change was ∆ G < 0 indicating that the adsorption process was spontaneous. The enthalpy and entropy changes of the process of the adsorbents for Th 4+ were greater than zero showing that the overall process was endothermic. After five times of repeated tests for the P(DEA- co -AA) microgels it still remained its excellent adsorption.