Sorption behavior of some lanthanides on polyacrylamide stannic molybdophosphate as organic–inorganic composite

Abstract

Sorption behavior of some lanthanide ions such as lanthanum and samarium ions on polyacrylamide stannic molybdophosphate {PASnMoP} as organic–inorganic composite has been investigated. The distribution coefficients of La3+ and Sm3+ ions in different pH media on PASnMoP were determined with the selectivity order La3+ > Sm3+. Capacity of PASnMoP for La3+ and Sm3+ ions was determined and found 24.66 and 15.38 mg g−1 for La3+ and Sm3+ ions, respectively. The resin dosage dependence for the sorption behavior for La3+ and Sm3+ ions on polyacrylamide stannic molybdophosphate was conducted. The adsorption isotherms were described by means of Langmuir and Freundlich isotherms for La3+ and Sm3+ ions. The Langmuir model represented the adsorption process better than the Freundlich model. The kinetic data were tested using Logergren-first-order and Pseudo-second-order kinetic models. The data correlated well with the Pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate limiting step. Thermodynamic parameters ΔG°, ΔH° and ΔS° were also calculated and the data showed that the ion exchange of La3+ and Sm3+ ions on PASnMoP was spontaneous and endothermic in nature.