عنوان مقاله [English]
نویسنده [English]چکیده [English]
In this research composite adsorbents consisting of nano clinoptilolite and polyacrylonitrile (PAN) was prepared. The composites were characterized by XRD, XRF, FT-IR, DTG and SEM analysis. The adsorption behavior of the composites toward zirconium was investigated. In this nano adsorbent, nano-zeolite clinoptilolite acts as an active ingredient to absorb zirconium ions, and polyacrylonitrile is binder. The absorption rate by nanocomposites was very rapid and more than 75% of the maximum absorption capacity for zirconium was obtained in the first 5 hours. The effect of pH, initial ion concentration, contact time and temperature was examined. The optimum contact time and pH were 24 h and 2, respectively. The maximum adsorption capacity of the composite was 18.65 mg g-1.
The kinetic and thermodynamic parameters were extracted. The experimental data were well fitted with a pseud-second order kinetic model with good correlation coefficients. Positive ΔH° and negative ΔG° were indicative of the endothermic and spontaneous nature of process. The equilibrium data were analyzed by the Langmuir, Freundlich, and Dubinin–Radushkviech isotherm models. D-R isotherm model indicated that ions were uptake through an ion exchange process. The obtained RL values were in the range of 0-1, indicating Zr adsorption was favorable.