Journal of Radiation Research and Radiation Processing ›› 2019, Vol. 37 ›› Issue (3): 3-030203-8.doi: 10.11889/j.1000-3436.2019.rrj.37.030203

• RADIATION CHEMISTRY • Previous Articles     Next Articles

Modified clinoptilolite adsorption of Sr(Ⅱ) in aqueous solutions

LUO Qun(),JIANG Dingwen,HOU Dengyong,CHEN Wei,HU Xiuting,HE Ying()   

  1. Department of Protection Medicine, Naval Characteristic Medical Center, The Second Military Medical University, Shanghai 200433, China
  • Received:2019-01-08 Revised:2019-03-21 Accepted:2019-03-21 Online:2019-06-20 Published:2019-06-18
  • Contact: Ying HE E-mail:qun246013@163.com;yinghe_hys@163.com
  • About author:LUO Qun(male) was born in January 1986, and obtained his doctoral degree from Naval University of Engineering in 2013. Now he is an assistant professor, majoring in radiation protection. E-mail: qun246013@163.com
  • Supported by:
    Supported by Shanghai Natural Science Foundation(16ZR1414200)

Abstract:

A natural clinoptilolite was modified using high temperature and chemical agents for adsorption of Sr2+ from aqueous solutions. The adsorption capacity was determined to select the optimum modification method. The adsorption capacities of Sr2+ were as high as 79.386 mg/g when the natural clinoptilolite was modified using high temperature, NaOH, and NaCl sequentially. Scanning electron microscopy and X-ray diffraction were used to characterize the produced zeolite and identify the crystal structure, morphology, and elemental composition of the samples. The removal and adsorption processes of Sr2+ using the modified clinoptilolite were performed under various experimental conditions by varying the temperature, initial concentration, and contact time. Adsorption isotherm models (Langmuir and Freundlich) were applied and equilibrium adsorption data were better fitted to the Langmuir isotherm. The reaction kinetic data were studied by Lagergren first and second order models as well as the Elovich particle diffusion kinetic model. The adsorption kinetics were accurately described by the Lagergren second order model and the rate-controlling step was determined to be chemical adsorption. The thermodynamic parameters of ΔH 0 and ΔS 0 were positive, indicating that the adsorption of Sr2+ onto the modified clinoptilolite zeolite was an endothermic process. The value of ΔG 0 was negative at low initial concentrations, indicating that the adsorption process was spontaneous and the absolute value of ΔG 0 increased with an increase in temperature. The value of ΔG 0 was positive at high initial concentrations and decreased with an increase in temperature and a decrease in initial concentration.

Key words: Clinoptilolite, Adsorption, Sr(II), Adsorption isotherm, Adsorption kinetics, Adsorption thermodynamics

CLC Number: 

  • TQ424.3