Effect of pH, ionic strength and temperature on sorption of Pb(II) on NKF-6 zeolite studied by batch technique

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2011-01, Vol.168 (1), p.86-93
• Main Authors: Yang, Xin, Yang, Shubing, Yang, Shitong, Hu, Jun, Tan, Xiaoli, Wang, Xiangke
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Applied sciences; Aqueous solutions; Chemical engineering; Complexation; Exact sciences and technology; Ion exchange; Ionic strength; Liquids; NKF-6 zeolite; Pb(II); solidification; Sorption; sorption isotherms; Strength; temperature; Thermodynamic data; Zeolites
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2010.12.039

The effect of pH, ionic strength, solid/liquid ratio, contact time and temperature on sorption of Pb(II) to NKF-6 zeolite is investigated using batch technique under ambient conditions. The NKF-6 zeolite is characterized using XRD and FTIR. The sorption results indicate that the sorption of Pb(II) on NKF-6 zeolite is strongly dependent on pH. The sorption of Pb(II) is affected by ionic strength at pH < 6, while it is independent of ionic strength at pH > 6. The sorption of Pb(II) is dominated by ion exchange or outer-sphere surface complexation at low pH values, and by inner-sphere surface complexation at high pH values. The thermodynamic parameters (Δ H 0, Δ S 0 and Δ G 0) calculated from the temperature dependent sorption isotherms suggest that the sorption of Pb(II) on NKF-6 zeolite is endothermic and spontaneous process. The results are quite important to understand the interaction of Pb(II) with zeolite in aqueous solutions. This investigation shows that the NKF-6 zeolite can be used as a suitable adsorbent for the preconcentration and solidification of Pb(II) from large volumes of aqueous solutions.