Chinese Journal of Applied Chemistry ›› 2015, Vol. 32 ›› Issue (12): 1402-1409.DOI: 10.11944/j.issn.1000-0518.2015.12.150207

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Adsorption of Palladium by Pectin and Its Application in Organic Synthesis

ZHOU Yu,HE Yuan,ZHOU Wenjun()   

  1. College of Chemistry and Chemical Engineering,Neijiang Normal University,Neijiang,Sichuan 641112,China
  • Received:2015-06-18 Accepted:2015-09-17 Published:2015-12-01 Online:2015-12-01
  • Contact: ZHOU Wenjun
  • Supported by:
    Supported by the Sichuan Province Education Office Fostering Projects(No.12ZZ012), Youth Found of Sichuan Province Education Office(Nos.12ZB074), the Startup Foundation of Ph.D.Scientific Research of Neijiang Normal University(No.2012B05)

Abstract:

The adsorption of palladium from aqueous solution by pectin was studied. The effect of solution pH value, temperature, pectin dosage, contact time and initial concentration of palladium solution on the adsorption was investigated. The kinetics data were analyzed by the Pseudo-First-order, Pseudo-Second-order and Intraparticle Diffusion models. The equilibrium data were simulated using Langmuir, Freundlich, and Temkin isothermal equations. The results show that pectin has good adsorption ability and the adsorption ratio is as high as 96%. With the best pH of 6.5 and the best temperature of 50 ℃, the adsorption capacity decreases with the increase of the pectin dosage, while it increases as the initial concentration of palladium solution increases. The adsorption kinetics of palladium obeys the Pseudo-Second-order model to show that this is a chemical adsorption. The isotherm adsorption is fitted in the Freundlich equation. Gibbs free energy is negative, the enthalpy change is 3.23 kJ/mol and the entropy change is 13.32 J/(mol·K), showing that it is a spontaneous endothermic process. The adsorbed palladium was used as the catalyst for Suzuki reaction with a good catalytic activity.

Key words: pectin, palladium, adsorption, Suzuki reaction