Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (03): 278-282.doi: 10.3866/PKU.WHXB19980318

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Study on the Comparison of the Kinetics of Ion Diffusion and Ilon Exchange in Charged Colloid

Li Hang, Chen Ming-Shu   

  1. College of Resources and Environment,Southwest Agricultural University,Chongqing 400716|Biology Department ,Southwest Teachers University,Chongqing 400716
  • Received:1997-05-19 Revised:1997-10-24 Published:1998-03-15
  • Contact: Li Hang

Abstract:

Taking soil colloid and hydrated silica (quartz sand) as the experimental material, the comparative study has been made on the kinetics of ion diffusion and ion exchange in charged colloid and charged coarse disperse systems. The results showed that ion exchange kinetics in the two systems conform to the kinetic law of ion diffusion. Besides, through this comparative study on the kinetics of ion exchange and ion diffusion, a method has been advanced theoretically to estimate the quantity of adsorbed ion that is located in the inner of the Helmholtz layer. As far as hydrated silica is concerned , there were about 33 per cent of the total adsorbed quantity of Mg2+that were located in the inner of the Helmholtz layer under the given experimental conditions, bu tfor soil colloid the percentage was only 7.5.

Key words: Colloid, Coarse dispersion, Ion diffusion, Ion exchange, Kinetics