Kinetic evaluation of sorption and desorption

• Sorption is often quantified by a distribution coefficient, K-d, which is the equilibrium ratio between species sorbed to the rock and species in solution. Traditionally K-d-values are determined in batch experiments from equilibrium concentrations. In this work we describe an approach to determine rate constants for sorption and desorption from data obtained in ordinary batch sorption experiments. By varying the surface area to solution volume ratio in experiments where the dynamics for sorption equilibration is monitored, the rate constants (and consequently the K-d-value, which is the quota between forward and backward reactions) can be determined. To demonstrate the method, sorption of strontium to crushed granite was studied. The K-d-value obtained with the kinetic approach was in good agreement with that obtained from equilibrium concentrations.

Subject headings

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Keyword

Sorption

Kinetics

Cation

Mineral

Sr2

Granite

Physical chemistry

Fysikalisk kemi

Publication and Content Type

ref (subject category)

art (subject category)