[Kinetic characteristics of Cd2+ desorption in minerals and soils under simulated acid rain]

Huan Jing Ke Xue. 2004 Jul;25(4):117-22.
[Article in Chinese]

Abstract

The kinetic characteristics of Cd2+ desorption in minerals and soils under simulated acid rain were studied by using the flow-stirred method. It showed that Cd2+ desorption could be described by first-order kinetics. Percents of desorption amounts of Cd2+ calculated were 70%-100% in red soil and goethite, and 25%-50% in latosols and kaolinite. Parabolic diffusion could describe Cd2+ desorption kinetics in latosols and not suitable for red soil and goethite and kaolinite. Cd2+ desorption, regarded as a heterogeneous diffusion in minerals and soils, could be fitted by Elovich equation more than Parabolic diffusion and two-constant equation. Cd2+ desorption could be divided into fast reaction and slow reaction. Except for latosols, fast reaction would be over during 60 min and be close to quasi-equilibrium. Adsorption forms of Cd2+ in soil surface could be exchangeable and specific. Fast reaction was relative to easily desorbed Cd2+. The affinity of edge hydroxyl to Cd2+ would lead to the difference of Cd2+ desorption rate and amounts. Increase of pH value in effluent indicated H+ consumption in the processes of Cd2+ desorption.

Publication types

  • English Abstract
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Rain / adverse effects*
  • Acid Rain / analysis
  • Adsorption
  • Cadmium / analysis
  • Cadmium / metabolism*
  • Kinetics
  • Soil Pollutants / analysis
  • Soil Pollutants / metabolism*

Substances

  • Acid Rain
  • Soil Pollutants
  • Cadmium