Effect of Organic Matter on Aggregation of Soil Colloidal Particles in Water Bodies of Three Gorge Reservoir Region[J]. 2017, 31(4): 166-171.
DOI:
Effect of Organic Matter on Aggregation of Soil Colloidal Particles in Water Bodies of Three Gorge Reservoir Region[J]. 2017, 31(4): 166-171. DOI: 10.13870/j.cnki.stbcxb.2017.04.027.
Effect of Organic Matter on Aggregation of Soil Colloidal Particles in Water Bodies of Three Gorge Reservoir Region
Based on the method of combined determination and light scattering
we studied the effect of organic matter on the surface charge properties of soil colloidal particles and condensation process of colloidal particles in water bodies. The results showed that the addition of organic matter significantly changed the surface charge properties of soils
because of the total charge number increased about 6.8%
the specific surface area decreased about 12.3%
and organic matter addition decreased the surface charge density of the particles and the surface potential. Further theoretical calculations showed that the addition of organic substance reduced the electrostatic repulsion between colloidal particles
which made the net gravity increase and aggregation of soil colloids become easier. The aggregation characteristics of soli colloids in the water bodies were studied by the method of light scattering
the results showed that the critical coagulation concentration (CCC) was 91.6 mmol/L before removing organic matter
and it was 139.3 mmol/L after organic matter was removed
and the difference betweent these two values was significant. The critical surface potentials for colloidal particle dispersive or aggregate were both about -150.0 mV at the corresponding concentrations. And the above concentrations were the critical concentrations that net gravitational attraction appeared between particles. The effect of organic matter on the aggregation characteristics of colloidal particles in water bodies was mainly through changing surface properties and the corresponding interactions of particles.