THE INFLUENCE OF Рh OF THE ENVIRONMENT ON SOIL STABILITY

Abstract

Abstract. In world practice, the process of structure formation of mineral dispersions with polymers is one of the effective methods for solving many environmental problems. Patent research over the past 15 years has shown that the developments available in this area relate mainly to the structure formation of soils and soils with salts of low molecular weight substances and polymers. The main disadvantages of modern structure formers are the high salt content in the polycomplex formulation, insufficient water resistance, low aggregation ability and unsatisfactory adhesive properties. Soil particles having a diameter of 12 microns, in the pH range 10.0 - 3.0, the soil suspension should be practically stable, since the value of the energy barrier significantly exceeds the energy of thermal movement of the particles and is 166 kT (pH 10.0), 125 kT (pH 8.0), 63 kT (pH 6.0) and 41kT (pH 5.0). A further decrease in pH leads to a natural decrease in the barrier, which at pH 4.0 is 6 kT, and completely disappears at pH 3.0. Thus, for a fraction of a soil suspension with a diameter less than 12 µm, noticeable coagulation can be observed at pH £ 4.0. It is easy to show that larger soil particles with a diameter of 30-33 microns should be practically aggregatively stable even at pH 3.0, since the energy barrier in this case is 10-15 kT. When interacting with the smallest particles (a = 1 μm), the energy barrier values are: 44 kT (pH 10.0), 28 kT (pH 8.0), 18 kT (pH 6.0), 7 kT (pH 5.0) and 2 kT (pH 4.0) and only for these particles at pH < 4.0 can one expect a noticeable loss of aggregation stability by the dispersion. However, the experiment shows that significant coagulation of particles occurs already at pH 5.0 and continuously increases as the pH decreases. Key words: structure-forming agent; soil; flocculation; coagulation; interaction energy; optical density; potentiometric titration; electrophoretic mobility.