Kinetics of disaggregation of humic acid in water

The extent of disaggregation of humic acid particles in water was measured as a function of time, initial concentration, pH of the suspension and the temperature. In all experiments the amount of humic acid particles disaggregated was characterized by the corresponding fraction of the suspension, which was able to pass a 0.01 μm membrane filter.It was found that the amount disaggregated after 1000 hours was proportional to the initial concentration of the humic acid particles in the aqueous suspension and increased considerably with the temperature. Decreasing the pH of the suspension from about 6 to zero caused the extent of disaggregation also to decrease continuously.The kinetic measurements revealed that about 3% of the humic acid are disaggregated within 25 hours, 4% within 200 hours and 5% within 1500 hours at a pH around 4. The rates of disaggregation were found to be proportional to the initial concentration of the particles and increased considerably with the temperature.