The Adsorpting and Releasing of Toxic Heavy Metal Cations by Sewer-Mud Colloid, in Hochi Minh City Canals

Abstract

Through the results of 11 experiments, we have the following conclusions about the adsorption and release of Heavy metal Cation in different environmental pH conditions: 1. The higher the concentration of cations in the medium (soil solution), the greater the adsorption and release capacity. However, this relationship follows a certain curve for each given type of heavy metal cation, depending on the concentration of that metal in the solution, corresponding to certain pH of the environment, with a certain time. 2. The adsorption of heavy metal cations of colloidal bottom mud as well as colloidal alluvial soil occurs very quickly, creating distinct characteristic curves, 3. The release of heavy metal cation cations of colloidal bottom mud as well as colloidal alluvium in the field occurs 2h to 6h behind their adsorption capacity.

We have studied the absorption and contrast of Swere slud adsorbed with 7 toxic cations but only for example: For example: Cation: Fe²⁺: Were-Mud Colloid, in the time from 0-6h, the adsorption capacity of the glue takes place quickly. When pH = 5, the adsorption capacity of colloid is highest, then at pH = 4 and pH = 3. Time from 6 -12h: Colloid stops adsorbing and turns to release Fe²⁺ out of colloidal soil. Meanwhile, the ability to release at pH = 5 is greatest, Under the same pH conditions, the alluvial soil colloid adsorbed Fe²⁺ ions higher than the bottom mud colloid. In addition, the pH of the medium also greatly affects the adsorption-release ability of the soil colloid for Fe²⁺ The curve has an inflection point at Fe²⁺= 248ppm, 7h. The extreme peak (Cmax) at C (Fe²⁺) = 700ppm. The ability to release Fe²⁺ ions is highest after 1 hour, gradually decreasing after 2 hours to 4 hours.