Abstract:

The authors constructed the simulation system of heavy metals’ distribution in the coexistence system of solid phases (including the biofilm, the sediment, the suspended solid) in the aquatic environment, and studied the redistribution behavior of Pb,Cd,Cu caused by pH value change in the coexstence system. The result shows that the pH value change of the balanced system could markedly affect the distributing characteristics of these three heavy metals in the solid phases, which enabled the heavy metals to redistribute in system. The redistributing processes were all composed of an initial rapid adsorptiondesorption stage and a stage slowly closing to balance, which could be described via the Langmuir adsorptiondesorption kinetic equation. The research also indicated that the changing characteristics of Cd differed from those of Pb and Cu on pH value decreasing, and the changing characteristics of Pb displayed difference from those of Cd and Cu on pH value increasing.

Key words: pH value； biofilm； sediment； suspended solid； heavy metals； redistribution