Adsorption Of Pb Onto Solid Phases And The Effect Of PH Values On The Adsorption In Multi-solid Coexisting Aquatic System

As a major environmental pollutant, the toxicity of heavy metals can not be neglected. In aquatic environment, the concentration, speciation and the fate of heavy metals are mainly depends on their distribution in solid phases, including biofilm(BF) suspended particulate materials(SPM) and deposited sediment(DS). These solid phases combined with aqueous phase make up of a multi-phase system, which decides the fate of heavy metals in natural aquatic environment. Most of the studies on the role of solid phase in heavy metals pollution aquatic environment are mainly select a single solid-phase material. However there are few studies considered the synthetically role of the multi-phase system in actual aquatic environment. In recent years, our research group has done lots of works on the adsorption behaviors of heavy metals on each solid phase in the multi-phase concomitant system. We acquired many fruit but also found some problems. In this study, the effect of pH on the adsorption of heavy metals on solid phases was in-depth researched.In order to simulate the relative state of existence of the solid-phase material more realistically in natural water environment, to study the solid phase material with each other to do the role of heavy metals in the coexistence of a variety of solid-phase material system, I improved on the original simulation device in the study. Simulation the coexistence of multi-phase system of the natural water environment with the devices, compare the regular of thermodynamics and kinetics of adsorption the heavy metal of Pb with the different solid-phase material; review the change of the amount of the adsorption that the solid phase material between the single-phase and the multi-phases with the different pH values.The study suggests that the solid-phases adsorption of Pb in the selected water body accords well with thermodynamic Langmuir and Freundlich adsorption isotherms. In a single solid-phase material systerm, the adsorption ability of Pb in solid phase followed the order as: DS> SPM> BF; in multi-phase system, the adsorption ability in biofilm is lowest; when the equilibrium concentration was low, the adsorption amount in sediment is larger than that in particulate matter, when the equilibrium concentration of the solution is over a certain value, the adsorption amount in sediment increased rapidly and exceeded that in particulate matter. In the multi -phase system, the adsorption amount of Pb in the all solid phases changed with time and emerged two stages: the fast reaction phase : in the short time of the beginning period of the experiment , the adsorption changed rapidly; the slow reaction phase when the adsorption amount increased slowly and to be saturated. In the first phase, the adsorption ability followed the order as: SPM