Biosorption Of Hg²⁺ And Cu²⁺ By The Three Kinds Of Aquatic Plants

Water is the source of life,The interference caused by human activities rising water pollution. Eutrophication and heavy metal pollution is the main pollution type in aquatic ecosystems, the water Eutrophication can reduce water utilization, and cause water ecosystem degradation; however, the heavy mental contamination makes the human being face with health and survival crisis.When the heavy mentals into the water ,part of them were adsorbed by the solid particles and with the particles sank to the bottom in normal physico-chemical condition,the rest continues to dilute and diffuse;The heavy metals in the natural waters can be adsorbed by surface coatings, and can also release to the aquatic environments because of the change of environment conditions or the effects of the microorganisms. It produces the secondary pollution and enrichment by the food chain .Aquatic plants are the primary producers in aquatic ecosystems;they have the function of water purification,bank protection and have an important role under control.Endogenous pollution, especially the function of submersed macrophtes are not replaceable. This paper selects submersed macrophtes Myriophyllum spicatum (L.), Hydrilla varticillata (L. f.) Royle, and floating leaved plant Trapaceae, experiment on Hg²⁺, Cu²⁺ absorption characteristics; Experimental parameters affecting the biosorption process such as contact time, pH,the initial concentration of heavy metal ions and temperature were studied in order to campare their absorption capability.experiment on adsorption and desorption This research work has discussed the effect by different desorption agent :distilled water,HC1 (0.5mol/L),NaCl (5%) on the desorption rations of Hg²⁺ and Cu²⁺ adsorption by aquatic plants.The adsorption analysis shows that sorbent and heavy metal ions contact time, pH, heavy metal ions of initial concentration, temperature had influence on the adsorption quantity,the temperature had the least effect and the pH had the biggest factor. Experimental determination of three kinds of aquatic plants in the optimal pH adsorption mercury is 7-8,copper in 5-6 relatively appropriate; with heavy metal ions adsorption ratio of initial concentration increases,when the absorption rate reaches saturation concentration increases adsorption;using the isothermal adsorption equation Langmuir and Freundlich the linear and nonlinear fitting description adsorption characteristic, adsorption process conforms to Langmuir linear form, the adsorption process that may occur in the single molecule layer;the maximum adsorption quantity of mercury copper Qmax 8.24mg/g,10.2 mg/g,5.5 mg/g and 10.6 mg/g, 17.8 mg/g, 9.75 mg/g respectively, according to the theoretical calculation of single molecule layer 3 kinds of aquatic plants,the largest adsorption surface copper was bigger than mercury S_max(S=(?),S_max0.97 m²/g,1.05 m²/g, 0.65 m²/g and 1.64 m²/g, 2.66m²/g, 1.51m²/g, respectively; the results of adsorption temperature showed that, the solution of the adsorption quantity of temperature rise, and no significant influence to the temperature of adsorption process does not affect control.In the end of Myriophyllum spicatum L.,Hydrilla varticillata (L. f.) Royle,Trapa bispinosa Roxb adsorption kinetic study shows that the adsorption kinetic equation of secondary relative to the accurate dynamic equation can better must level with the description of the sorbent capacity balance concentration. Experiments show that desorption HCl in (0.5 mol/L), NaCl (5%) to mercury, copper desorption rate is higher than the distilled water and desorption rates lower than mercury, statistical analysis of copper desorption results show that the efficiency of the time desorption.