Studied Adsorption Performance For Lead Zinc Cadmium Ions By Camellia Shell

Heavy metal pollution has become a global concerning issue. "Biosorption as a kind of heavy metal biological treatment technology" has many advantages, such as low cost, low environmental pollution and easy process of treatment. Camellia shell is an important adsorption material. If it is applied to adsorb and enrich heavy metal, the heavy metal pollution can be treated effectively. Meanwhile, the heavy metal can be recycled, and the amount of trace metals in water can be determined.In this study, camellia shell, acid modified camellia shell and coking camellia shell respectively were used to adsorb Pb2+/Zn2+/Cd2+ in three heavy metal ions solution, respectively, the effect factors of the adsorption heavy metal ions, adsorption thermodynamics, adsorption kinetics were investigated; trace Pb2+/Cd2+ in tap water were enriched and determined by coking camellia shell. The optimal work conditions were discussed.Through the research of heavy metal ions adsorption with camellia shell, the effects of size/pH/temperature/initial concentration and dosage of absorbent on the adsorption were discussed. While the size exceed 40 mesh, the pH of experiment was between 4 and 6, experimental temperature was around 25℃(room temperature), all three kinds of camellia shell sorbents had high efficient for the Pb2+/Zn2+/Cd2+ adsorption.The thermodynamic equilibrium of heavy metal adsorption with camellia shells was studied by linearly fitting the Langmuir adsorption model and Freudlich adsorption model. The experimental results showed that the camellia shell adsorption isotherms for Pb2+/Zn2+/Cd2+ were consisted with Langmuir adsorption isotherm, and the maximum adsorbent adsorption capacities for those three heavy metal ions were obtained, respectively. The adsorption capacity order of camellia shell for three heavy metal ions was Pb2+>Cd2+>Zn2+. Coking camellia shell had much higher adsorption capacity than other two camellia shells.The adsorption dynamic result showed that the heavy metal ions adsorption by camellias shell reached equilibrium in a relatively short time, and 60 total equilibrium percent of the heavy metal ions were absorbed within 20 minutes. Camellia shell adsorption process fitted second orders of dynamic equation. The correlation coefficient was 0.99, accounting that the adsorption process was mainly dominated by the first two front stages of physical chemical reaction process. This inferred aspeed characteristics of adsorption process and a theoretical foundation for industrial application.Based on the adsorption study, the heavy metal adsorption efficiency by shell coking camellia far surpassed efficiencies by acid modified shell and camellia shell, and it could be used as enrichment of trace heavy metal materials. Coking camellia shell enrichment coordination compound formed by APDC and trace heavy metal in water were chosen in this research to determine heavy metal ions in tap water. By optimizing the treatment in laboratory, the optimal operation parameters were obtained:pH of 4 to 6,1 mL APDC solution addition,1 mL eluent addition, and room temperature.