Study On Adsorption Characteristics By Oil Shale Fly Ash Of HuaDian

A large quantity of heavy matel ions are contained in industrial and agricultural wastewater, municipal sewage, and mining wastewater, the pollution of heavy matel in water not only cause momentous economical losses, but also can seriously endanger health of lives, which including human beings. The main components and physical properties of oil shale ash in power plants determained them with strong adsorbability, so it is suitable for treating the wastewater. It has important social and economic meaning to test the oil shale fly ash as adsorbent.This study puts forward a new adsorbent-oil shale fly ash (OSFA) adsorbent and evaluates the potential use of it to remove heavy metal ions from aqueous solutions as a low-cost-adsorbent. The properties of the novel adsorbent were presented and the adsorbent were then used in batch experiments to study the adsorption properties of Pb2+, Zn2+, Cu2+ and Cd2+ in simulated wastewater. On the basis of theoretical analysis of the adsorption kinetics, adsorption thermodynamics, Langmuir and Freundlich adsorption isotherm, the adsorption mechanism of the four heavy metal ions by oil shale fly ash was investigated. The affects of influential factors including oil shale fly ash dosage, contact time, pH, temperature and initial metal concentration were evaluated in the experiments. The Pb2+ accords with Pseudo second order kinetics model, Cd2+ accords with both Pseudo second order kinetics model and Elovich kinetics model, Cu2+, Zn2+ accords with the all of the three kinetics models. The process of adsorption was a endothermic nature. Equilibrium isotherms at different temperatures have been determined and analyzed by Langmuir model andFreundlich model,we could conclude that Freundlich model. We could conclude that Cu2+, Zn2+, Cd2+ was accordesd with both Langmuir model andFreundlich model, and the Pb2+ did not accord with both of them.Compared with OSFA, adsorption capacity of the acidification OSFA had increased, and the homeostasis times were shorter than the OSFA adsorption times. The adsorption capacity of Pb2+ was increased first and then descreased with the increased pH, and the Cu2+, Zn2+, Cd2+ could reach to the adsorbed homeostasis when pH greater than 6. The reacted of four heavy matel ions were all the endothermic reaction, and could accord with the Pseudo frist order kinetics model, Pseudo second order kinetics model and Elovich kinetics model welly. The process of adsorbed was a non-spontaneous process for all of four ions. The studies of adsorption isotherms showed that both the Langmuir model and Freundlich model could characterizetion the four heavy matel ions welly, but the Langmuir model fits better than the Freundlich model for them.