Study On Adsorption Performance Of Hydrothermal Stabilized Fly Ash Towards Ions Zn And Pb In Waste Water

The heavy metal ion of wastewater is not only in great damage to the environment, but also harmful to human health. Some of the heavy metal ions are very poisonous substances, which can cause adverse reactions and even death. Some heavy metal ions are chronic toxic substances, which exit in plant, poultry, and fish and finally accumulate in the body of human beings by eating the food of heavy metal pollution, heavy metal ions will enter into the body for accumulation, and the consequence is unimaginable. Therefore, it is necessary to explore a new type of low cost absorbent which can adsorb the heavy metal ions in waste water effectively, and at the same time, it can be reused.The raw material comes from waste incineration plant fly ash. Four different working conditions for hydrothermal method are choosed, then the two kind of heavy metal ions Zn2+, Pb2+separate out of the fly ash. Through the contrast of the adsorption quantity by different solution temperature, initial pH value and adsorption time on the influence. More accurately of the adsorption quantity and adsorption mechanism can be predicted through the adsorption dynamics model and the isothermal adsorption model contrast, what’s more, the result of priority adsorption of Zn2+, Pb2+ions through a mixture of ion adsorption performance study comparing to the single ion adsorption can be get.The result shows:hydrothermal stabilized fly ash was utilized as potential adsorbent for the removal of Zn2+and Pb2+. The optimum conditions for adsorption by using a batch method were evaluated by changing various parameters such as contact time, initial pH of the solution and temperature. The result showed that NO.2fly ash performed the best adsorption capacity of Zn2+and Pb2+:28.90mg、57.06mg/g-, the adsorption capacity increased by the decreasing of the pH and the increasing of the temperature. Kinetics of heavy metals sorption is observed to confirm Lagergren pseudo-second-order rate kinetics and Isothermal adsorption model match Freundlich adsorption model well.As we may see from the mixed ion adsorption,the adsorption capacity of Pb2+is merely twice of Zn2+. That is to say,the hydrothermal stabilized fly ash prefered Pb2+than Zn2+, adsorption followed pseudo-second-order rate kinetics, the same as the single ion adsorption.