Removal Of Heavy Metals From Wastewater By Fly Ash Improved

Many industry including metals finishing, planting and mining acidic bring waste water containing cadmium, lead, copper, et al. Long-term ingestion of water containing higher concentration of heavy metals can cause many diseases such as stomach ailment, metal retardation, liver and kidney damage. Research in heavy metals removal and recovery are always a key problem in environmental protection. Fly ash has lots of advantages in the treatment of wastewater, such as simple process, high efficiency and low cost. Modification of Fly ash can improve its adsorption ability greatly and so makes it adsorb the contaminants such as heavy metal ions in wastewater more effectively.The first step of the issue in the modification of fly ash have been studied, the experimental results showed that the fly ash by 1 mol/L hydrochloric acid and 1 mol/L acid mixture of sulphuric acid at 80℃soak 60 min, including hydrochloric acid, sulfuric acid volume ratio To 1:3, fly ash and acid ratio of solid to liquid to 1/8 (g/mL), immersion in the process of accession to iron 0.2 g/L, sodium chloride 0.3 g/L, by removal good Modification of fly ash.Improved fly ash was used to remove Cd²⁺, Pb²⁺, Cu²⁺ from simulated wastewater. The experiment results show that the adsorption capability was affected by the initial concentration of Cd²⁺, Pb²⁺, Cu²⁺, pH,adsorption time and the concentration of fly ash .The result also demonstrated that the remove rate of Cd²⁺,Pb²⁺,Cu²⁺ could reach 96.53%,99.21%,97.49%,within 2 hours at the solid/liquid ratio of 14,10,12 g?L-1, pH=7, when Cd²⁺, Pb²⁺, Cu²⁺ concentration at 40mg?L-1. Simulation to the adsorption process showed that the process could be fitted well by both Freundilich and Langmuir Equation.The third step is subject to the second step of further study, the heavy metal ions in the mixed system of multi-absorption tests, found that when Pb²⁺ metal ions and the other two were mixed, the remaining two is conducive to the removal of heavy metal ions, and when Cd²⁺as interference by adding Cu²⁺ ions in the solution or as an interference Cu²⁺ or Cd²⁺adding the solution of these two kinds of fly ash on the removal of metal ions are reduced, that Cu²⁺, Cd²⁺ mixed at each other Interference and impact the effect of the absorption.