Research On Leaching Charateristics And Phytoremediation Of Heavy Metals In Fly Ash

Waste incineration fly ash contains a certain amount of Pb, Cd, Cr, Cu, Zn, Hg, Ni and other heavy metal.These heavy metal ions has a long residence time in natural environment.Although they can not be microbially degradated, but it can be accumulated in human and animals, and can be converted into highly toxic heavy metal compounds which cause various diseases, directly or indirectly.Hyperaccumulator plants have been used to repair heavy metal pollution of the environment. Then, heavy metals in Hyperaccumulator plants were isolated and extracted.Thus to achieve the purpose of Utilization of heavy metals and to achieve environmental benefits and economic benefits.Fly ash collected from Wenzhou Linjiang garbage power plant and Wenzhou Yongqiang power plant waste was used as material, and static and dynamic filtration properties of four kinds of it's leaching solutionin in distilled water, river water, sea water and simulated acid rain were studied.By collecting plant samples and corresponding soil samples, plants with high ability of accumulating heavy metals were screened.Selected plants were used to accumulate heavy metals and then heavy metals in plants were extracted. the main results are as follows:1 Based on the research on content composition and leaching characteristics of Heavy metal of fly ash,dynamic leaching characteristics of fly ash's heavy metal in simulated acid rain, sea water, river water and distilled water were focused on.Its findings were similar to reality of the percolation characteristics law that heavy metals in fly ash obeyed to. So it can provide a more ideal measures and theoretical basis to resolve the problem of secondary pollution caused by the methods.2 The capacity of accumulation and biological repair for heavy metals in fly ash leachate by dozens of plants were studied, such as camphor, Bauhinia, cedar, white orchids, banyan tree, and weeping willows.The results showed that the above 6 species of plants have strong ability of accumulating heavy metals from fly ash. Thus it can provide new ideas and methods of bioremediation approach on solving heavy metal pollution from fly ash. 3 Camphor, Bauhinia, and banyan was used to bioremediating several heavy metals from fly ash leachate,such as Cu, Cd, Pb and Zn. Then, the methods of harvesting, extraction and resource research of heavy metal from the above hyperaccumulator were preliminary studied.The use of "NH4C1-NH3-H20 system," to recovery four metal elements as Cu, Cd, Pb and Zn from plant was developed on the basis of the burning. Experimental results show that the method has a high recovery, and can recover the relevant metal well.