Solubility and adsorption characteristics of Pb in leachate from MSW incinerator bottom ash.

The solubility and adsorption characteristics of Pb in leachate from municipal solid waste incineration (MSWI) bottom ash was studied by batch experiments. The solubility of Pb in leachate was 1-2 orders of magnitude lower than that of Pb in carbonate solutions. Adsorption experiments showed bottom ash have high adsorption capacity for Pb. To evaluate a controlling component in bottom ash, quartz, Al and Fe powder as well as their ions were examined over wide ranges of pH at 25 degrees C. The results showed that only Fe powder had high adsorption capacities for Pb, indicating that iron oxides in bottom ash would be one major adsorbent for Pb. Adsorption diagram, constructed by using the data of adsorption experiments, fitted the experimental data of Pb in leachate very well. It suggests that the decrease of Pb solubility in leachate is mainly due to adsorption reaction.