Adsorption properties of heavy metal ions on fly ash modified by alkali and chitosan
壳聚糖联合碱改性粉煤灰对重金属离子的吸附特性

The modified fly ash was prepared by charging chitosan on fly ash modified by alkali using im-pregnation method. The experimental results of adsorbing Pb~(2+) and Cd~(2+) in aqueous solution show that with in-creasing the mass fraction of chitosan,the removal efficiency increase. When the mass fraction of chitosan is 8%,the adsorption temperature and time are 30 ℃ and 120 min respectively,the removal efficiencies of Cd~(2+)and Pb~(2+) are the maximums (98.9% and 91.5% respectively). The adsorption behaviors of modified fly ash correspond with the Freundlich model well. However,the adsorption isotherm data appear as two distinct linear regions. The modification mechanism of fly ash loading chitosan with positive charge is chemical bonding reaction between the two substances.