壳聚糖联合碱改性粉煤灰对重金属离子的吸附特性

采用浸渍法将壳聚糖负载在经NaOH改性的粉煤灰上，制备了联合改性的粉煤灰。随粉煤灰上壳聚糖负载量的增加，粉煤灰对Pb²⁺和Cd²⁺的吸附率均提高。当负载壳聚糖的质量分数为8%，吸附温度为30℃，吸附时间为120 min时，粉煤灰对Pb²⁺的吸附率最高（为98.9%），对Cd²⁺的吸附率也最高（为91.5%）。其吸附行为符合Freundlich等温吸附模型，但表现为2个线性区。粉煤灰负载壳聚糖的改性机理是粉煤灰与带正电荷的壳聚糖的化学键合作用。

Adsorption properties of heavy metal ions on fly ash modified by alkali and chitosan

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.