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以壳聚糖为吸附剂,考察溶液pH值、Pb2+初始浓度等条件对壳聚糖吸附性能的影响,研究不同温度下壳聚糖对Pb2+的吸附等温线、热力学和动力学行为,并研究表观活化能.结果表明,当pH为5~6时,壳聚糖对Pb2+的吸附能力达到最大值;随着Pb2+初始浓度增加,平衡吸附量随之增加并达到最大值,此后基本不变;当温度在298~313 K变化时,平衡吸附量随Pb2+平衡浓度增大而增大,达到最大值后基本不变,吸附行为符合Langmuir方程;不同温度下的△G均小于零,且温度越高,△G越小,△H大于零,温度越高越有利于吸附;随着吸附时间延长,初始阶段吸附速率较快,此后逐渐下降,吸附动力学行为符合拟二级速率模型,吸附表观活化能为18.658 kJ/mol.
Chitosan was used as adsorbent to study the effect of pH value and Pb2 + initial concentration on the adsorption properties of chitosan. The adsorption isotherms, thermodynamics and kinetics of chitosan on Pb2 + at different temperatures were studied. The results showed that the adsorption capacity of chitosan to Pb2 + reached the maximum when pH was 5 ~ 6. With the increase of Pb2 + initial concentration, the equilibrium adsorption increased and reached the maximum, When the temperature was changed from 298 to 313 K, the equilibrium adsorption increased with the increase of Pb2 + concentration. After reaching the maximum, the adsorption was basically unchanged, and the adsorption behavior was in accordance with the Langmuir equation. The △ G at different temperatures was less than zero, High, △ G smaller, △ H greater than zero, the higher the temperature the more conducive to adsorption; with the adsorption time, the initial stage of the adsorption rate faster, then gradually decreased, the adsorption kinetics consistent with the proposed two-rate model adsorption table View activation energy of 18.658 kJ / mol.