固定化海带生物吸附剂的制备及其吸附Ni^(2+)的动力学特性

Preparation of Immobilized Laminaria Japonica Biosorbent and Its Sorption Kinetics for Ni^(2+)

以海藻酸钠、明胶和海带粉为原料制备了固定化海带生物吸附剂。固定化海带生物吸附剂对Ni2+的吸附过程可分为3个阶段:快速吸附阶段、缓慢吸附阶段和吸附平衡阶段。动力学过程可用Lagergren准二级反应动力学方程描述,限速步骤为化学吸附。随Ni2+初始质量浓度的增加,固定化海带生物吸附剂的Ni2+吸附量逐渐增大,Ni2+去除率逐渐降低。吸附过程符合Langmuir和Freundlich吸附等温方程,说明该吸附体系既有物理吸附又有化学吸附,从吸附状态看属于多层吸附,由Langmuir吸附等温方程得出固定化海带生物吸附剂对Ni2+的最大吸附量为39.43mg/g,说明固定化海带生物吸附剂对Ni2+有较好的吸附性能。

Alginate sodium, glutin and powder laminaria japonica were used to prepare immobilized Laminaria Japonica biosorbent. The results of the kinetic studies show that the sorption of nickel ions on immobilized Laminaria Japonica biosorbent can be divided into three phases： rapid sorption phase, relatively slow sorption phase and sorption equilibrium phase. The sorption of nickel ions on the biosorbent follows Lagergren pseudo second order kinetics, suggesting that the determined step of the biosorption is chemisorption process. The uptake capacity of the biosorbent increases and the removal rate of Ni2＋ decreases with increasing the initial nickel ion concentration. The experimental results fit satisfactory to Langmuir and Freundlich isotherm models, explaining that the sorption of nickel on the biosorbent is physical and chemical sorption, and the sorption is to heterogeneous surface. The maximum uptake capacity for nickel ions of the immobilized Laminaria Japonica biosorbent is 39.43 mg/g showing high adsorptive capacity for nickel ions.