聚合氯化铁与三氯化铁吸附电中和特征的比较研究

Comparative Study on Adsorption and Charge Neutralization Characteristics of Polyferric Chloride and Ferric Chloride

通过吸附历时过程、饱和吸附量、吸附过程中Na+离子交换释放量、絮凝过程中蒙脱土胶体颗粒的Zeta电位测试等试验,考察了FeC l3和聚合氯化铁(PFC)两种不同Fe(Ⅲ)形态的絮凝剂对蒙脱土悬浮水样的吸附电中和特征,并探讨了其作用机理。结果表明,随着碱化度(B)的增大,PFC吸附的趋势增强,吸附平衡时PFC(B=0.7)的饱和吸附量高达6.5×10-5mol/L,高出FeC l3的30%以上。除浊试验表明,PFC的投加量范围较FeC l3明显增大,说明高分子絮凝剂中的水解多核多羟基络合物在溶液中比较稳定。PFC和FeC l3对钠化蒙脱土的吸附方式不同,FeC l3以离子交换为主;PFC的吸附既有离子交换又存在表面络合作用,吸附能力较FeC l3强;PFC比FeC l3具有更强的吸附电中和能力。

The adsorption and charge neutralization characteristics of two Fe-based flocculants, FeCl3 and polyferric chloride （PFC）, in montmorillonite suspension system were studied by investigating the time required to reach equilibrium, saturated extent of adsorption, Na^＋ exchange capacity, and the Zeta potential of montmorillonite particles. The interaction mechanisms between Fe-based flocculant and montmorillonite particles were also discussed. The experimental results show that the adsorption ability of PFC is enhanced with its B value increasing. The maximum saturated extent of adsorption of PFC （B = 0.7 ） is 6.5 × 10^-5 mol/L under a adsorption equilibrium state, which is 30% higher than that of FeCl3. The turbidity removal experimental results show that the dosage of PFC is obviously wider than that of FeCl3, which indicates that the multi-nucleus hydroxy complex of polymeric flocculant is quite stable in the solution. PFC and FeCl3 have a different adsorption mechanism to Na-montmorillonite. The adsorption mechanism involves mostly ion exchange for FeCl3, but also surface complexation for PFC. PFC has higher adsorption and charge neutralization ability than FeCl3.