载镁鸡蛋壳的制备及其对水体中磷酸盐的吸附特性

Preparation and adsorption properties for phosphate in water of magnesium modified eggshells

摘要:

采用氯化镁溶液对鸡蛋壳进行改性，制得载镁鸡蛋壳（MgES）并应用于水中磷酸盐的去除。采用XRF、SEM、FTIR和XRD等对材料进行表征。通过静态吸附实验分析MgES对水体中磷酸盐的去除性能。结果表明：Langmuir模型能够较好地拟合吸附等温线，25 ℃时最大吸附量为112.156 mg/g；MgES对磷酸盐的吸附是自发的吸热过程；吸附动力学遵循准二级动力学模型；酸性条件有利于其吸附进程；MgES具有较好的再生性能，经5次再生使用后对磷酸盐的去除率仍达61.22%。应用MgES去除磷酸盐，可实现回收再利用蛋壳废弃物的同时降低废水中的磷酸盐含量，实现以“废”治“废”。

Abstract:

The eggshells are modified with magnesium chloride solution to prepare magnesium-loaded eggshells (MgES) and applied to the removal of phosphate in water. The materials were characterized by XRF， SEM， FTIR and XRD. The performance of MgES on the removal of phosphate in water was analyzed by static adsorption tests on adsorption thermodynamics, isotherms, kinetics and initial solution pH. The results show that the Langmuir model can fit the adsorption isotherm well and the maximum adsorption capacity at 25 ℃ is 112.156 mg/g. The adsorption of phosphate by MgES is a spontaneous endothermic process. The adsorption kinetics follows the quasi-second-order kinetics model. Acidic conditions are conducive to its adsorption process. In addition, after 5 regeneration times, the removal rate of phosphate by MgES still is 61.22%. The application of MgES to remove phosphate can realize the recycling and reuse of eggshell waste while reducing the phosphate content in the waste water, which is of practical significance.