麦羟基硅钠石的可控合成及其阳离子交换性能研究

目前，开发绿色高效的重金属吸附材料受到人们的广泛关注。以硅藻土为原料，经水热法选择性地制备了2类硅酸盐材料即麦羟基硅钠石和方沸石。吸附测试结果表明，麦羟基硅钠石层间的钠离子能够与锂离子、镁离子、锌离子、钴离子、镍离子、铜离子等进行阳离子交换且能保持层状母体框架的稳定性。以钴离子、镍离子为例深入研究其吸附动力学和吸附机制发现，钴离子和镍离子的嵌入分别将麦羟基硅钠石的层间距由本征的1.56 nm减小到0.24、0.23 nm；室温下，对钴离子、镍离子的最大吸附量分别可达45、39 mg/g，均符合Langmuir单层吸附模型；钠离子的置换量大约是吸附的钴离子、镍离子量的两倍，证实层间离子交换主导吸附化学过程。因此，麦羟基硅钠石材料在多金属硅酸盐功能材料的合成以及环境吸附净化领域具有较大的应用潜力。

Study on controlled synthesis of magadiite and its metal ion exchange properties

At present，the development of green and efficient heavy metal adsorption materials has attracted extensive attention.Using diatomite as raw material，two kinds of silicate materials，namely，magadiite and analcime，were selectively prepared by hydrothermal method.The Na⁺ between the layers of wheat hydroxysodalite could exchange cations with Li⁺，Mg²⁺，Zn²⁺，Co²⁺，Ni²⁺，Cu²⁺，etc.，and maintain the stability of the layered parent framework.The adsorption kinetics and mechanisms were detailedly studied by using Co²⁺ and Ni²⁺ adsorption.It is indicated that the distance of magadiite lamellar structure was reduced from 1.56 nm to 0.24 nm（Co²⁺）and 0.23 nm（Ni²⁺）.The maximum adsorption capacity towards Co²⁺ and Ni²⁺ reached 45 mg/g and 39 mg/g at room temperature，respectively.The adsorption processes were fitted with the Langmuir model.The released Na⁺ was approximate double of the adsorbed divalent Co²⁺ and Ni²⁺，showing that cation exchange dominated the adsorption processes.Thus，the prepared magadiite materials demonstrated great potentials for constructing multi-metal silicates and environmental purification applications.