高岭石为原料超临界水热法快速合成类沸石材料及其脱汞性能

Rapid Synthesis of Zeolitic Materials from Kaolinite by the Supercritical Hydrothermal Method for Mercury Removal

基于超临水的独特性能,以高岭石(kaolinite)为硅源和铝源,利用超临界水热合成法(SCHS)合成类沸石材料。在反应温度为400℃时,高岭石与1 mol/L碳酸钠(Na2CO3)溶液、1 mol/L氢氧化钠(Na OH)溶液和2 mol/L氢氧化钾(KOH)溶液在超临界水热条件下,5 min内分别制得方钠石(sodalite)、钙霞石(cancrinite)和钾霞石(kalsilite)。采用X射线衍射(XRD)、扫描电子显微镜(SEM)与傅里叶变换红外光谱(FT-IR)等分析手段,对产品的结构和形态进行表征。并通过脱除废水中汞离子来考察合成的类沸石材料的吸附性能。实验结果表明,钾霞石的吸附效率最高,当吸附剂投入量为6 mg/m L时,其吸附效率可达到50.57%,使废水中汞离子浓度从10 mg/L减少至4.94 mg/L。在同样条件下,方钠石和钙霞石的吸附效率分别为30.49%和31.80%。

Kaolinite, as the source of SiOz and AlzO3, issued to synthesize zeolite-like materials by the supercritical hydrothermal synthesis （SCHS） method, which is a new approach for the preparation of new materials based on the particular characteristics of the supercritieal water （SCW）. Sodalite, cancrinite and kalsilite are successfully produced from kaolinite with 1 mol/L Na2CO3, 1 mol/L NaOH, and 2 tool/ L KOH at 400 ℃ by SCHS within 5 rain. The structures and morphologies of the products are characterized by X-ray diffraction （ XRD）, scanning electron microscopy （SEM） and Fourier transform infrared spectroscopy （FF-IR）, respectively. In addition, the adsorption properties of the as-prepared zeolitic materials are investigated while removing of Hg2＋ from wastewater. The experimental results indicate that kalsilite has the highest Hg2＋ adsorption efficiency 50.57% and can reduce the Hg2＋ concentration from an initial level of 10 mg/L to 4.94 mg/L with asorbent dosage of 6 mg/mL. The Hg2＋ adsorption efficiencies of sodalite and cancrinite are 30.49% and 31.80%respectively.