钴掺杂NaP分子筛合成及其吸附Pb(II)性能

以硅酸钠和偏铝酸钠为原料,通过水热合成法制备钴掺杂NaP分子筛,通过X射线衍射光谱(XRD)、扫描电子显微镜(SEM)、N₂吸附-脱附等表征手段对样品的晶相、形貌和孔结构进行表征分析,并对其Pb(II)吸附性能进行评价。结果表明:与未掺杂钴的NaP分子筛相比,掺杂量为n(Al₂O₃)∶n(Co(NO₃)₂)=8∶1的Co-NaP分子筛的比表面积增大了约5倍(从26.767 m²/g增大到162.490 m²/g);其孔容约增大了约2.5倍(从0.029 cm³/g增大到0.104 cm³/g)。吸附时间为120 min,吸附温度为25 ℃,Pb(II)初始浓度为100 mg/L时,Co-NaP分子筛对Pb(II)的去除率可达98.8%,以乙二胺四乙酸二钠为再生助剂,在30 ℃下再生30 min,可使吸附后时Co-NaP分子筛完全再生,再生后的吸附剂经过3次吸附-再生循环后,Pb(II)去除率仍可达97%。

Preparation of NaP Zeolite Doped with Cobalt and Its Adsorption Performance for Pb(II)

A series of NaP zeolites doped with cobalt were synthesized by hydrothermal synthesis method using the sodium silicate and the sodium meta-aluminate as raw material. The crystal phase, morphology and pore structures of NaP zeolite samples were characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM), and N₂ adsorption-desorption methods. Moreover, the adsorption performance of NaP zeolite doped with cobalt for Pb(II) was evaluated. The results show that the NaP zeolite doped with cobalt at n(Al₂O₃)∶n(Co(NO₃)₂)=8∶1 has a specific surface area of 162.490 m²/g, which is 5 times more than the undoped NaP zeolite (from 26.767 m²/g to 162.49 m²/g), and a pore volume of 0.104 cm³/g, which is 2.5 times more than the undoped NaP zeolite (from 0.029 cm³/g to 0.104 cm³/g). When the adsorption time is 120 min, the adsorption temperature is 25 ℃, and the initial concentration of Pb(II) is 100 mg/L, Co-NaP zeolite has a removal rate of 98.8% for Pb(II). Employing the EDTA-2Na as the regeneration regent, the adsorbed NaP zeolite is regenerated completely at 30 ℃ for 30 min. After three adsorption-regeneration cycles, Co-NaP zeolite has a better adsorption property for Pb(II), and the removal rate of Pb(II) keeps over for 97%.