巯基化多孔氧化硅纳米球及其对汞的吸附富集

Enrichment of Mercury Ions from Aqueous Solutions by Thiol-modified Porous Silica Nanospheres

采用原位共缩聚法,合成了巯基功能化多孔氧化硅纳米球,利用红外光谱、扫描电镜、透射电镜、氮气吸附-脱附)和热重分析等对合成的样品进行了表征,并研究了所合成样品对水中Hg^(2+)的富集分离性能。结果表明,巯基多孔氧化硅纳米球具有较高的比表面积(789 m^(2)/g)和较大的孔体积(2.66 cm^(3)/g);通过调节反应条件,可以调控多孔纳米球的比表面积、孔体积、孔径和巯基负载量;巯基的引入可以提高纳米球对Hg^(2+)的吸附富集率和吸附量,10 min内富集率超过97%,最大平衡吸附量达340 mg/g。吸附过程符合准2级动力学吸附模型和Freundlich吸附等温线模型。巯基化多孔氧化硅纳米球的吸附性能具有较好的稳定性,经过3次循环使用,对Hg2+的去除率仍能达到95%左右。

The in-situ copolycondensation method was used to synthesize sulfhydryl functionalized porous silica nanospheres. The synthesized samples were characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption and thermogravimetric analysis. The enrichment and separation performance of the synthesized sample for Hg^(2+) in aqueous solution was also studied. The results indicated that, sulfhydryl functionalized porous silica nanospheres had high specific surface areas(789 m^(2)/g) and large pore volume(2.66 cm^(3)/g).The specific surface area, pore volume, and pore diameter and the sulfhydryl group capacity in porous silica materials could be controlled by adjusting the experiment conditions. The introduction of sulfhydryl groups could improve the adsorption enrichment rate and adsorption capacity of nanospheres for Hg^(2+), the enrichment rate exceeded 97% within 10 min, and the maximum equilibrium adsorption capacity reached 340 mg/g. The adsorption process conformed to the pseudo-second-order kinetic adsorption model and Freundlich adsorption isotherm model. The adsorption performance of the sulfhydryl porous silica nanospheres had good stability. After three cycles of use, the removal rate of Hg2+ could still reach about 95%.