新型硅镁胶(MgO·2SiO_2)对模拟放射性废水中Co^(2+)的吸附性能

Adsorption properties of Co^(2+) from simulated radioactive wastewater onto magnesium silicon gel(MgO·2SiO_2)

以泡花碱和氯化镁为原料合成出了一种新型硅镁胶(MgO·2SiO2)吸附材料,用傅里叶红外光谱仪对其进行了表征,并对模拟放射性废水中的Co2+进行吸附实验。结果表明,控制合成pH在10.50~11.00,可以得到目标硅镁胶(MgO·2SiO2),在460 cm-1处出现了较强的吸收峰,这是由Mg—O伸缩振动和Si—Mg—O弯曲振动引起。在500℃焙烧4h后,可以得到吸附性能良好的硅镁胶,随着溶液pH的升高,去除率增大,在pH为4~8时达到最大。25℃时,最大吸附量可达135.5 mg/g,吸附过程符合Langmuir等温吸附方程和准二级动力学方程。重复使用4次,对Co2+的吸附量仍然达到130 mg/g,说明硅镁胶是一种可重复利用的吸附剂。

A novel type of magnesium silicon gel material（MgO · 2SiO2） was synthesized and characterized by FT-IR. Adsorption properties of Co2＋ on magnesium silicon gel were investigated. Studies showed that target magnesium silicon gel could be synthesized if pH range was controlled at 10.50 - 11.00. Mg-O stretching vibra- tions and Si--Mg--O bending vibrations account for the absorptions near 460 cm-1. The optimum calcining con- ditions were 500℃ ,4 h; the removal increased with the increase of pH value and could reach best at pH 4- 8. The maximum adsorption amount was 135.5 mg/g at 25℃. The equilibrium data were found to be well represen- ted by the Langmuir isotherm equation and pseudo-second-order kinetic equation. The adsorption capacity of Co2 ＋ still amounted to 130 mg/g after reusing four times. Consequently,MgO ·2SiO2 is a reusable and high-efficient adsorbent.