不同炭材料吸附Cr(VI)的热力学研究

以4种碳基材料作为吸附剂,研究了不同吸附剂对Cr(VI)的去除效果,并对吸附热力学进行了研究。研究结果表明,木质活性炭和煤质活性炭对Cr(VI)的吸附效果较好;温度对木质活性炭与煤质活性炭的吸附能力影响较大,随着温度由298 K提升至343 K,其对Cr(VI)吸附能力提高50%以上,在343 K其最大吸附量分别为160.72 mg/g和151.88 mg/g;热力学参数研究说明2种活性炭吸附的过程为熵增过程;且随着温度升高,ΔG0的值变小,说明升高温度使吸附过程的自发程度增高。

Study of thermodynamics for adsorption of Cr(VI) by different carbon materials

Four carbon-based materials were employed as adsorbents to remove Cr(VI) from aqueous solution. Cr(VI) removal efficiency was investigated under different experimental conditions. The results demonstrated that wood-based activated carbon and coal-based activated carbon exhibited better Cr(VI)-adsorption performance. The experimental data indicating better Cr(VI) adsorption by wood-based and coal-based activated carbon illustrated that adsorption temperature plays a key role in determining adsorption performance. With rising temperature (298 to 343 K), the Cr(VI) adsorption capacity increased by more than 50%. The maximum Cr(VI) adsorption capacity of wood-based and coal-based activated carbon at 343 K were 160.72 and 151.88 mg/g, respectively. Thermodynamic parameters showed that the Cr(VI) adsorption processes of the two activated carbons were both entropy-increasing processes. As the temperature rose, the value of ΔG0 became smaller, which increased the degree of spontaneous adsorption.