pH值对硫化氢在碱浸渍活性炭内扩散机制的影响

Effects of pH on Diffusion Activities of H_2S in Activated Carbon Particles Impregnated by KOH Aqueous Solution

采用自制的固定吸附床吸附装置,对碱浸渍活性炭脱除沼气中硫化氢的动态吸附进行了初步研究。研究结果表明,随着浸渍液pH值的升高,碱浸渍活性炭对硫化氢的吸附容量增加。pH值为8.0,10.0和12.0时的硫化氢吸附容量分别为2.37,4.96和9.33 mg·g^(-1)。利用Weber-Morris孔扩散模型,Boyd准一级颗粒扩散模型和Dumwald-Wagner模型研究了改性活性炭吸附硫化氢的吸附动力学行为,发现活性炭表面性质的改变,使边界条件的影响减小,削弱了气膜扩散的影响。Boyd准一级颗粒扩散模型描述硫化氢在碱浸渍活性炭上的整个吸附行为较其它两个模型准确。

Effects of pH on diffusion activities of H2 S in activated carbon impregnated by KOH aqueous solution were stud- ied in this paper. Results showed that adsorption capacity of H2 S increased with the increase of pH. The adsorption capaci- ty of H2 S were 2.37 mg g - 1,4.96 mg g -1 and 9.33 mg g-1 in KOH impregnated activated carbon under pH of 8.0, 10.0 and 12.0, respectively. The Pore diffusion model of Weber-Morris, the pseudo-first order particle diffusion model of Boyd , and the kinetic diffusion models of Dumwald-Wagner, were used to analysis effects of pH on H2S diffusion activi- ties, and found that the surface properties of activated carbon changed by the KOH impregnation, reduced the influence of boundary conditions and gas film diffusion. The Boyd model could describe the adsorption process better than the other two models.