粉煤灰对阴离子水溶性混合染料的吸附动力学

以燃煤废弃物粉煤灰作为吸附剂,对活性红23与活性蓝4、活性黄4、酸性黑1、酸性蓝193的混合染料溶液进行吸附性能研究.结果表明,在不同的混合体系中,活性红23的脱色率基本保持在60%~70%;体系中酸性染料的脱色率均超过90%;活性蓝4的脱色率高达85%;活性黄4的脱色率仅为50%.准二级吸附动力学能够更好地描述粉煤灰对水溶性混合染料的吸附过程.染料在溶液中的外扩散系数均为10-4cm·s-1数量级,染料在粉煤灰颗粒的内扩散系数为10-8cm2·s-1数量级.根据BN数,水溶性染料在粉煤灰上的竞争吸附是外扩散控制的吸附过程.

Adsorption Kinetic Mechanism of Ionic Soluble Dye Mixture on Fly Ash

The fly ash from coal combustion was used as adsorbent for the removal of binary mixtures of dyes from aqueous solution. The binary solution included reactive red 23 and one of reactive blue 4, reactive yellow 4, acid black 1 and acid blue 193. The experimental findings show the removal efficiency of reactive red 23 is about 60%-70% while the removal of acid dyes exceeds 90%. The removal value of reactive blue 4 is about 85%, while the value is only 50% for reactive yellow 4. The adsorption kinetic data are good fitted with the pseudo-second-order kinetic model. The external diffusion coefficient solution is in the order of 10^-4 cm·s^-1, while the intraparticle diffusion coefficient is in the order of 10^-8 cm²·s^-1. Because all B_N numbers are smaller than 100, adsorption of dyes on fly ash is mainly controlled by the external diffusion mechanism.