十二烷基磺酸钠在赤铁矿表面吸附动力学

利用带耗散功能的石英晶体微天平研究十二烷基磺酸钠在Fe2 O3石英晶体谐振器表面的吸附动力学及吸附层构象。结果表明：十二烷基磺酸钠在赤铁矿表面的吸附是一个快速达到吸附平衡的过程,pH值对十二烷基磺酸钠的吸附影响较为明显,pH值在3~9的范围内,随着pH值增加,药剂吸附层黏弹性逐渐增大,吸附层稳定性减弱,赤铁矿回收率逐渐下降,十二烷基磺酸钠的吸附过程只有一个吸附阶段,且吸附过程符合准一级动力学模型,吸附层不发生明显构象变化；当pH值为10和11时,十二烷基磺酸钠吸附量明显增加,赤铁矿回收率也开始回升,吸附过程存在多个吸附阶段,吸附的第一阶段符合准二级动力学模型,吸附的第二阶段符合Elovich方程,并且随着吸附的进行,吸附层发生明显构象变化。

Adsorption kinetics of sodium dodecyl sulfonate onto hematite

The adsorption kinetics and conformation change of sodium dodecyl sulfonate ( SDS) onto Fe2 O3-coated crystal sensors were studied by quartz crystal microbalances with dissipation ( QCM-D) . The results show that the adsorption of SDS onto Fe2 O3 sur-faces is a rapid adsorption process. The pH value has a great influence on the adsorption of SDS. When the pH value increases, the viscoelasticity of the adsorption layer improves, the stability of the adsorption layer deteriorates, and thus the recovery of hematite flota-tion gradually decreases. There is only one adsorption stage which is best fitted by the pseudo-first order model without any change in conformation in the pH range of 3 to 9. At the pH values of 10 and 11, the adsorption of SDS markedly increases and the recovery of hematite flotation also recovers. There are two distinguishable adsorption stages with the first adsorption stage best-fitted by the pseudo-second order model and the second adsorption stage by the Elovich equation. The adsorption layer also experiences an obvious confor-mation change as the adsorption continues.