高岭土悬浮液的ζ电位对MD膜驱剂吸附性能的影响

EFFECT OF ζ POTENTIAL OF KAOLIN IN SUSPENSION ON THE ADSORPTION OF MOLECULAR DEPOSITION FILM FLOODING AGENT

采用静态吸附法研究了MD 1膜驱剂在高岭土上的吸附特性。结果表明,高岭土悬浮液的pH值显著影响其颗粒表面的带电性,ζ电位是决定高岭土对MD 1膜驱剂吸附的主要因素,饱和吸附量As随着ζ电位的降低而增加。当高岭土的pHzpc=3.14,且悬浮液的pH>3.14时,pH值越高,表面负电荷(带电量)越多,MD 1膜驱剂在高岭土颗粒上的吸附量越大。动力学研究发现,高岭土颗粒表面电位愈低,对MD 1膜驱剂的吸附活化能越小,要克服的吸附势能垒越低,吸附MD 1膜驱剂的速度越快,MD 1膜驱剂与高岭土颗粒间的静电相互作用越强。温度对吸附速率影响不大。热力学研究表明,碱性条件下吸附过程是自发且放热的,pH值愈高,放出的热量愈多,pH=10.56时,ΔH=-36.31kJ/mol。

The adsorption behavior of molecular deposition (MD) film flooding agent MD-1 on kaolin in suspension was studied by static adsorption method. The results show that the pH value affects apparently the surface potential of kaolin particles in suspension. It is found that ζ potential is the main factor for MD-1 film flooding agent to be adsorbed on kaolin particles. When pH value of kaolin is 3.14 at ζ potential zero (pHZPC) and the pH value of the suspension >3.14, the higher the pH value, the more the negative charges also the more amount of MD-1 adsorbed on the kaolin surface. The saturated adsorption amount of As of MD-1 increases with the decrease of ζ potential. Kinetic study shows that the lower the surface potential of the kaolin particles, the less the adsorption active energy, i.e., the lower the adsorption potential barrier to overcome, and the stronger the electrostatic interaction between MD-1 and kaolin particles and the quicker the adsorption occurred. Temperature has little effects on adsorption. Thermodynamics study reveals that the adsorption process is spontaneous and a large amount of heat is released in basic environment, enthalpy change (ΔH) is -36.31 kJ/mol when pH value of the suspension is 10.56.