阴离子／两性表面活性剂在大庆油砂／水界面的混合吸附滞留研究

采用静态吸附方法测定了45℃下十二烷基硫酸钠（SDS）十六烷基二甲基甜菜碱（C。6B）以及n（SDS）：n（C，。B）：20：80混合物在带负电荷的大庆油砂上的吸附滞留。结果表明：SDS和C，6B的饱和吸附量分别为0．0034mmol／g和0．0237mmol／g。以气／液界面上的单分子层饱和吸附量为参比，估算出两者在油石少／水界面的吸附层数分别为0．31和1．55，表明c。。B先通过静电吸引作用吸附到界面，随后形成表面胶束；二者混合物的吸附是非均匀的，其中C，6B发生了优先吸附：混合体系中两组分的吸附量皆大于单一体系相同平衡浓度下各自的吸附量，即表现出较强的协同效应。这种优先吸附和协同效应对于降低驱油用表面活性剂在油，石少／水界面的吸附滞留和色谱分离效应是不利的。

Study on the Mixed Adsorption Retention of Anionic/Amphoteric Surfactants at Daqing Sandstone/Water Interface

The adsorption retention of an anionic surfactant, sodium dodecyl sulfate（ SDS）, and an amphoteric surfactant, hexadecyldimethylearboxyl betaine（ C16B） , as well as their mixture at a molar ratio of 20：80 at negatively charged Daqing sandstone/water interface at 45℃ were studied. The saturated adsorption of SDS and C16 B are 0. 003 4 mmol/g and 0.023 7 mmol/g respectively. Referring to the saturated adsorption at air/water interface an adsorption layer at solid/water interface can be estimated, which are 0.31 and 1.55 for SDS and Cl6 B respectively. It is suggested that CI6 B molecules in- itially adsorb on the solid surface via electrostatic interaction between the positive charge in CI6B molecule and the negative charge on the solid surface, followed by forming admicelles. The adsorption of CIrB and SDS from their mixture solution is non - even where C16B displays a prior adsorption. Moreover the adsorption of C16B and SDS from their mixture solution is all larger than that from their individual solutions at the same equilibrium concentration, or a strong synergistic effect is present, which is not beneficial to the reduction of adsorption retention and chromatographic separation effects of mixed sur- factants for enhanced oil recovery.