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本文对二烷基二硫代磷酸锌在不同温度下自液体石蜡溶液中于铁表面的等温吸附进行了试验研究。结果表明,在285—353K的温度范围内,恒温搅拌3小时就基本达到了吸附平衡。在285K和303K这两种温度下的吸附等温线均属S型曲线,这表明二烷基二硫代磷酸锌主要是以分子形态和表面反胶团的形式被吸附;而其在较高温度(333K和353K)下的吸附等温线却发生了显著的变化,这是二烷基二硫代磷酸锌在铁表面催化分解和氧化作用开始加速的结果。将285K和303K下的吸附试验数据用以二阶段吸附模型为基础的S型吸附等温线公式处理,结果是实测值与理论曲线符合。热力学计算表明,二烷基二硫代磷酸锌在铁表面的缔合过程不是熵驱动的,因而形成的表面缔合物是表面反胶团、由于得出的胶团聚集数在2左右,故表面反胶团基本是以二聚体形式存在的。
In this paper, the isothermal adsorption of zinc dialkyldithiophosphate on iron surface from liquid paraffin solution at different temperatures was studied. The results show that in the temperature range of 285-353K, the equilibrium temperature is basically reached after stirring at constant temperature for 3 hours. The adsorption isotherms at both 285 K and 303 K are S-shaped curves, indicating that the dialkyldithiophosphates are mainly adsorbed on the molecular form and on the surface in the form of reverse micelles, whereas at higher temperatures (333 K and 353 K), the adsorption isotherm has undergone a significant change, which is the result of accelerated oxidation of zinc dialkyldithiophosphate on the iron surface. Adsorption test data at 285 K and 303 K were processed using the S-type adsorption isotherm based on the two-stage adsorption model. The results were in agreement with the theoretical curves. Thermodynamic calculations show that the association of zinc dialkyldithiophosphate on the iron surface is not entropy-driven, and thus the surface association is formed on the surface of the micelles, the number of micelles gathered in about 2, so Surface reverse micelles basically exist as dimers.