不同介质中石油污染物吸附过程的动力学及热力学研究

以3个不同地域的土壤为研究对象,采用平衡振荡法,研究了石油污染物在不同土壤中的吸附动力学和热力学特征。试验数据分别采用4种动力学模型进行拟合。结果表明,不同土壤对石油污染物的吸附均表现为快反应和慢反应2个阶段,0～15 min为快反应阶段,吸附量达到饱和吸附量的85%。3种土壤对石油污染物的吸附动力学符合拉格朗日假二级动力学方程。不同温度下3种供试土的吉布斯自由能变均为负值,3种土壤对石油污染物吸附过程的焓变、熵变依次为:ΔH029.11、29.12、52.70 kJ/mol;ΔS0-100.85、-103.09、-182.66 J/(mol.K)。表明,土壤对石油污染物的吸附是自发进行且为放热过程,温度升高吸附量减少,石油被吸附的过程中混乱度降低。

Study on Kinetics and Thermodynamics of Petroleum Adsorption onto the Different Media

Adsorption kinetics and thermodynamics of petroleum onto these soils from different regions were determined by equilibrium method in the laboratory.The data were fitted to four different kinetic models respectively.The results showed that the reaction of adsorption could be divided into two types: a fast reaction in the first 15min and a slow reaction in the later reaction course.The amounts of petroleum adsorbed by the fast reaction exceeded 85% of the adsorption capacity.Adsorption processes for petroleum onto the three soils were found to follow pseudo-second order type adsorption kinetics.The Gibbs free energy change of test soils was negative at different temperatures.The enthalpy and entropy changes of different test soils in adsorption process were as follows: ΔH0 29.11,29.12,52.70 kJ/mol;ΔS0-100.85,-103.09,-182.66 J/(mol·K).It showed that the adsorption of petroleum onto soil was a spontaneous and exothermic process.The amounts of petroleum adsorption gradually slowed down with the increasing temperature,and the confusion degree reduced in the adsorption process.