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研究报告

摘要：通过动力学和热力学吸附实验,研究了汽油在西北地区黄土上的吸附行为,同时研究了提取的天然腐植酸对汽油在黄土上吸附行为的影响.结果表明,汽油在黄土上的吸附在6 h内达到平衡.无论是否加入腐植酸,汽油在黄土上的吸附动力学过程均符合Elovich方程,其热力学吸附符合Freundlich方程.腐植酸的存在使汽油在黄土上的吸附能力减小.反应温度从25℃升高到45℃,汽油在土壤上的饱和吸附量从6.300 mg·g^-1减小到1.365 mg·g^-1,表明汽油在黄土上的吸附属于放热反应.溶液pH和土壤粒径的增大,均不利于汽油在黄土上的吸附,溶液pH和土壤粒径越大,其在黄土上的吸附量越小.另外,在室温下对吸附了汽油的土壤样品和纯汽油挥发行为的研究表明,吸附了汽油的土壤样品的汽油挥发比纯汽油慢,其挥发率与时间成对数关系.

Abstract：Dynamic and thermodynamics experiments were carried out to study adsorption characteristics of gasoline on loess soil in Northwest China. The influence of natural humic acid on adsorption behavior of gasoline on loess soil was investigated. The results showed that the adsorption balance of gasoline on loess soil was reached within 6 h. The adsorption kinetics of gasoline was well fitted with Elovich kinetics equation and the adsorption thermodynamics was fitted well with Freundlich isothermal equation in either the presence or absence of humic acid. The presence of humic acid resulted in a decrease of the adsorption capacity of gasoline on loess soil. When the temperature increased from 25℃ to 45℃, the adsorption capacity of gasoline decreased from 6.300 mg·g^-1 to 1.365 mg·g^-1, indicating a spontaneous exothermic process of the adsorption of gasoline on loess soil. Also higher pH and larger soil particle size led to decreased adsorption capacity of gasoline. In addition, the evaporation of gasoline adsorbed on soil samples was slower than that of pure gasoline at ambient temperature. The relationship between evaporation rate and time was well fitted with logarithmic expression.