表面活性剂对柴油在土壤中吸附的影响

INFLUENCE OF SURFACTANT ON SORPTION OF DIESEL OIL ON SOILS

通过静态吸附实验,研究土壤对十二烷基苯磺酸钠(LAS)和十六烷基三甲基溴化铵(CTAB)的吸附行为,探讨表面活性剂对柴油吸附的影响.结果表明,土壤对LAS和CTAB的吸附等温线均为非线性,其吸附能力的大小顺序为:轻壤土>轻粘土>中壤土>砂壤土>重壤土>紧砂土.同一土壤中,CTAB的吸附量大于LAS的吸附量.LAS和CTAB均利于柴油在土壤表面的解吸,且LAS的解吸效果更好.柴油的吸附量随LAS浓度的升高而降低.当CTAB的浓度小于临界胶束浓度CMC时,吸附量随CTAB浓度的升高而升高,当CTAB的浓度等于或大于临界胶束浓度(CMC)时,吸附量随CTAB浓度的升高而降低.

Static adsorption experiments were carried out to investigate the adsorption of sodium dodecyl benzene sulfonate （LAS） and cetyltrimethyl ammonium bromide （CTAB） on soils, and to analyze the effect of surfactants on sorption of diesel oil. The results indicated that the adsorption isotherms of LAS and CTAB on six soils were non-linear, and the adsorption capacity of the six soils from high to low was.. light loam, light clay, medium loam, sand loam, dense loam and dense sand. The adsorbed amount of CTAB is higher than that of LAS on the same soil. Both LAS and CTAB have a positive effect on desorption of diesel oil from soil, and LAS plays a much more important role in desorption than CTAB. The adsorbed quantity of diesel oil decreases with increasing LAS concentration. When CTAB concentration is lower than the critical micelle concentration （CMC）, adsorption increases with increasing CTAB concentration. When CTAB concentration is equal to or higher than CMC, adsorption decreases with increasing CTAB concentration.