北京土壤对甲苯和萘的吸附及影响因素分析

Adsorption of Toluene and Naphthalene on Beijing Soils and Its Influence Factor

通过静态吸附实验,研究了北京地区土壤对甲苯和萘的吸附行为,考察了温度和表面活性剂对甲苯和萘吸附的影响.结果表明,尽管7种土壤对甲苯和萘的吸附能力差别较大,但其吸附等温线均很好的符合Freundlich吸附模式;同一土壤中,萘的吸附量大于甲苯的吸附量.温度升高不利于甲苯和萘在土壤中的吸附.十六烷基三甲基溴化铵(CTAB)和十二烷基苯磺酸钠(SDBS)均利于甲苯和萘在土壤表面的解吸,CTAB和SDBS对甲苯和萘的解吸率最高分别可达27.5%、12.1%和64.3%、48.8%,说明SDBS的解吸效果更好.甲苯和萘的吸附量随SDBS浓度的升高而降低;当CTAB的浓度小于临界胶束浓度CMC时,甲苯和萘的吸附量随CTAB浓度的升高而升高;当CTAB的浓度等于或大于CMC时,甲苯和萘的吸附量随CTAB浓度的升高而降低.

Static adsorption experiments were carried out to investigate the adsorption of toluene and naphthalene on Beijing soils, and to determine the influence of temperature and surfactants on adsorption. Although the affinity of petroleum hydrocarbons for seven soils is different, the adsorption isotherms of toluene and naphthalene on seven soils are well described by the Freundlich type. The adsorbed amount of naphthalene is higher than that of toluene on the same soil. High temperature doesn＇ t benefit adsorption. Cetylrimethyl ammonium bromide （CTAB） and sodium dodecyl benzene sulfonate （SDBS） both have a positive effect on desorption of toluene and naphtalaene from soil. The desorption rate of toluene and naphthalene in the presence of CTAB and SDBS is 27.596 , 12.1% and 64.3 % ,48.8 % , respectively, which show that SDBS plays a much more important role in desorption than CTAB. The adsorbed quantities of toluene and naphthalene decrease with increasing SDBS 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.