[Adsorption characteristics of three types of surfactants in soils].
Surfactants after entering soil may interact with other xenobiotics of sufactant and alter their behaviors. These interactions are very complex, and depend heavily on a range of parameters including surfactant concentration in soil-water, its CMC and adsorption characteristics of sufactant and pollutant etc. In this paper, batch sorption experiment was employed to study the adsorption characteristics of three types of surfactants, viz. an anionic, a cationic, and two nonionic surfactants, in 6 soils. The results showed that the adsorption isotherms of cetyltrimethylammonium bromide (CTMAB) were L-shape, with distribution coefficients (Kd) varied between 300 to 4800 L x kg(-1) in lower concentration range. The adsorption isotherms of sodium dodecyl benzene sulfonate C12 LABS, OP and Tween-20 were L- or S-shape, depending on surface-active molecular and soil properties. The affinity of anionic and nonionic surfactants to soil was weaker than that of cationic surfactant. The Kd for C12 LABS, Tween-20 and OP was within 5.3-39, 0.13-0.44 and 4.4-22.4 L x kg(-1), respectively. For sodium dodecyl benzene sulfonate, Kd was positively correlated with soil clay fraction, and the charge property of soil was also influential in its sorption. For OP and Tween-20, the empirical relations of Kd to soil properties, clay, silt, sand contents, and surface area, were established by using regression analysis. Cationic exchange capacity showed a strong positive correlation with the maximum adsorption capacity of soils, which might indicate that the ionic exchange mechanism played an important role in adsorption of CTMAB.
Li
Kebin
K
Institute of Environmental Science, Zhejiang University, Hangzhou 310029, China. kebinli@sohu.com
Liu
Huijun
H
Ma
Yun
Y
Zhang
Yong
Y
Liu
Weiping
W
D000327:Adsorption; D001557:Benzenesulfonates / Q000494:pharmacology*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000494:pharmacology*; D012987:Soil / Q000032:analysis*; D013501:Surface-Active Agents / Q000494:pharmacology*
D001557:Benzenesulfonates; D002593:Cetrimonium Compounds; D012987:Soil; D013501:Surface-Active Agents; C001114:dodecylbenzenesulfonic acid; D000077286:Cetrimonium