吐温80对硝基苯的增溶作用和无机电解质作用机理研究

Solubilization of Nitrobenzene in Micellar Solutions of Tween 80 and Inorganic Salts

研究了在10℃条件下,非离子表面活性剂吐温80对硝基苯的增溶作用.结果表明,吐温80在临界胶束浓度(CMC)以上能够显著提高硝基苯的溶解度,对硝基苯的增溶曲线呈线性关系,MSR值为5.093,lgKm为3.499.硝基苯的增溶作用为吐温80胶束中聚氧乙烯链形成的聚醚微环境作用的结果.并考察了4种无机电解质NaCl、KCl、CaCl2、MgCl2对硝基苯增溶作用的影响,结果表明,4种高浓度(≥500 mg.L-1)无机电解质的加入,均使吐温80溶液中硝基苯的浓度有所增加,增溶曲线仍呈线性关系.在吐温80与无机电解质质量比为2∶1、5∶1和10∶1时,增溶曲线的MSR值与lgKm值均有提高,硝基苯在吐温80胶束中的分配增强.原因为随着无机电解质与吐温80胶束发生盐析作用,吐温80胶束体积变大,为硝基苯提供了更大的增溶空间.非离子表面活性剂-无机电解质复配体系可以作为表面活性剂强化修复中的一种冲洗液,提高非离子表面活性剂的使用效率,降低成本.

The solubilization of nitrobenzene by a nonionic surfactant Tween 80 was investigated at 10℃.Experimental results indicated that the solubility of nitrobenzene in water was greatly enhanced by Tween 80 at surfactant concentration above CMC（critical micelle concentration） and a linear relationship was obtained between surfactant concentration and nitrobenzene concentration from the solubility curve.The molar solubilization ratio（MSR） value was 5.093 and lgKm was 3.499.The solubilization was attributed to the ethoxylation group in Tween 80 micellar.Effect of four inorganic salts such as NaCl,KCl,CaCl2,MgCl2 on water solubilities of nitrobenzene in Tween 80 micellar solutions was also investigated by a matrix of batch experiments.Mix the Tween 80-inorganic salts at the total mass ratios of 2∶1,5∶1 and 10∶1.The results show that the inorganic salts at a high concentration（≥500mg·L^-1） can enhance the solubilization capacities of Tween 80 micellar solution and increase the value of MSR and lgKm.Because of the saltingout effect between the micellar of Tween 80 and inorganic salts,the volume of micelle turns bigger,which may provide larger solubility volume for nitrobenzene.The mixture of nonionic surfactant and inorganic salts can be used in subsurface remediation as a flushing solution.