温度和离子强度对SDBS增溶菲的影响及机理

EFFECTS OF TEMPERATURE AND IONIC STRENGTH ON SOLUBILITY ENHANCEMENT OF PHENANTHRENE BY SDBS AND THEIR MECHANISMS

研究了不同温度(15,20,25,30,35和50℃)和离子强度(0.03,0.15和0.30 mol.l-1)对十二烷基苯磺酸钠(SDBS)增溶菲的影响,并探讨了其增溶热力学,结果表明,SDBS对菲的增溶量随温度的升高而增大,而增溶能力(Kmn,Km c)减小,主要是由菲在水中溶解度增大所致;离子强度增大,SDBS的临界胶束浓度(CMC)降低、胶团变大和菲的溶解度减小,导致SDBS对菲的增溶量和增溶能力增大.菲在SDBS单体/水和胶束/水的表观分配焓变分别为-21.08kJ.mol-1和-16.54 kJ.mol-1,因此,升高温度不利于菲在SDBS单体和胶束中的分配作用;菲在水、SDBS单体和胶束中的表观熔解热分别为35.16kJ.mol-1,14.08 kJ.mol-1和18.62 kJ.mol-1,故温度升高菲在水、SDBS单体和胶束中的溶解量增大.

The effects of temperatures （15, 20, 25, 30, 35, 50℃） and ionic strengths （0. 03, 0. 15, 0. 30 mol ·l^-1） on solubility enhancement of phenanthrene by sodium dodecylbenzene sulfonate （SDBS） and their mechanisms were investigated by a batch of experiments. The thermodynamics of the solubility enhancement process was also discussed. The apparent solubility of phenanthrene enhancement by SDBS solution increased with temperature increasing, while the partition coefficients of phenanthrene between SDBS monomer and water （Kmn） or between micelle and water （Kmc） decreased with temperatures increasing, because aqueous solubility of phenanthrene increased with temperature increasing and the values of critical micelle concentration （CMC） of SDBS were almost independent on temperature. The apparent solubility enhanced-amount, Kmn and Kmc of phenanthrene increased with increasing ionic strengths in solution, which were attributed to decreasing of CMC of SDBS, enlarging of micelle volume, and declining of aqueous solubility of phenanthrene. The enthalpy changes of distribution of phenanthrene between monomer and water and between micelle and water were-21.08kJ·mol^-1 and- 16.54 kJ·mol^-1, respectively, which was exothermic process, indicated that temperature increase was disfavored to partitioning aqueous phananthrene into SDBS monomer and micelle. The apparent enthalpy changes of phenantherene, dissolved into water, SDBS monomer and micelle were 35.16kJ ·mol^-1, 14. 08kJ ·mol^-1and 18.62kJ·mol^-1, respectively, which was endothermic process, suggested that temperature increase was favored to dissolving phananthrene solid into aqueous solution, SDBS monomer and micelle