Wu Wen-Ling, Sun Hong-Wen
Key Laboratory on Environmental Pollution Processes and Standards of Ministry of Education, Nankai University, Tianjin 300071, China.
Huan Jing Ke Xue. 2009 Apr 15;30(4):1133-8.
Batch experiments were employed to investigate the influences of salinity on the sorption of phenanthrene. Influences of initial phenanthrene concentration, sediment properties and salinity on desorption of phenanthrene were also studied and the mechanism for desorption hysteresis was deeply discussed. Salinity enhanced the sorption of phenanthrene on sediments, and the enhancement extent was related to sediment organic matter (SOM). A salting constant of 0.125 L x mol(-1) was derived from the PHE solubility in fresh water and salt water, and in the presence of sediment, salting constant was enhanced to 0.299 L x mol(-1). Desorption of phenanthrene all exhibited hysteresis to some extents and desorption hysteresis were described by a thermodynamic index TII. With the initial phenanthrene concentration increasing from 0.5 mg x L(-1) to 2.5 mg x L(-1), the value of TII first decreased from 0.80 to 0.38 and then increased to 0.55, suggesting the desorption hysteresis of phenanthrene first decreased and then increased. Sediment treated by NaOH showed a reduced sequestration ability on phenanthrene than the original sediment did, with the value of TII decreased from 0.55 to 0.33. Desorption of phenanthrene in fresh water was found for the first time to have a greater hysteresis than in salt water, indicated by the greater TII value of 0.55 in fresh water than that of 0.42 in salt water. Desorption hysteresis could be explained by the sorption of phenanthrene to sorption sites of different energies and sequestration inside the micropores of the sediments.
采用批次实验研究了盐度对菲吸附的影响。还研究了初始菲浓度、沉积物性质和盐度对菲解吸的影响，并深入探讨了解吸滞后的机制。盐度增强了菲在沉积物上的吸附，增强程度与沉积物有机质（SOM）有关。根据菲在淡水和盐水中的溶解度得出盐析常数为0.125 L·mol⁻¹，在有沉积物存在时，盐析常数增至0.299 L·mol⁻¹。菲的解吸均在一定程度上表现出滞后现象，解吸滞后用热力学指数TII描述。随着初始菲浓度从0.5 mg·L⁻¹增加到2.5 mg·L⁻¹，TII值先从0.80降至0.38，然后增至0.55，表明菲的解吸滞后先减小后增大。经氢氧化钠处理的沉积物对菲的固存能力比原始沉积物降低，TII值从0.55降至0.33。首次发现菲在淡水中的解吸滞后比在盐水中更大，淡水中TII值为0.55，大于盐水中的0.42。解吸滞后可通过菲对不同能量吸附位点的吸附以及在沉积物微孔内的固存来解释。
