• 关键词：鼠李糖脂  三氯生  阳离子强度  分配

• 基金项目：国家自然科学基金（No.21277050）

• 陈源波
• 华南理工大学环境与能源学院, 工业聚集区污染控制与生态修复教育部重点实验室, 广州 510006

• 胡勇有
• 华南理工大学环境与能源学院, 工业聚集区污染控制与生态修复教育部重点实验室, 广州 510006

• 郭倩
• 华南理工大学环境与能源学院, 工业聚集区污染控制与生态修复教育部重点实验室, 广州 510006

• 摘要：探讨了阳离子强度（Na⁺/Ca²⁺）对鼠李糖脂（RL）胶束形态的影响，并据此阐述了阳离子强度对RL作用下三氯生（TCS）在底泥-水相中分配的影响规律.结果表明，阳离子对TCS的表观溶解度和其在底泥-水中的分配无明显作用，但能通过与RL分子间产生的盐桥作用影响RL的胶束聚集程度及溶液的稳定性，使水相中的RL浓度发生变化，进而导致RL作用下TCS的表观溶解度及其在底泥-水相中分配的差异.随着阳离子强度的增加，RL胶束粒径在Na⁺溶液中先减小后增大，而在Ca²⁺溶液中持续减小；RL溶液的zeta电位在Na⁺/Ca²⁺溶液中逐渐减小，其溶液的稳定度下降.相比Na⁺，Ca²⁺与RL分子间的盐桥作用更强.低浓度Na⁺（<50 mmol·L^-1）可促进RL胶束的形成，提高其对TCS的增溶能力，促进TCS从底泥迁移至水相，提高了TCS在水相的分配比例（K_d^*值从64.16 L·kg^-1降低到40.81 L·kg^-1（30 mmol·L^-1 Na⁺））；但高浓度Na⁺（>50 mmol·L^-1）会因盐析作用降低TCS的表观溶解度，并抑制其在RL作用下向水相的迁移.而Ca²⁺在很低浓度下（>1 mmol·L^-1）就能与RL分子产生强的盐桥作用而生成紧密的胶束聚集体，致使RL沉淀，大大降低RL对TCS的增溶作用，反而提高TCS在底泥相的分配比例（K_d^*值从64.16 L·kg^-1提高到4987.76 L·kg^-1（30 mmol·L^-1 Ca²⁺））.

• Abstract：This paper first studied the influence of cationic strength (Na⁺/Ca²⁺) on the morphology of rhamnolipid (RL) micelles, and then explored the effect of cationic strength on the RL functioned distribution of triclosan (TCS) in sediment-water system. The results show that cationic strength had little influence on the solubility of TCS and its distribution in sediment-water system. The salt bridge between RL and cations changed the morphology of RL micelles and the stability of RL solutions and resulted in the difference of residual RL concentration in water. This in turn affected the solubility of TCS and the distribution of TCS in sediment-water-RL system. With the increase of ionic strength, the micellar size of RL first increased and then decreased in Na⁺ solutions and kept decreasing in Ca²⁺ solutions, and the zeta potential of RL solutions decreased in both Na⁺/Ca²⁺ solutions, indicating that the stability of RL solutions decreased. The salt bridge between RL and Ca²⁺ was stronger than that between RL and Na⁺. low concentration of Na⁺ (<50 mmol·L^-1) facilitated the formation of RL micelles, increased the solubility of TCS and enhanced the distribution of TCS in water (K_d^* decreased from 64.16 L·kg^-1 to 40.81 L·kg^-1 (30 mmol·L^-1 Na⁺)). high concentration of Na⁺ (>50 mmol·L^-1) decreased the solubility of TCS for "salting out" effect and inhibited the migration of TCS to water. The stronger salt bridge between RL head groups and low concentration of Ca²⁺ (>1 mmol·L^-1) generated densely packed micelles, induced precipitation, decreased the solubility of TCS and enhanced the distribution of TCS in sediment (K_d^* increased from 64.16 L·kg^-1 to 4987.76 L·kg^-1 (30 mmol·L^-1 Ca²⁺)).

• Key words：rhamnolipid  triclsan  cationic strength  distribution

• 
  摘要点击次数： 1161 全文下载次数： 2121