中文摘要：

选用石英砂填充柱模拟土壤体系，通过对比不同环境条件下得到的纳米二氧化钛（纳米TiO：）穿透曲线和持留分布曲线，考察溶液离子强度、铁（羟基）氧化物、腐殖酸对纳米TiO2在多孔介质中迁移行为的影响．研究结果表明在石英砂多孔介质中，离子强度对纳米TiO2的迁移有着巨大的影响．随着离子强度的增大，纳米TiO2和石英砂的ζ电位相应减小（绝对值减小），纳米TiO2的迁移能力逐渐减弱，其在多孔介质中的持留量增大．当在石英砂上载一层均匀的铁（羟基）氧化物时，纳米TiO2与铁（羟基）氧化物所带表面电荷相反从而产生吸引力，利于纳米TiO2在饱和多孔介质中的持留，因此纳米TiO2在载铁（羟基）氧化物石英砂多孔介质中的持留量明显高于相同离子强度下纳米TiO2在石英砂多孔介质中的持留量．纳米TiO2在载铁（羟基）氧化物石英砂饱和多孔介质中的迁移实验结果表明纳米TiO2处于有利条件吸附时，溶液离子强度对纳米TiO2在载铁（羟基）氧化物石英砂多孔介质中迁移能力的影响并不显著．与石英砂上载一层均匀的铁（羟基）氧化物情况相反，腐殖酸促进纳米TiO2在石英砂多孔介质中的迁移．纳米TiO2悬浮液中有腐殖酸存在时，即使浓度低至1mg／L，由于静电排斥作用及空间排斥作用，腐殖酸明显增强纳米TiO2在石英砂多孔介质中的迁移能力，减弱离子强度的影响．

英文摘要：

In order to systemically investigate the influence of ionic strength, iron （hydr） oxide and curves and retained profiles. The results showed ionic strength greatly affected the transport of TiO2 nanaparticles in bare quartz sand. With increasing ionic strength, the magnitude of ζ potentials of both TiO2 nanopartieles and sand decreased, as a result, the mobility of TiO2 nanoparticles decreased and the retention increased. Compared with the results obtained in bare quartz sand, the retention of Ti02 nanoparticles was significantly enhanced under the same ironic strength by the presence of iron （hydr） oxide presented on the quartz sand. Since the retention of TiO2 nanoparticles was under favorable conditions in iron due to the existence of a net attractive interaction between iron nanoparticles. The results obtained in iron （hydr） oxide-coated sand ionic strength on TiO2 nanopartieles transport and retention can （hydr） oxide-coated sand （hydr） oxide and Ti02 suggested the influence of be neglected under this favorable deposition condition. Contrary to the results obtained in the presence of iron （hydr） oxide, humic acid in nanoparticles suspensions facilitated the transport of TiOz nanoparticles in bare quartz sand. The presence of humic acid, even at concentration as low as l mg/L significantly enhanced the mobility of TiO2 nanoparticles, as well as weakened the influence of