粒径和浓度对胶体颗粒在多孔介质中迁移的影响

摘要

Column experiments were employed to study the effect of particle size and concentration on the migration of colloids in simulated aquifer environment.Polystyrene latex microspheres were used as a colloid model,and three different particle sizes(50,200 and 500 nm)and two colloid concentrations(2 and 20 mg·L -1)were tested.Experimental results indicate that,colloid transport demonstrated a clean bed deposition process at 2 mg ·L -1colloid concentration while it shifted to a transient process described by colloidal blocking at 20 mg · L -1colloid concentration.Thusly, increased colloid concentration may promote colloid movement.The results show that,in both the clean bed deposition and blocking processes,the mobility of colloids increased with increasing particle size.%基于柱实验,研究了胶体粒径和浓度对胶体颗粒在地下含水层介质中迁移的影响.以乳胶球为胶体模型,粒径采用50、200和500 nm,溶液中胶体质量浓度采用2和20 mg·L -1.柱实验结果表明在胶体质量浓度为2 mg·L -1时胶体迁移过程为清洁床沉积,在胶体质量浓度为20 mg·L -1时胶体迁移为暂态迁移,且呈现出阻塞效应(blocking effect),使胶体迁移能力随时间而增加,粒径越大,阻塞效应越明显,迁移速度变化越快.结果表明,不论在高浓度呈现的阻塞作用下还是在低浓度的清洁床沉积作用下,胶体粒径越大,胶体迁移能力越强,胶体的流出量增加.