绿茶制备纳米铁在饱和多孔介质中的迁移特性及影响因素

绿茶还原制备纳米铁颗粒(GT-NIPs)由于成本低,对环境二次污染风险较小,在地下水环境修复中具有较好的应用前景。为研究GT-NIPs在饱和多孔介质中的迁移特性及影响因素,通过批试验和一维模拟柱试验,分析GT-NIPs颗粒沉降及迁移情况,并计算其最大迁移距离。结果表明：GT-NIPs在乙醇溶液中具有较好的悬浮稳定性,2000min内,相对吸光度保持在0.95以上；在石英砂介质中,GT-NIPs迁移能力随介质粒径的增大而增强,其在粗砂中的截留量仅为在中砂和细砂中的1/2和1/3；离子强度及二价阳离子对GT-NIPs运移影响较小；粘土矿物促进了GT-NIPs在介质中的沉积,使其截留率增加了1倍；GT-NIPs在天然砂中的迁移能力大幅降低,出流率较在石英砂中降低了36.67%；利用滤床理论模型对GT-NIPs的最大迁移距离进行预测是合理且符合实际的,其在不同介质条件下的最大迁移距离约为1~5m。

Transport Characteristics and Influencing Factors of Nanoiron Particles Produced by Green Tea in Saturated Porous Media.

Nanoiron particles produced by green tea (GT-NIPs) haveSa good applicationSprospect due to their lower production cost and risk of secondary pollution to the environment. To investigate the transport properties in saturated porous media and influencing factors of GT-NIPs, batch and column experiments were conducted, settlement and transport conditions of GT-NIPs were analyzed,and maximal migration distances were calculated . The results show that GT-NIPs have good suspension stability in ethanol solution and relative absorbance remain above 0.95 in 2000 min. The transport of GT-NIPs is facilitated by larger size of quartzSsand, and the retention mass in coarse sand is only about 1/2 and 1/3 of that in the medium and fine sand, respectively. Ionic strength and bivalent cation have less impact on GT-NIPs transport. ClaySmineral enhances the deposition of GT-NIPs on the quartzSsand resulting in a doubling of retention rate. The transport ability of GT-NIPs greatly decreases in natural sand for the outflow rate reducing by 36.67%. Under different aquifer media conditions, the calculated values of maximum migration distance of GT-NIPs are in the range of 1~5 m, which is proved reasonable and realistic.