TX100悬浮的多壁纳米碳管在土壤中运移及其对菲迁移的影响

Transport of TX100 suspended multi-walled carbon nanotubes (MWCNTs) and its effect on the mobility of phenanthrene in soils

采用柱淋溶实验研究了TX100悬浮的多壁纳米碳管在土柱中的淋溶行为及其对菲在土壤中迁移的影响,并用胶体运移的一级动力学对流-弥散模型对纳米碳管在土柱中的迁移能力进行了估算.实验结果表明,在砂土和粉砂壤土中分别有83.5%和73.4%的多壁纳米碳管能够穿透土柱,模型估算的最远迁移距离均大于200cm,说明多壁纳米碳管有向深层土壤迁移的可能性.多壁纳米碳管的存在显著促进了菲在土壤中的迁移能力.在砂土中,多壁纳米碳管结合态菲是菲迁移的主要形态,而在粉砂壤土中多壁纳米碳管结合态菲是菲迁移的唯一形态.在迁移过程中,菲能够从多壁纳米碳管上不同程度地解吸,解吸的比率与土壤对菲的吸附亲和力有关,土壤对菲的吸附亲和力越高,菲从多壁纳米碳管上解吸的比率越大.

Transport of TX100 suspended MWCNTs in soils as well as the effect of MWCNTs on the mobility of phenanthrene were studied by leaching experiments. The results showed 83.5% and 73.4% breakthrough of MWCNTs in sandy and silt sandy loam soils,respectively. The estimated potential transport distances of MWCNTs in the two tested soils were more than 200 cm,indicating potential risks to deep soil layers by MWCNTs in these soils. The mobility of phenanthrene in the soils was significantly enhanced by MWCNTs. MWCNTs-bound phenanthrene was the main transportation form for sandy soil,while it was the sole form for silt sandy loam soil. Phenanthrene was partially desorbed from MWCNTs during transport and an increase in sorption capacities of soils for phenanthrene induced an enhancement in desorption rate.