| 摘要: |
| 【目的】了解有机酸对硅酸盐纳米颗粒（SBA-15）和碳纳米管（CNTs）在多孔介质中迁移行为的影响差异。【方法】采用恒定流速柱迁移试验，探讨不同浓度（0，1，2.5和5 mmol/L）乙酸、酒石酸、柠檬酸对CNTs和SBA-15纳米颗粒在多孔介质(石英砂)中穿透曲线的影响。【结果】平衡对流-弥散方程能描述多孔介质中CNTs和SBA-15迁移过程的穿透曲线。在石英砂多孔介质中，CNTs的迁移能力强于SBA-15。体系不含有机酸时，CNTs、SBA-15流出液中的纳米颗粒浓度（C）与纳米悬液进入砂柱前的初始浓度（C0）比值（C/C0）的峰值分别为0.74和0.25，最远迁移距离Lmax分别为221.2和45.1 cm。3种有机酸对 CNTs和SBA-15在多孔介质中的迁移具有类似的抑制作用，随着介质中3种有机酸浓度的增加，CNTs和SBA 15纳米颗粒的C/C0减小，C/C0平台峰值对应空隙体积（PV）倍数增大，迁移阻滞因子R和不可逆吸附系数μ增大，最远迁移距离Lmax减小。柠檬酸对CNTs和SBA-15迁移的抑制作用强于乙酸和酒石酸。Zeta电位分析表明，当体系中引入有机酸后，随着有机酸浓度的增加，石英砂、CNTs和SBA-15纳米颗粒悬液的Zeta电位均逐渐增大。【结论】有机酸会改变多孔介质和CNTs、SBA-15这2种纳米颗粒的表面电荷特征，从而使得纳米颗粒悬液在多孔介质中的迁移行为更容易受团聚、滞留和沉积作用的影响。不管在何种有机酸中，CNTs的迁移能力均强于SBA-15。 |
| 关键词: 小分子有机酸 多孔介质 纳米颗粒 迁移 滞留 |
| DOI： |
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| 基金项目:国家自然科学基金项目（41101288） |
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| Effect of small molecule organic acids on transport of CNTs and SBA-15 in porous media |
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LIANG Wen,QIN Rui,HUANG Hui,et al
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| Abstract: |
| 【Objective】This paper compared the effect of organic acids on transport of multiwall carbon nanotubes (CNTs) and silicate nanoparticles (SBA 15) in porous media.【Method】Column experiments with constant flow rate were conducted to explore the effects of citric acid,acetic acid,and tartaric acid with different concentrations (0,1,2.5 and 5 mmol/L) on breakthrough curves and deposition profiles of CNTs and SBA-15 in porous media.【Result】The balanced convection diffusion equation could be used to describe the breakthrough curves of CNTs and SBA-15 nanoparticles transport.The mobility of CNTs was higher than that of SBA-15 in sand porous media.Without organic acids in porous media,the peak C/C0 values of CNTs and SBA-15 effluents were 0.74 and 0.25,and the farthest migration distances (Lmax) were 221.2 cm and 45.1 cm,respectively.The presence of three organic acids inhibited the migration of CNTs and SBA-15 nanoparticles.With the increase of organic acids concentrations from 0 mmol/L to 5 mmol/L,the C/C0 and Lmax decreased,while the porous volume multiple (PV) of peak C/C0,the retardation factor (R) and the irreversible adsorption coefficient (μ) increased.Citric acid had stronger inhibition effect on transport of CNTs and SBA-15 nanoparticles than acetic acid and tartaric acid.Zeta potential analysis indicated that the presence of organic acids increased the surface charge of the sand porous media,CNTs and SBA-15 nanoparticles.【Conclusion】The presence of organic acids changed the surface charge characterization of sand porous media,CNTs and SBA 15 nanoparticles,resulting in agglomeration,retention and deposition effects.SBA-15 was easier to transport than CNTs in all organic acids. |
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