羧基功能化炭黑纳米颗粒在饱和多孔介质中的运移：柱实验与模型分析
Transport of carboxyl-functionalized carbon black nanoparticles in saturated porous media: Column experiments and model analyses.
作者信息
Kang Jin-Kyu, Yi In-Geol, Park Jeong-Ann, Kim Song-Bae, Kim Hyunjung, Han Yosep, Kim Pil-Je, Eom Ig-Chun, Jo Eunhye
机构信息
Environmental Functional Materials & Biocolloids Laboratory, Seoul National University, Republic of Korea.
Environmental Functional Materials & Biocolloids Laboratory, Seoul National University, Republic of Korea; Department of Rural Systems Engineering and Research Institute of Agriculture and Life Sciences, Seoul National University, Republic of Korea.
出版信息
J Contam Hydrol. 2015 Jun-Jul;177-178:194-205. doi: 10.1016/j.jconhyd.2015.04.009. Epub 2015 May 2.
The aim of this study was to investigate the transport behavior of carboxyl-functionalized carbon black nanoparticles (CBNPs) in porous media including quartz sand, iron oxide-coated sand (IOCS), and aluminum oxide-coated sand (AOCS). Two sets of column experiments were performed under saturated flow conditions for potassium chloride (KCl), a conservative tracer, and CBNPs. Breakthrough curves were analyzed to obtain mass recovery and one-dimensional transport model parameters. The first set of experiments was conducted to examine the effects of metal (Fe, Al) oxides and flow rate (0.25 and 0.5 mL min(-1)) on the transport of CBNPs suspended in deionized water. The results showed that the mass recovery of CBNPs in quartz sand (flow rate=0.5 mL min(-1)) was 83.1%, whereas no breakthrough of CBNPs (mass recovery=0%) was observed in IOCS and AOCS at the same flow rate, indicating that metal (Fe, Al) oxides can play a significant role in the attachment of CBNPs to porous media. In addition, the mass recovery of CBNPs in quartz sand decreased to 76.1% as the flow rate decreased to 0.25 mL min(-1). Interaction energy profiles for CBNP-porous media were calculated using DLVO theory for sphere-plate geometry, demonstrating that the interaction energy for CBNP-quartz sand was repulsive, whereas the interaction energies for CBNP-IOCS and CBNP-AOCS were attractive with no energy barriers. The second set of experiments was conducted in quartz sand to observe the effect of ionic strength (NaCl=0.1 and 1.0mM; CaCl2=0.01 and 0.1mM) and pH (pH=4.5 and 5.4) on the transport of CBNPs suspended in electrolyte. The results showed that the mass recoveries of CBNPs in NaCl=0.1 and 1.0mM were 65.3 and 6.4%, respectively. The mass recoveries of CBNPs in CaCl2=0.01 and 0.1mM were 81.6 and 6.3%, respectively. These results demonstrated that CBNP attachment to quartz sand can be enhanced by increasing the electrolyte concentration. Interaction energy profiles demonstrated that the interaction energy profile for CBNP-quartz sand was compressed and that the energy barrier decreased as the electrolyte concentration increased. Furthermore, the mass recovery of CBNPs in the presence of divalent ions (CaCl2=0.1 mM) was far lower than that in the presence of monovalent ions (NaCl=0.1 mM), demonstrating a much stronger effect of Ca(2+) than Na(+) on CBNP transport. Mass recovery of CBNPs at pH 4.5 was 55.6%, which was lower than that (83.1%) at pH 5.4, indicating that CBNP attachment to quartz sand can be enhanced by decreasing the pH. The sticking efficiencies (α) calculated from the mass recovery by colloid filtration theory were in the range from 2.1×10(-2) to 4.5×10(-1), which were far greater than the values (2.56×10(-6)-3.33×10(-2)) of theoretical sticking efficiencies (αtheory) calculated from the DLVO energy by the Maxwell model.
本研究的目的是研究羧基功能化炭黑纳米颗粒（CBNPs）在包括石英砂、氧化铁涂层砂（IOCS）和氧化铝涂层砂（AOCS）在内的多孔介质中的传输行为。在饱和流条件下，对保守示踪剂氯化钾（KCl）和CBNPs进行了两组柱实验。分析突破曲线以获得质量回收率和一维传输模型参数。第一组实验旨在研究金属（铁、铝）氧化物和流速（0.25和0.5 mL min⁻¹）对悬浮在去离子水中的CBNPs传输的影响。结果表明，在石英砂中（流速 = 0.5 mL min⁻¹）CBNPs的质量回收率为83.1%，而在相同流速下，在IOCS和AOCS中未观察到CBNPs的突破（质量回收率 = 0%），这表明金属（铁、铝）氧化物在CBNPs与多孔介质的附着中可发挥重要作用。此外，当流速降至0.25 mL min⁻¹时，石英砂中CBNPs的质量回收率降至76.1%。使用DLVO理论针对球 - 板几何形状计算了CBNP - 多孔介质的相互作用能曲线，表明CBNP - 石英砂的相互作用能是排斥性的，而CBNP - IOCS和CBNP - AOCS的相互作用能是吸引性的且没有能垒。第二组实验在石英砂中进行，以观察离子强度（NaCl = 0.1和1.0 mM；CaCl₂ = 0.01和0.1 mM）和pH值（pH = 4.5和5.4）对悬浮在电解质中的CBNPs传输的影响。结果表明，在NaCl = 0.1 mM和1.0 mM时，CBNPs的质量回收率分别为65.3%和6.4%。在CaCl₂ = 0.01 mM和0.1 mM时，CBNPs的质量回收率分别为81.6%和6.3%。这些结果表明，增加电解质浓度可增强CBNP与石英砂的附着。相互作用能曲线表明，随着电解质浓度增加，CBNP - 石英砂的相互作用能曲线被压缩且能垒降低。此外，在二价离子（CaCl₂ = 0.1 mM）存在下CBNPs的质量回收率远低于在一价离子（NaCl = 0.1 mM）存在下的质量回收率，表明Ca²⁺对CBNP传输的影响比Na⁺强得多。在pH 4.5时CBNPs的质量回收率为55.6%，低于pH 5.4时的质量回收率（83.1%），表明降低pH值可增强CBNP与石英砂的附着。根据胶体过滤理论通过质量回收率计算的黏附效率（α）在2.1×10⁻²至4.5×10⁻¹范围内，远大于通过麦克斯韦模型根据DLVO能量计算的理论黏附效率（α理论）值（2.56×10⁻⁶ - 3.33×10⁻²）。
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