Sorption of peat humic acids to multi-walled carbon nanotubes.
Sorption of peat humic acids to multi-walled carbon nanotubes.
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DOI：
10.1021/es202258q
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发表时间：
2011-10
影响因子：
11.4
通讯作者：
Xilong Wang;L. Shu;Yanqi Wang;Bingbing Xu;Yingchen Bai;S. Tao;B. Xing
中科院分区：
文献类型：
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作者：
Xilong Wang;L. Shu;Yanqi Wang;Bingbing Xu;Yingchen Bai;S. Tao;B. Xing
研究了多壁碳纳米管（MWCNTs）对泥炭土中腐殖酸的吸附作用。多壁碳纳米管对羟基磷灰石的吸附速率主要受其从液相-多壁碳纳米管界面向多壁碳纳米管表面扩散的控制。尺寸排阻色谱分析没有检测到HA级分在平衡时对MWCNT的优先吸附，而在一些HA级分中具有较低分子量的组分（例如，HA 1）在初始吸附阶段将更优先地吸附到MWCNT上。多壁碳纳米管的平衡吸附强度取决于它们的表面积和介孔和大孔体积的总和。多壁碳纳米管对给定HA的表面积和中孔标准化和大孔标准化吸附系数（K（d））值之和随着多壁碳纳米管外径的增加而增加，因为外径较大的多壁碳纳米管被HA分散得更强，从而使更多的吸附位点暴露用于HA吸附。多壁碳纳米管对羟基乙酸的吸附主要是烷基组分之间的货车范德华力作用，而不是芳香族组分。本研究重点探讨了多壁碳纳米管对同一来源腐殖酸的吸附速率控制步骤以及影响其平衡吸附强度的主要因素。
Sorption of humic acids (HAs) from a peat soil by multiwalled carbon nanotubes (MWCNTs) was examined in this work. Sorption rate of HAs to MWCNTs was dominantly controlled by their diffusion from liquid-MWCNT boundary to MWCNT surfaces. Size exclusion chromatography analysis did not detect preferential sorption of HA fractions to MWCNTs at equilibrium, whereas the components with lower molecular weight in some HA fractions (e.g., HA1) would more preferentially be sorbed to MWCNTs at the initial sorption stage. Equilibrium sorption intensity of HAs by MWCNTs was dependent on their surface area and a sum of meso- and macropore volume. The surface area and sum of meso- and macroporosity-normalized sorption coefficient (K(d)) values of a given HA by MWCNTs increased with increasing outer diameter of MWCNTs, because MWCNTs with larger outer diameter were more strongly dispersed by HAs thereby making more sorption sites exposed for HA sorption. Van der Waals interaction between the alkyl components rather than the aromatic ones of HAs with MWCNTs was likely the key driving force for their sorption. This study highlights the sorption rate-controlling step of HAs from a same source to MWCNTs and the major factors affecting their sorption intensity at equilibrium.