奥荷科学家合作发明新型污水处理方法

奥地利和荷兰研究者日前在新一期美国学术刊物《环境科学与技术》（Environmental Science and Technology）上报告说，他们发明了一种被动采样污水处理法，这种方法采用碳纳米管净化污水，效果好于传统方法。

参与研究的奥地利维也纳大学的蒂洛·霍夫曼指出，碳纳米管具有很强的电子、机械和化学特性，十分适合用于净化污水，能有效降低水中污染物的浓度。
 
如果是处理污水中的非水溶性污染物，那么使用单孔直径只有几纳米的过滤器就会显得成本太高，但由于活性炭很难有效清除污水中的许多水溶性污染物，这时采用碳纳米管技术就能较好地达到目的。它能够过滤掉废水中的抗生素或止痛药成分，甚至能除去废水中含量极低的污染物。
 
为此，维也纳大学的研究者与荷兰乌得勒支大学合作，发明了一种被动采样法，它能确定碳纳米管吸附致癌的多环芳烃等多种污染物的水平。
 
污水中含有多种化学污染物，在污水处理过程中，不同的污染物在过滤器中“争夺”吸附位置的现象十分常见，而这种“竞争”会使得过滤器的功效因污染物的种类、数量不同而发生改变。如果使用传统方法对高度污染的水进行过滤，当水中的多环芳烃种类还不到3种时，这种“竞争”就会变得尤其激烈。而奥荷研究者的新试验显示，在水中有13种多环芳烃的情况下，使用被动采样法，各种污染物之间也没有什么“竞争”。

Measuring and Modeling Adsorption of PAHs to Carbon Nanotubes Over a Six Order of Magnitude Wide Concentration Range

Melanie Kah, Xiaoran Zhang, Michiel T.O. Jonker, and Thilo Hofmann
Citation：Environ. Sci. Technol., 2011, 45 (14), pp 6011–6017, DOI: 10.1021/es2007726

Abstract：Understanding the interactions between organic contaminants and carbon nanomaterials is essential for evaluating the materials’ potential environmental impact and their application as sorbent. Although a great deal of work has been published in the past years, data are still limited in terms of compounds, concentrations, and conditions investigated. We applied a passive sampling method employing polyoxymethylene (POM-SPE) to gain a better understanding of the interactions between polycyclic aromatic hydrocarbons (PAHs) and multiwalled carbon nanotubes (CNTs) over a 6 orders of magnitude wide concentration range. In the low-concentration range (pg-ng L–1), sorption of phenanthrene and pyrene was linear on a nonlogarithmic scale. Here, sorption could thus be described using a single sorption coefficient. Isotherm fits over the entire concentration range showed that (i) monolayer sorption models described the data very well, and (ii) the CNTs sorption capacity was directly related to their surface area. Sorption coefficients for 13 PAHs (11 of which have not been reported to date) were also measured at environmentally relevant low concentrations. No competition seemed to occur in the low-concentration range and sorption affinity was directly related to the solubility of the subcooled liquid of the compounds.
 

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