Institute of Water Chemistry, Technische Universität Dresden, 01062 Dresden, Germany.
Water Res. 2011 Oct 1;45(15):4544-50. doi: 10.1016/j.watres.2011.06.006. Epub 2011 Jun 21.
The adsorption of the taste and odour (T&O) compounds geosmin and 2-methylisoborneol (2-MIB) onto powdered activated carbon (PAC) has been studied under conditions which are typical for a drinking water treatment plant that uses reservoir water for drinking water production. The reservoir water as well as the pre-treated water (after flocculation) contains NOM that competes with the trace compounds for the adsorption sites on the carbon surface. Although the DOC concentrations in the reservoir water and in the pre-treated water were different, no differences in the competitive adsorption could be seen. By using two special characterisation methods for NOM (adsorption analysis, LC/OCD) it could be proved that flocculation removes only NOM fractions which are irrelevant for competitive adsorption. Different model approaches were applied to describe the competitive adsorption of the T&O compounds and NOM, the tracer model, the equivalent background compound model, and the simplified equivalent background compound model. All these models are equilibrium models but in practice the contact time in flow-through reactors is typically shorter than the time needed to establish the adsorption equilibrium. In this paper it is demonstrated that the established model approaches can be used to describe competitive adsorption of T&O compounds and NOM also under non-equilibrium conditions. The results of the model applications showed that in particular the simplified equivalent background compound model is a useful tool to determine the PAC dosage required to reduce the T&O compounds below the threshold concentration.
研究了在使用水库水作为饮用水生产水源的饮用水处理厂中典型条件下，粉末活性炭（PAC）对土臭素和 2-甲基异莰醇（2-MIB）这两种气味化合物的吸附情况。水库水和预处理水（絮凝后）中均含有天然有机物（NOM），它会与痕量化合物竞争活性炭表面的吸附点位。尽管水库水和预处理水中的 DOC 浓度不同，但竞争吸附中并未观察到差异。通过使用两种特殊的 NOM 特征化方法（吸附分析、LC/OCD），可以证明絮凝仅去除与竞争吸附无关的 NOM 部分。应用了不同的模型方法来描述 T&O 化合物和 NOM 的竞争吸附，包括示踪模型、等效背景化合物模型和简化等效背景化合物模型。所有这些模型都是平衡模型，但在实际的流动反应器中，接触时间通常比建立吸附平衡所需的时间短。本文证明了所建立的模型方法也可以用于描述非平衡条件下 T&O 化合物和 NOM 的竞争吸附。模型应用的结果表明，特别是简化等效背景化合物模型是一种有用的工具，可以确定去除 T&O 化合物所需的 PAC 剂量，使其低于阈值浓度。
