Department of Civil, Environmental and Architectural Engineering, University of Colorado, Boulder, Colorado 80309-0428, USA.
Environ Sci Technol. 2010 Jul 15;44(14):5403-8. doi: 10.1021/es9037462.
The role of particle size on the reduction of granular activated carbon (GAC) adsorption capacity for trace organic contaminants by dissolved organic matter (DOM) is examined and applied to performance scale-up. The adsorption capacity reduction, termed fouling, must be scalable in order to use bench scale tests, such as the rapid small-scale column test (RSSCT) to predict full-scale breakthrough. Equilibrium adsorption capacity tests with GAC preloaded with DOM and RSSCT breakthrough curves at three different GAC particle sizes indicate that GAC adsorption capacity is dependent on GAC particle size when DOM is present. Thus, the RSSCT cannot be expected to match full-scale results regardless of which RSSCT design approach is used (constant or proportional diffusivity), unless a scaling factor is applied to the results. Proportional diffusivity RSSCT breakthrough curves demonstrate that surface concentration of DOM is not a good measure of fouling. It is hypothesized that pore blockage is the mechanism responsible for the dependence on particle size. As GAC particle size increases, the microporous surface area behind a constricted pore also increases. The result is lower adsorption capacity per mass of adsorbent in the larger GAC particles. A scaling methodology for equilibrium and breakthrough data is presented that accounts for the dependence of NOM preloading effects on GAC particle diameter.
考察了粒径对溶解有机物（DOM）降低颗粒活性炭（GAC）吸附痕量有机污染物能力的作用，并将其应用于性能放大。为了能够使用实验室规模的测试（例如快速小型柱测试（RSSCT））来预测全规模突破，必须可扩展这种吸附容量的减少，即所谓的“污垢”。在三种不同的 GAC 粒径下，用预加载 DOM 的 GAC 进行平衡吸附容量测试和 RSSCT 突破曲线表明，当存在 DOM 时，GAC 的吸附容量取决于 GAC 的粒径。因此，无论使用哪种 RSSCT 设计方法（恒扩散率或比例扩散率），RSSCT 都不能期望与全规模结果匹配，除非对结果应用缩放因子。比例扩散率 RSSCT 突破曲线表明，DOM 的表面浓度不是污垢的良好衡量标准。据推测，孔堵塞是导致对粒径依赖性的原因。随着 GAC 粒径的增加，受限孔后面的微孔表面积也增加。结果是较大 GAC 颗粒中每单位吸附剂质量的吸附容量降低。提出了一种平衡和突破数据的缩放方法，该方法考虑了 NOM 预加载效应对 GAC 粒径的依赖性。
