Bullen Jay C, Saleesongsom Sarawud, Gallagher Kerry, Weiss Dominik J
Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom.
Géosciences/OSUR, University of Rennes, Rennes 35042, France.
Langmuir. 2021 Mar 16;37(10):3189-3201. doi: 10.1021/acs.langmuir.1c00142. Epub 2021 Mar 4.
The development of new adsorbent materials for the removal of toxic contaminants from drinking water is crucial toward achieving the United Nations Sustainable Development Goal 6 (clean water and sanitation). The characterization of these materials includes fitting models of adsorption kinetics to experimental data, most commonly the pseudo-second-order (PSO) model. The PSO model, however, is not sensitive to parameters such as adsorbate and adsorbent concentrations ( and ) and consequently is not able to predict changes in performance as a function of operating conditions. Furthermore, the experimental conditionality of the PSO rate constant, , can lead to erroneous conclusions when comparing literature results. In this study, we analyze 103 kinetic experiments from 47 literature sources to develop a relatively simple modification of the PSO rate equation, yielding . Unlike the original PSO model, this revised rate equation (rPSO) provides the first-order and zero-order dependencies upon and that we observe empirically. Our new model reduces the residual sum of squares by 66% when using a single rate constant to model multiple adsorption experiments with varying initial conditions. Furthermore, we demonstrate how the rPSO rate constant ' is more appropriate for comparing literature studies, highlighting faster kinetics in the adsorption of arsenic onto alumina versus iron oxides. This revised rate equation should find applications in engineering studies, especially since the rPSO rate constant ' does not show a counter-intuitive inverse relationship with increasing reaction rates when is increased, unlike the PSO rate constant .
开发用于去除饮用水中有毒污染物的新型吸附材料对于实现联合国可持续发展目标6（清洁水和卫生设施）至关重要。这些材料的表征包括将吸附动力学模型与实验数据拟合，最常用的是伪二级（PSO）模型。然而，PSO模型对诸如吸附质和吸附剂浓度（ 和 ）等参数不敏感，因此无法预测性能随操作条件的变化。此外，PSO速率常数 的实验条件性在比较文献结果时可能导致错误的结论。在本研究中，我们分析了来自47个文献来源的103个动力学实验，以对PSO速率方程进行相对简单的修正，得到 。与原始PSO模型不同，这个修正后的速率方程（rPSO）提供了我们通过实验观察到的对 和 的一级和零级依赖性。当使用单个速率常数对具有不同初始条件的多个吸附实验进行建模时，我们的新模型将残差平方和降低了66%。此外，我们展示了rPSO速率常数 ' 更适合比较文献研究，突出了砷在氧化铝上的吸附动力学比在氧化铁上更快。这个修正后的速率方程应该在工程研究中得到应用，特别是因为与PSO速率常数 不同，当 增加时，rPSO速率常数 ' 与反应速率增加没有反直觉的反比关系。
