State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Environ Pollut. 2019 Dec;255(Pt 1):113224. doi: 10.1016/j.envpol.2019.113224. Epub 2019 Sep 11.
Predicting adsorption of volatile organic compounds (VOCs) on activated carbons is of major importance to understand activated carbons' adsorption properties and explore their potential applications. In this study, adsorption of 38 VOCs on a commercial granular activated carbon (GAC) was examined using inverse gas chromatography (IGC) at infinite dilution, and the adsorption coefficients (K), dispersive and specific components of adsorption free energy were calculated. We found that the dispersive interaction was well described by adsorbate's molar polarizability (P), and the specific interactions well by dipolarity/polarizability (S), hydrogen-bond acidity (A) and hydrogen-bond basicity (B). Based on the result, a polyparameter linear free energy relationship (PP-LFER) was established: logK = (0.96 ± 0.23) S + (2.23 ± 0.34) A + (0.84 ± 0.25) B + (0.69 ± 0.050) P + (0.13 ± 0.35); (n = 38, R = 0.859, root mean square error (RMSE) = 0.25), which exhibited a more accurate prediction compared to the classical PP-LFER (E, S, A, B and L as descriptors, R = 0.765, RMSE = 0.33). Moreover, it overcame the drawbacks of indistinguishable dispersive interaction and unavailable relative contribution of each interaction for classical PP-LFER in explaining adsorption mechanism. As suggested by the developed model, the dispersive interaction was the dominant contribution to the adsorption of VOCs on GAC (42-100%), following by dipole-type interactions (0-30%) and hydrogen bonding (hydrogen-bond acidity 0-32%, hydrogen-bond basicity 0-11%). Additionally, it also accurately predicted the K values of VOCs on other three activated carbons.
预测挥发性有机化合物（VOCs）在活性炭上的吸附对于理解活性炭的吸附性质和探索其潜在应用具有重要意义。在这项研究中，使用无限稀释的反气相色谱法（IGC）研究了 38 种 VOC 在商业颗粒活性炭（GAC）上的吸附，计算了吸附系数（K）、色散和吸附自由能的特定分量。我们发现，色散相互作用可以很好地用吸附质的摩尔极化率（P）来描述，而特定相互作用可以很好地用偶极/极化率（S）、氢键酸度（A）和氢键碱度（B）来描述。基于这一结果，建立了一个多参数线性自由能关系（PP-LFER）：logK=（0.96±0.23）S+（2.23±0.34）A+（0.84±0.25）B+（0.69±0.050）P+（0.13±0.35）；（n=38，R=0.859，均方根误差（RMSE）=0.25），与经典的 PP-LFER（E、S、A、B 和 L 作为描述符，R=0.765，RMSE=0.33）相比，预测结果更为准确。此外，它克服了经典 PP-LFER 在解释吸附机制时无法区分色散相互作用和每个相互作用相对贡献的缺点。根据所建立的模型，色散相互作用是 VOC 在 GAC 上吸附的主要贡献（42-100%），其次是偶极型相互作用（0-30%）和氢键（氢键酸度 0-32%，氢键碱度 0-11%）。此外，它还能准确预测 VOC 在其他三种活性炭上的 K 值。
