Chemosphere ( IF 5.778 ) Pub Date : 2021-02-22 , DOI: 10.1016/j.chemosphere.2021.130021 Qi Yu; Jingyi Feng; Jie Li; Anfei He; G. Daniel Sheng
Surface oxygen-containing functional groups (OFGs) at different sites of carbonaceous materials showed different effects on the normalized monolayer adsorption capacity (QBET/A) obtained from the modified BET model. The OFGs on mesoporous surfaces inhibited the adsorption via the water competition, whereas those on the external surface promoted the adsorption due to the enhanced hydrophobic driving force and electrostatic forces, as analyzed from the adsorption molar free energy. Multiple linear relationships were established between the monolayer adsorption capacity QBET/A and the amounts of OFGs on mesoporous and the external surfaces ([O]meso and [O]external, respectively). The properties of aromatic adsorbate compounds, the polar area radio of aromatic molecule to water (PAad/w), and the log Kow together influenced the inhibition or promotion effects of OFGs. These results would allow predictions of adsorption behavior of aromatic compounds on carbonaceous materials on the basis of OFGs parameters. Theoretical calculations and simulations projected the configuration of aromatic molecules being parallel to the graphene sheets of carbonaceous materials. The symmetry-adapted perturbation theory (SAPT) energy decomposition showed that the electrostatic forces intensified with the increase of adsorbate polarity. These analyses revealed that the electrostatic forces were enhanced in the presence of OFGs and that the π-π EDA (electron donor-acceptor) was the main force.
含碳材料不同位置的表面含氧官能团（OFGs）对从改良BET模型获得的归一化单层吸附容量（Q BET / A）表现出不同的影响。从吸附摩尔自由能分析，介孔表面的OFG通过水竞争抑制了吸附，而外表面的OFG由于疏水驱动力和静电力的增强而促进了吸附。在单层吸附能力Q BET / A与中孔和外表面上的OFG的量之间建立了多个线性关系（[O]中观和[O]外部， 分别）。芳香族吸附化合物的性质，芳香族分子对水的极区辐射（PA ad / w）和log K ow共同影响了OFG的抑制或促进作用。这些结果将允许基于OFGs参数预测芳族化合物在含碳材料上的吸附行为。理论计算和模拟预测芳族分子的构型与碳质材料的石墨烯片平行。对称自适应扰动理论（SAPT）能量分解表明，静电力随着吸附物极性的增加而增强。这些分析表明，在OFG存在下，静电力得到了增强，而π-πEDA（电子供体-受体）是主要作用力。