Department of Environmental Engineering, North China Institute of Science and Technology, Beijing 101601, China.
China Merchants Ecological Environmental Protection Technology CO., LTD., Chongqing 400060, China.
Molecules. 2019 Sep 30;24(19):3534. doi: 10.3390/molecules24193534.
From the macroscopic point of view, the hydrophilicity of symbiotic carbon pyrite is weakened overall compared to that of pure pyrite. It is very important to explain the impact of elemental carbon accreted on a pyrite surface on the surface's hydrophobicity from the perspective of quantum chemistry. To study the influence of adsorbed carbon atoms on the hydrophilicity of a coal pyrite surface versus a pyrite surface, the adsorption of a single water molecule at an adjacent Fe site of a one-carbon-atom-covered pyrite surface and a carbon atom monolayer were simulated and calculated with the first-principles method of density functional theory (DFT). The water molecules can be stably adsorbed at the adjacent Fe site of the carbon-atom-covered pyrite surface. The hybridization of the O 2p (H2O) and Fe 3d (pyrite surface) orbitals was the main interaction between the water molecule and the pyrite surface, forming a strong Fe-O covalent bond. The water molecule only slightly adsorbs above a C atom on the carbon-atom-covered pyrite and the carbon atom monolayer surfaces. The valence bond between the water molecule and the pyrite surface changed from an Fe-O bond to an Fe-C-O bond, in which the C-O bond is very weak, resulting in a weaker interaction between water and the surface.
从宏观角度来看，共生碳硫铁矿的亲水性整体上弱于纯硫铁矿。从量子化学的角度解释元素碳在硫铁矿表面上的聚集对疏水性的影响非常重要。为了研究吸附碳原子对煤硫铁矿表面和硫铁矿表面亲水性的影响，采用密度泛函理论（DFT）的第一性原理方法模拟并计算了单水分子在一单碳原子覆盖的硫铁矿表面和碳原子单层相邻 Fe 位的吸附情况。水分子可以在碳原子覆盖的硫铁矿表面的相邻 Fe 位稳定吸附。O 2p（H2O）和 Fe 3d（硫铁矿表面）轨道的杂化是水分子与硫铁矿表面之间的主要相互作用，形成了强的 Fe-O 共价键。水分子仅在碳原子覆盖的硫铁矿和碳原子单层表面上的 C 原子上方略微吸附。水分子与硫铁矿表面之间的价键从 Fe-O 键变为 Fe-C-O 键，其中 C-O 键非常弱，导致水与表面的相互作用减弱。
