Nano-TiO₂ Surface-Imprinted Polymers For Removal Of Organosulphur Compounds In Petroleum And Its Mechanism Research

Benzothiophenes are important organosulphur compounds which are mostly found in gasoline and diesel, and they are rather diffcultly to be removed because of their steric hindrance, thus they have become a challenge in desulfurization investigations. These organosulphur compounds, when burned, produce sulfur dioxide which is not only a major source of acid rain, but also leads to equipment corrosion and catalyst poisoning. Additionally, people with asthma, emphysema, and other pulmonary diseases are most deleteriously affected by air born sulfur compound pollutants.Nano-TiO2 as a multifunctional material has increasingly attracted much attention. Additionally, it has been widely applied to many important fields. Molecular imprinting technique (MIT) is a novel developed technique that prepared imprinted polymer that has high selectivity for imprint molecules. Molecular imprinted polymers (MIPs) exhibit excellent application foreground especially in analytical chemistry field such as chromatographic separation, chiral separation, biomimetic sensors, solid phase extraction and so no, which can be ascribed to its high affinity and selectivity, strong resisting harsh environment, strong stability, and long life-span.In this work, nano-TiO2 was selectived as the support matrix for preparing surface-imprinted polymers, and these polymers were used to remove organosulphur compounds of benzothiophenes in simulated oil.The work mainly included the following items:(1) Study on selective adsorption of organosulphur compounds by the nano-TiO2 surface-imprinted polymerThe batch adsorption experiments for the surface-imprinted polymer were performed to study in terms of adsorption kinetics, isotherms, and thermodynamic parameters, additionally, investigating the possible adsorption mechanism. Results indicated that the imprinted polymer prepared by this method can selectively remove DBT from similar compounds present in simulated oil solution (n-octane).(2) Study on selective adsorption of organosulphur compounds by the modification of nano-TiO2 surface-imprinted polymerA novel surface molecular imprinting approach was developed to synthesize surface-modified imprinted polymer in toluene. The structure and characters of the surface-modified imprinted polymer were investigated by using Fourier transmission infrared spectrometry, X-ray diffractometer, Scanning electron microscopy and nitrogen adsorption-desoption analysis. The adsorption behavior of the surface-modified imprinted polymer was evaluated using batch adsorption experiments to determine the kinetic, equilibrium and thermodynamic experimental results. Results indicated that the surface-modified imprinted polymer showed faster association kinetics,higher adsorption capacity and selectivity than those of the imprinted polymer that nano-TiO2 had not been modified.(3) Study on selective adsorption of organosulphur compounds by the molecular imprinted polymer prepared using the molecular imprinting technique combining with the sacrificial matrix processA surface-imprinting technique combined with a sacrificial matrix process was established to synthesize a novel imprinted polymer in which nano-TiO2 acts as the sacrificial matrix. The sacrificial imprinted polymer was compared with nano-TiO2, the sacrificial non-imprinted polymer, and with the imprinted polymer which nano-TiO2 acts as the matrix. Batch experiments were performed to evaluate adsorption kinetics, adsorption isotherms, and selective recognition of the sacrificial imprinted polymer. Results showed that the absorption abilities for DBT from the simulated oil followed the order the sacrificial imprinted polymer> the surface-imprinted polymer> the sacrificial non-imprinted polymer nano-TiO2.