Study On Desulfurization Performance Of Modified Montmorillonite

With rapid development of world economy and continuous exploiture of resource for years, exploitation of high sulfur fuel is inevitable due to the fossil fuels with low sulfur are being depleted. It is important to environment problems solution by studying on the process of interface pollutants adsorption in fuel system, as well as preparation and characterization of new desulfurization adsorbent.Absorbents of organic modified montmorillonite, characterized by X-ray Photoelectron Spectroscopic (XPS), FTIR, were developed by sol - gel and modification. To optimize the absorption of the desulfurization process, the reaction conditions, such as different modifiers, adsorption temperature, balance time and absorbent amount were test by carrying out experiments in a simulated fuel system. the applicability of MEA theory in thiophene- modified montmorillonite system was tested by macro-experiments; the absorption behavior of thiophene was characterized by X-Ray Diffraction(XRD), XPS, Transmission Electron Microscopy (TEM), Fourier transform infrared spectra (FT-IR), Nuclear Magnetic Resonance (NMR), etc. Finally, 3 kinds of Cu2+ modified PTMAB-MMT were developed to study the mechanism of absorption by performancing in thermodynamic tests and characterized by XRD, FT-IR, Electron Paramagnetic Resonance (EPR), etc.The preparation of materials indicated that, the absorbent with best desulfurization performance was modified with phenyltrimethylammonium tribromide (PTMAB), heat-treated by 200℃for 3 hours, absorbing in 60℃, 2 hours. the structure characterization of MMT showed that, 200℃heat treatment reduced the water content of MMT layer and improved the hydrophobicity of MMT; PTMAB was successfully inserted into the silicate layers of montmorillonite, which enlarged the interlayer space and improved the absorption capacity.MEA theory is applicable in the adsorption system of thiophene-modified MMT. There was obvious effect of solid concentration and initial concentration of solutes in this system. Micro-characterization indicated that, most thiophene molecular inserted into the internal layers of absorbent. It was absorbed into the PTMAB-MMT by forming a component of electron donor- electron accepter, which was produced by H of thiophene and the Al-O octahedron or Si-O tetrahedron of MMT layer.After characterized the modified MMT with Cu²⁺, 3 structures of Cu²⁺ were found in them: Cu²⁺ [Cu(H₂O)₄]²⁺ , hydrated ions, existed between the layers of MMT, and Cu²⁺ exists in the form of montmorillonite hexagon holes of Si-O tetrahedron or the spare space of Al-O octahedrone [Cu(AlO)_n(H₂O)_n]^X. The former belongs to the exchange adsorption, and the latter belongs to the specific adsorption, with two of which Cu²⁺ is able to insert MMT.