Preparation And Properties Of Dibenzothiophene Molecular Imprinted Polymer On The Surface Of Carbon Microspheres

Molecularly imprinted polymer (MIP) is a new kind of macromolecular material with high molecular recognition characteristics. Owing to predetermined property with specific recognition capability and wide practicability, it has developed quickly in recent years, exhibiting extensive application potentials in separation, extraction, enrichment, enzyme mimic, biomimic sensor and other fields. In this paper, the surface chemical modification of carbon microspheres (CMSs) was firstly carried out. Then the new surface molecular imprinted materials with priority recognition and adsorption were gained through grafting, polymerization, and molecular template crosslinking steps. It is very important for deep desulfurization of oils.In this paper, first of all, CMSs were synthesized by chemical vapor deposition method (CVD), using deoiled asphalt and acetylene as carbon sources. Subsequently, the surface chemical modification of CMSs was carried out in KMnO₄, the mixture of KMnO₄ and HNO₃, and the mixture of KMnO₄ and H₂SO₄, and MnO₂-coated CMSs and oxidized-CMSs were obtained separately. In addition, polymethyl acrylic acid (PMAA) was grafted onto the surface of modified-CMSs, and dibenzothiophene molecularly imprinted polymers on CMSs were prepared. The morphologies and surface microstructures of different products were characterized by field emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, thermogravimetry and fourier transformation infra-red spectrometry. The results are as follows:1. CMSs with the diameter 350 nm were prepared by CVD. KMnO₄, KMnO₄/HNO₃, KMnO₄/H₂SO₄ solution were used to modify the CMSs. The obtained products were MnO₂-coated CMSs particles. The MnO₂/CMSs composites are expected to be efficient candidate for supercapacitor. And then H₂C2O₄ solution was used to wash MnO₂-modified CMSs, forming oxidized CMSs. The oxidized CMSs had good dispersion in water and ethanol. After the CMSs were oxidized, some active sites were formed on the surface of CMSs, which was effective to change the inert nature of the surface of CMSs, thus laying the foundation for further modification.2. The oxidized CMSs were modified using the coupling agent 3-methacryloxypropyl trimethoxysilane, so as to introduce C=C bonds on the surface of CMSs. PMAA was grafted on the surface of CMSs by photo-initiating or thermal-initiating approach. This laid an experimental and theoretical foundation for the preparation of molecular imprinting materials.3. Surface molecular imprinting polymers were prepared on the surface of CMSs using dibenzothiophene as template, MAA as functional monomer, chloroform as solvent, azobisisobutyronitrile as initiator, ethylene glycol dimethacrylate as crosslinking agent. The adsorption behavior of MIP showed that the adsorption equilibrium time was about 5h and the adsorption amount was 0.595mmol/g. Compared with blank polymers, MIP possessed a better adsorption property toward dibenzothiophene, showing its portential for deep desulfurization.