Research on self-degradation of RGO/TiO2-P(AM-DAC) organic-inorganic composite flocculant prepared by surface initiated polymerization and its flocculation mechanism of oil sand tailings

Abstract

In recent years, compared to commercial flocculants, organic-inorganic composite flocculants exhibit unique advantages in the field of oil sand tail flocculation, instilling technical strength of the new era into the traditional petrochemical industry. However, there are also defects in organic-inorganic composite flocculants, such as insufficient adsorption of tailings particles by polymers, and weak interface bonding between inorganic particles and polymers. In addition, the residual macromolecule in the solution after flocculation causes serious harm to the environment. In order to solve the above problems, the free radicals generated by RGO/TiO2 inorganic particles under illumination are used to initiate the copolymerization of AM and DAC monomers, which enables the copolymer P(AM-DAC) to grow in situ on the surface of inorganic particles, thereby preparing organic-inorganic composite flocculant that is closely bonded at the interfaces and able to electrostatically adsorb oil sand tailings particles. In this paper, the structure of the product is characterized by infrared spectrum, thermal analysis and XPS. The bonding of organic and inorganic interfaces is observed by TEM. The zeta potential is used to study the charged properties of the material. In addition, the simulated oil sand tailings are used to evaluate the effect of the proportion of cationic monomer on the flocculation, and the self-degradation performance of the material is tested under illumination as well as the degradation mechanism is analyzed by infrared spectroscopy with different illumination time. The results found that method can copolymerize both monomers in situ on the surface of the inorganic particles to form a copolymer and the organic-inorganic two-phase interface is tightly combined. The introduction of the cationic monomer (DAC) increases the flocculant cationicity and zeta potential. When the content of the cations is 30%, the flocculation effect reaches the highest. The photo-degradation test shows that the RGO/TiO2-P(AM-DAC) flocculant is capable of self-degradation under illumination conditions. After 8 h of illumination, the degradation rate is 26.1%. The work provides a theoretical basis and technical prototype for the development of polymerization technology and the design of a new generation of dedicated flocculant for oil sand tailings.