Design of a Cross-linked PTHF-Based Network as an Oil/Organic Solvent Sorbent

Abstract

Novel effective oil/organic solvent sorbents were designed and comprised entirely from polytetrahydrofuran (PTHF)-based networks in a two-step approach: (1) preparing PTHF-based macro-cross-linkers and (2) cross-linking of PTHF polymers using the prepared PTHF-based macro-cross-linkers. With this approach, different molecular weights of hydroxy-functional PTHF polymers were turned into ethoxysilane-functional macro-cross-linkers by the modification of hydroxyl groups of PTHF polymers with 3-(triethoxysilyl)propyl isocyanate. Then, the prepared ethoxysilane-functional macro-cross-linkers were condensed with hydroxy-functional PTHF polymers to synthesize PTHF-based networks as oil/organic solvent sorbents. The synthesized PTHF-based sorbents demonstrated superior absorption properties in various oils and organic solvents such as dichloromethane, tetrahydrofuran, benzene, toluene, ethylbenzene, xylene, methyl tertiary butyl ether (MTBE), gasoline, and crude oil. The recovery of the sorbents after repeating the application for the absorption of dichloromethane and MTBE is essential, and they can be reused effectively for at least 50 days without any capacity loss. All the synthesized PTHF-based sorbents depicted high thermal stability. The characterization of the macro-cross-linkers and PTHF-based sorbents were determined by using H-1, C-13, and Si-29 nuclear magnetic resonances and Fourier transform infrared spectroscopies. Thermal characteristics of the sorbents were identified by thermogravimetric analysis and differential scanning calorimetry. Absorption kinetics of the sorbents were further analyzed using pseudo-kinetic models and an intraparticle diffusion model.