Study on the iodine adsorption properties of hexaphenylsilole-triazine porous organic polymer

Abstract

The hexaphenylsilole-based porous organic polymer (THPS), was synthesized for the first tine via a Friedel-Crafts reaction with 1,1,2,3,4,5-hexabenylthirole and cyanuric chloride in 1,2-dichloroethane under the catalysis of anhydrous aluminum muriate. The specific surface areas of Brunauer-Emmett-Teller and Langmuir reach 1579 and 2081 m² g⁻¹, respectively. THPS can efficiently and reversibly adsorb I₂ in both the gas phase (1.94 g g⁻¹) and the liquid phase. Because THPS has weak adsorption on water and cyclohexane, its adsorptive capacities and adsorption efficiencies in both solution are high, and up to 23.91 mg g⁻¹ and 95.62 % in 100 mg mL⁻¹ iodine-cyclohexane solution, 260.04 mg g⁻¹ and 91.01 % in the 300 mg L⁻¹ iodine-water solution. The adsorption behaviors fit the pseudo-first kinetic model, with high linear correlation coefficient (R²) of 0.9965, 0.9965, and 0.9967 in vapor at 77 °C, in iodine-cyclohexane solution, and iodine-water solution, respectively. Iodine adsorption is the result of electron transfer from THPS to iodine molecules. The adsorbed iodine can be released by heating or in ethanol. After 5 cycles, its iodine adsorption capacity and desorption efficiency of THPS did not change significantly.