Synthesis And Properties Of Hypercrosslinked Polystyrene Resins Modified With Polar Groups

Hypercrosslinked polystyrene resins are efficient polymeric adsorbents which are widely used in adsorption and separation. Commercial hypercrosslinked polystyrene resins are prepared by post-crosslinking of slightly crosslinked polystyrene resins, and they adsorb molecules with hydrophobic groups from aqueous solution via hydrophobic interaction. If polar groups are introduced into the hypercrosslinked resins, their adsorption performance for organic compounds with polar groups will be improved due to the dipole-dipole interaction and/or hydrogen bonding between the polar functional groups of the resins and those of the adsorbates. For this reason, three hypercrosslinked polystyrene resins with polar groups were synthesized by introduction of nitro, amino, and acetamino groups were introduced into the hypercrosslinked polystyrene, and then their adsorption performance were investigated in this thesis.1. Three hypercrosslinked polystyrene resins modified with polar groups were synthesized by introducing nitro, amino, and acetamino groups via nitration of hypercrosslinked polystyrene, reduction of the nitro groups, and acetylation of the amino groups in sequence(the three resins were shorted as nitro resin, amino resin, and acetamino resin respectively). The pore structure and chemical structure of the initial hypercrosslinked resin and three resins modified with polar groups were characterized.2. Adsorption properties of the resins for phenol in aqueous solution were studied. Static adsorption capacity of the initial resin, the nitro resin, the amino resin, and the acetamino resin for phenol with an equilibrium concentration of 300 mg/L at 25 ℃reached 0.34 mmol/g, 0.70 mmol/g, 0.74 mmol/g, 0.75 mmol/g, respectively. The dynamic saturated adsorption capacity of the nitro resin, the amino resin, and the acetamino resin for 500 mg/L phenol solution at room temperature reached 0.76 mmol/g, 0.81 mmol/g, 0.85 mmol/g, respectively. Adsorption capacity of the modified resins was obviously greater than that of the initial resin. Desorption peaks of the modified resins had no tailing effect, and the desorption rate of the modified resins reached more than 96 %. Decrease of the adsorption capacity after regeneration of the modified resins was little, and the resins could be used repeatedly.3. Adsorption properties of the resins for gallic acid in aqueous solution were studied. Static adsorption capacity of the initial resin, the nitro resin, the amino resin, and the acetamino resin for gallic acid with an equilibrium concentration of 300 mg/L at 25 reached ℃ 0.17 mmol/g, 0.36 mmol/g, 0.39 mmol/g and 0.41 mmol/g, respectively. The dynamic saturated adsorption capacity of the nitro resin, the amino resin, and the acetamino resin for 500 mg/L gallic acid solution at room temperature reached 0.42 mmol/g, 0.46 mmol/g, 0.49 mmol/g, respectively. Adsorption capacity of the modified resins was obviously greater than that of the initial resin. Desorption peaks of the modified resins had no tailing effect, and the desorption rate of the modified resins reached more than 96 %. Decrease of the adsorption capacity after regeneration of the modified resins was little, and the resins could be used repeatedly.