Application And Preparation Of High Surface Adsorbent Resins

Adsorption resins have been widely used in extraction and isolation fields because of its higher specific surface area and plenty of micropore structure. To further increase the adsorptive selectivity and adsorptive capacity, the polarity modification of adsorption resins backbone has also attracted more interesting to meet the practical application.In this thesis, microcrosslinking polystyrene is synthesized by suspension polymerization in aqueous solution when vinyl benzylchloride, divinylbenzene and polyvinyl alcohol is used as monomer, crosslinker and dispersant, respectively. The obtained polymer is further crosslinked using iron chloride as catalyst in dichloroethane to prepare hypercrosslinked adsorption resins, and phenol is used as polar monomer in the post-linking process to moderate the polarity of adsorption resins.The properties of adsorption resins are characterized by nitrogen adsorption method, scanning electron microscopy, FT-IR spectra and solid-state nuclear magnetic resonance. The results indicate that phenol is successfully grafted onto the backbone of polystyrene. Moreover, the specific surface area of adsorption resins is decreased with the increasing of polar monomer, while the diameter of micropore is almost unchanged. Furthermore, phenol, aniline and nitrobenzene are used as adsorbate to investigate the static absorptive properties of adsorption resins. The measurement shows that the saturated adsorption capacity of resins in 1000 mg/L of phenol, aniline and nitrobenzene solution is 290,320 and 760mg.g-1,. respectively.The saturated adsorption time is 110,180 and 150min, respectively. Meanwhile, the effects of concentration, temperature and pH on the adsorption behavior of resins are also investigated in detail.Vinyl benzylchloride-divinylbenzene copolymeric resin was chemically modified with phenol and the hypercrosslinked adsorption resins were synthesized. The effect of phenol addition on adsorption of phenol, aniline and nitrobenzene was discussed. Combination of thermodynamic characteristics of adsorption, the adsorption enthalpy, free energy and entropy for phenol, aniline, nitrobenzene adsorpted on two kinds of resins were calculated and the adsorption behavior was a reasonable explanation. The adsorption isotherms at 293K,303K and 313k indicated that the adsorption of resins is fit for Freundlich equation. Moreover, according to the relative adsorption capacity and isosteric adsorption enthalpy, phenol, aniline, nitrobenzene were physically adsorbed.