Study On Synthesis Of Polymeric Adsorbents With Hydroxyl Group And Properties Of Selectively Adsorbing Aromatics

As the pioneer functional polymer, adsorption resins, which are also named by polymeric adsorbent, have porous and high cross-linked characteristic. With larger specific surface area and suitable aperture, they can adsorb substance from gas or liquid phase, and are used to extract metal ions or deal with organic sewage. But they have been seldom reported as selective adsorbing resins to separate organic compounds. Phenolic adsorption resins with big aperture and hypercrosslinked polymeric resins modified by phenolic hydroxy groups were synthesised in this paper. Their properties of selective adsorbing aniline andβ-naphthol from different systems were studied. The effects of solvents, pH values and physical properties of adsorbents on adsorbing characteristics were analyzed. The idea for synthesizing and researching new hydrogen-bonded polymeric adsorbent was provided, and some theoretic gists were also provided to explore new functional adsorbent polymers.Methods of Invert suspension polymerization and solution condensation polymerization were used to synthesis polymeric adsorbents with different monomer ratios. Hydroxyl-modified hypercrosslinked polymeric adsorbents were prepared wih bromethyl as cross linker instead of chloronethyl ether. The results show that adsorption resins which were synthesized by invert suspension polymerization are better than which were synthesized by solution condensation polymerization. Comparing the typical properties of adsorbents which mass ratio of phenol and formaldehyde is 10.0:6.0 and 10.0:7.0, the former is more excellent. According to screen experiment, LM-4 and LM-6 were selected as adsorbents in this research. Basing on SEM analysis, the characteristics of synthesised resins are corresponded with sorbing and separating functional polymers.The experiments of selective adsorbing aniline on resins in mixture solution which consisting of benzene and aniline show that the adsorbing aniline and benzene of LM-4 and LM-6 in aqueous solution are mainly by physical force. Adsorbing aniline also partly depends on chemical force, and the value of adsorptive enthalpy illuminates the characteristic of hydrogen-bonded sorption. With the increasing of pH value, adsorptive capacity and selectivity of aniline on LM-4 increase, but those of benzene on LM-4 decrease. Selectivity of LM-6 adsorbing aniline is lightly enhanced by the increasing of pH value, while the adsorptive capacity of benzene on LM-6 considerablely declines, and the selectivity of aniline distinctly increases. Adsorption of aniline and benzene on LM-4 are impulsed by grain diffusion and film diffusion. Before the process of adsorbing aniline and benzene, there exist produres of adsorbing and desorption of water. In nonaqueous solution which consists of n-heptane and absolute ethyl alcohol, the adsorptive capacity of aniline and benzene on LM-4 and LM-6 increase with the increment of n-heptane content. When volume ratio of n-heptane and ethanol is 40:60, the selectivity of LM-4 adsorbing aniline reach 6.90; and when volume ratio of n-heptane and ethanol is 20:80, the selectivity of LM-4 adsorbing aniline reach 4.53.The experiments on the selective adsorbingβ-naphthol of resins in mixture solution which consists of naphthalene andβ-naphthol show that the adsorbing naphthalene andβ-naphthol of LM-4 and LM-6 in aqueous solution are mainly by physical force. But the adsorbing naphthol of resins may depend on hydrogen-bonded force accompanied by slight chemical force. In nonaqueous solution, ifβ-naphthol content is more than nephthalene content, LM-4 will be prior to adsorb naphthol, on the contrary, resin will preferably adsorb nephthalene. Adsorption ofβ-naphthol and nephthalene on LM-6 are forced by grain diffusion and film diffusion. Adsorptive capacities ofβ-naphthol and nephthalene on LM-4 or LM-6 increase with the increment of pH value. In aqueous solution, selectivity of LM-4 adsorbingβ-naphthol increase with the increment of pH value, but in nonaqueous solution, the selectivity decrease with the increment of pH value. In aqueous or nonaueous solution, selectivity of LM-6 adsorbingβ-naphthol decrease with the increment of pH value.