Study On Preparation And Adsorption Behaviors Of 5-sulfosalicylic Acid Imprinted Polymers

Aromatic acids are an important class of fine chemical products that are widely used in industrial production.Therefore,the wastewater containing aromatic acids has a wide range of sources,which causes great harm to the natural environment and human health.However,such wastewater also has great recycling value.5-sulfosalicylic acid（SSA）is a typical complex aromatic acid.Therefore,in order to recover SSA in the wastewater,it is necessary to prepare a material having a selective adsorption ability.The calculation simulation was conducted using the density functional theory at the B3LYP/6-31G（d,p）level by Gaussian 09 in order to screen suitable functional monomers.MIP-4 and the non-imprinted resin NIP-4 were synthesized with three functional bases after optimizing the synthesis conditions.Under the optimum synthesis conditions,MIP-1,MIP-2 and MIP-3 with only one functional base,as well as corresponding NIPs were synthesized.MIP-4 and NIP-4 were employed to conduct static adsorption experiments for SSA,studying the effects of pH,temperature,salt content and reaction time on the adsorption properties of two resins.The selective adsorption properties of MIP-4 and NIP-4 were investigated to explore competitive effects of three-dimensional structure and functional groups of competitors on two resins adsorbing SSA.The imprinting effect of the multifunctional resin and single functional resins was compared to verify the rationality of the calculation simulation.The calculation simulation results showed that N-methylpropenylamine（G1）,diallylamine（G12）and triallylamine（G13）were the optimal composite functional monomer for the preparation of SSA imprinted materials.The interactions of G1,G12and G13 with the corresponding-OH,-COOH and-SO₃H of SSA were respectively electrostatical-dominated medium-strength hydrogen bond,electrostatical-dominated medium-strength hydrogen bond and strong electrostatic interaction,which was non-hydrogen bond.The static adsorption experiment results showed that the optimum pH value of adsorption was about 2.2.The adsorption isotherm conformed to the Langmuir model,and the adsorption was a spontaneous exothermic process.The kinetic data could be well matched with the pseudo-second-order model.Intraparticle diffusion was not the only rate limiting step,while mass transfer was also affected by factors such as liquid membrane diffusion and chemical reaction.Sodium chloride or sodium sulfate coexisting in water inhibited the adsorption of SSA,MIP-4 had better salt tolerance than NIP-4.The effective regeneration of resins was achieved while 8%NaOH-ethanol aqueous solution（V:V=1:1）was applied.Five cycles of adsorption and desorption experiments showed that the resin had a good stability.The selective adsorption experiment results showed that under single component solutions,MIP-4 had a stronger recognition ability than NIP-4 for salicylic acid（SA）,phenol（PH）and benzoic acid（BA）,while showing a weaker recognition ability than NIP-4 for p-Hydroxybenzoic acid（PHBA）,benzenesulfonic acid（BSA）and p-toluenesulfonic acid（PTSA）.Under binary component solutions,compared with NIP-4,MIP-4 showed excellent selective adsorption capacity and imprinting effect on SSA.Dynamically adsorbing the SSA-BSA binary component solution,MIP-4 had better quality recovery effect on SSA than NIP-4.The results of imprinting effect contrast experiments showed that under single component solutions,MIP-4 with multi functional bases had a larger Imprinting Factor,which showed better recognition performance than MIP-1,MIP-2 and MIP-3with the single functional base.Under binary component solutions,the relative selective adsorption coefficients of MIP-4 were larger than those of MIP-1,MIP-2and MIP-3,which indicated that the selective adsorption performance of MIP-4 was superior.