Study On Nitration And Adsorption Properties Of Macroporous Adsorption Resin

A novel MAR resin was prepared by modification of the nitro,carboxyl groups of the base macroporous adsorption resin,and the adsorption mechanism and adsorption properties of different polar resins in different solvents were investigated.Nitration modification of recycled macroporous adsorption resin(RNMAR)was synthesized by using the recycled macroporous adsorption resin(RMAR),and the adsorption properties of two resins were investigated.1.NMAR was synthesized by nitration reaction with MAR as raw material.The NMAR was Characterized by IR and elemental analysis.The amount of carboxyl groups introduced on NMAR by oxidation reaction was determined by the exchange rate measurement.The specific surface area and pore structure parameters of the resin were determined by nitrogen adsorption desorption method.The results showed that compared with MAR,the specific surface area decreased,water content increased and total acid exchange increased.The total acid exchange rate of NMAR was 1.64 mmol.g-1.2.The adsorption mechanism and adsorption properties of MAR and NMAR in cyclohexane solvent and water solvent were investigated.It is concluded that the adsorption mechanism of resins in aqueous solvents is that the ?-? interaction is greater than the hydrogen bond.In the cyclohexane solvent,the hydrogen bond is greater than the ?-?interaction.The adsorption properties of MAR and NMAR was found.Adsorption resin for aniline and phenol is a process of ?H<0,?S<0,?G<0 and the absolute value of delta ?G of NMAR is greater than the absolute value of ?G of MAR,which shows that the adsorption of NMAR to aniline and phenol molecules is easier to be carried out.3.RNMAR was synthesized by nitration reaction with RMAR as raw material.The adsorption properties of aniline and phenol with water and cyclohexane as solvent,respectively,were compared.The results showed that the adsorption capacity of RNMAR in cyclohexane solvent was greater than that of RMAR and the adsorption amount of RNMAR in water solvent is less than that of RMAJR.Adsorption resin for aniline and phenol is a process of ?H<0,?S<0,?G<0 and the absolute value of delta ?G of RNMAR is greater than the absolute value of ?G of RMAR,which shows that the adsorption of RNMAR to aniline and phenol molecules is easier to be carried out.4.The adsorption properties of new resins and recycled resins were explored and the results showed that there were polar impurities in recycled resins,which led to the difference in adsorption of phenol and aniline in water and cyclohexane.Two methods were used to explore the desorption properties of new resins and recycled resins.The removal effect of recycled resins was better than that of the new resins with hot water,which was opposite to the effect with anhydrous ethanol.