| The traditional adsorption resin mainly realizes the hydrophobic action to separate organic matter from water phase while its purification effect is excellent and the resources are effectively saved.However,their adsorption-separation capacities toward aniline are poor because of its non-polar skeleton and lack of chemical force between adsorbate and adsorbent.Hence,it is urgent to develop new modified hyper-crosslinked resins for aniline adsorption.In addition,for the preparation of the novel modified hyper-crosslinked resin,there is few detailed discussions on the influence of adsorption toward aniline,such as the ways of introduction,the kind of the functional groups,and the chloromethyl distribution of the precursor resin.Therefore,in this paper,new modified hyper-crosslinked resins were prepared,and the above issues were also discussed.The results are as follows:(1)Chloromethylated styrene-divinylbenzene copolymer was used as precursor to prepare WH-0 resin with a certain degree of crosslinking as modified precursor.Subsequently,a series of modified resins were prepared by using chloromethyl and benzene ring as active sites respectively,and their static adsorption capacity of p-aminobenzoic acid is higher than that of WH-0 resin and was similar to commercial resin H-103.Among them,the static adsorption capacities of L-malic acid modified resin WH-6 and L-tartaric acid modified resin WH-7 were promoted and is 1.47 times higher than that of WH-0,while the succinic anhydride modified WH-SG resin is 1.08 times.It might because the chloromethyl-based modification can acquire a higher functional group loading ratio.(2)The preferred functional monomers L-malic acid and succinic anhydride in the above system were selected to optimize the physical and chemical structure of the resin.Then the superior resin FL-3,HSG-2 and FSG-2 were obtained respectively.Their equilibrium adsorption capacities order is in accordance with the order of FSG-2 resin>HSG-2 resin>FL-3 resin>H-103 resin,and their equilibrium adsorption capacities were 1.23,1.15 and 1.08 times of the commercial resin H-103,respectively.According to the characterization analysis,the benzene ring modified resin has a higher specific surface area,which is very advantageous for the adsorption of aniline.In addition,even though the physical structure of HSG-2 resin is not dominant,its adsorption capacity is still higher than that of H-103 resin according to the comparative analysis between HSG-2 resin and H-103 resin.This is enough to reflect the necessity of chemical modification.(3)According to the study of the adsorption behavior,the adsorption isotherms of FL-3,HSG-2 and FSG-2resins are consistent with the Langmuir equation,the adsorption is exothermic and spontaneous.The adsorption kinetic equations are consistent with pseudo second order equations,FL-3 and FSG-2 resins have faster adsorption rates,which can reach adsorption equilibrium in about 200 min,while HSG-2 takes longer.In terms of film diffusion,FL-3,FSG-2 and H-103 resins have a faster film diffusion rate.The internal diffusion fitting of all resins presents multiple linear relationships,indicating that the rate limiting step is not unique.In summary,the modified resins with chloromethyl and benzene ring as active sites were prepared,the superior functional monomer L-malic acid and succinic anhydride under two modified modes was obtained after screening.By further adjusting the physical-chemical structures of the resins,the superior resins HSG-2,FSG-2 and FL-3 were obtained,and their adsorption capacities were higher than those of commercial H-103 resin.In addition,after comparative analysis,it was found that FSG-2 resin has the best adsorption performance in the modified resins,which is attributed to its superior physical-chemical structure. |
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