| The process of antibiotic manufacturers includes microbial fermentation,plate and frame filtration,solvate extraction,decolorization and crystallization.In this study,the tetracycline and tylosin raw material liquid was studied for the practical problem of low product yield in its process,and the tetracycline and tylosin were purified by resin adsorption method to optimize the separation conditions.In order to improve the adsorption capacity of the resin,it was modified with chemical functional groups and finally used to adsorb and recover tetracycline and tylosin from aqueous solution and raw material liquid,and the adsorption capacity,adsorption isotherms and adsorption kinetics of tylosin and tetracycline were investigated as follows:(1)The boric acid functionalized adsorption resin PSA-B was prepared by hydrothermal method using reagents p-carboxyphenylboronic acid pinacol ester(CPBAPE),SOCl2,AlC13,CH2Cl2 and resin PSA,with the improvement of resin adsorption and desorption rates as evaluation indexes.At initial concentrations of CTC=3500 mg/L and CTYL=2800 mg/L,the adsorption rates of PSA-B resin for TC and TYL were 87.1%and 84.9%,respectively,and the maximum adsorption capacities were 99.7 mg/g and 82.5 mg/g,respectively;the maximum adsorption capacities were increased by 18.4 mg/g and 2.4 mg/g,respectively,compared with those of the unmodified resin PSA.The adsorption is mainly due to the affinity between polyhydroxy TC and TYL and boronic acid functional groups,the increase of π-π sites between polystyrene backbones and hydrogen bonding.In addition,the adsorption resin PSA-B still had good adsorption capacity after five adsorption-desorption cycles in the regeneration test.The PSA-B resin has good adsorption and reusability properties.(2)To further improve the adsorption of TC and TYL,the sulfonic acid functionalized adsorbent resin PSA-S was prepared.The maximum adsorption capacities of the resin for TC and TYL were 145.9 mg/g and 94.8 mg/g at an initial concentration of CTC=3200 mg/L and CTYL=2400 mg/L,respectively,which were improved by 46.2 mg/g compared with PSA-B resin and 12.3 mg/g.The adsorption was in accordance with the pseudo-secondary kinetic model and Langmuir model,and the adsorption between the adsorbent resins PSA-S and TC/TYL was mainly due to the strong affinity interaction and ππinteraction between the antibiotic and sulfonic acid groups.The desorption and regeneration performance showed that the optimal elution solvent was 95%ethanol,which could be cycled adsorptiondesorption five times,and the PSA-S resin could be used as an effective adsorbent for the separation and purification of TC and TYL.(3)The improvement of corporate tetracycline and tylosin recovery was used as an evaluation index.The chromatographic column was selected for adsorption test and cyclic regeneration adsorption test,according to the optimized operating parameters of the single-factor test method,combined with the regeneration and stability of the resin itself,so as to determine the optimal adsorption conditions and operating parameters of PSA-S resin for tetracycline and tylosin raw material liquid:at the initial concentrations of CTC=400 mg/L and C TYL=1 0000 mg/L,respectively,the injection rate was 2 BV/h,the eluent was 95%ethanol,and the elution rate was 1 BV/h.Under suitable operating conditions,the recoveries of PSA-S resin in TC and TYL aqueous solutions were 81.4%and 83.3%,respectively,an increase of 5.9 and 8.9 percentage points over the unmodified resin PSA;the recoveries in TC and TYL raw material liquid were 78.9%and 76.7%,respectively,which were 7.0 and 4.3 percentage points higher than those of the unmodified resin PSA.In addition,ethanol was used as eluent,and the adsorption capacity did not decrease significantly after 5 adsorption-desorption cycles,and the adsorbent resin had good reusability. |
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