The New Process Research For 2-Keto-L-Gulonic Acid Separation And Purification By Ion Exchange Resin

2-keto-L-gulonic acid is the precursor of the Vitamin C. The extraction of 2-keto-L-gulonic acid from fermenting liquid is a very important step on the production of Vitamin C. However, the actual state of this step exists many problems, for example the flow using nowadays is too long and the cost of equipments is too high.To solve these problems, this article put forwards a complete new method to extract 2-keto-L-gulonic acid from the fermenting liquid. The method is as follows: Firstly, we synthesized several different anion resins, and then these resins were used to adsorb the 2-keto-L-gulonic acid from the fermenting liquid, after that we screened out one kind of them which is named D02 to adsorb the 2-keto-L-gulonic acid because of its good performance during the experiment. According to the static experiment, the adsorption capacity of this resin to 2-keto-L-gulonic acid achieved 0.1275 g. KGA/g. wet resin and the elution rate reaches to 71.3%.Secondly, the thermodynamics and kinetics behavior of 2-keto-L-gulonic acid in aqueous solution by D02 resin have been investigated. The analysis of adsorption results obtained at 298.15K, 308.15K and 318.15K showed that the adsorption pattern on D02 resin followed the Langmuir isotherms. Thermodynamic parameters such asâ–³H,â–³G andâ–³S were calculated from the slope of the linear plot of ln(1/Ce) against 1/T. Theâ–³H andâ–³G values of 2-keto-L-gulonic acid adsorption on D02 resin showed endothermic heat of adsorption; higher temperatures favor the process. The kinetics experiments showed that the particle diffusion was the rate-controlling step and furthermore the diffusion coefficient was calculated. Thirdly, we researched the optimal values of the factors which affect the adsorption and elution through single factorial by software Statistica 6.0. The optimal parameters were as follows:(1) Adsorption conditions: concentration:10g/L, velocity of flow:0.35ml/min, pH:1.5, temperature:303K, H/D:5. Under these conditions, the average adsorption capacity reached to 0.170g.KGA/g.wrs which was 16 times larger than before.