| Act as a natural drug raw material, quebrachitol is derived from natural rubber latexserum, which is of high medicinal value. However, it is often drained away as wastewater in industrial production, which causes a great waste of resources. Therefore, theresearch on recovery of high added value in quebrachitol has an important significance.While the traditional methods of heating concentration, separation and purification, havedisadvantages such as complex process, high energy consumption and toxic reagentsaddition, which is difficult to meet the demand of industrial production. Exploring amethod that is easy to industrialize to separate and extract raw products of quebrachitolis one of the urgent problems which has to be solved in natural rubber industry.Macroporous resin has advantages such as a large specific surface area, high adsorptionrate, fast switching speed, long service life and low cost, which has been widely used inthe field of environmental protection, food and medicine, and attracted increasingattention in the application of separation, enrichment and purification of natural drugs.Based on the previous work, the macroporous resin was used in the separation andextraction of quebrachitol in natural rubber latex serum in this work, which contains thepretreatment and purification of serum, developing the analytical method fordetermining quebrachitol by HPLC-DAD, the kinetics and thermodynamics of staticadsorption of quebrachitol in macroporous resin and process optimization of dynamicadsorption of quebrachitol in macroporous resin were investigated. The main researchcontents and results are as follows:Processing of pretreatment of Nature Rubber Latex Serum, the removal rate of ionby ion exchange resin is, K+,99.77%; Ca2+,99.79%; Na+,98.02%; Mg2+,95.73%; Cu2+,80.24%; Cl-,98.52%; SO42-,100%; PO43-,98.9%; the total nitrogen removal rate is 94.8%; the decolorization effect of ion exchange resin is better than that of active carbonpowder.An analytical method was developed for determining L-quebrachitol in NatureRubber Latex Serum by HPLC-DAD. Quebrachitol was separated by Inertsil ODS-SPC18column(150mm×4.6mm,5μm) and diode array detector using acetonitrile andwater (10:90by Volume) as mobile phase with the flow rate of1.0mL·min-1, theinjection volume was10μL, the column temperature is30℃and the detectionwavelength is190nm. Results: the mass fraction of quebrachitol in Natural Rubber is(0.10.02)%.According to the differences of polarity and aperture, macroporous resin ADS-17,HPD400, HPD-417, HPD826, ADS-7, S-8, HPD500and silica gel and amino bondedsilica gel were selected. The adsorption rate and desorption rate of quebrachitol inpretreatment serum were used as index, HPD500resin and amino bonded silica gel wereselected as better adsorption adsorbents. Taking into account of the cost of industrialproduction, HPD500is the best candidate which can be used for the separation andpurification of quebrachitol in natural rubber latex serum and has a good popularizationand application value.Kinetics and thermodynamics of adsorption of quebrachitol on HPD500resin werediscussed, dynamics test showed that: the adsorption process of quebrachitol on HPD500resin close to the first-order kinetic equation. With the quebrachitol concentration innatural rubber latex serum is0.954g/L, temperature is25℃, the adsorption rate constantis1.402h-1; The conditions of low temperature, neutral pH, higher initial concentrationand high oscillation speed is conducive to the adsorption; thermodynamic test resultsshowed that: the equilibrium adsorption capacity increases with the increase of theconcentration, decreased as the temperature increases, indicating that low temperature is favorable to adsorption, adsorption isotherms can be fitted by Langmuir model,indicating that the adsorption of quebrachitol on HPD500resin is monolayer adsorption,and the adsorption is an exothermic physical adsorption.The dynamic adsorption process for preheating quebrachitol on HPD500resin wasinvestigated, and the optimization conditions were obtained:18mL sample volume/mLresin, the concentration of sample is0.954g/L, the flow rate of column eluent is1BV/h,using60%ethanol and dosage is6BV, then the extraction rate of quebrachitol couldreach70.5%.Rotation analysis results showed that the sample is left-handed light, differentialscanning calorimetry analysis showed that the melting point of sample was uniform tothe standard one, whose purity is high. Infrared spectroscopy analysis showed that thegroup contained in samples was uniform to the standard one. Gas chromatography-massspectrometry and nuclear magnetic resonance analysis showed that the sample isquebrachitol. |
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