Static and dynamic studies of adsorption by four macroporous resins to enrich oridonin from Rabdosia rubescens

Oridonin,one of the active ingredients in Rabdosia rubescens(R.rubescens),has been reported to induce cell apoptosis and cell cycle arrest in many cancers.Conventional extraction methods tend to result in unsatisfied enrichment and poor quality of oridonin present in a given biomass.This paper aims to evaluate the performance and separation characteristics of four different macroporous resins to arrive at the most suitable methodology for the isolation and purification of highquality oridonin.Static absorption kinetics,thermodynamic and dynamic adsorption were evaluated.HP20 was selected for further study due to its high adsorption capacity of 32 mgg 1 and desorption ratio with 98.5%.The pseudosecondorder model was considered to be the most suitable for kinetic results,and Langmuir model was chosen to better describe the absorption thermodynamics.Under optimum conditions(flow rate of 4 ml min 1,bed depth with 6 cm and initial concentration of 2.15 mg·ml^1),the effective content of oridonin increased from 33.9%to 79.1%in the dry extract with a recovery of 81%and the purity of oridonin improved from 76%to 93%.The results confirm that HP20 provides an efficient method to purify most oridonin from R.rubescens.

Separation and purification of Arabinogalactan obtained from Larix gmelinii by macroporous resin adsorption

Arabinogalactan （AG） obtained from Larix gmelinii R. waS purified with the method of macroporous resin adsorption. Effects of various parameters on the adsorption, including adsorption time and temperature, the concentration and the dosage of raw AG the reused numbers of resin, were investigated. The effect of purification was tested through the removal rate of impurity and the contents of AG and impurity. The optimal condition was determined as follows： adsorbed at 30℃ for 2 h with the concentration of raw AG 〈0.1 g·mL^-1 and its dosage 〈 7 mL, the dose of resin was 3 g and reused for 4 times. On the basis of these, macroporous resin column was used for AG purification. The result showed that the AG yield could reach 68.28% with sugar content of 95.02%. The analysis of IR and UV showed that the effect of macroporous resin characteristics on the purification of AG was significant. The obtained product had the same functional groups with standard sample.

Preparation and adsorption properties of macroporous tannin resins

In this paper, a new kind of adsorption resin with multi-phenolic hydroxyl was created by immobilizing black wattle bark tannins to chloromethyl polystyrene resin. Its adsorption capacity to cation dye was tested. With an orthogonal test the optimal conditions of synthesis were determined： the concentration of sodium hydroxide solution 1.0 mol.L^-1; the reaction time is one hour and the mass concentration of tannins 5%. With single factorial experiment the optimal conditions of adsorption were confirmed： a solidified pH of 5.0; an adsorption temperature of 25℃ and a cation dye concentration of 100 mg.L^-1. The adsorption for cation dye can be similar to Langmuir isotherms.

Adsorption of Macroporous Phosphonic Acid Resin for Nickel

Tje adsorption bchavior and mechanism of a novel chelate resin,macroporous phosphonic acid resin（PAR）for Ni（Ⅱ）were imestigated.The stotically saturated adsorption capacity is 64.3mg·g^-1 resin at 298K in HAc-NaAc medium.The Ni（Ⅱ）adsorbed on PAR can be eluted by 0.5mal·L^-1 HCl and the elution percentage reaches 96.6%.The resin can be regenerated and reused without abvious decrease in adsorption capacity.The apparent adsorption rate constant is k298=2.6×10^-5s^-1.The adsorption behavior of PAR for Ni（Ⅱ）obeys the Freundllich isotherm.The thermodynamie adsorption parameters.enthalpy change △H,free energy change △G and entropy change △S of PAR for Ni（Ⅱ）are 3.36kJ·mol^-1,-5.47kJ·mol^-1 and 29.6J·mol^-1·K^-1,respectively.The apparent activation energy is Ea=12.2kJ·mol^-1,The molar coordination ratio of the functional group of PAR to Ni（Ⅱ）is about 4：1.The adsorption mechanism of PAR for Ni（Ⅱ）was examined by a chemical method and IR spectrometry.

ADSORPTION OF TANNIN ACID ONTO AN AMINATED MACROPOROUS RESIN FROM AQUEOUS SOLUTIONS

A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique. Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 for removal of tannin acid from aqueous solutions. NG-9 could be used directly without a wetting process and had higher adsorption capacity than NG-8, which might be attributed to the enhanced adsorbent-adsorbate interaction due to the tertiary amino groups on the polymeric matrix. The Langmuir equation was successfully employed to describe the adsorption process. The adsorption enthalpy change further validated the uptake of tannin acid on NG-9 to be an enhanced physical adsorption because of the Lewis acid-base interaction. In addition, adsorption kinetic studies testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate maybe for the hindrance of the tertiary amino groups and water clusters built up.

Separation of salidroside from the fermentation broth of engineered Escherichia coli using macroporous adsorbent resins

Salidroside(8-O-β-D-glucoside of tyrosol),a plant-derived natural product,is used for treatment of hypoxia,fatigue and aging diseases.The availability of salidroside is restricted since it is extracted from3-5 years old Rhodiola roots,which grow very slowly in the cold region of northern hemisphere of Earth.Our laboratory has constructed an engineered Escherichia coli and established a fermentation process to produce salidroside from glucose.In this article,nine macroporous resins from polarity to non-polarity,including NKA-9,S-8,AB-8,SP825,D101,LSA-8,LX-12,LX-18 and LX-68 resins,were tested to separate salidroside from fermentation broth.After static and dynamic experiments,the weakly polar SP825 resin had a better separation efficiency among nine resins.The adsorption kinetic and isotherm of salidroside on the SP825 resin were determined,and the pseudo-second-order kinetic model and Langmuir model could be fitted well.The effects of the pH on adsorption and ethanol concentration on desorption were investigated,and an optimal separation process was established.The adsorption for salidroside in the SP825 resin column was conducted with loading 150 ml at pH 7,and desorpted by washing 50 ml of80%ethanol solution.Under the best process conditions,the purity and yield of salidroside in the final product were 91.6%and 74.0%,respectively.The results showed that the macroporous SP825 resin would be feasible and effective to prepare salidroside and has promising application in the downstream process of microbial fermentation.

Adsorption Behaviors and Mechanism of Macroporous PhosphonicAcid Resin for Gadolinium

The adsorption behaviors and mechanism of a novel chelate resin, macroporous phosphonic acid resin(PAR)for Gd(Ⅲ)were investigated. The statically and dynamically saturated adsorption capacity is respectively 308 mg·g^(-1)resin and 296 mg·g^(-1)resin at 298 K in HAc-NaAc medium at pH 5.6. Gd(Ⅲ)adsorbed on PAR can be reductively eluted by 0.5～5.0 mol·L^(-1) HCl used as eluant and the elution percentage is up to 94.7% in 1.0 mol·L^(-1) HCl. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is k_(298)=3.96×10^(-5) s^(-1). The adsorption behavior of PAR for Gd(Ⅲ) conforms to the Freundlich isotherm. The thermodynamic adsorption parameter, enthalpy change △H of PAR for Gd(Ⅲ)is 22.6kJ·mol^(-1). The apparent adsorption activation energy(Ea)of PAR for Gd(Ⅲ)is 5.0 kJ·mol^(-1). The molar coordination ratio of the functional group of PAR to Gd(Ⅲ)is about 3∶1. The adsorption mechanism of PAR for Gd(Ⅲ)was examined by using chemical method and IR spectrometry.

Synthesis and Efficiency of a SphericalMacroporous Epoxy-dicyandiamide ChelateResin for Preconcentrating and SeparatingTrace Au, Hg, Pd and Ru from Samples

A novel spherical macroporous epoxy-dicyandiamide chelate resin was synthesized simply and rapidly from epoxy resin and used for the preconcentration and separation of trace amounts of Au (Ⅲ ), Hg (Ⅱ ), Pd (Ⅳ) and Ru (Ⅲ) ions from solution samples. The analyzed ions can be quantitatively concentrated by the resin at a flow rate of 2. 0 mL/min at pH 4, and can also be desorbed with 15 mL of 4 mol/L HCl + 0. 3 g thiourea from the resin column with recoveries of 96. 5%-99. 0%. After the chelate resin was reused for 7 times, the recoveries of these ions were still over 92%, and 400-1 000 times of excess of Fe(Ⅲ ), Al(Ⅲ ), Ni( II), Mn( Ⅱ ), Cr (Ⅲ ), Cu ( Ⅱ ), Cd (Ⅱ ) and Pb (Ⅱ ) caused little interference with the determination of these ions by an inductively coupled plasma optical emission spectrometer (ICP-OES ). The capacities of the resin for the analytes are in the range of 0. 35~0. 92 mmol/g. The RSDs of the proposed method are in the range of 1. 1 % ~4. 0% for each kind of the analyzed ions. The recoveries of a standard added in real solution samples are between 96. 5% and 98. 5%, and the results for the analyzed ions in a powder sample are in good agreement with their reported values.

Adsorption behavior and mechanism of D113 resin for lanthanum

The sorption properties of macroporous weak acid resin （D113） for La^3＋ ion were studied by chemical analysis and IR spectra. Experimental results indicate that the D113 resin has a good adsorption ability for La^3＋ at pH = 6.0 in the HAc-NaAc medium. The statically saturated adsorption capacity is 273.3 mg/g. Separation coefficients of βLa^3＋/Ce^3＋, βLa^3＋/Gd^3＋, βLa^3＋/Er^3＋, and βLa^3＋/Y^3＋ are 2.29, 3.64, 4.27, and 0.627, respectively. The apparent activation energy of adsorption, Ea is 18.4 kJ/mol, the thermodynamics parameters AH, AS, and AG of sorption are 4.53 kJ/mol, 61.8 J/（mol·K）, -13.9 kJ/mol, respectively. The adsorption behavior of D113 for La^3＋ obeys the Freundlich isotherm. La^3＋adsorbed on resin can be eluted by 2.0 mol/L HCl quantitatively.

Sorption Behaviour and Mechanism of Lanthanum (Ⅲ) on HD-2 Resin

La(Ⅲ) was quantitatively adsorbed by macroporous weak acid resin (HD-2) in the medium of pH=6.16. The statically saturated sorption capacity is 231 mg·g -1(resin). 3.0 mol·L -1 HCl can be used as an eluant. The elution percentage is 100%. The sorption rate constant is k_ 298=3.04×10 -5 s -1. The apparent sorption activation energy of HD-2 for La(Ⅲ) is 31.2 kJ·mol -1. The sorption behavior of HD-2 for La(Ⅲ) obeys the Freundlich isotherm. The adsorption parameters of thermodynamic are ΔH=9.56 kJ·mol -1, ΔS=35.7 J·mol -1·K -1, ΔG=-1.08 kJ·mol -1, respectively.

Preparation of Macroporous Poly (vinyl alcohol-co-triallyl isocyanurate) Beads Bearing Aminocarboxylic Acid as Functional Groups by Suspension Polymerization

Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.

大孔吸附树脂吸附红曲色素的工艺条件和动力学研究

研究了各种因素对大孔吸附树脂吸附红白色素的影响，确定了吸附和洗脱的工艺条件，并利用回归的方法得到了吸附过程随时间变化的动力学方程。

Research Progress on the Separation of Alkaloids from Chinese Medicines by Column Chromatography

Alkaloids have a variety of bioactivities and great development value in the fields of pharmaceuticals, cosmetics and health food. Column chromatography is a common method for preparing alkaloids. In this paper, the research status of the separation and purification of alkaloids from Chinese medicines by column chromatography is reviewed, and the factors that influence the refining of alkaloids via a macroporous adsorption resin, ion exchange resin and silica gel are summarized. The thermodynamic and kinetic modeling methods for the static adsorption of adsorbents are also reviewed in this paper. It is suggested that the modeling method of the column chromatography process be deeply studied to establish a more stringent quality control method for sampling liquid and to strengthen the online detection of the chromatography process to improve the refining effect of alkaloids.

Separation of gibberellic acid (GA3) by macroporous adsorption resins

The adsorption effects of several macroporousadsorption resins for gibberellic acid (GA3) were investigated.The dynamic adsorption capacity is 58.38 mg/g drybeads for resin R4 and 96.46 mg/g dry beads for resin R5which is consistent with the surface area. Aqueous methanol(50%, V/V) is a good eluent and the yield of GA3 isabove 95%. The concentration of GA3 could increase fivefoldafter an adsorption-elution cycle and this is importantwhen considering further crystallization of GA3 in anindustrial process.

Extraction and purification of ustiloxin A from rice false smut balls by a combination of macroporous resin and high-speed countercurrent chromatography

Rice false smut is an emerging plant disease worldwide.Ustiloxin A(UstA)is the major mycotoxin found in rice false smut balls,which are fungal colonies in rice florets.In this study,a new method consisting of macroporous resin column chromatography and high-speed countercurrent chromatography(HSCCC)was developed for UstA separation.UstA was extracted by a 3.81%HCOOH solution and adsorbed by XAD-4 resin.UstA was then eluted by a 40%methanol solution supplemented with 0.1%trifluoroacetic acid(TFA).Further purification was achieved by HSCCC using a two-phase solvent system consisting of n-butanol/TFA/H_(2)O(1/0.05/1,v/v/v).Under the optimized conditions,225 mg of UstA was obtained with a purity of 97.39%in a single run,with a final recovery of 65.2%.An inhibitory effect on seed germination of wheat and maize caused by UstA was observed in a preliminary phytotoxicity assay.

Selective adsorption of silver ions from aqueous solution using polystyrene-supported trimercaptotriazine resin

Tdmercaptotriazine-functionalized polystyrene chelating resin was prepared and employed for the adsorption of Ag（I） from aqueous solution. The adsorbent was characterized according to the following techniques： Fourier transform infrared spectroscopy, elemental analysis, scanning electron microscopy and the Brunauer-Emmet-Teller method. The effects of initial Ag（I） concentration, contact time, solution pH and coexisting ions on the adsorption capacity of Ag（I） were systematically investigated. The maximum adsorption capacity of AgO） was up to 187.1 mg/g resin at pH 0.0 and room temperature. The kinetic experiments indicated that the adsorption rate of Ag（I） onto the chelating resin was quite fast in the first 60 rain and reached adsorption equilibrium after 360 min. The adsorption process can be well described by the pseudo second-order kinetic model and the equilibrium adsorption isotherm was closely fitted by the Langmuir model. Moreover, the chelating resin could selectively adsorb more Ag（I） ions than other heavy metal ions including： Cu（Ⅱ）, Zn（Ⅱ）, Ni（Ⅱ）, Pb（Ⅱ） and Cr（Ⅲ） during competitive adsorption in the binary metal species systems, which indicated that it was a highly selective adsorbent of Ag（I） from aqueous solution.

Optimization of microwave-assisted extraction of polysaccharides in the flower of Platycodon grandiflorum by response surface methodology

Platycodon grandiflorum polysaccharides(PGPs)are naturally occurring compounds derived from the flowers of platycodon grandiflorum.the microwave assisted extraction(MAE)of PGPs was studied.A three-level and three-factor Box-Behnken design was used to optimize MAE conditions,and the effects of operating conditions including microwave power(180-540 W),extraction time(20-60 s)and liquid to solid ratio(20-30 v/w)on the extraction yield of PGPs were studied through response surface methodology(RSM).The results showed that the highest yield of PGPs reached 8.35 g/(100 g)at 360 W microwave power,40 s extraction time and 25.2 v/w liquid to solid ratio.The extraction yield of PGPs was significantly affected by liquid to solid ratio(P<0.01),microwave power and extraction time(P<0.05).Compared with the conventional solvent extraction,MAE is more efficient and rapid due to the disruption of the flower tissue microstructure as a result of microwave acoustic cavitation as observed with the scanning electron microscopy(SEM).A macroporous resin,HPD400,was found to be effective for purifying the PGPs extract.