Macroporous Resin Research Articles

Extraction of Antioxidants from Aronia mitschurinii Juice Using Macroporous Resins

Antioxidants play a vital role in the human body by defending cells from damage caused by free radicals, highly reactive products of oxidation reactions. A major source of antioxidants is fruits and vegetables. Aronia mitschurinii, a breed created at the end of the 19th century by crossbreeding wild Aronia melanocarpa and Russian Mountain Ash, produces fruits with one of the highest known content of hydrophilic antioxidants. Aronia fruit contains a potent blend of anthocyanins, polyphenols, and flavonoids. The most popular way of consuming the fruit is through juicing. Yet, due to very high concentrations of tannins in the juice, very few food-related applications have been developed. Resin extraction of antioxidants provides an alternative for utilizing valuable phytochemicals from crops for applications in the food industry as nutraceutical supplements and more. To increase the market value of the plant, it is important to determine what resins can extract the optimum concentration of antioxidants from aronia juice, pulp, and whole berries. We have shown that macroporous resins such as Amberlite XAD 1180N, Amberlite XAD 7HP, Amberlite XAD 761, and Amberlite FPX66, which have been reported to be effective in extracting the anthocyanins and polyphenols from other fruit juices, skins of red grapes, and the wild breed, are also effective for use in juice, pulp, and whole fruits of Aronia mitchurinii. However, the extremely high content of antioxidants presents a challenge to obtaining high recovery; a notable change in the juice/resin ratio is required to obtain a higher recovery value. Our results showed that Amberlite FPX66 was the best at extracting anthocyanins, polyphenols, and flavonoids from aronia juice. A separate experiment conducted to determine how to optimize the efficiency of FPX66 extraction revealed that increasing the resin/juice ratio increased the percent recovery of anthocyanins from aronia juice. Moreover, we have compared recovery between juice, pulp, and whole aronia berries and batch versus column extraction.

Glycerol valorization: Development of selective protocols for acetals production through tailor-made macroreticular acid resins

Bio-based glycerol and aldehydes have been valorized by acetalization reaction over novel macroporous sulfonated polystyrene-type resins (MR-SP20-SO3H and MR-SP50-SO3H). The influence of reactants molar ratio, catalyst amount, temperature, and reaction time on the activity and selectivity to acetals have been investigated. Results showed that MR-SP20-SO3H and MR-SP50-SO3H confirm a high performance in the acetalization of the glycerol derivatives 1,2- propandiol, 1,3-propandiol, 3-methoxy-1,2-propandiol and monoacetin; these catalytic systems enable recover and reuse.

Ultrasonic-assisted extraction and adsorption separation: Large-scale preparation of trans-ε-Viniferin, suffruficosol B and trans-Gnetin H for the first time

In this study, a Standard Operating Procedure (SOP) for the large-scale extraction, enrichment, and separation of suffruticosol B (SB), trans-ε-Viniferin (TV), trans-gnetin H (TG) from oil tree peony seeds shell (PSS) was successfully constructed. The ultrasonic-assisted extraction (UAE), macroporous adsorption resin (MAR), and column chromatography (CC) were employed to extract, enrich and separate SB, TV and TG from PSS, and the conditions were optimized. The results implied that SB (1.6937 g), TV (0.5884 g) and TG (3.8786 g) with the purity of 99.67 %, 99.32 % and 98.54 %, respectively, were obtained after the extraction, enrichment and separation. The total yields of the SB, TV and TG were 0.61 mg/g, 0.02 mg/g and 6.64 mg/g with the total extraction rates at 70.55 %, 69.77 % and 78.36 %, respectively. This is the first report on the large-scale extraction, enrichment and separation of oligostilbenes. The SOP in this paper could produce high purity SB, TV and TG, and provide a new idea for PSS as a new oligostilbene resource. The study expands the new development and research field of PSS and provides theoretical support for the green utilization of oil tree peony.

Cellular antioxidant and viability efficacy of Harpephyllum caffrum peel and Syzygium guineense seed extracts

Crude phenolic extracts of indigenous sub-Saharan fruit byproducts have potent antioxidant activity. Purification of these extracts and evaluation of their antioxidant activity and viability using appropriate biological models, has, however, not yet been completed. The current study quantitatively evaluated the phenolic composition and in vitro antioxidant activity of crude and purified extracts (PE) of Harpephyllum caffrum peel (HCP) and Syzygium guineense seed (SGS), and cellular antioxidant and viability efficacy of the PE. Phenols were extracted by 60% ethanol (v/v) solvent system and purified using XAD7HP macroporous adsorption resin. The UPLC/Q-TOF-MS was used for the characterization and identification of phenols. Cellular antioxidant activity (CAA) assay was applied to assess the antioxidant efficacy and cytotoxicity of the PE. Analysis of variance of data was done using a generalized linear mixed model with fruit type, extract purity and their interaction as fixed effects. Purification increased (P ≤ 0.05) HCP total phenolic concentration (TPC) by over 200%, while SGS TPC decreased (P ≤ 0.05) by 20%. Regardless of fruit type, PE had higher (P ≤ 0.05) quantities of proanthocyanidins and anthocyanins than crude extracts. The HCP-PE had greater (P ≤ 0.05) in vitro antioxidant activity than the other extracts (P ≤ 0.05). Cellular antioxidant activity of HCP-PE was comparable to that of sodium metabisulphite (P > 0.05). Also, HCP-PE had lower (P ≤ 0.05) cytotoxic effects than SGS and sodium metabisulphite with increasing antioxidant concentration. It was concluded that HCP-PE is a potential source of safe natural antioxidants for nutraceutical applications.

Purification and ultra-high-performance liquid chromatography tandem mass spectrometry analysis of phenolics extracted from male walnut flowers

ABSTRACT In this study, phenolics extracted from male walnut flowers were purified and analyzed by ultra-high-performance liquid chromatography tandem mass spectrometry. After ultrasonic extraction of male walnut flowers with 60% ethanol, AB-8, D3520, NKA-9, D101, and NKA macroporous adsorption resins were compared for purification. The AB-8 macroporous resin gave the best adsorption and desorption performance for 0.7 mg gallic acid equivalents/mL samples (pH 3.0) loaded at a flow rate of 1 mL/min. Elution was carried out with 50% ethanol without pH adjustment. The purity of the phenolics in the eluate (72.5%) was 3.1 times that in the original extract. Analysis by ultra-high-performance liquid chromatography tandem mass spectrometry identified 16 compounds, including phenolic acids, flavonoids, and coumarins in the purified phenolics. The most abundant compounds were chlorogenic acid, kaempferol, and methoxycoumarin. Two compounds were got in male walnut flowers for the first time, and those need yet to be proved by further experiments.

Determination of absolute configuration of a new triterpenic acid in leaves of Ilex hainanensis

This study aimed to explore the triterpenic acid components in leaves of Ilex hainanensis. Alkaline water extraction, macroporous resin adsorption, and high performance liquid chromatography were used to separate and purify the triterpenic acid components in leaves of I. hainanensis. The physical and chemical property analysis, MS, NMR spectroscopy, and literature comparison were performed to identify the structures, and a new triterpene acid compound was discovered:(3S, 4R, 5R, 8R, 9R, 10R, 14S, 17S, 18S, 19R)-3,19-dihydroxyursa-12,20(30)-diene-24,28-dioic-acid, and named ilexhainanin F. In addition, according to its structural characteristics, the ~(19)F-NMR Mosher method was further employed to study its absolute configuration. By comparison of the ~(19)F-NMR chemical shifts of Mosher esters, it was determined that the absolute configuration of the 3-position chiral center of the compound was the S configuration.

Micro-mesoporous polystyrene resins prepared by nanosecond pulsed discharge plasma for the efficient adsorption of PAHs

Adsorption method has been widely used in purification, trace pollutant control, biomedicine, and other fields, and preparing an efficient adsorbent with low cost is very important for the applications. In this work, we employed nanosecond pulsed discharge plasma as a pore-forming agent to produce micro-mesoporous in polystyrene macroporous resins and reported the adsorption behavior of naphthalene on resins. By plasma induced pore-forming and functional groups-grafting, the equilibrium adsorption amount of micro-mesoporous resins for naphthalene is 324.4 % higher than that of the raw polystyrene macroporous resins. The characterization results show that a new pore size ranging from 0.5 to 2 nm and a vastly increased content of oxygen group of CO appears on the surface of the resin after plasma treatment. Additionally, the novel micro-mesoporous resins had good reusability without apparent capacity loss after five adsorption–desorption cycles.

Enrichment of soy isoflavone extracts through macroporous resin for characterization of toxicity and estrogenic activities.

The online version contains supplementary material available at 10.1007/s13197-022-05491-4.

Screening of acetylcholinesterase inhibitory and antioxidant active compounds from Terminalia chebula fruits by spectrum‐effect relationship and liquid chromatography‒mass spectrometry analysis

Screening and identification of active components from traditional Chinese medicines is rather challenging due to the diversity and complexity of chemical components. Herein, a comprehensive strategy based on a spectrum-effect relationship model and LC-MS analysis was developed to screen active components from Terminalia chebula fruits. The water extract of T. chebula fruits was subjected to macroporous resin column and then eluted successively with water and 30%, 50%, 70%, and 95% ethanol. The 30% ethanol eluate fractions of eighteen batches from T. chebula fruits were used for the spectrum-effect relationship study. The IC50 values for acetylcholinesterase inhibitory and 2,2-diphenyl-1-picrylhydrazyl scavenging activities were measured, LC fingerprints were established, and 15 common peaks were specified. The spectrum-effect relationship between common peaks and IC50 values was investigated by principal component analysis, gray relational analysis, partial least square and multiple linear regression. The 30% ethanol eluate fraction was further characterized by LC-MS analysis. The chromatographic peaks (Peaks 1, 2, 3, 5, 12, 14, 15) making great contributions to the efficacy were screened through a spectrum-effect relationship model, and sixteen components were further identified. The results suggested that the proposed strategy is simple and effective for acquiring active components from a complex matrix.

Ultrasound treatment degrades, changes the color, and improves the antioxidant activity of the anthocyanins in red radish

Ultrasonic technology is commonly used to extract anthocyanins from food. This study extracted anthocyanins from red radish (ARR), which were purified using AB-8 macroporous resin. UHPLC-QQQ-MS/MS analysis identified 25 anthocyanins in the ARR, of which pelargonidin-3-(feruloyl)diglucoside-5-(malonyl)glucoside (P3FD5MG), pelargonidin-3-(p-coumaroyl)diglucoside-5-(malonyl)glucoside (P3PD5MG), and pelargonidin-3-(caffeoyl)diglucoside-5-(malonyl)glucoside (P3CD5MG) were the most abundant. Ultrasound treatment at 136–358 W for 120 min decreased the contents of P3FD5MG, P3PD5MG, and P3CD5MG by 19.5%–34.7%, 18.9%–42.7%, and 21.5%–37.3%, respectively. The degradation of P3FD5MG, P3PD5MG, and P3CD5MG increased by applying ultrasound treatment for an extended period and higher power, following a second-order kinetic equation. The degradation process during ultrasound treatment produced p-hydroxybenzoic acid (PHBA) and protocatechuic acid (PA), improving the ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenging activity of ARR. Moreover, ultrasound treatment caused degradation of anthocyanins, thereby leading to distinct color changes in the ARR. Therefore, ultrasound treatment should be used cautiously when processing red radish to preserve their color.

Purification of ferulic acid from corn fibre alkaline extracts for bio-vanillin production using an adsorption process

Ferulic acid is the most widely studied precursor for bio-vanillin production. This work assesses the use of an alkaline extract from corn fibre for bio-vanillin production. The results show that after extraction an additional step is needed to purify ferulic acid removing toxic/inhibitor compounds. An adsorption process was selected to purify the ferulic acid. The performances of four different macroporous resins prepared from different matrix materials were evaluated. Macronet® MN102 (not yet reported for ferulic acid purification) offered the highest ferulic acid adsorption capacity. A column packed with Macronet® MN102 was used to perform dynamic adsorption and desorption experiments, which showed a maximum ferulic acid adsorption capacity of 176 mgferulic acid.g−1dry resin at pH 4.5 at a flow rate of 3.7 BV (bed volumes).h−1. The breakthrough point was at 115 min, corresponding to an adsorption capacity of 85 mgferulic acid.g−1dry resin. In the desorption step, 90.9% of ferulic acid was recovered using absolute ethanol ≥ 99.8%) as eluent, at the same flow rate of 3.7 BV (bed volumes).h−1. This procedure confirmed the removal of compounds with a microbial inhibitory effect, such as organic acids, metals and some aldehydes. The purified ferulic acid extract was then used to produce bio-vanillin. The bio-vanillin production by Amycolatopsis sp. ATCC 39116, using a single pulse of an extract with 10 g.L-1 of ferulic acid extract, led to a maximum vanillin concentration of 5 g.L-1 and a vanillin yield of 0.52 gvanillin.gferulic acid-1, values comparable to those obtained with a commercial solution containing 10 g.L-1 of ferulic acid.

Molluscicidal activity of the secondary metabolites from Streptomyces nigrogriseolus XD 2-7 against Oncomelania hupensis and its preliminary mechanisms of molluscicidal actions

To evaluate the storage stability of metabolites from actinomycetes Streptomyces nigrogriseolus XD 2-7 and the mollcuscicidal activity against Oncomelania hupensis in the laboratory, and to preliminarily explore the mechanisms of the molluscicidal activity. The fermentation supernatant of S. nigrogriseolus XD 2-7 was prepared and stored at -20, 4 °C and 28 °C without light for 10 d; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation supernatant was boiled in a 100 °C water bath for 30 min and recovered to room temperature, and then the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The pH values of the fermentation supernatant were adjusted to 4.0, 6.0 and 9.0 with concentrated hydrochloric acid and sodium hydroxide, and the fermentation supernatant was stilled at room temperature for 12 h, with its pH adjusted to 7.0; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation product of S. nigrogriseolus XD 2-7was isolated and purified four times with macroporous resin, silica gel and octadecylsilane bonded silica gel. The final products were prepared into solutions at concentrations of 10.00, 5.00, 2.50, 1.25 mg/L and 0.63 mg/L, and the molluscicidal effect of the final productswas tested against O. hupensis following immersion for 72 h, while dechlorination water served as blank controls, and 0.10 mg/L niclosamide served as positive control. The adenosine triphosphate (ATP) and adenosine diphosphate (ADP) levels were measured in in O. hupensis soft tissues using high performance liquid chromatography (HPLC) following exposure to the final purified fermentation products of S. nigrogriseolus XD 2-7. After the fermentation supernatant of S. nigrogriseolus XD 2-7 was placed at -20, 4 °C and 28 °C without light for 10 d, immersion in the stock solution and solutions at 10- and 50-fold dilutions for 72 h resulted in a 100% (30/30) O. hupensis mortality. Following boiling at 100 °C for 30 min, immersion in the stock solution and solutions at 10- and 50-fold dilutions for 72 h resulted in a 100.00% (30/30) O. hupensis mortality. Following storage at pH values of 4.0 and 6.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2-7 for 72 h resulted in a 100.00% (30/30) O. hupensis mortality, and following storage at a pH value of 9.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2-7 for 72 h resulted in a 33.33% (10/30) O. hupensis mortality (χ2 = 30.000, P < 0.05). The minimum concentration of the final purified fermentation products of S. nigrogriseolus XD 2-7 was 1.25 mg/L for achieving a 100% (30/30) O. hupensis mortality. The ATP level was significantly lower in O. hupensis soft tissues exposed to 0.10 mg/L and 1.00 mg/L of the final purified fermentation products of S. nigrogriseolus XD 2-7 than in controls (F = 7.274, P < 0.05), while no significant difference was detected in the ADP level between the treatment group and controls (F = 2.485, P > 0.05). The active mollcuscicidal ingredients of the S. nigrogriseolus XD 2-7 metabolites are maintained stably at -20, 4 °C and 28 °C for 10 d, and are heat and acid resistant but not alkali resistant. The metabolites from S. nigrogriseolus XD 2-7 may cause energy metabolism disorders in O. hupensis, leading to O. hupensis death.

Extraction and recovery of chlorogenic acid from sunflower disks using a high‐efficiency system composed of deep eutectic solvents and macroporous resins

Conventional methods to extract and recover chlorogenic acid (CGA) from plants exhibit plenty of flaws, like over-consumption of organic solvents, low extracting rate, and low enrichment efficiency. Herein, an ultrasound-assisted deep eutectic solvent extraction (UAE-DESs) was introduced to extract CGA from sunflower disks. And NKA-II macroporous resin was used as adsorbent to adsorb CGA from dilute DESs extracts. Then NKA-II was collected by filtration followed by desorption to obtain CGA separated from DESs. The extraction yield of CGA was 6.16 mg/g with liquid–solid ratio 31 ml/g, ultrasonic temperature 47°C, ultrasonic time 54 min, and deep eutectic solvent (DES) composed of choline chloride/1,4-butanediol (1/2, mol/mol) and water content 30% (w/w). After NKA-II enrichment, the recovery efficiency of CGA was 80.76% and the purity was 75.84%. Moreover, the recovered DESs could be reused during the extraction. The present research provided a time-saving, green, and sustainable method for extracting and recovering CGA from sunflower disks. Practical applications The research proposed a method for the extraction and recovery of CGA from sunflower disks by combining UAE-DESs and NKA-II macroporous resins. The combination of diluted DESs with macroporous resins can effectively overcome the disadvantages of DESs and provide an efficient method for the recovery of natural products. The CGA extracted can be applied in medicine, food, and other fields.

A Strategy for Identification and Structural Characterization of Compounds from Plantago asiatica L. by Liquid Chromatography-Mass Spectrometry Combined with Ion Mobility Spectrometry.

Plantago asiatica L. (PAL) as a medicinal and edible plant is rich in chemical compounds, which makes the systematic and comprehensive characterization of its components challenging. In this study, an integrated strategy based on three-dimensional separation including AB-8 macroporous resin column chromatography, ultra-high performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF MS), and ultra-high performance liquid chromatography-mass spectrometry with ion-mobility spectrometry (UHPLC-IM-MS) was established and used to separate and identify the structures of compounds from PAL. The extracts of PAL were firstly separated into three parts by AB-8 macroporous resin and further separated and identified by UHPLC-Q-TOF MS and UHPLC-IM-MS, respectively. Additionally, UHPLC-IM-MS was used to identify isomers and coeluting compounds, so that the product ions appearing at the same retention time (RT)can clearly distinguish where the parent ion belongs by their different drift times. UNIFI software was used for data processing and structure identification. A total of 86 compounds, including triterpenes, iridoids, phenylethanoid glycosides, guanidine derivatives, organic acids, and fatty acids, were identified by using MS information and fragment ion information provided by UHPLC-Q-TOF MS and UHPLC-IM-MS. In particular, a pair of isoforms of plantagoside from PAL were detected and identified by UHPLC-IM-MS combined with the theoretical calculation method for the first time. In conclusion, the AB-8 macroporous resin column chromatography can separate the main compounds of PAL and enrich the trace compounds. Combining UHPLC-IM-MS and UHPLC-Q-TOF MS can obtain not only more fragments but also their unique drift times and RT, which is more conducive to the identification of complex systems, especially isomers. This proposed strategy can provide an effective method to separate and identify chemical components, and distinguish isomers in the complex system of traditional Chinese medicine (TCM).

Ultrasound-Assisted Extraction of Anthocyanins from Malus 'Royalty' Fruits: Optimization, Separation, and Antitumor Activity.

Red Malus ‘Royalty’ fruits are rich in anthocyanins. This study aimed to obtain the optimal parameters for the extraction and separation of anthocyanins from Malus ‘Royalty’ fruits and to evaluate the inhibitory effect of the enriched anthocyanin fraction on gastric cancer cells. Ultrasonic-assisted extraction was used for the extraction of the anthocyanins of Malus ‘Royalty’ fruit, and the extraction results showed that the optimum parameters were an extraction temperature of 20 °C, a solid–liquid ratio of 1:6 (g/mL), ethanol and formic acid contents of 70% and 0.4%, respectively, an extraction time of 40 min, and an ultrasonic power of 300 W. The optimum extraction parameters to achieve the highest anthocyanin yield by a single-factor experiment coupled with response surface methodology were identified. The separation results showed that the AB-8 macroporous resin was a better purifying material, with 60% ethanol as an adsorbent, and the adsorption–desorption equilibrium times were 6 h and 1 h, respectively. Cyanidin-3-galactoside was the main body composition separation of anthocyanins by a high-performance liquid chromatography-diode array detector. The antitumor activity results showed that the anthocyanins of Malus ‘Royalty’ fruits have a significant inhibitory effect on the gastric cancer cell line BGC-803. The in vitro cell viability test of CCK-8 showed that the inhibitory effect on tumor cells was more significant with the increased anthocyanin concentration, with a half maximal inhibitory concentration (IC50) value of 105.5 μg/mL. The cell morphology was observed by an inverted microscope, and it was found that the backbone of BGC-803 treated with a high concentration of anthocyanins was disintegrated and the nucleoplasm was concentrated. The mechanism of apoptosis was analyzed by Western blotting, and the results showed that with increasing anthocyanin concentration in the medium, the expression levels of the proapoptotic proteins Bax and Bak increased, and the expression levels of the antiapoptotic proteins Bcl-2 and Bcl-xL decreased, which coordinated the regulation of cell apoptosis. This research suggests that the enriched anthocyanin fraction from Malus ‘Royalty’ fruits have potential antitumor and adjuvant therapeutic effects on gastric cancer.

Recovery and Concentration of Polyphenols from Roasted Hazelnut Skin Extract Using Macroporous Resins

Hazelnut skin is a rich source of polyphenols but is generally discarded during the roasting process of hazelnuts. Previous studies reported the extraction and identification of these compounds using different solvents and procedures; however, there are few reports on their enrichment and purification. In this study, three types of Amberlite macroporous resins (XAD 16, XAD 4, and XAD 7) were compared to evaluate the enrichment of polyphenols via adsorption and desorption mechanisms. The operating condition parameters for polyphenol adsorption/desorption of each resin were determined, the kinetics of adsorption were examined, and a method for polyphenol recovery was developed using static and dynamic adsorption/desorption. Antioxidant activity and high-performance liquid chromatography-diode array detection were used to confirm the increase in polyphenols obtained using the adsorption/desorption technique. XAD16 showed the highest adsorption capacity, with a recovery of 87.7%, and the adsorption kinetics fit well with a pseudo-second-order model. The highest poly-phenol desorption ratio was observed using an ethanol/water solution (70% v/v) at a flow rate of 1.5 bed volume/h.

Isolation and Characterization of Flavonoids from Fermented Dandelion (Taraxacum mongolicum Hand.-Mazz.), and Assessment of Its Antioxidant Actions In Vitro and In Vivo

Flavonoids are famous for their diverse sources, strong biological activity, and low toxicity and could be used as a natural antioxidant in animal husbandry. In this study, the purification process and antioxidant activity of flavonoids from fermented dandelion were investigated. The adsorption and desorption characterizations of AB-8 macroporous resin for flavonoids from fermented dandelion (FD) were determined and purification parameters were optimized. Qualitative analysis using UPLC-MS/MS analysis was explored to identify the components of the purified flavonoids of FD (PFDF). The antioxidant activity of PFDF in vitro and in vivo was analyzed. The optimum purification parameters were as follows: a sample concentration of 2 mg/mL, 120 mL of the sample volume, a pH of 2.0, and eluted with 90 mL of 70% ethanol (pH 5). After purification, the concentration of the flavonoids in PFDF was 356.08 mg/mL. By comparison with reference standards or the literature data, 135 kinds of flavonoids in PFDF were identified. Furthermore, PFDF had a strong reducing power and scavenging ability against 8-hydroxy radical and DPPH radical. PFDF can effectively reduce the oxidative stress of zebrafish embryos and IPCE-J2 cells by modulating antioxidant enzyme activities. In summary, the purified flavonoids from fermented dandelion have good antioxidant activity and display superior potential as a natural antioxidant in animal husbandry.

The Efficiency of Nuclear Ion Exchange Resins Applied in the Primary Circuit Demineralizers of NPP Krško

Chemistry can influence dose rates by two aspects: chemistry conditions applied in the primary circuit and removal of (in)soluble particles. Since the primary coolant activity can have a significant impact on area dose rates and personnel doses, the main objective of purifying the primary coolant is to act on the radioactive source and keep it as low as reasonably achievable. Reduction of occupational exposure maintains confidence among workers and the public. Other factors, such as fuel duty, cycle operation, length and history, materials, steam generator (SG) surface area and particulate redeposition, also have significant contribution to the doses. Ion exchange (IEX) is one of the most common and effective liquid effluents treatment methods in nuclear fuel cycle operations. IEX technology encompasses the sciences of thermodynamics, kinetics, ion chemistry, fluid mechanics, and economics. In the industrial water treatment, cation exchangers are used in combination with downstream anion exchangers or as a mixed bed demineralizer (combination of both cation and anion) for full demineralization. IEX is also an effective treatment method for liquid radioactive waste. In spite of its advanced stage of development, various aspects of ion exchange technology are being studied to improve its efficiency and economy in its application to radioactive waste management and coolant cleaning processes. Over the years desire to improve the efficiency of fine colloidal particles removal and corrosion particulate removal in the primary systems has increased. There is a need for more and more efficient purification in order to decrease worker’s dose during maintenance but also to decrease volumes of radioactive resin waste. Homogenization of products and usage on primary coolant treatment take into account the compromise between source term reductions, liquid and solid waste, and buying and disposal cost. As the disposal costs are much greater than the buying costs, optimization of the lifetime of the purification media, along with an increasing efficiency of pollutant removal is a major goal. One of the effective purification methods for particulate removal is layering of macroporous (MP) resin in clean-up beds, spent fuel pit (SFP) and radwaste beds. Lately, MP resins were also implemented in the primary circuit demineralizers of NPP Krško. The paper evaluates resin purification efficiency of different primary media, and assesses performance of gel and macroporous resin types.

Static decolorization of polysaccharides from the leaves of Rhododendron dauricum: Process optimization, characterization and antioxidant activities

In this study, polysaccharides from the leaves of Rhododendron dauricum L. (RDPs) were decolorized using the static macroporous resin adsorption method. The RDPs were characterized and their antioxidant activities were investigated. An analytical hierarchy process (AHP) and a response surface method (RSM) were used to determine the optimum decolorization conditions as: a polysaccharide concentration of 8 mg/mL, decolorization time of 70 min, liquid–solid ratio of 6 mL/g, and decolorization temperature of 52 °C, with D101 as the best resin. Furthermore, two novel polysaccharides (RDP-1 and RDP-2) were isolated from R. dauricum leaves and characterized, which demonstrated that RDP-1 and RDP-2 were both composed of mannose, glucose, galactose, and arabinose in different molar ratios. These RDPs also exhibited a triple helix conformation, and primarily contained →6)-Glcp-(1→, →5)-Araf-(1→, →2,4)-Manp-(1→, →6)-Galp-(1→ and Glcp-(1→ residues with different connection sequences. Biological activity tests showed that the two polysaccharides possessed scavenging capacity against 1,1-Diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and 2,2-Azino-bis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) radicals. The results indicated that the antioxidant activities of the RDPs obtained by the static decolorization method improved, which lays a theoretical foundation for developing techniques for utilising R. dauricum.

Isolation and identification of polyphenol monomers from celery leaves and their structure-antioxidant activity relationship

This study aimed to isolate, purify and identify phenols from the celery leaves and further evaluate the antioxidant activities of the monomers in chemical system. Seven polyphenol monomers (a-g) were identified by HPLC-ESI-MS/MS after being separated by D101 macroporous resin, semi-preparative reversed-phase high-performance liquid chromatography (RP-HPLC) and sephadex LH-20. Interestingly, chrysoeriol 7-O-glucoside was identified from celery leaves by UV, IR, one dimensional nuclear magnetic resonance (NMR) and two-dimensional NMR for the first time. In addition, these polyphenol monomers manifested desirable DPPH• scavenging capacity (EC50: 39.55 ± 1.43–612 ± 8.45 μM) and ABTS+• scavenging capacity (EC50: 32.12 ± 0.58–512 ± 25.12 μM), respectively. Among them, the polyphenol monomers (a and b) with two hydroxyl groups (-OH) on the B ring in flavone skeleton had the strongest antioxidant activities. Moreover, the analysis of the structure-activity relationship showed that the position and quantity of -OH on the B-ring and the methylation degree of 3-OH played an important role in regulating antioxidant activities.