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Extraction of Bioactive Compounds from Haskap Leaves (Lonicera caerulea) Using Salt/Ethanol Aqueous Two-Phase Flotation

Aqueous two-phase flotation (ATPF) was used for the extraction and partial purification of bioactive compounds from haskap leaves. Two ATPF systems, ammonium sulfate/ethanol and sodium phosphate/ethanol, were compared. A Box-Behnken approach was used to investigate the operating parameters which included sample loading (5.0, 52.5, and 100.0 mg), flotation time (5, 62.5, 120 min), and air flow rate (11.4, 20.0, 28.6 mL/min). Response surface optimization was performed to maximize the yields of chlorogenic acid (CGA), flavonoids, and total phenolics (total phenolic content, TPC). At the optimized parameters for the ammonium sulfate/ethanol ATPF system (i.e., 5-mg leaves, 120-min flotation time, and air flow rate of 28.6 mL/min), the extraction efficiencies were 97.1%, 98.7%, and 99.6% for CGA, flavonoids, and TPC, respectively. The corresponding partition coefficients were 29.6 for CGA, 62.4 for flavonoids, and 231.4 for TPC. Quantitation of individual compounds using high-performance liquid chromatography showed that ATPF with ammonium sulfate/ethanol achieved yields of 0.031 mg CGA/mg dry mass leaves, 0.027-mg rutin/mg dry mass leaves, 0.006-mg luteolin-7-O-glucoside/mg dry mass leaves, and 0.007-mg diosmin/mg dry mass leaves. Based on the overall extraction performance, ammonium sulfate/ethanol ATPF is the preferred system in comparison to sodium phosphate/ethanol ATPF, for the extraction of bioactive compounds from haskap leaves.

Mercury speciation in edible seaweed by liquid chromatography - Inductively coupled plasma mass spectrometry after ionic imprinted polymer-solid phase extraction

In contrast to most of essential and heavy metals, mercury levels in seaweed are very low, and pre-concentration methods are required for an adequate total mercury determination and mercury speciation in this foodstuff. An ionic imprinted polymer-based solid phase extraction (on column) pre-concentration procedure has been optimized for mercury species enrichment before liquid chromatography hyphenated with inductively coupled plasma mass spectrometry determination. The polymer has been synthesized by the precipitation polymerization method and using a ternary pre-polymerization mixture containing the template (methylmercury), a non-vinylated monomer (phenobarbital), and a vinylated monomer (methacrylic acid). Factors affecting the adsorption/desorption of Hg species (extract pH, loading and elution flow rates, volume of eluent, etc.), and parameters such as breakthrough volume and reusability, were fully studied. Mercury species were first isolated from seaweed by ultrasound assisted extraction using a 0.1% (v/v) HCl, 0.12% (w/v) l-cysteine, 0.1% (v/v) mercaptoethanol solution. Under optimized conditions, the limits of detection were 0.007 and 0.02 μg kg−1 dw for methylmercury and Hg(II), respectively. The pre-concentration factor (volume of 10 mL of seaweed extract) was 50. Repeatability and reproducibility of the method were satisfactory with relative standard deviations lower than 16%. The proposed methodology was finally applied for the selective pre-concentration and determination of methylmercury and Hg (II) in a BCR-463 certified reference material and in several edible seaweeds.

Heat pipe flat plate solar collectors operating with nanofluids

The aim of this work is to characterize numerically the performance of a heat pipe flat plate solar collector operating with nanofluids. A mathematical formulation under a 1-dimensional transient heat transfer model was introduced for this purpose. Spatio-temporal temperature variation of each collector subelement was predicted for a typical sunny day in the Moroccan city, Fez. CuO, Al2O3 and TiO2-based nanofluids were compared energetically and exergetically under various operating modes. The nanoparticle loading and mass flow rate of the working fluid were varied in the range of 0–3% and 0.018–0.036 kg/s, respectively. For the flow regime under focus, the decreased specific heat of nanofluids is the main thermal property responsible for the performance enhancement when nanofluids are used. CuO-based nanofluid was found to engender the highest relative enhancements in the energetic and exergetic efficiencies which were estimated at 2.7% and 11.1%, respectively compared to the base fluid (water). Using nanofluids for this collector class can ensure up to 2.95% surplus daily thermal energy generation compared to the base fluid. Moreover, the use of CuO-based nanofluid caused the largest increase in the pressure drop across the collector with a maximum value of 13.26% predicted for 3% nanoparticle loading.

Biodistribution of Graphene Oxide Determined through Postadministration Labeling with DNA-Conjugated Gold Nanoparticles and ICPMS.

Recent research has revealed the use of graphene oxide (GO) and its derivatives as a potential biomaterial because of their attractive physicochemical characteristics and functional properties. However, if GO and related derivatives are to become useful materials for biomedical applications, it will be necessary to evaluate their biodistribution for health and safety considerations. To obtain a more accurate biodistribution for GO, we (i) developed a postadministration labeling strategy employing DNA-conjugated gold nanoparticles (DNA-AuNPs) to selectively label administered GO in Solvable-treated tissue samples and (ii) constructed an automatic sample pretreatment scheme (using a C18-packed minicolumn) to effectively separate the DNA-AuNP-labeled GO from the unbound DNA-AuNPs and the dissolved tissue matrices, thereby enabling ultrasensitive, interference-free quantification of GO through measurement (inductively coupled plasma mass spectrometry) of the Au signal intensities. The DNA-AuNPs can bind to GO in a concentration- and time-dependent manner. After optimizing the labeling conditions (DNA length, incubation pH, DNA-AuNP concentration, and incubation time) and the separation scheme (sample loading flow rate, rinsing volume, and eluent composition), we found that A20R20-AuNPs (R20: random DNA sequence including A, T, C, and G) had the strongest binding affinity for labeling of the administered GO (dissociation constant: 36.0 fM) and that the method's detection limit reached 9.3 ag L-1 with a calibration curve having a working range from 10-1 to 1010 fg L-1. Moreover, this approach revealed that the intravenously administered GO accumulated predominantly in the liver and spleen at 1 and 12 h post administration, with apparent discrepancies in the concentrations measured using pre- and postadministration labeling strategies.

Batch and dynamic adsorption of lysozyme from chicken egg white on dye-affinity nanofiber membranes modified by ethylene diamine and chitosan

Adsorption of lysozyme on the dye-affinity nanofiber membranes was investigated in batch and dynamic modes. The membrane matrix was made of electrospun polyacrylonitrile nanofibers that were grafted with ethylene diamine (EDA) and/or chitosan (CS) for the coupling of Reactive Blue 49 dye. The physicochemical properties of these dye-immobilized nanofiber membranes (P-EDA-Dye and P-CS-Dye) were characterized microscopically, spectroscopically and thermogravimetrically. The capacities of lysozyme adsorption by the dye-affinity nanofiber membranes were evaluated under various conditions, namely pH, dye immobilized density, and loading flow rate. The adsorption of lysozyme to the dye-affinity nanofiber membranes was well fitted by Langmuir isotherm and pseudo-second kinetic models. P-CS-Dye nanofiber membrane had a better performance in the dynamic adsorption of lysozyme from complex chicken egg white solution. It was observed that after five cycles of adsorption-desorption, the dye-affinity nanofiber membrane did not show a significant loss in its capacity for lysozyme adsorption. The robustness as well as high dynamic adsorption capability of P-CS-Dye nanofiber membrane are promising for the efficient recovery of lysozyme from complex feedstock via nanofiber membrane chromatography.

The role of heterogeneous catalysts in the plasma-catalytic ammonia synthesis

Ammonia, being the second largest produced industrial chemical, is used as a raw material for many chemicals. Besides, there is a growing interest in the applications of ammonia as electrical energy storage chemical, as fuel, and in selective catalytic reduction of NOx. These applications demand on-site distributed ammonia production under mild process conditions. In this paper, we investigated 16 different transition metal and oxide catalysts supported on γ-Al2O3 for plasma-catalytic ammonia production in a dielectric barrier discharge (DBD) reactor. This paper discusses the influence of the feed ratio (N2/H2), specific energy input, reaction temperature, metal loading, and gas flow rates on the yield and energy efficiency of ammonia production. The optimum N2/H2 feed flow ratio was either 1 or 2 depending on the catalyst – substantially above ammonia stoichiometry of 0.33. The concentration of ammonia formed was proportional to the specific energy input. Increasing the reaction temperature or decreasing gas flow rates resulted in a lower specific production due to ammonia decomposition. The most efficient catalysts were found to be 2 wt% Rh/Al2O3 among platinum-group metals and 5 wt% Ni/Al2O3 among transitional metals. With the 2 wt% Rh catalyst, 1.43 vol% ammonia was produced with an energy efficiency of 0.94 g kWh−1. The observed behaviour was explained by a combination of gas-phase and catalytic ammonia formation reactions with plasma-activated nitrogen species. Plasma catalysts provide a synergetic effect by activation of hydrogen on the surface requiring lower-energy nitrogen species.

Synthesis of Lactulose in Continuous Stirred Tank Reactor With β-Galactosidase of Apergillus oryzae Immobilized in Monofunctional Glyoxyl Agarose Support.

Lactulose synthesis from fructose and lactose in continuous stirred tank (CSTR) reactor operation with glyoxyl-agarose immobilized Aspergillus oryzae β-galactosidase is reported for the first time. The effect of operational variables: inlet concentrations of sugar substrates, temperature, feed substrate molar ratio, enzyme loading and feed flow rate was studied on reactor performance. Even though the variation of each one affected to a certain extent lactulose yield (YLactulose), specific productivity (πLactulose) and selectivity of the reaction (lactulose/transgalactosylated oligosaccharides molar ratio) (SLu/TOS), the most significant effects were obtained by varying the inlet concentrations of sugar substrates and the feed substrate molar ratio. Maximum YLactulose of 0.54 g⋅g–1 was obtained at 50°C, pH 4.5, 50% w/w inlet concentrations of sugar substrates, feed flowrate of 12 mL⋅min–1, fructose/lactose molar ratio of 8 and reactor enzyme load of 29.06 IUH⋅mL–1. At such conditions SLu/TOS was 3.7, lactose conversion (XLactose) was 0.39 and total transgalactosylation yield was 0.762 g⋅g–1, meaning that 76% of the reacted lactose corresponded to transgalactosylation and 24% to hydrolysis, which is a definite advantage of this mode of operation. Even though XLactose in CSTR was lower than in other reported modes of operation for lactulose synthesis, transgalactosylation was more favored over hydrolysis which reduced the inhibitory effect of galactose on β-galactosidase.

Microwave pyrolysis for valorisation of horse manure biowaste

Biomass-based feedstock is an attractive alternative to fossil fuel due to its sustainability and potential as a clean energy source. The present work focuses on the valorisation of horse manure biowaste to produce bioenergy via microwave-assisted pyrolysis technique. The thermal decomposition process is conducted by considering the effects of pyrolysis temperature, catalyst loading and carrier gas flow rate on the yield and quality of end products. The pyrolysed gaseous product contains up to 73.1 vol% of syngas components. The solid biochar obtained contains a heating value of 35.5 MJ/kg with high surface to pore volume ratio. The relatively high specific energy contents of gaseous products and biochar indicate their potential as biofuels. The liquid product is found to contain oxygenated phenolic compound of up to 79.4 wt%. In spite of an overall energy deficit achieved when comparing the total energy of end products with the feedstock, the energy balance analysis indicates the optimum production parameters. The least energy deficit is achieved at the reactive conditions of 350–450 °C and manure-to-catalyst ratio of 1:1. A reaction mechanism pathway for the pyrolysis of horse manure is presented to show the production route for bioenergy and valuable chemicals.

Effect of 17-4PH stainless steel powders interaction on feedstocks

The objective of this work is to investigate the effects of 17-4PH stainless steel powders interaction on properties of feedstocks. γ-aminopropyltriethoxy silane (KH550), γ-(2,3-epoxypropoxy)propyltrimethoxy silane (KH560), and propyltrimethoxy silane (N313) were used to modify 17-4PH stainless steel powders, and described as KH550-m, KH560-m and N313-m with amino, epoxy and propyl group, respectively. The properties of feedstocks prepared from the pristine, KH550-m, KH560-m and N313-m were compared with that of equal amount of KH550-m and KH560-m (KH550-m/KH560-m). The experimental results revealed that the critical solids loading, density and melt flow rate of KH550-m/KH560-m feedstocks were 62.8 vol%, 5.24 g/cm3 and 51.42 g/10 min, respectively, which were higher than that of others. Besides, the debinded parts shape retention of KH550-m/KH560-m was also better than others. The good properties of KH550-m/KH560-m feedstocks originate from the strong interaction between KH550-m and KH560-m, which comes from the reaction and hydrogen bond between amino group and epoxy group.

Antibacterial activity of tea saponin from Camellia oleifera shell by novel extraction method

Natural preservatives are substances that are secreted by organisms or present in the body and have bacteriostatic effects, so they are not toxic to humans. Natural preservatives have become a research focus because of their high safety and strong antibacterial effects. Some commodities in the market are added with tea saponins, such as a brand of foaming cleanser, shampoo, and toothpaste rich in tea saponins. In this study, A high concentration of tea saponin was obtained through extraction and purification from Camellia oleifera shells, and its antibacterial activity for the two tested bacteria was determined in vitro. The results revealed that AB-8 macroporous adsorption resin was used in combination with Sephadex G-15 to obtain tea saponin with 82.5 % purity. The optimal purification process conditions were: the loading quantity of sample is 1 bed volume (BV), the loading solution is 25 mg/mL, the loading solution PH is 5, the loading flow rate is 3 BV/h, the elution volume is 4 BV, the elution flow rate is 3 BV/h, the eluent ethanol concentration is 95 %, and the eluent pH is 9. Tea saponin had good bacteriostatic effect on Escherichia coli and Staphylococcus aureus with its minimum inhibitory concentration of 1 and 0.5 mg/mL, respectively. In addition, its minimum bactericidal concentration was 4 mg/mL. Tea saponin could change membrane permeability, destroy cell membrane structure, and inhibit bacterial growth. This study provides basic guidance for the application of tea saponin in the development of natural antibacterial agents, is conducive to the high-value utilization of tea saponin, provides a reference for the economical of camellia tea waste, and plays a benefit in increasing agricultural income.

Removal mechanisms of cadmium and lead ions in contaminated water by stainless steel slag obtained from scrap metal recycling

In this work, steel slag was shown to be a successful filter material for the removal of lead and cadmium from natural waters with a removal efficiency of >95 %, even under acidic conditions (pH 3.5). Overall, precipitation was found to be the main removal mechanism over adsorption with a tight relationship with the final matrix pH. Batch experiments showed fast removal kinetics with >98 % removal efficiency for lead and cadmium in 5 and 15 min, respectively. The removal kinetics followed a pseudo second-order reaction (R2 = 0.999), and the K2 was calculated to be 927 h−1 and 204 h−1 for lead and cadmium, respectively. A strong interference for the removal was observed with ethylenediaminetetraacetic acid (EDTA) but slightly with fulvic and humic acids, and non-significant with polymeric acid e.g. isosaccharinic acid. In addition, the column experiment showed spontaneous removal kinetics for lead and cadmium with a contact time of 3.6–36 seconds depending on loading flow-rates. Column experiments at similar liquid to solid ratios showed a high removal capacity with gradient over isocratic solution loading. The high removal efficiencies in combination with limited hazardous metals leaching led to the conclusion that slag is an appropriate filter material for treating contaminated waters. Moreover, the slag treated solutions with alkaline conditions showed reacted efficiently with CO2 in flue gas. Consequently, the pH of the treated solution is neutralized making it easier to waste and this reaction may contribute to reducing CO2 gas emissions.

Evaluation of exosome loading characteristics in their purification via a glycerol-assisted hydrophobic interaction chromatography method on a polyester, capillary-channeled polymer fiber phase.

Exosomes are membrane-secreted vesicles, with sizes ranging from 30 to 150 nm, which play key roles in intercellular communication. There is intense interest in developing methods to isolate and quantify exosomes toward clinical diagnostics, fundamental studies of intercellular processes, and use of exosomes as delivery vehicles for therapeutic agents. Current methods for exosomes isolation and quantification are time consuming and have operational high costs; few combine isolation and quantification into a singular operation unit. This report describes the use of hydrophobic interaction chromatography on a polyester capillary-channeled polymer fiber column, employing a step gradient for exosome elution, including use of glycerol as a solvent modifier. The entire procedure is completed in 8 min, while maintaining the structural integrity and biological activity of the isolated exosomes. Electron microscopy was used to verify the size and structural fidelity of single exosomes. Absorbance response curves for a commercial exosome sample were used for exosome quantification in the chromatographic separations. In order to determine the dynamic loading capacity for exosomes, different volumes of Dictyostelium discoideum cell culture milieu supernatant were loaded at different column lengths (5-30 cm) and loading flow rates (0.2-0.5 ml/min). A loading capacity of 5.4 × 1012 exosomes derived from D. discoideum milieu was obtained on a 0.8 × 300 mm column; yielding recoveries of over 80%. It is believed that this isolation and purification strategy holds many advantages toward the use of exosomes across a wide breadth of medical and biotechnology applications.

Hydrogen production via catalytic pulsed plasma conversion of methane: Effect of Ni–K2O/Al2O3 loading, applied voltage, and argon flow rate

Despite industrial application of methane as an energy source and raw material for chemical manufacturing, it is a potent heat absorber and a strong greenhouse gas. Evidently reduction of methane emission especially in the natural gas sector is essential. Methane to hydrogen conversion through non-thermal plasma technologies has received increasing attention. In this paper, catalytic methane conversion into hydrogen is experimentally studied via nano-second pulsed DBD plasma reactor. The effect of carrier gas flow, applied voltage, and commercial Ni–K2O/Al2O3 catalyst loading on methane conversion, hydrogen production, hydrogen selectivity, discharge power, and energy efficiency are studied. The results showed that in the plasma alone system, the highest methane conversion and hydrogen production occurs at argon flow rate of 70 mL/min. Increase in the applied voltage increases the methane conversion and hydrogen production while it decreases the energy efficiency. Presence of 1 g Ni–K2O/Al2O3 catalyst shifts the optimum voltage for methane conversion and hydrogen production to 8 kV, reduces the required power, and increases the energy efficiency of the process. Finally in the catalytic plasma mode the optimum process condition occurs at the argon flow rate of 70 mL/min, applied voltage of 8 kV, and catalyst loading of 6 g. Compared with the optimum condition in the absence of catalyst, presence of 6 g Ni–K2O/Al2O3 catalyst increased the methane conversion, hydrogen production, hydrogen selectivity and energy efficiency by 15.7, 22.5, 7.1, and 40% respectively.

Amino-modified Scholl-coupling mesoporous polymer for online solid-phase extraction of plant growth regulators from bean sprouts

A new amino-modified Scholl-coupling mesoporous polymer (NH2@SMPA)-online solid-phase extraction method, coupled with high-performance liquid chromatography (online SPE-HPLC) was established for the analysis of six plant growth regulators (PGRs) in bean sprouts. NH2@SMPA was synthesized by acid-catalyzed deacetylation of acetylamino-Scholl-coupling mesoporous polymer (SMPA). The diversity of functional groups, such as aromatic, acetylamino, and NH2, was conducive to multiple binding interactions between NH2@SMPA and PGRs. NH2@SMPA exhibited superior extraction capability for PGRs, compared with SMPA and commercial adsorbents. The extraction conditions, including loading solvent, pH of loading solution, eluting solvent, and flow rates of loading and elution, were optimized. Under the optimized conditions, wide linear ranges (0.01–500 μg kg−1) and low detection limits (2.34–20.2 ng kg−1) were obtained. The recoveries were satisfactory, i.e., 86.0% to 109% with relative standard deviations ≤9.8% (n = 3). Finally, the online SPE-HPLC method was successfully used for determination of PGRs in bean sprouts.

Beyond carbon capture towards resource recovery and utilization: fluidized-bed homogeneous granulation of calcium carbonate from captured CO2

Atmospheric carbon dioxide (CO2) imbalance due to anthropogenic emissions has direct impact in climate change. Recent advancements in the mitigation of industrial CO2 emissions have been brought about by a paradigm shift from mere CO2 capture onto various adsorbents to CO2 conversion into high value products. The present study proposes a system which involves the conversion of CO2 into high purity, low moisture, compact and large CaCO3 solids through homogeneous granulation in a fluidized-bed reactor (FBR). In the present study, synthetic solutions of potassium carbonate (K2CO3) and calcium hydroxide (Ca(OH)2) were used as sources of carbonate and precipitant, respectively. The effects of the degree of supersaturation (S) as chemical loading and influx flow rate (QT) as hydraulic loading on CaCO3 granulation efficiency were investigated. In the study, S was varied from 10.2 to 10.8 and QT from 40 to 80 mL min−1 while the operating pH and calcium-is-to-carbonate molar ratio ([Ca2+]/[CO32−]) were set at 10 ± 0.2 and 1.50, respectively. Results showed that carbonate ions end product distribution had a highest carbonate granulation efficiency at [Carbonate]G of 95–96% using S of 10.6 and QT of 60 mL min−1. Characterization of the granules confirmed high purity calcium carbonate. Overall, the transformation of industrial CO2 emissions into a valuable solid product can be a significant move towards the mitigation of climate change from anthropogenic emissions.

Ionic imprinted polymer solid-phase extraction for inorganic arsenic selective pre-concentration in fishery products before high-performance liquid chromatography – inductively coupled plasma-mass spectrometry speciation

Low levels of inorganic arsenic [As(III) and As(V)] in fishery products have been selectively isolated from fish extracts (1.0 g of wet fish samples pre-treated with 10 mL of 1:1 methanol/water under sonication at 25 °C for 30 min) by ionic imprinted polymer (IIPs) based solid phase extraction procedure (on-column mode). The selective adsorbent was synthesized using sodium (meta) arsenite as a template, 1-vinyl imidazole as a functional monomer, divinylbenzene as a cross-linker, and 2,2′-azobisisobutyronitrile as an initiator. Optimized pre-concentration conditions imply fish extract (10 mL) pH adjustment at 8.5 before loading (flow rate of 0.25 mL min−1), and elution with ultrapure water (2 mL) at 0.50 mL min−1. A pre-concentration factor of 50 was finally obtained after evaporation to dryness (N2 stream) and re-dissolution in 0.2 mL of ultrapure water before HPLC-ICP-MS. Synthesized material was found to pre-concentrate inorganic arsenic species; whereas organic arsenic compounds, mainly arsenobetaine (the major organoarsenic compound in fish/seafood products), were not found to interact with the adsorbent. The developed selective method gave limits of quantification of 1.05 and 1.31 µg kg−1 for As (III) and As (V), respectively, and good precision [relative standard deviations lower than 12% in fish extracts spiked at several As (III) and As (V) levels]. The proposed method was finally applied to the selective determination of As (III) and As (V) species in several fishery products.

Detection of trace metal ions in high-purity boric acid by online two-dimensional valve switching coupled with ion chromatography-inductively coupled plasma mass spectrometry

In this paper, a two-dimensional valve switching technique was established to detect 10 trace metal ions in high-purity boric acid by ion chromatography-inductively coupled plasma mass spectrometry (IC-ICPMS). The system consisted of a quantitative loop, a matrix capture column, an iminodiacetic acid cationic chelating column, an ion chromatography column, two sample valves and an inductively coupled plasma mass spectrometer. The iminodiacetic acid cationic chelating column coupled the metal ions in the sample with its carboxyl functional groups to separate them from the matrix boric acid solution, and then eluted the chelated metal ions into the ion chromatographic column and inductively coupled plasma mass spectrometer. The proposed method feasibly achieved an online, rapid and efficient detection of 10 trace ions in high-purity boric acid with the optimized experimental conditions (1.0 mol/L HNO3), such as loading solution, loading flow rate, type of eluent, concentration of the eluent, sample matrix, etc. The experimental data showed that this method had good linearity in the range of 0.01–2.0 μg/L for 10 metal ions, such as Cr, Fe, Ni, Co, V, Mn, Cu, Zn, Cd and Pb in high-purity boric acid samples, with a correlation coefficient greater than 0.998. The limit of detection (LOD, S/N = 3) and the limit of quantitation (LOQ, S/N = 10) were 0.001–0.023 μg/L and 0.003–0.077 μg/L, respectively. The relative standard deviation (RSD) of each element was less than 3.0% (n = 6) and the spiked recoveries ranged between 83% and 110%. This method could be proposed to be suitable for determination of trace metal ions in real samples.

Continuous Saturated Steam Assisted Low‐temperature Pyrolysis of Corncobs and Selective Production of Furfural

AbstractA facile and selective furfural production technology was introduced by using corncobs as raw materials under saturated steam atmosphere in a fixed bed reactor. It was found that Al2(SO4)3 catalyst has showed a good selective performance with furfural selectivity 64.2% (15.8 wt%). The optimal conditions were pyrolysis temperature 230 °C, steam flow 10 g/min (160 °C) and catalyst loading 7.5 mmol. The reaction parameters such as pyrolysis temperature, catalyst loading and steam flow rate all displayed a positive effect on both corncob conversion and furfural selectivity.The higher steam flow displayed a positive effect on furfural dissolving and products desorption. Removal degree of hemicellulose on each catalytic condition analysis indicated that hemicellulose depolymerization was mainly promoted by lower temperature pyrolysis, and furfural selected production was mainly affected by catalytic effect. This technology provided a low‐cost and low‐temperature catalytic reaction to synthesize furfural, which shows a great potential in industrial production.

Hybrid ionic liquid-3D graphene-Ni foam for on-line preconcentration and separation of Hg species in water with atomic fluorescence spectrometry detection

A preconcentration method based on a novel hybrid sorption nanomaterial consisting in a 3D graphene-Ni foam functionalized with an ionic liquid (IL) was developed for Hg species determination. The capability of different phosphonium-ionic liquids (PILs) to functionalize the hybrid material and form ion-pairs with Hg(II) chlorocomplex was evaluated. A comparative study with PILs containing the trihexyl(tetradecyl)phosphonium cation but different anions (dicyanamide and decanoate) and trihexyl(tetradecyl)phosphonium chloride was performed. Inorganic Hg (InHg) species was selectively retained forming a chlorocomplex (HgCl42−) followed by its retention in a column filled with the IL-3D graphene-Ni foam material implemented in an on-line micro solid phase extraction system (μSPE). The elution of Hg from the column was performed with SnCl2, which was also used as reducing agent for subsequent detection by cold vapor generation atomic fluorescence spectrometry (CV-AFS). Organic mercury species (OrgHg) were not retained on the sorption material of the column. The effect of several parameters determining the efficiency of the preconcentration and detection system (sample loading and elution flow rate, sample volume, instrumental conditions, etc.) was investigated. A sensitivity enhancement factor (EF) of 180 was achieved for InHg. The detection limit obtained after the preconcentration of 100 mL of sample was 3.6 ng L−1 of InHg. The relative standard deviation (RSD) was 4.1% (at 1 μg L−1 InHg and n = 10) calculated from the peak height of the absorbance signals (Gaussian form and reproducible peaks). This work reports the first application of the IL-3D graphene-Ni foam in an on-line μSPE preconcentration system for the speciation analysis of Hg in mineral, tap, and river water samples.

An efficient procedure for preparing high-purity pingyangmycin and boanmycin from Streptomyces verticillus var. pingyangensis fermentation broth via macroporous cation-exchange resin and subsequent reversed-phase preparative chromatography

Pingyangmycin (PYM) and boanmycin (BAM), two individual components of bleomycin (bleomycin A5 and bleomycin A6), are glycopeptide antitumor antibiotics. An efficient procedure for the preparation of PYM and BAM from Streptomyces verticillus var. pingyangensis fermentation broth using macroporous cation-exchange (MCE) resin followed by medium-pressure preparative liquid chromatography (MPLC) based on monodisperse poly(styrene-co-divinylbenzene) (p(st-dvb)) microspheres was investigated in this paper. Nine frequently used MCE resins were screened by static adsorption and desorption to enrich PYM and BAM fromthe fermentation broth, and D157 resin was found to be the most effective. After one run of column-based dynamic adsorption and desorption, the contents of PYM and BAM were increased by factors of 13.8 and 12.1 with recovery yields of 84.21% and 81.47%, respectively. The enriched samples were subjected to MPLC with columns prepacked with the PolyRP 10-300 microspheres. The operational parameters of the MPLC, including the stationary phase and mobile phase compositions, sample/stationary phase ratio, sample loading scale and flow rate, were screened and optimized. The results showed that the separation and purification for PYM and BAM by MPLC were dramatically improved with a mobile phase modifier of 0.15 mol/L ammonium chloride aqueoussolution, a flow rate of 10 mL/min and a sample/stationary phase ratio of 1.0:100 (m/v, g/mL), and PYM and BAM with purities of more than 98.65% and 99.12% were obtained, respectively. The total recoveries of PYM and BAM reached 75.38% and 70.31%. The separation and purification method is simple, efficient, energy-saving, environmentally friendly and suitable for the large-scale preparation of high-purity PYM and BAM from Streptomyces verticillus var. pingyangensis fermentation broth.