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The fabrication of chitosan (CH) biocomposite beads with variable copper (Cu2+) ion doping was achieved with a glutaraldehyde cross-linker (CL) through three distinct methods: (1) formation of CH beads was followed by imbibition of Cu(II) ions (CH-b-Cu) without CL; (2) cross-linking of the CH beads, followed by imbibition of Cu(II) ions (CH-b-CL-Cu); and (3) cross-linking of pristine CH, followed by bead formation with Cu(II) imbibing onto the beads (CH-CL-b-Cu). The biocomposites (CH-b-Cu, CH-b-CL-Cu, and CH-CL-b-Cu) were characterized via spectroscopy (FTIR, 13C solid NMR, XPS), SEM, TGA, equilibrium solvent swelling methods, and phosphate adsorption isotherms. The results reveal variable cross-linking and Cu(II) doping of the CH beads, in accordance with the step-wise design strategy. CH-CL-b-Cu exhibited the greatest pillaring of chitosan fibrils with greater cross-linking, along with low Cu(II) loading, reduced solvent swelling, and attenuated uptake of phosphate dianions. Equilibrium and kinetic uptake results at pH 8.5 and 295 K reveal that the non-CL Cu-imbibed beads (CH-b-Cu) display the highest affinity for phosphate (Qm = 133 ± 45 mg/g), in agreement with the highest loading of Cu(II) and enhanced water swelling. Regeneration studies demonstrated the sustainability and cost-effectiveness of Cu-imbibed chitosan beads for controlled phosphate removal, whilst maintaining over 80% regenerability across several adsorption-desorption cycles. This study offers a facile synthetic approach for controlled Cu2+ ion doping onto chitosan-based beads, enabling tailored phosphate oxyanion uptake from aqueous media by employing a sustainable polysaccharide biocomposite adsorbent for water remediation by mitigation of eutrophication.
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Over the past two decades, there has been increasing interest in the use of low-cost and effective sorbents in water treatment. Hybrid chitosan sorbents are potential materials for the adsorptive removal of phosphorus, which occurs in natural waters mainly in the form of orthophosphate(V). Even though there are numerous publications on this topic, the use of such sorbents in industrial water treatment and purification is limited and controversial. However, due to the explosive human population growth, the ever-increasing global demand for food has contributed to the consumption of phosphorus compounds and other biogenic elements (such as nitrogen, potassium, or sodium) in plant cultivation and animal husbandry. Therefore, the recovery and reuse of phosphorus compounds is an important issue to investigate for the development and maintenance of a circular economy. This paper characterizes the problem of the presence of excess phosphorus in water reservoirs and presents methods for the adsorptive removal of phosphate(V) from water matrices using chitosan composites. Additionally, we compare the impact of modifications, structure, and form of chitosan composites on the efficiency of phosphate ion removal and adsorption capacity. The state of knowledge regarding the mechanism of adsorption is detailed, and the results of research on the desorption of phosphates are described.
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Quitosana , Poluentes Químicos da Água , Purificação da Água , Humanos , Fosfatos , Quitosana/química , Águas Residuárias , Fósforo , Adsorção , Purificação da Água/métodos , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , CinéticaRESUMO
In this work, chitosan beads were used as a cost-effective platform for the covalent immobilization of unmodified single-stranded DNA, using glutaraldehyde as a cross-linking agent. The immobilized DNA capture probe was hybridized in the presence of miRNA-222 as a complementary sequence. The target was evaluated based on the electrochemical response of the released guanine, using hydrochloride acid as a hydrolysis agent. Differential pulse voltammetry technique and screen-printed electrodes modified with COOH-functionalized carbon black were used to monitor the released guanine response before and after hybridization. The functionalized carbon black provided an important signal amplification of guanine compared to the other studied nanomaterials. Under optimal conditions (6 M HCl at 65 °C for 90 min), an electrochemical-based label-free genosensor assay exhibited a linear range between 1 nM and 1 µM of miRNA-222, with a detection limit of 0.2 nM of miRNA-222. The developed sensor was successfully used to quantify miRNA-222 in a human serum sample.
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Técnicas Biossensoriais , Quitosana , MicroRNAs , Humanos , DNA de Cadeia Simples , Guanina , Hidrólise , Fuligem , Hibridização de Ácido Nucleico/métodos , Técnicas Biossensoriais/métodos , Eletrodos , Técnicas Eletroquímicas/métodosRESUMO
Natural product waste treatment and the removal of harmful dyes from water by adsorption are two of the crucial environmental issues at present. Traditional adsorbents are often not capable in removing detrimental dyes from wastewater due to their hydrophilic nature and because they form strong bonds with water molecules, and therefore they remain in the dissolved state in water. Consequently, new and effective sorbents are required to reduce the cost of wastewater treatment as well as to mitigate the health problems caused by water pollution contaminants. In this study, the adsorption behaviour of methyl orange, MO, dye on chitosan bead-like materials was investigated as a function of shaking time, contact time, adsorbent dosage, initial MO concentration, temperature and solution pH. The structural and chemical properties of chitosan bead-like materials were studied using several techniques including SEM, BET, XRD and FTIR. The adsorption process of methyl orange by chitosan bead materials was well described by the Langmuir isotherm model for the uptake capacity and followed by the pseudo-second-order kinetic model to describe the rate processes. Under the optimal conditions, the maximum removal rate (98.9%) and adsorption capacity (12.46 mg/g) of chitosan bead-like materials were higher than those of other previous reports; their removal rate for methyl orange was still up to 87.2% after three regenerative cycles. Hence, this chitosan bead-like materials are very promising materials for wastewater treatment.
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The existence of heavy metals in ecological systems poses great threats to living organisms due to their toxicant and bio-accumulating properties. Mercury is a known toxicant with notable malignant impacts. It has long been known to cause toxic threats to the health of living organisms since the break out of Minamata disease. The turbulent expulsion of mercury-based pollutants from the industrial sector, requires a proper solution. Many attempts have been made to design a greener and more efficient route for a satisfactory removal of mercury. In the current study, bismuth sulfide nanoparticles (BiSNPs) have been synthesized via the co-precipitation method. The BiSNPs were supported with crosslinked chitosan to enhance their sorption capacity and avoid leaching. The average size of the BiSNPs was 42 nm based on SEM micrographs. The SEM analysis of the bismuth sulfide chitosan-crosslinked beads (BiS-CB) showed that the beads possessed a spherical and smooth morphology with a size of 1.02 mm. The FTIR analysis showed that the beads possessed the characteristics bands of imine groups of chitosan, bismuth, sulfur, and glycosidic linkages present in the molecules. The XRD analysis confirmed the phase crystallinity of the BiS-CB with an average crystallite size of 11 nm. The BiS-CB was employed for the sorption of mercury from water samples. The maximum sorption capacity of 65.51 mg/g was achieved at optimized conditions of pH 5, concentration 80 ppm, in 45 min at 30 °C. The mechanism studied for mercury removal showed that sorption followed the complexation mechanism according to the SHAB concept. In conclusion, the results showed that the BiS-CB sorbent exhibited an excellent sorption capacity to remove mercury.
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Quitosana , Poluentes Ambientais , Mercúrio , Metais Pesados , Nanopartículas , Poluentes Químicos da Água , Adsorção , Bismuto , Quitosana/química , Concentração de Íons de Hidrogênio , Iminas , Cinética , Mercúrio/química , Rios , Sulfetos , Enxofre , Água/química , Poluentes Químicos da Água/químicaRESUMO
The photocatalytic effect of ferrous and cerium loaded catalysts produced from chitosan beads (CB) was investigated for dye removal and textile wastewater degradation. Commercially available chitosan was initially shaped into beads form and modified with ferrous and cerium compounds. The amount of ferrous and cerium loaded on the chitosan beads were calculated as 22 mg Fe/g CB, 60 mg Ce/g CB, respectively. The chemical formation and morphology of the catalysts were characterized with SEM-EDS. Photocatalytic studies with UVA irradiation were carried out using 20 mg/L Direct Orange 46 (DO46) textile dye solution, 1 g/L catalyst and 10 mM H2O2 and the dye removal efficiencies for CB, Fe/CB and Ce/CB were obtained as 10%, 60% and 26%, respectively As a result of the characterization and photocatalytic studies, the produced Fe/CB was then used for the treatment of the textile industry wastewater and while 21% total organic carbon (TOC) removal efficiency was obtained, 30, 23 and 26% color removal efficiencies were calculated for 436, 525 and 620 nm wavelengths, respectively.
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Quitosana , Poluentes Químicos da Água , Catálise , Cátions , Corantes/química , Peróxido de Hidrogênio , Indústria Têxtil , Têxteis , Raios Ultravioleta , Águas Residuárias/química , Poluentes Químicos da Água/análiseRESUMO
The unstable proteins in white wine cause haze in bottles of white wine, degrading its quality. Thaumatins and chitinases are grape pathogenesis-related (PR) proteins that remain stable during vinification but can precipitate at high temperatures after bottling. The white wine protein stabilization process can prevent haze by removing these unstable proteins. Traditionally, bentonite is used to remove these proteins; however, it is labor-intensive, generates wine losses, affects wine quality, and harms the environment. More efficient protein stabilization technologies should be based on a better understanding of the main factors and mechanisms underlying protein precipitation. This review focuses on recent developments regarding the instability and removal of white wine proteins, which could be helpful to design more economical and environmentally friendly protein stabilization methods that better preserve the products´ quality.
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Bentonita/química , Quitinases/química , Temperatura Alta , Proteínas de Plantas/química , Vitis , VinhoRESUMO
A simple protocol was proposed for the preparation of magnetic chitosan beads ZnFe2O4-CS via a co-precipitation method. The use of synthesized magnetic ZnFe2O4-CS beads as catalyst for the heterogeneous photo-Fenton treatment of chlordimeform insecticide (CDM) was evaluated. The photo-Fenton experiments were carried out with different synthesized catalysts by varying the molar ratio Zn/Fe in chitosan beads, the catalyst concentration and pH. Under optimal conditions using 1 g of ZnFe2O4-CS beads with a molar ratio Zn/Fe = 0.35 and at pHinitial = 3, a real wastewater doped with 20 mg L-1 of CDM was treated and complete removal of the insecticide was achieved after 7 min with a total TOC removal after 2 h of treatment. The generated carboxylic acids and ions during the photo-Fenton process were identified and quantified. The stability of the photocatalytic activity of the best catalyst in terms of pollutant removal, ZnFe2O4-CS(0.35) beads with a molar ratio Zn/Fe equal to 0.35, was satisfactory validated by four consecutive cycles. This optimal catalyst was characterized, before and after use, by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy, X-Ray Powder Diffraction and Vibrating Sample Magnetometry analysis.
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Quitosana , Clorfenamidina , Catálise , Peróxido de Hidrogênio , Ferro , Águas ResiduáriasRESUMO
The context of this study responds to the need for sorbent technology development to address the controlled removal of inorganic sulfate (SO42-) from saline water and the promising potential of chitosan as a carrier system for organosulfates in pharmaceutical and nutraceutical applications. This study aims to address the controlled removal of sulfate using chitosan as a sustainable biopolymer platform, where a modular synthetic approach was used for chitosan bead preparation that displays tunable sulfate uptake. The beads were prepared via phase-inversion synthesis, followed by cross-linking with glutaraldehyde, and impregnation of Ca2+ ions. The sulfate adsorption properties of the beads were studied at pH 5 and variable sulfate levels (50-1000 ppm), where beads with low cross-linking showed moderate sulfate uptake (35 mg/g), while cross-linked beads imbibed with Ca2+ had greater sulfate adsorption (140 mg/g). Bead stability, adsorption properties, and the point-of-zero charge (PZC) from 6.5 to 6.8 were found to depend on the cross-linking ratio and the presence of Ca2+. The beads were regenerated over multiple adsorption-desorption cycles to demonstrate the favorable uptake properties and bead stability. This study contributes to the development of chitosan-based adsorbent technology via a modular materials design strategy for the controlled removal of sulfate. The results of this study are relevant to diverse pharmaceutical and nutraceutical applications that range from the controlled removal of dextran sulfate from water to the controlled release of chondroitin sulfate.
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Quitosana/química , Águas Salinas/química , Sulfatos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Água/química , Adsorção , Cálcio/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Reagentes de Ligações Cruzadas/química , Glutaral/química , Concentração de Íons de Hidrogênio , Cinética , Microesferas , Espectroscopia Fotoeletrônica , TermogravimetriaRESUMO
Scaffold development for cell regeneration has increased in recent years due to the high demand for more efficient and biocompatible materials. Nanomaterials have become a critical alternative for mechanical, thermal, and antimicrobial property reinforcement in several biopolymers. In this work, four different chitosan (CS) bead formulations crosslinked with glutaraldehyde (GLA), including titanium dioxide nanoparticles (TiO2), and graphene oxide (GO) nanosheets, were prepared with potential biomedical applications in mind. The characterization of by FTIR spectroscopy, X-ray photoelectron spectroscopy (XRD), thermogravimetric analysis (TGA), energy-dispersive spectroscopy (EDS) and scanning electron microscopy (SEM), demonstrated an efficient preparation of nanocomposites, with nanoparticles well-dispersed in the polymer matrix. In vivo, subdermal implantation of the beads in Wistar rat's tissue for 90 days showed a proper and complete healing process without any allergenic response to any of the formulations. Masson's trichrome staining of the histological implanted tissues demonstrated the presence of a group of macrophage/histiocyte compatible cells, which indicates a high degree of biocompatibility of the beads. The materials were very stable under body conditions as the morphometry studies showed, but with low resorption percentages. These high stability beads could be used as biocompatible, resistant materials for long-term applications. The results presented in this study show the enormous potential of these chitosan nanocomposites in cell regeneration and biomedical applications.
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Quitosana/química , Grafite/química , Nanocompostos/química , Nanopartículas/química , Alicerces Teciduais , Titânio/química , Animais , Materiais Biocompatíveis , Sobrevivência Celular/efeitos dos fármacos , Quitosana/farmacologia , Grafite/farmacologia , Histiócitos/citologia , Histiócitos/efeitos dos fármacos , Histiócitos/fisiologia , Masculino , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura , Ratos , Ratos Wistar , Pele/citologia , Pele/efeitos dos fármacos , Engenharia Tecidual/métodos , Titânio/farmacologiaRESUMO
Maltose syrups have got wide-range utilizations in a variety of applications from bakery to drug-development. α-Amylases are among the most widely utilized industrial enzymes due to their high specificity in production of maltose syrup from starch. However, enzymes are not stable in ex vivo conditions towards alteration in pH, temperature, and such other parameters as high salt concentrations and impurities, where immobilization is required to advance the stability of the enzyme with which approach the requirement of isolation of the enzyme from media is eliminated as well. In this study, Termamyl® α-amylase was immobilized on the none-modified chitosan beads (NMCB), L-lysine-modified chitosan beads (LMCB), and L-asparagine-modified chitosan beads (AMCB) to assess effects of the support material on optimum conditions and kinetic parameters of the α-amylase activity in production of maltose from starch. Immobilization on NMCB, LMCB, and AMCB puts a strong influence on optimum pH, optimum temperature, stability, and kinetic parameters of α-amylase. Modification of chitosan beads with L-lysine and L-asparagine dramatically altered the overall immobilization yield, and enzyme's response to pH and temperature variations and the kinetic parameters. AMCB provided the best immobilization yield (49%), while LMCB only improved the yield by 2% from 22 to 24%.
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Asparagina/química , Quitosana/química , Enzimas Imobilizadas/química , Lisina/química , alfa-Amilases/química , Concentração de Íons de HidrogênioRESUMO
In this study, novel composite titanium-based metal-organic framework (MOF) beads were synthesized from titanium based metal organic framework MIL-125 and chitosan (CS) and used to remove Pb(II) from wastewater. The MIL-125-CS beads were prepared by combining the titanium-based MIL-125 MOF and chitosan using a template-free solvothermal approach under ambient conditions. The surface and elemental properties of these beads were analyzed using scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopies, as well as thermal gravimetric analysis. Moreover, a series of experiments designed to determine the influences of factors such as initial Pb(II) concentration, pH, reaction time and adsorption temperature was conducted. Notably, it was found that the adsorption of Pb(II) onto the MIL-125-CS beads reached equilibrium in 180 min to a level of 407.50 mg/g at ambient temperature. In addition, kinetic and equilibrium experiments provided data that were fit to the Langmuir isotherm model and pseudo-second-order kinetics. Furthermore, reusability tests showed that MIL-125-CS retained 85% of its Pb(II)-removal capacity after five reuse cycles. All in all, we believe that the developed MIL-125-CS beads are a promising adsorbent material for the remediation of environmental water polluted by heavy metal ions.
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Quitosana/química , Chumbo/química , Estruturas Metalorgânicas/química , Poluentes Químicos da Água/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Metais Pesados/químicaRESUMO
S-naproxen by enantioselective hydrolysis of racemic naproxen methyl ester was produced using immobilized lipase. The lipase enzyme was immobilized on chitosan beads, activated chitosan beads by glutaraldehyde, and Amberlite XAD7. In order to find an appropriate support for the hydrolysis reaction of racemic naproxen methyl ester, the conversion and enantioselectivity for all carriers were compared. In addition, effects of the volumetric ratio of two phases in different organic solvents, addition of cosolvent and surfactant, optimum pH and temperature, reusability, and inhibitory effect of methanol were investigated. The optimum volumetric ratio of two phases was defined as 3:2 of aqueous phase to organic phase. Various water miscible and water immiscible solvents were examined. Finally, isooctane was chosen as an organic solvent, while 2-ethoxyethanol was added as a cosolvent in the organic phase of the reaction mixture. The optimum reaction conditions were determined to be 35 °C, pH 7, and 24 h. Addition of Tween-80 in the organic phase increased the accessibility of immobilized enzyme to the reactant. The optimum organic phase compositions using a volumetric ratio of 2-ethoxyethanol, isooctane and Tween-80 were 3:7 and 0.1% (v/v/v), respectively. The best conversion and enantioselectivity of immobilized enzyme using chitosan beads activated by glutaraldehyde were 0.45 and 185, respectively.
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Quitosana/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Lipase/química , Lipase/metabolismo , Naproxeno/química , Naproxeno/síntese química , Candida/enzimologia , Técnicas de Química Sintética , Enzimas Imobilizadas/antagonistas & inibidores , Concentração de Íons de Hidrogênio , Hidrólise , Lipase/antagonistas & inibidores , Metanol/farmacologia , Solventes/química , Estereoisomerismo , Tensoativos/química , TemperaturaRESUMO
This research presents a feasibility study of using a continuous packed-bed reactor (PBR), containing immobilised native plant cysteine proteases, as a specific and mild alternative technique relative to the usual bentonite fining for white wine protein stabilisation. The operational parameters for a PBR containing immobilised bromelain (PBR-br) or immobilised papain (PBR-pa) were optimised using model wine fortified with synthetic substrate (Bz-Phe-Val-Arg-pNA). The effectiveness of PBR-br, both in terms of hazing potential and total protein decrease, was significantly higher than PBR-pa, in all the seven unfined, white wines used. Among the wines tested, Sauvignon Blanc, given its total protein content as well as its very high intrinsic instability, was selected as a control wine to evaluate the effect of the treatment on wine as to its soluble protein profile, phenolic composition, mineral component, and sensory properties. The treatment in a PBR containing immobilised bromelain appeared effective in decreasing both wine hazing potential and total protein amount, while it did not significantly affect the phenol compounds, the mineral component nor the sensory quality of wine. The enzymatic treatment in PBR was shown to be a specific and mild technique for use as an alternative to bentonite fining for white wine protein stabilisation.
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A recombinant, thermostable fungal chitinase from the thermophilic fungus, Thermomyces lanuginosus, was immobilized on glutaraldehyde cross-linked chitosan beads, and the properties of the immobilized chitinase were studied. The enzyme was found to be almost completely immobilized in 6 H under shaking condition at 30 °C. The immobilized enzyme exhibited much wider pH optimum and was more stable at alkaline pH values as compared with the soluble enzyme. Both the forms of the enzyme were optimally active at 60 °C and stable at 50 °C for 3 H, and after 3 H, the activity of the soluble enzyme declined sharply, whereas the immobilized chitinase was stable up to 6 H without any significant loss in the activity. KM and Vmax values of the immobilized enzyme were 1.18 mM and 445.7 µmol/Min/mg of protein, respectively. The immobilized enzyme was stable at least for 1 month at 4 °C without any significant loss in the activity.
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Ascomicetos/enzimologia , Quitinases/química , Quitosana/química , Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Estabilidade Enzimática , Temperatura Alta , Proteínas Recombinantes/químicaRESUMO
A novel chitosan-cinnamon bead carrier was prepared in this study. Chitosan was mixed with cinnamon powder (CP) and cinnamon extract (CE) to obtain chitosan-cinnamon powder (CCP) beads and chitosan-cinnamon extracted (CCE) beads, respectively. The potential antifungal and nematicidal activities of CCP and CCE were investigated against Rhizoctonia solani and Meloidogyne incognita in vitro. Relative antifungal activity of the CCP (5% CP) bead-treated R. solani was 30.9 and 23.9% after 1 and 2 day incubations, respectively. Relative antifungal activity of the CCE (0.5% CE) bead-treated R. solani was 4.3, 3.0 and 4.2% after 1, 2 and 3 days of incubation. Inhibition of hatch by CCP beads with CP of 5% was 78.8%. Inhibition of hatch by CCE beads with CE of 0.5% was 82.0%. J2 mortality following the CCP (5% CP) and CCE (0.5% CE) bead treatments was 85.0 and 95.8%, respectively against M. incognita after 48 h incubations.
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Quitosana/química , Cinnamomum zeylanicum/química , Extratos Vegetais/farmacologia , Rhizoctonia/efeitos dos fármacos , Tylenchoidea/efeitos dos fármacos , Animais , Antifúngicos/farmacologia , Antinematódeos/farmacologia , Extratos Vegetais/química , Pós/química , Pós/farmacologiaRESUMO
Covalent cross-linked hydrogels based on chitosan and poly(maleic acid-alt-vinyl acetate) were prepared as spherical beads. The structural modifications of the beads during the preparation steps (dropping in liquid nitrogen and lyophilization, thermal treatment, washing with water, and treatment with NaOH) were monitored by FT-IR spectroscopy. The hydrogel beads have a porous inner structure, as shown by SEM microscopy; moreover, they are stable in acidic and basic pH due to the covalent crosslinking. The swelling degree is strongly influenced by the pH since the beads possess ionizable amine and carboxylic groups. The binding capacity for Cu2+ ions was examined in batch mode as a function of sorbent composition, pH, contact time, and the initial concentration of Cu2+. The kinetic data were well-fitted with the pseudo-second-order kinetic, while the sorption equilibrium data were better fitted with Langmuir and Sips isotherms. The maximum equilibrium sorption capacity was higher for the beads obtained with a 3:1 molar ratio between the maleic copolymer and chitosan (142.4 mg Cu2+ g-1), compared with the beads obtained using a 1:1 molar ratio (103.7 mg Cu2+ g-1). The beads show a high degree of reusability since no notable decrease in the sorption capacity was observed after five consecutive sorption/desorption cycles.
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The aggressive search for unique materials in recent years has put forward chitosan and modified-chitosan as materials with unique structural and morphological characteristics for various important applications. Just as imidazolium-based ionic liquids are the commonly applied ionic liquids (ILs) type for chitosan modifications for various applications, their further modifications into beads for enhancing their properties is now gaining most attention. However, most of the currently prepared imidazolium ILs modified-chitosan beads are not in nano size due to preparation difficulties. In response to this and referencing the research works in the literature, the possible breakthrough directions including synthesis routes, and physical and mechanical transformation processes are proposed. These procedures are expected to provide certain theoretical and empirical basis, as well as technical guide for developing nano-micro size chitosan beads using imidazolium based ILs.
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Quitosana , Líquidos Iônicos , Líquidos Iônicos/química , Quitosana/química , Imidazóis/químicaRESUMO
This study investigates the use of chitosan hydrogel microspheres as a template for growing an extended network of MOF-type HKUST-1. Different drying methods (supercritical CO2, freeze-drying, and vacuum drying) were used to generate three-dimensional polysaccharide nanofibrils embedding MOF nanoclusters. The resulting HKUST-1@Chitosan beads exhibit uniform and stable loadings of HKUST-1 and were used for the adsorption of CO2, CH4, Xe, and Kr. The maximum adsorption capacity of CO2 was found to be 1.98 mmol·g-1 at 298 K and 1 bar, which is significantly higher than those of most MOF-based composite materials. Based on Henry's constants, thus-prepared HKUST-1@CS beads also exhibit fair selectivity for CO2 over CH4 and Xe over Kr, making them promising candidates for capture and separation applications.
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The trace amounts of human tissue cells or body fluids left at the crime scene are often mixed with inhibitors such as rust, pigments, and humic acid. The extraction of the DNA from the trace cells is crucial for the investigation of cases. Usually, specially designed magnetic nanoparticles were chosen by the case investigators to enrich and elute DNA, which was then used for polymerase chain reaction (PCR) and short tandem repeat (STR) analysis. The traditional approach often had the following problems, such as low DNA enrichment efficiency, possible DNA breakage, and complex operations. Here, the 1%(w/v) of chitosan (75% deacetylation degree) was used to modify the 50 nm magnetic nanoparticles to gain the Chitosan@Beads, which theoretically carried positively charged in the pH = 5 of lysis buffer so as to adsorb negatively charged DNA through electrostatic interactions. The XPS and FT-IR results demonstrated that chitosan was successfully attached to the surface of magnetic nanoparticles. A set of simulated samples, containing 20 mg/µL of humic acid, pigments, iron ions (Fe2+, Fe3+), and the coexistence of the above three substances, were prepared to simulate the case scene. Human bronchial epithelial cells were mixed with the 200 µL of the above simulated samples for DNA extraction. 400 µL of lysis buffer, 20 µL of proteinase K (10 mg/mL) and 20 µL of Chitosan@Beads solution (20 mg/mL) was used for cell disruption and DNA enrichment. The extraction sensitivity of Chitosan@Beads was confirmed to be 10 cells, superior to commercial reagent kits. The Chitosan@Beads@DNA can directly use for "In-situ PCR" with elution-free operations. The STR loci rate of DNA extracted by Chitosan@Beads was around 97.9%, higher than the commercial kit (66.7%). In short, we foresee here developed novel Chitosan@Beads and modified lysis buffer could provide a new model for the DNA extraction of forensic trace evidence.