Amount Of Glutaraldehyde Research Articles

Study on the preparation of a novel acrylic modified magnetic chitosan adsorbent and the adsorption behavior on Ga (III)

In the current study, a novel acrylic modified magnetic chitosan adsorbent (M- AA −CTS) was prepared, and then characterized using SEM, FTIR, and XPS. The preparation conditions, adsorption conditions, adsorption kinetics and thermodynamics were also studied. FTIR results indicate that acrylic acid is grafted onto the amino groups of chitosan in the form of poly acrylic acid and the amino groups are also crosslinked with glutaraldehyde. For the preparation process, the removal efficiency of Ga (III) ions is higher when the amount of acrylic acid is 3 mL, the reaction temperature is 308 K, the crosslinking time is 80 min, and the amount of glutaraldehyde is 0.6 mL. During the adsorption process, the higher adsorption capacity of Ga (III) ions can be achieved under the condition of the initial concentration of Ga (III) ions 50 mg/L, the adsorbent dose 0.05 g, the oscillation temperature 308 K and pH 3. The study on the adsorption kinetic indicates that the adsorption follows the pseudo-second-order kinetic model. The study on isotherm adsorption and thermodynamic indicates that the adsorption isotherm fits the Langmuir isotherm model better and the saturated adsorption capacity of Ga (III) ions on M−CTS−AA can reach 183.09 mg/g. Study on desorption and regeneration shows that after four cycles of desorption and reuse, the regeneration rate decreased from the initial 91.47 % to 73.3 %.

Cellulase entrapment into alginate-PEG beads cross-linked with glutaraldehyde: Optimization of the immobilization conditions and kinetic characterization of the immobilized enzyme

Immobilization methods for cellulase entrapped into alginate beads with glutaraldehyde (GA) cross-linking were investigated. Cellulase entrapped into alginate-polyethylene glycol beads with glutaraldehyde cross-linking (SA-PEG-E) showed more superiority both in terms of catalytic performance and reusability than other methods. Several conditions during SA-PEG-E immobilization such as cellulase concentration, GA amount, pH of immobilization, cross-linking time and hardening temperature were evaluated to study their effect on immobilized enzyme activity, immobilization yield and immobilization efficiency. Based on the results, GA amount, pH of immobilization and hardening temperature were selected for process optimization of SA-PEG-E using the Box-Behnken design of response surface methodology. The results showed that the optimum immobilized conditions were obtained with a GA amount of 0.8 mL, pH of immobilization 4.7, and hardening temperature of 47.5 °C when the cellulase concentration was 7.5 mg/mL and cross-linking time was 2 h. Then, the characterization of SA-PEG-E was studied. The optimum pH of SA-PEG-E was observed to be 4, 1 unit lower than that of the free enzyme (pH 5). The optimum temperature was the same for both free and immobilized cellulase at 50 °C. In addition, the SA-PEG-E exhibited broad pH and temperature adaptability.

Ultra-fast fabrication of MXene/PVA composite films through glutaraldehyde induced microgel framework

In this study, Ti3C2Tx/PVA microgels were assembled through the introduction of glutaraldehyde and PVA into Ti3C2Tx colloids. Subsequently, the microgels underwent vacuum-assisted filtration (VAF) and drying processes to fabricate Ti3C2Tx/PVA self-assembled films (MPGF). This research effectively reduced VAF time by introducing a small amount of glutaraldehyde. The findings demonstrate that glutaraldehyde's chemical crosslinking prompts the formation of temporary microgel frameworks between Ti3C2Tx and PVA, enhancing water molecule transfer during VAF and improving film formation efficiency. Further analysis links VAF time is related to the particle size distribution of the microgels. Adjusting crosslinking and PVA quantity alters microgel crystalline structure and –OH hydrogen bonds, affecting particle size and VAF time. Additionally, films produced via rapid VAF exhibit promising mechanical properties for practical applications.

Sodium alginate/ diatom -based blotting hydrogel material for Pb(II) removal: Effect of crosslinker optimization on its composition, selectivity, and desorption rate

In this study, we report a novel adsorption material (SAD-IIP), which is used for the directional adsorption of Pb (II), the polymerization time, the amount of crosslinking agent and the crosslinking time were optimized by response surface design, and the effect of the amount of crosslinking agent on the adsorption of lead on SAD-IIP was analyzed. The numerical control of cross-linking agent directly determines the number of effective imprinting sites, which affects the orientation selectivity of target ions and the desorption rate of the adsorbent. The results showed that the best adsorption performance was obtained when the polymerization temperature was 59.14 ° C, the amount of glutaraldehyde was 1.20 ml, and the crosslinking time was 92.55 min. The adsorption amount and imprinting factor were 244.09 mg/G and 9.90, respectively, the self-polymerization and self-crosslinking of the adsorbent in the imprinting process are effectively avoided. The adsorption mechanism of SAD-IIP is ion exchange with Ca2+ and chelation coordination of sulfhydryl, hydroxy, carboxyl with lead ion. After 10 cycles, the removal rate of Pb (II) and desorption rate of SAD-IIP were 92.75% and 70.43%, respectively. These results indicate that the rational control of the introduction conditions of cross-linking agent is of theoretical and practical value for the preparation of new hydrogel imprinting materials for selective adsorption of target ions and efficient recovery of Pb (II).

Agar Graft Modification with Acrylic and Methacrylic Acid for the Preparation of pH-Sensitive Nanogels for 5-Fluorouracil Delivery.

Agar, a naturally occurring polysaccharide, has been modified by grafting it with acrylic (AcA) and methacrylic (McA) acid monomers, resulting in acrylic or methacrylic acid grafted polymer (AA-g-AcA or AA-g-McA) with pH-sensitive swelling behavior. Different ratios between agar, monomers, and initiator were applied. The synthesized grades of both new polymer series were characterized using FTIR spectroscopy, NMR, TGA, DSC, and XRD to ascertain the intended grafting. The percentage of grafting (% G), grafting efficiency (% GE), and % conversion (% C) were calculated, and models with optimal characteristics were further characterized. The swelling behavior of the newly synthesized polymers was studied over time and in solutions with different pH. These polymers were subsequently crosslinked with varying amounts of glutaraldehyde to obtain 5-fluorouracil-loaded nanogels. The optimal ratios of polymer, drug, and crosslinker resulted in nearly 80% loading efficiency. The performed physicochemical characterization (TEM and DLS) showed spherical nanogels with nanometer sizes (105.7-250 nm), negative zeta potentials, and narrow size distributions. According to FTIR analysis, 5-fluorouracil was physically incorporated. The swelling and release behavior of the prepared nanogels was pH-sensitive, favoring the delivery of the chemotherapeutic to tumor cells. The biocompatibility of the proposed nanocarrier was proven using an in vitro hemolysis assay.

Synthesis and characterization of chitosan/polyvinylpyrrolidone hydrogels for controlled amoxicillin release

Hybrid crosslinked hydrogel-based drug delivery systems can deliver therapeutically beneficial drug release effects through controlled release on a temporal and spatial scale. Due to their tuneable physicochemical properties and the ability to prevent drug degradation, these systems facilitate different physicochemical interactions that control drug release. This research aims to synthesize a potent pH-sensitive crosslinked chitosan/polyvinylpyrrolidone hydrogel using different ratios of both the polymers and varying the glutaraldehyde crosslinking agent amount by the solution casting technique for controlled amoxicillin-release properties to mitigate gastrointestinal tract bacterial infection. The effect of polymer ratios and glutaraldehyde amount is investigated by the developing porosity, gel fraction, and extent of swelling in simulated physiological fluids of pH 1.2, 6.8, and 7.4 and in vitro biodegradation at pH 7.4. Interaction between the polymers with the formation of crosslinked structures, good stability, amorphous phase nature, and honeycomb-like structures of the hydrogels is revealed by Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Based on these properties, a chitosan/polyvinylpyrrolidone hydrogel (ratio of 60:40) crosslinked with 600 μL glutaraldehyde in 8 g of the polymers displaying adequate swelling in acidic to basic pH and in vitro biodegradation at pH 7.4 is chosen for the in situ loading of 200 mg of the drug amoxicillin. The cumulative drug release in simulated physiological fluids and the drug release kinetics using different models show that the best-fit Korsmeyer-Peppas model suggests amoxicillin release from the matrix follows diffusion and swelling-controlled time-dependent non-Fickian transport related to hydrogel erosion. This composition displays excellent antimicrobial activity against Streptococcus pyogenes and Escherichia coli.

Encapsulation of Rice Bran Oil (RBO) by Complex Coacervation Using Glutaraldehyde as Crosslinking Agent

<p><strong>Abstract.</strong> Rice bran is a significant by-product of the processing of rice, and rice bran oil (RBO) can be extracted from it to provide a very valuable product. It has a high smoke point but is less stable in the heating process. Further research is carried out to increase the stability of Rice Bran Oil in its utilization. Many environmentally friendly methods are being developed in storing and packaging food, including the application of microencapsulation. This study aims to determine the effect of the use of glutaraldehyde crosslinking agent on rice bran oil microencapsulation by utilizing the natural polymers of kappa carrageenan, glucomannan, and chitosan as encapsulants using the coacervation method. Microcapsules were analyzed for their encapsulation efficiency and yield and were characterized using Fourier Transform Infrared Spectrophotometer (FTIR), Scanning Electron Microscope (SEM), and Particle Size Analyzer (PSA). Results show that increasing the amount of glutaraldehyde tends to increase the yield and efficiency of encapsulation. A yield of 49.20% was obtained by adding 1 mL of glutaraldehyde with an encapsulation efficiency of 48.22%. All samples have irregular shapes and the surfaces were rough and folded. FTIR spectra show that all samples indicated the presence of RBO as well as other polymers used in the research: carrageenan, chitosan, and glucomannan. The results of PSA show that particles are in micron size except for the addition of 1 mL glutaraldehyde.</p><p><strong>Keywords:</strong></p><p align="left">Rice Bran Oil. Glutaraldehyde, Complex Coacervation</p><p><strong><br /></strong></p>

Ag-lignin hybrid nanoparticles for high-performance solar absorption in photothermal antibacterial chitosan films

There is an urgent need for antimicrobial films based on sustainable resources and production methods. In this study, we present a bio-based nanocomposite film composed of chitosan (∼60 wt%), lignin nanoparticles (LNPs, ∼40 wt%), a small amount of glutaraldehyde (1.5 wt%), and a trace level of silver nanoparticles (AgNPs, 0.072 wt%). The uniform dispersion with LNPs prevented aggregation of metallic silver, resulting in small (diameter 3.3nm) AgNPs. The nanocomposite film absorbs 89% of radiation across the entire solar spectrum and exhibits a remarkable photothermally triggered antibacterial effect, which is further enhanced by the dark color of lignin. Under simulated solar light illumination, the nanocomposite films demonstrated a significant reduction in viable Escherichia coli count compared to control scenarios. The potential applications of these nanocomposites extend to sunlight-activated antimicrobial films and coatings, addressing the growing demand for sustainable and effective antimicrobial materials.

Hydrolysable Chestnut Tannin Extract Chemical Complexity in Its Reactions for Non-Isocyanate Polyurethanes (NIPU) Foams

Non-isocyanate polyurethane (NIPU) foams from a commercial hydrolysable tannin extract, chestnut wood tannin extract, have been prepared to determine what chemical species and products are taking part in the reactions involved. This method is based on two main steps: the reaction with dimethyl carbonate and the formation of urethane bonds by further reaction of the carbonated tannin with a diamine-like hexamethylene diamine. The hydroxyl groups on the tannin polyphenols and on the carbohydrates intimately linked with it and part of a hydrolysable tannin are the groups involved in these reactions. The carbohydrate skeleton of the hydrolysable tannin is also able to participate through its hydroxyl groups to the same two reactions rendering the whole molecular complex able to react to form NIPUs. The analysis by Matrix-Assisted Laser Desorption Ionization (MALDI-TOF) mass spectrometry and 13C Nuclear Magnetic Resonance (13C NMR) to further investigate the reaction mechanisms involved revealed the unsuspected complexity of chestnut hydrolysable tannin, with different fragments reacting in different manners forming a hardened network of considerable complexity. As the morphology and performance of these types of foams changes slightly with the change in the amount of glutaraldehyde and hexamine hardeners, the best performing foam formulation previously determined was scanned by SEM and analysed chemically for the structures formed.

Glutaraldehyde Crosslinked High Content of Amylose/Polyvinyl Alcohol Blend Films with Potent Tensile Strength and Young's Modulus.

In recent years, with the development of green environmental protection, starch film has become of interest due to the wide availability of sources, low price, and biodegradability. Amylose/polyvinyl alcohol (PVA) blend films crosslinked with different amounts of glutaraldehyde (GLU) were prepared by a solution casting method. The cross-linking degree, water sorption, tensile property, crystallization and section morphology of the films were examined. With the increase in glutaraldehyde concentration, the cross-linking degree of the blend film was improved. The wide-angle X-ray scattering (WAXS) result indicated that cross-linking hindered the crystallization of film. The section morphology of films was examined by scanning electron microscope (SEM). The results showed that the cross-linking degree of amylose film improved while the crystallinity decreased with the increase in glutaraldehyde content. Cross-linking had no obvious effect on the water sorption property of the blend films. The cross-linking modification significantly enhanced the tensile strength and Young's modulus, while it reduced the elongation at break of the blend films. It was found that the film with 0.5 wt % glutaraldehyde possessed the best performance: the tensile strength increased by 115%, while the elongation at break decreased by 18% even at high relative humidity (RH) of 90% compared to non-crosslinked films. The developed amylose/PVA blend films have promising application prospects as agricultural mulch films and packaging materials.

Effect of hydrogen bond interaction in precursor on photocatalytic oxidation of MB by C-GA/g-C3N4 composites

It is well known that the design of precursor structure is an effective method to optimize the photocatalytic activity of g-C3N4, and it will be interesting to investigate the relationship between the precursor structure and the structure of the target catalyst. In this paper, by adjusting the addition amount of glutaraldehyde (GA), three kinds of glutaraldehyde/dicyandiamide (GA/DCDA) precursors with equilibrium/imbalance hydrogen bond interaction can be obtained, and the carbonized glutaraldehyde (C-GA)/g-C3N4 composite catalysts with different carbon content can be obtained after calcination. The obtained C-GA/g-C3N4 composite catalysts have different photocatalytic activity for methylene blue degradation. Compared with the original g-C3N4, the photocatalytic activity of C-GA/g-C3N4-2 composite is increased by 2.69 times. Through the analysis of thermal decomposition kinetics and structural characterization, we can see that the equilibrium interaction in the structure of GA/DCDA-2 precursor can promote the conversion of dicyandiamide to melamine, and glutaraldehyde carbonization will form more C-GA, and form a composite catalyst with closer interaction with g-C3N4. C-GA with close interaction and higher content can effectively promote the separation of photogenerated carriers and visible light absorption, thus improving its photocatalytic activity.

The Effect of Application of Chicken Gelatin on Reducing the Weight Loss of Beef Sirloin after Thawing.

Freezing is one of the oldest and most-often-used traditional methods to prolong the shelf life of meat. However, the negative phenomenon of this process is the weight loss of water that occurs after the meat is thawed. Together with the water that escapes from the meat during thawing, there are large weight losses in this valuable raw material. Another negative aspect is that mineral and extractive substances, vitamins, etc. also leave the meat, resulting in irreversible nutritional losses of nutrients in the meat, which are subsequently missing for use by the consumer of the meat. The main goal of this work is to reduce these losses by using gelatin coatings. Gelatin was prepared from chicken paws according to a patented biotechnological procedure, which uses the very gentle principle of obtaining gelatin with the usage of enzymes. This unique method is friendly to the environment and innocuous for the product itself. At the same time, it ensures that the required principles achieve a circular economy with the use of the so far very-little-used slaughter byproducts, which in most parts of the world end up in uneconomic disposal by burning or landfilling without using this unique potential source of nutrients. Gelatin coatings on the surface of the beef steak were created by immersing the meat in a solution based on gelatin of different composition. A coating containing 3%, 5% or 8% gelatin with 10% or 20% glycerol (by weight of gelatin) and 1% glutaraldehyde crosslinker (by weight of gelatin) has proved to be effective. The amount of glutaraldehyde added to the coating is guaranteed not to exceed the permitted EU/U.S. legislative limits. In addition to weight loss, meat pH, color and texture were also measured. Freezing was done in two ways; some samples were frozen at a normal freezing temperature of −18 °C and the other part of the experiment at deep (shock) freezing at −80 °C. Defrosting took place in two ways, in the refrigerator and in the microwave oven, in order to use the common defrosting methods used in gastronomy. A positive effect of this coating on weight loss was observed for each group of samples. The most pronounced effect of coating was found for the least gentle method of freezing (−18 °C) and thawing (microwave), with the average weight loss of the coated samples differing by more than 2% from that of the uncoated sample. No negative effect of the coating was observed for other meat properties tested, such as pH, Warner-Bratzler Shear Force (WBSF) or color. Gelatin-based coating has a positive effect on reducing the weight loss of meat after thawing. Chicken gelatin prepared by a biotechnological process has a new application in improving the quality of meat due to the retention of water and nutrients in frozen and subsequently thawed beef, which can contribute to the better quality of the subsequently gastronomically prepared dish, while maintaining the weight and nutritional quality. This also results in economic savings in the preparation of highly-valued parts of beef.

Chemical bonds in precursors regulate g-C3N4 structure and its photocatalytic performance

It is well known that the enhanced photocatalytic performance of graphite-type carbon nitride (g-C3N4) will be limited by its microstructure, including its precursor structure, and the relationship between the precursor structure and the target catalyst structure will be an interesting question. Glutaraldehyde (GA) containing aldehyde group was introduced into melamine (MA) to form three GA/MA precursors connected by CN chemical bond, which cause the calcined composite catalysts of g-C3N4 and C with closer lamellar structure along with the increase of the amount of glutaraldehyde added. The study found that the CN chemical bond limits the conversion of melamine to melem by thermal decomposition kinetics analysis, which leads to the formation of the tighter interactions by carbonization. The resulting structure has more efficient photocatalytic performance than pure g-C3N4.

Ultralong phosphorescence cellulose with excellent anti-bacterial, water-resistant and ease-to-process performance

Herein, we present a phosphorescent cationized cellulose derivative by simply introducing ionic structures, including cyanomethylimidazolium cations and chloride anions, into cellulose chains. The imidazolium cations with the cyano group and nitrogen element promote intersystem crossing. The cyano-containing cations, chloride anions and hydroxyl groups of cellulose form multiple hydrogen bonding interactions and electrostatic attraction interactions, effectively inhibiting the non-radiative transitions. The resultant cellulose-based RTP material is easily processed into phosphorescent films, fibers, coatings and patterns by using eco-friendly aqueous solution processing strategies. Furthermore, after we construct a cross-linking structure by adding a small amount of glutaraldehyde as the cross-linking agent, the as-fabricated phosphorescent patterns exhibit excellent antibacterial properties and water resistance. Therefore, considering the outstanding biodegradability and sustainability of cellulose materials, cellulose-based easy-to-process RTP materials can act as antibacterial, water-resistant, and eco-friendly phosphorescent patterns, coatings and bulk materials, which have enormous potential in advanced anti-counterfeiting, information encryption, disposable smart labels, etc.

Study of Protective Layers Based on Crosslinked Glutaraldehyde/3-aminopropyltriethoxysilane.

In this paper, we report the synthesis and characterization of novel coatings based on (3-aminopropyl)-triethoxysilane (AP) mixed with different amounts of glutaraldehyde (GA). The synthesized coatings have been layered on a glass substrate and characterized by optical microscopy and roughness measurements, thermogravimetric analyses and differential scanning calorimetry, contact angle analysis, rheological measurement, and an adhesion test. It was observed that the higher the GA content (up to AP:GA ratio of 0.3), the sooner the crosslinking reaction starts, leading to a coating with increased hydrophobic and adhesion features without compromising the final AP cross-linked network. Hence, the obtained results show the effectiveness of AP modification with GA from the perspective of an application as protective coatings.

Characterization and Properties of Biodegradable Thermoplastic Arrowroot Starch Crosslinked by Glutaraldehyde Processed by Compression Molding Technique

Although starch is available and biodegradable, hydrophilicity and mechanical properties are still main disadvantages for many applications. In this study, arrowroot starch, a perennial herb found in tropical climates and extracted from the tubers of the arrowroot plant was used. The arrowroot starch was chemically modified by crosslinking with different amounts of glutaraldehyde in order to overcome the starch disadvantages. The crosslinked starch was then prepared as thermoplastic starch by plasticizing with glycerol, compounding in an internal mixer and finally shaping in a compression molding machine. An increase of gel fraction and decrease of swelling as well as the moisture uptake of different thermoplastic crosslinked arrowroot starch samples were observed, all of which indicated a crosslinking reaction of glutaraldehyde with the starch molecules. The thermal degradation temperature of thermoplastic crosslinked arrowroot starch, determined from thermogravimetric analysis technique, increased when compared with thermoplastic arrowroot starch. The extensibility of the thermoplastic crosslinked arrowroot starch also improved via glutaraldehyde crosslinking. Higher content of glutaraldehyde also caused lower swelling and moisture uptake including higher gel fraction and extensibility. Moreover, crystallinity, morphology and biodegradability were also examined.

EFFECTS OF GELATIN AND GLUTARALDEHYDE CONCENTRATIONS ON CHARACTERISTICS OF CANTIGI (Vaccinium Varingiaefolium Miq.) EXTRACT LOADED GELATIN NANOPARTICLES AS ANTIOXIDANT

Cantigi is an endemic plant of sub-alpine area of Mount Tangkuban Parahu in Bandung, Indonesia. Previous study showed ethanol extract of young red leaves had antioxidant activity, however no information on this activity if changed into nanoparticles. The purpose of this study was to determine the effects of gelatin and glutaraldehyde concentrations on the characteristics of Cantigi extract loaded gelatin nanoparticles and to evaluate the antioxidant activity of nanoparticles. Cantigi leaves were extracted by maceration using n-hexane, ethyl acetate, and ethanol 96%. The ethanol extract was dried, made into nanoparticles by varying gelatin (0.1; 0.2; and 0.3 g) and glutaraldehyde (0.1; 0.2; and 0.3 mL) amounts, and conducted at 500 rpm and 40 °C for 3 hours. Nanoparticles were evaluated for particle size, zeta potential, morphology, and antioxidant activity. Nanoparticles with glutaraldehyde amount variation had particle sizes (PS) of 105.9±26.2; 37.1±8.7; and 32.5±7.4 nm; polydispersity indeces (PI) of 0.508; 0.717; and 0.563; zeta potential values (ZPV) of 0.55; 0.89; and 0.78 mV; and antioxidant activities (IC50) of 56.15±0.16; 53.67±0.10; and 51.57±0.39 ppm, respectively. Then, nanoparticles with gelatin amounts variation had PS of 22.5±5.1; 37.1±8.7; and 83.3±21 nm; PI of 0.604; 0.717; 0.326; ZPV of 1.27; 0.89; 0.18 mV; and antioxidant activities of 51.58±0.19; 53.67±0.12; and 55.46±0.04 ppm, respectively. Nanoparticle morphology was spherical. Cantigi leaf extract can be made into gelatin nanoparticles; the smaller the concentration of the polymer used and higher the concentration of the glutaraldehyde, the smaller the resulted particle size and increased antioxidant activity. Antioxidant activities of nanoparticles was lower than those of the extract (IC50 16.84±0.30 ppm).

Gelatin-derived honeycomb like porous carbon for high mass loading supercapacitors

Using gelatin as the carbon source and glutaraldehyde as the cross linking agent, a novel honeycomb like porous carbon has been successfully prepared through simple cross linking reaction and KOH activation at high temperature. Compact and uniform honeycomb morphology has been formed in Gel/G-1.0 (Gel represents gelatin, G represents glutaraldehyde, and 1.0 represents the amount of glutaraldehyde) which brings micropores and high specific surface area (SSA). Heteroatoms including O and N have been introduced into carbon material which contribute pseudo-capacitance. Higher degree of graphitization for Gel/G-1.0 has improved the conductivity of the carbon material which exhibits good electrochemical performances under high mass loading. When the active carbon material mass loading is about 10 mg, the specific capacitance (Csp) of Gel/G-1.0 is 392 F g−1 at current density of 1 A g−1 in 2 M H2SO4, with high retention of 64% at current density of 10 A g−1. More importantly, the carbon material exhibits a high energy density of 6.39 W h kg−1 with the power density of 50.03 W kg−1, even at the power density of 502.79 W kg−1, the energy density remains 5.00 W h kg−1. This simple synthesis strategy and outstanding electrochemical performances of carbon materials with high mass loading are great significance in the application of supercapacitors.

Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application.

Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.

The synergistic effect of polyvinyl alcohol and graphene oxide on the corrosion resistance of waterborne coatings

In this study, a new type of environmentally friendly composite self-crosslinking water-based coating was systematically investigated. The results indicated that the smoothness and corrosion resistance were remarkably improved by graphene oxide (GO, used as corrosion-resistant material) and polyvinyl alcohol (PVA, used to cure waterborne epoxy resin). Appropriate amount of glutaraldehyde (GA) as cross-linking agent improved the cross-linking reaction in the curing process. Furthermore, the surface morphology was improved by crosslinking polyethylene with GA, thus reduced the occurrence of defects. GO increased the complexity of the cross-linking of the coating, enhanced the binding force between molecules, which resulted in dense and complete coating structure. The corrosion resistance was significantly improved by inhibiting corrosive media. Therefore, the degree of curing and crosslinking of the PVA-cured GO composite waterborne epoxy resin coating was enhanced by utilizing appropriate amount of GA, leading to excellent flatness and corrosion resistance (self-corrosion voltage approached 0.41 V, self-corrosion current of 0.098 μA/cm−2 and protection efficiency of 99.99%).