One-pot synthesis of a hierarchical microporous-mesoporous phosphotungstic acid-HKUST-1 catalyst and its application in the selective oxidation of cyclopentene to glutaraldehyde

A hierarchical microporous-mesoporous metal-organic framework of HKUST-l（Cu）-encapsulated phosphotungstic acid （HPW） material, referred to as HPWs@Meso-HKUST-1, is prepared by a one-pot synthesis method using cetyltrimethylammonium bromide as the supramolecular template. The addition of HPWs to the synthesis mixture of hierarchical porous HKUST-1 results in the direct encapsulation of HPWs inside the mesopores of the HKUST-1 structure, with a homogeneous distribution over the HKUST-1 crystals, which is confirmed by XRD, FT-IR, N2 adsorption, UV-Vis DRS, and TEM. FT-IR-CO adsorption experiments indicated that additional Lewis acid sites were present in the HPWs@Meso-HKUST-1 sample. The novel heterogeneous catalyst demonstrates excellent catalytic performance for the selective oxidation of cyclopentene （CPE） to glutaraldehyde CGA） using tert-butyl hydroperoxide and acetonitrile （MeCN） as the oxidant and solvent, respectively. The high activity of the catalyst is attributed to the mesostructure of the catalyst and the nature and appropriate abundance of the HPWs--being highly dispersed with the addition of Lewis sites. After a reaction for 36 h, the 30% wt% HPWs@Meso-HKUST-1 catalyst exhibits a CPE conversion of 92.5% and a high GA yield of 73%. Furthermore, the HPWs@Meso-HKUST-1 material is sufficiently stable to prevent the leaching of HPWs, and behaves as a true heterogeneous catalyst that can be repeatedly recycled without sustaining a loss of activity and selectivity in the selective oxidation of CPE.

Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads

The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.700, respectively. The optimum conditions of immobilization were 100 of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60 ℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant Km was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 4000 of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 4600 of its initial activity even after 35 d.

Characterization of Tungsten-Based Catalyst Used for Selective Oxidation of Cyclopentene to Glutaraldehyde

Tungsten-containing hexagonal mesoporous silica （W-HMS） supported tungsten oxide catalysts （WOx/W-HMS） was prepared for the selective oxidation of cyclopentene with aqueous hydrogen peroxide to glutaraldehyde. X-ray diffraction （XRD） results indicated that the crystal form of the active phase （tungsten oxide） of the WOx/W-HMS catalysts was dependent on the W loading and calcination temperature. X-ray photoelectron spec- troscopy （XPS） analysis revealed that the dispersed tungsten oxides on the surface of W-HMS support consisted of a mixture of W（V） and W（VI）. It was found that a high content of amorphous W species in （5＋） oxidation state resuited in the high catalytic activity. When the W loading was up to 12% （by mass） or the catalyst precursor was treated at temperature of 623 K, the catalytic activity decreased due to the presence of WO3 crystallites and the oxidation of W（V） to W（VI） on the catalyst surface. Furthermore, NH3-temperature-programmed-desorption （NH3-TPD） analysis showed that the effects of W loading and calcination temperature on the acidity of the catalysts were related to the catalytic activity. A high selectivity of 80.2% for glutaraldehyde with a complete conversion of cyclopentene was obtained over 8%WOx/W-HMS catalyst calcined at 573 K after 14 h of reaction.

Coating performance on glutaraldehyde-modified wood

Scots pine(Pinus sylvestris L.) panels were modified with glutaraldehyde(GA) to various weight percent gains and subsequently coated with several commercial coatings. The drying rate and adhesion of the coatings on the modified wood were measured; the coated/modified woods were exposed outdoors to analyze how the wood modifications influence the coating deterioration. The results showed that GA modification caused an increase in the drying rate of the waterborne coatings, but had no influence on drying of tested solvent-borne coatings. GAmodification did not change the dry adhesion but reduced the wood strength in a pull-off test. Wet adhesion of waterborne coatings was improved, while that of the solvent-borne coatings tended to be somewhat reduced. During 22 months of outdoor weathering, the coated/modified samples exhibited lower moisture content than the coated/unmodified samples, but GA modification didn't contribute a substantially synergistic effect with surface coatings on resistance to weathering.

A Facile Route for the Large Scale Fabrication of Graphene Oxide Papers and Their Mechanical Enhancement by Cross-linking with Glutaraldehyde

A facile route for the large scale production of graphene oxide(GO) papers and their mechanical enhancement has been presented in this work. The novel paper-like GO made from individual GO sheets in aqueous suspension can be achieved in large scale by a simple drop casting method on hydrophobic substrates.Significant enhancement in mechanical stiffness(341%) and fracture strength(234%) of GO paper have been achieved upon modification with a small amount(less than 10 wt%) of glutaraldehyde(GA). The cross-linking reaction takes place between hydroxyl groups on the surface of GO and aldehyde groups of GA, through forming hemiacetal structure, which can result in distinct mechanical enhancement of the GO papers.

PREPARATION AND ADSORPTION OF THIOUREA MODIFIED GLUTARALDEHYDE-CROSSLINKED CHITOSAN RESINS

The preparation and adsorption of thiourea modified glutaraldehyde-crosslinked chitosan resin （Thio-chitosan） using cyanuric chloride as activator was studied. The adsorptive capacity of thio-chitosan with 15% apparent degree of crosslinking （DC, mass ration of glutaraldehyde to chitosan） to Cu（Ⅱ） was 160mg/g （dry weight）. The adsorption of Cu（Ⅱ） was correlated with Freundlich and Langmuir isotherm equation. Cu（Ⅱ） adsorbed on thio-chitosan column （ 1cm×10cm） was eluted with 0.5mol/L H2SO4, 6mol/L HCI and 3% thiourea solution with the recovery of 88.3%, 86.1% and 95.3%, respectively. The thio-chitosan resin can be applied to the separation and recovery of metal ions.

Effects of albumin/glutaraldehyde glue on healing of colonic anastomosis in rats

To evaluate the effect of local surgical adhesive glue (albumin/glutaraldehyde-Bioglue) on the healing of colonic anastomoses in rats. METHODSForty Albino-Wistar male rats were randomly divided into two groups, with two subgroups of ten animals each. In the control group, an end-to-end colonic anastomosis was performed after segmental resection. In the Bioglue group, the anastomosis was protected with extraluminar application of adhesive glue containing albumin and glutaraldehyde. Half of the rats were sacrificed on the fourth and the rest on the eighth postoperative day. Anastomoses were resected and macroscopically examined. Bursting pressures were calculated and histological features were graded. Other parameters of healing, such as hydroxyproline and collagenase concentrations, were evaluated. The experimental data were summarized and computed from the results of a one-way ANOVA. Fisher’s exact test was applied to compare percentages. RESULTSBursting pressures, adhesion formation, inflammatory cell infiltration, and collagen deposition were significantly higher on the fourth postoperative day in the albumin/glutaraldehyde group than in the control group. Furthermore, albumin/glutaraldehyde significantly increased adhesion formation, inflammatory cell infiltration, neoangiogenesis, and collagen deposition on the eighth postoperative day. There was no difference in fibroblast activity or hydroxyproline and collagenase concentrations. CONCLUSIONAlbumin/glutaraldehyde, when applied on colonic anastomoses, promotes their healing in rats. Therefore, the application of protective local agents in colonic anastomoses leads to better outcomes.

The Stabilization Effect of Glutaraldehyde on the Spirulina platensis Phycobilisomes

The spectral properties of the glutaraldehyde-treated phycobilisomes were studied. The results showed that glutaraldehyde was effective in preventing phycobilisomes from dilution- induced dissociation and preserving the intra-phycobilisomes energy transfer.

Suture-Less Circumcision by Glutaraldehyde Albumin Glue Enhanced Laser Tissue Welding—A Comparative Study

Background: Suture-less circumcision by Feracrylate glue creates a weak and non waterproob bond. Hence, there is wound dehiscence and delayed healing which favor infection in many patients. I am describing a new technique for suture-less circumcision which is free from above limitations. Methods: In my center in the time span of 2 years, I did 51 cases of circumcision with Laser tissue welding technique (group A). Age range was 5 months to 21 years. During the same time span, in 56 patients circumcision was done by Feracrylate glue (group B). The age range was 3 months to 22 years. This group was kept as a control. Patients in both groups were randomly distributed. The technique of circumcision by Laser tissue welding is as follows. Patient is under short GA, the prepuce above the artery forceps is chopped off by scissors and bleeders are coagulated by bipolar cautery. Now, 0.9 ml 40% human albumin is taken in 1 ml syringe and mixed with 0.1 ml of 10% glutaraldehyde solution. The syringe is shaken vigorously to mix both the components. The skin and mucosa of penis are held by tooth forceps and a thin layer of this mixture is layered over it all around. Infrared Laser of 5 watts power and 850 nm illuminated over this bond for 60 seconds to polymerize it. Results: In group A, 2 (3.9%) patients developed partial wound gape, no patient had complete wound gape. 3 (5.88%) patients had grade 2 infections which settled with conservative treatment of oral antibiotics. In group B, 6 (10.71%) patients had partial wound gape and 8 (14.28%) patients had complete wound gapping. 11 (19.64%) patients developed grade 2 and 8 (14.28%) patients grade 3 wound infection. All these 19 patients’ post-operative antibiotics were started and given for 7 - 10 days. The Glutaraldehyde albumin mixture bond is already described in medical literature (Bioglue) for its use to seal coronary anastomosis after CABG operation, to seal sutures of cardiac surgery and for aortic dissection, etc. It is a surgical adhesive composed of purified bovine serum albumin (BSA) and glutaraldehyde and is already American FDA approved. It creates a flexible mechanical seal independently of the body’s clotting mechanism. In my technique, 0.9 ml of 40% human albumin is mixed with 0.1 ml 10% glutaraldehyde solution which costs only 50 cents which is a massive 1000 times cost reduction. Laser application polymerizes the glue and forms a waterproob bond in less than a minute. In my technique, percentage of glutaraldehyde used is only 10% compared to 50% in bioglue, hence it is non-toxic to the tissues. Conclusion: Suture-less circumcision by glutaraldehyde albumin glue enhanced Laser tissue welding is a safe, cheap and effective technique of performing circumcision. It is an important advance in circumcision surgery after a long time. The technique becomes a foundation for its vast application in other areas of surgery.

Influence of Glutaraldehyde on the Properties and Release Kinetic of α-Tocopherol from Chitosan-based Film

A crosslinked chitosan film with α-tocopherol was produced by a solution casting method. The appearance, mechanical properties, morphology, barrier properties and release kinetics of the α-tocopherol were evaluated. The addition of glutaraldehyde and α-tocopherol decreased the lightness and greenness and increased the yellowness of the chitosan-based film. Moreover, it also affected the compatibility of the film due to a decrease in the opacity values. The elongation at break(EB) and tensile strength(TS) values of the film decreased when the glutaraldehyde and α-tocopherol were added. In contrast, the Young’s modulus(YM) values increased. SEM micrographs showed coarse spots and pores on the surface and cross-section of the film when compared with the chitosan film. Based on the results, it was indicated that the chitosan structure was disconnected by the α-tocopherol, and the glutaraldehyde as a crosslinking agent generated a link between the chitosan network, which could be the cause of the reduced flexibility and the increased surface roughness of the film. However, the glutaraldehyde and α-tocopherol did not result in a significant difference in water vapour permeability(WVP) values. The glutaraldehyde influenced the release kinetics of the α-tocopherol as seen by the decrease of the diffusion coefficient values that were calculated using the Fickian diffusion model.

Removal of Cr(Ⅵ)by glutaraldehyde-crosslinked chitosan encapsulating microscale zero-valent iron:Synthesis,mechanism,and longevity

Microscale zero-valent iron(mZVI)has shown great potential for groundwater Cr(Ⅵ)remediation.However,low Cr(Ⅵ)removal capacity caused by passivation restricted the wide use of mZVI.We prepared mZVI/GCS by encapsulating mZVI in a porous glutaraldehydecrosslinked chitosan matrix,and the formation of the passivation layer was alleviated by reducing the contact between zero-valent iron particles.The average pore diameter of mZVI/GCS was 8.775 nm,which confirmed the mesoporous characteristic of this material.Results of batch experiments demonstrated that mZVI/GCS exhibited high Cr(Ⅵ)removal efficiency in a wide range of pH(2-10)and temperature(5-35℃).Common groundwater coexisting ions slightly affected m ZVI/GCS.The material showed great reusability,and the average Cr(Ⅵ)removal efficiency was 90.41%during eight cycles.In this study,we also conducted kinetics and isotherms analysis.Pseudo-second-order model was the most matched kinetics model.The Cr(Ⅵ)adsorption process was fitted by both Langmuir and Freundlich isotherms models,and the maximum Langmuir adsorption capacity of m ZVI/GCS reached243.63 mg/g,which is higher than the adsorption capacities of materials reported in most of the previous studies.Notably,the column capacity for Cr(Ⅵ)removal of a mZVI/GCS-packed column was 6.4 times higher than that of a mZVI-packed column in a 50-day experiment.Therefore,mZVI/GCS with a porous structure effectively relieved passivation problems of mZVI and showed practical application prospects as groundwater Cr(Ⅵ)remediation material with practical application prospects.

水环境温度对戊二醛杀菌效果的影响

为了解水环境温度对戊二醛(glutaraldehyde,GA)杀菌效果的影响,在20℃、25℃和30℃三个温度条件下,定期检测了2株细菌(副溶血弧菌Vibrio parahaemolyticus、维氏气单胞菌Aeromonas veroni)在不同浓度戊二醛水溶液中的致死情况。检测结果显示,戊二醛对维氏气单胞菌的杀菌率与温度正相关,低药物浓度时(0.45 mg/L),30℃水体中的杀菌率在24 h达到90%以上,而较低温度(20℃)实现90%杀菌率需要27 h;当浓度升至1.8 mg/L时,30℃、5 h杀菌率可以达到90%,20℃时则需要延长至7 h;当更高药物浓度(18 mg/L)时,30℃、20 min可实现90%以上杀菌率,20℃时所需时间相应延长至30 min。戊二醛对副溶血弧菌灭菌效果的影响也呈现相似规律性,当药物浓度0.18 mg/L时,杀菌率分别在15 h(30℃)和18 h(20℃)达到90%以上;当药物浓度1.8 mg/L和18 mg/L时,30℃水体中分别于100 min和3 min达到90%以上的杀菌率;20℃时时间延长至180 min和5 min。该研究结果可为科学合理使用戊二醛提供参考。

Electrospinning Preparation ofβ-Cyclodextrin/Glutaraldehyde Crosslinked PVP Nanofibrous Membranes to Adsorb Dye in Aqueous Solution

The insoluble β-cyclodextrin/glutaraldehyde crosslinked polyvinylpyrrolidone nanofibrous membranes were prepared by electrospinning technique. The membranes were extensively characterized by various techniques including attenuated total reflectance Fourier transform infrared spectroscopy（ATR-FTIR）, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and UV-visible absorption to correlate membrane characteristics with their performance. The adsorption ability of the nanofibrous membranes was tested by performing extraction of Methyl orange（MO） dye in water. It was observed that β-cyclodextrin incorporated in polyvinylpyrrolidone provided the characteristics of high adsorption capacity of polyvinylpyrrolidone. Results of sorption experiments show that the nanofibrous membranes exhibited an adsorption rate of more than 95% for MO and the MO absorbent was 39.82 mg to per gram of fl-cyclodextrin glutaraldehyde（β-CDXFM） crosslinked PVP under the optimized experimental conditions.

Abatement of sulfide generation in sewage by glutaraldehyde supplementation and the impact on the activated sludge accordingly

Hydrogen sulfide emission in sewer systems is associated with toxicity, corrosion, odour nuisance and high costs treatment. In this study, a novel method to inhibit sulfide generation from sewage by means of glutaraldehyde supplementation has been suggested and evaluated under anaerobic conditions. Different concentra- tions of glutaraldehyde at 10, 15, 20, 30 and 40mg.L1 have been investigated. Besides, the possible impacts of glutaraldehyde supplementation on an activated sludge system and an appraisal of the economic aspects are presented as well. As observed from the experimental results, a dosage of 20 mg. L-1 glutaraldehyde resulted in a significant decrease of the sulfide production by 70%-80% in the simulated sewage. Moreover, the impacts of additional glutaraldehyde at 20mg·L^-1 on activated sludge, in terms of chemical oxygen demand removal and oxygen uptake rates, were negligible. From an economical point of view, the cost of the commercial glutaraldehyde products required in the operation, which was calculated on the basis of activated sulfide removal avoidance, was around ε3.7-4.6 S·kg^-1. Therefore it is suggested that glutaraldehyde supplementation is a feasible technique to abate the sulfide problems in sewer systems. Yet further research is required to elucidate the optimum ＂booster＂ dosage and the dosing frequency in situ accordingly.

In vitro genotoxicity evaluation and metabolic study of residual glutaraldehyde in animal-derived biomaterials

Glutaraldehyde(GA)is an important additive that is mainly used in animal-derived biomaterials to improve their mechanical and antimicrobial capacities.However,GA chemical toxicity and the metabolic mechanism remain relatively unknown.Therefore,residual GA has always been a major health risk consideration for animal-derived medical devices.In this study,extracts of three biopatches were tested via the GA determination test and mouse lymphoma assay(MLA).The results showed that dissolved GA was a potential mutagen,which could induce significant cytotoxic and mutagenic effects in mouse lymphoma cells.These toxic reactions were relieved by the S9 metabolic activation(MA)system.Furthermore,we confirmed that GA concentration decreased and glutaric acid was generated during the catalytic process.We revealed GA could be oxidized via cytochrome P450 which was the main metabolic factor of S9.We found that even though GA was possibly responsible for positive reactions of animal-derived biomaterials’biocompatibility evaluation,it may not represent the real situation occurring in human bodies,owing to the presence of various detoxification mechanisms including the S9 system.Overall,in order to achieve a general balance between risk management and practical application,rational decisions based on comprehensive analyses must be considered.

FACILE REGULATION OF GLUTARALDEHYDE-MODIFIED GRAPHENE OXIDE FOR PREPARING FREE-STANDING PAPERS AND NANOCOMPOSITE FILMS

Colloidal suspensions of glutaraldehyde （GA） crosslinked or grafted graphene oxide （GO） sheets were fabricated by simply tailoring the feed sequence. The different structures were confirmed by Fourier transform infrared spectra and X-ray diffraction. As demonstration of the utilities, the different colloidal suspensions were used to prepare free-standing papers by flow-directed filtration and poly（vinyl alcohol） （PVA）-based nanocomposite films by casting. Free-standing papers from GA crosslinked GO sheets exhibited better mechanical properties than unmodified GO paper, while nanocomposite films from GA grafted GO exhibit higher tensile strength and Young＇s modulus.

Fluorescence "turn-on" Sensing Platform for Glutathione Detection Using Chitosan-Based Glutaraldehyde Non-conjugated Polymers

We established a f uorescence“turn-on”sensing platform for glutathione(GSH)detection utilizing chitosan-based glutaraldehyde non-conjugated polymers(GCPF)as nanomaterials via f uorescence resonance energy transfer(FRET)principle.Owing to the overlapping property of absorption spectrum of MnO^(2)nanosheets with f uorescence spectrum of GCPF,f uorescent intensity of GCPF was quenched in the presence of MnO^(2)nanosheets because of FRET principle.When GSH was added,MnO^(2)nanosheets were reduced and decomposed into large amounts of Mn^(2+)ions owing to reducing property of GSH.Accordingly,the quenched f uorescent intensity was turned on again.Therefore,this platform based on MnO^(2)nanosheet has been f rst applied to f uorescence“turn-on”detection of GSH from 0.5 to 50μmol/L with sdetection limit of 84 nmol/L.It showed high selectivity in GSH detection towards other ions and biomolecules such as L-lysine,L-threonine,L-valine,L-glutamic acid and DL-aspartic acid.When it was utilized in detecting GSH in serum samples,satisfactory recoveries ranged from 101.5%to 103.2%,indicating the accuracy of this f uorescence“turn-on”platform in bioanalysis.

Acid-catalyzed crosslinking of cellulose nanofibers with glutaraldehyde to improve the water resistance of nanopaper

In this study,cellulose nanofibers(CNFs)were crossed-linked with glutaraldehyde(GA)under acid condition for tailoring the mechanical properties and water-resistance of nanopaper or films.The impact of carboxyl content of CNFs,GA concentration,temperature,pH,and reaction time on the crosslinking was investigated,and the process conditions for the crosslinking were optimized.FT-IR analyses showed that CNFs/GA cross-linked nanopaper was successfully fabricated by acetalization between the-OH groups of CNFs and the-CHO groups of GA,resulting in the formation of a dense,three-dimensional network.The elastic modulus of CNFs/GA cross-linked film was 7.66GPa,62.98%higher than that of CNFs film.The water-resistance of the cross-linked CNFs/GA films was improved.The crossed-linked CNFs/GA films was still intact after 24 h after being immersed in water,while the CNFs films almost dissolved completely after 20 min of soaking in water.This method provides a facile route to enhance the elastic modulus and water-resistance of CNFs for potential applications including bullet-proof glass interlayer,flexible electronic device,and new packing materials.

Lacunary silicotungstic heteropoly salts as high-performance catalysts in oxidation of cyclopentene

The development of polyoxometalates for olefin oxidation is critical to achieving the green chemical process of the C5 fraction further processing.Di-lacunary silicotungstic anions were easily obtained by continuously adjusting the p H instead of the traditional step-by-step method,which exhibited excellent performance in the catalytic oxidation of cyclopentene(CPE)to aldehydes or alcohols.The 93.69%CPE conversion and 97.15%total product selectivity(41.38%for glutaraldehyde(GA)and 55.77%for 1,2-cyclopentanediol(1,2-diol)were achieved by using H_(2)O_(2)as the oxidant and acetonitrile as the solvent.Through complementary characterization,it was found that the optimized di-lacunary silicotungstic polyoxometalate retained a complete Keggin structure,and exhibited better catalytic activity and stability than the mono-lacunary or saturated silicodecatungstate because it exposed more catalytic active centers.Furthermore,in situ FT-IR spectra was utilized to monitor the reaction process,revealing the formation of the active species W(O_(2))on the di-lacunary silicotungstic polyoxometalate and the intermediate epoxycyclopentane during the catalytic oxidation of cyclopentene.

Selective oxidation of cyclopentene with H2O2 by using H3PW12O40 and TBAB as a phase transfer catalyst

The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantly improved the oxidation selectivity of cyclopentene. The effects of the reaction conditions on the conversion of cyclopentene were investigated in detail. The optimal reaction conditions are as follows: the H3PW12O40 to TBAB molar ratio, 1:1–1:3;H3PW12O40 to cyclopentene molar ratio,0.54:100–0.64:100;and molar ratio of H2O2 to cyclopentene, 1.6:1. The conversion reached to 59.8% in 4h at 35.0 ℃, while the selectivity of glutaraldehyde was 38.0% and the selectivity of 1,2-cyclopentanediol was 55.6%. In addition, a route for oxidation of cyclopentene by aqueous H2O2 using a heteropoly acid and quaternary ammonium salt as a phase transfer catalyst was proposed.