A comparative study for petroleum removal capacities of the bacterial consortia entrapped in sodium alginate,sodium alginate/poly(vinyl alcohol),and bushnell haas agar

The purpose of this study was to identify and compare the degradation efficiencies of free and entrapped bacterial consortia(Staphylococcus capitis CP053957.1 and Achromobacter marplatensis MT078618.1)to different polymers such as Sodium Alginate(SA),Sodium Alginate/Poly(Vinyl Alcohol)(SA/PVA),and Bushnell Haas Agar(BHA).In addition to SA and SA/PVA,which are cost-effective,non-toxic and have different functional groups,BHA,which is frequently encountered in laboratory-scale studies but has not been used as an entrapment material until now.Based on these,the polymers with different surface morphologies and chemical compositions were analyzed by SEM and FT-IR.While the petroleum removal efficiency was higher with the entrapped bacterial consortia than with the free one,BHA-entrapped bacterial consortium enhanced the petroleum removal more than SA and SA/PVA.Accordingly,the degradation rate of bacterial consortia entrapped with BHA was 2.039 day^(-1),SA/PVA was 1.560,SA was 0.993,the half-life period of BHA-entrapped bacterial consortia is quite low(t_(1/2)=0.339)compared with SA(t_(1/2)=0.444)and SA/PVA(t_(1/2)=0.697).The effects of the four main factors such as:amount of BHA(0.5,1,1.5,2,2.5,3 g),disc size(4,5,6,7,8 mm),inoculum concentration(1,2.5,5,7.5,10 mL),and incubation period on petroleum removal were also investigated.The maximum petroleum removal(94.5%)was obtained at≥2.5 mL of bacterial consortium entrapped in 2 g BHA with a 7 mm disc size at 168 h and the results were also confirmed by statistical analysis.Although a decrease was observed during the reuse of bacterial consortium entrapped in BHA,the petroleum removal was still above 50%at 10th cycle.Based on GC-MS analysis,the removal capacity of BHA-entrapped consortium was over 90%for short-chain n-alkanes and 80%for medium-chain n-alkanes.Overall,the obtained data are expected to provide a potential guideline in cleaning up the large-scale oil pollution in the future.Since there has been no similar study investigating petroleum removal with the bacterial consortia entrapped with BHA,this novel entrapment material can potentially be used in the treatment of petroleum pollution in advanced remediation studies.

Electrodeposited 3D hierarchical NiFe microflowers assembled from nanosheets robust for the selective electrooxidation of furfuryl alcohol

A robust and green strategy for the selective upgrading of biomass-derived platform chemicals towards highly valuable products is important for the sustainable development.Herein,the efficient electrocatalytic oxidation of biomass-derived furfuryl alcohol(FFA)into furoic acid(FurAc)catalyzed by the electrodeposited non-precious NiFe microflowers was successfully reached under the low temperature and ambient pressure.The 3D hierarchical NiFe microflowers assembled from ultrathin nanosheets were controllably synthesized by the electrodeposition method and uniformly grown on carbon fiber paper(CFP).Electrochemical analysis confirmed that NiFe nanosheets more preferred in the selective oxidation of FFA(FFAOR)than oxygen evolution reaction(OER).The linear sweep voltammetry(LSV)in FFAOR displayed a clear decrease towards lower potential,resulting in 30 mV reduction of overpotential at 20 mA cm^(-2) compared with that of OER.The optimal catalyst Ni_(1)Fe_(2) nanosheets exhibited the highest selectivity of FurAc(94.0%)and 81.4%conversion of FFA within 3 h.Besides,the influence of various reaction parameters on FFAOR was then explored in details.After that,the reaction pathway was investigated and rationally proposed.The outstanding performance for FFAOR can be ascribed to the unique structure of 3D flower-like NiFe nanosheets and oxygen vacancies,resulting in large exposure of active sites,faster electron transfer and enhanced adsorption of reactants.Our findings highlight a facile and convenient mean with a promising green future,which is promising for processing of various biomass-derived platform chemicals into value-added products.

Modification of Wood by Tannin-Furfuryl Alcohol Resins-Effect on Dimensional Stability,Mechanical Properties and Decay Durability

Furfurylation is a well-known wood modification technology.This paper studied the effect of tannin addition on the wood furfurylation.Three kinds of dicarboxylic acids,adipic acid,succinic acid,and tartaric acid,as well as glyoxal as a comparing agent,were used to catalyse the polymerisation of furanic or tannin-furanic solutions during wood modification.Impregnation of furanic or tannin-furanic solution at a certain concentration into the wood followed with curing at 103℃for a specific duration was performed for the wood modification.Different properties of the modified woods like dimensional stability,resistance of treatment to leaching,mechanical properties,decay durability against white-rot(Coriolus versicolor,Pycnoporus sanguineus)and brown-rot(Coniophora puteana)as well as their chemical and anatomical characteristics were evaluated.Results revealed that the partial substitution of FA by the tannins improved the fixation of the chemicals impregnated in wood.Further,dimensional stability,leaching resistance,Brinell hardness,modulus of elasticity/modulus of rupture,and decay durability properties of the furfurylated wood were also improved in the presence of tannins.Scanning electron microscopy revealed the deposition of the polymer in the wood lumen cells and in the wood cell walls.

Graphene quantum dots doped poly(vinyl alcohol)hybrid membranes for desalination via pervaporation

Pervaporation desalination by highly hydrophilic materials such as poly(vinyl alcohol)(PVA)based separation membrane is a burgeoning technology of late years.However,the improvement of membrane flux in pervaporation desalination has been a difficult task.Here,a novel hybrid membrane with doped graphene oxide quantum dots(GOQDs)which is rich in hydrophilic groups and small size into the matrix of PVA was prepared to improve the membrane flux.The membranes structures were described by field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM),Fourier transform infrared(FT-IR),differential scanning calorimetry(DSC),thermogravimetric analysis(TGA)and X-ray diffraction(XRD).And more,Water contact angle,swelling degree,and pervaporation properties were carried out to explore the effect of GOQDs in PVA matrix.In addition,GOQDs content in the hybrid membrane,NaCl concentration,and feed temperature were investigated accordingly.Moreover,the hydrogen bonds between PVA chains were weakened by the interaction between GOQDs and PVA chains.Significantly,the hybrid membrane with optimized doped GOQDs content,200 mg·L^(-1),displays a high membrane flux of 17.09 kg·m^(-2)·h^(-1)and the salt rejection is consistently greater than 99.6%.

Improving physical properties of poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels via the Hofmeister effect

Hydrogel is a kind of three-dimensional crosslinked polymer material with high moisture content.However,due to the network defects of polymer gels,traditional hydrogels are usually brittle and fragile,which limits their practical applications.Herein,we present a Hofmeister effect-aided facile strategy to prepare high-performance poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels.Layered montmorillonite nanosheets can not only serve as crosslinking agents to enhance the mechanical properties of the hydrogel but also promote the ion conduction.More importantly,based on the Hofmeister effect,the presence of(NH_(4))_(2)SO_(4)can endow nanocomposite hydrogels with excellent mechanical properties by affecting PVA chains'aggregation state and crystallinity.As a result,the as-prepared nanocomposite hydrogels possess unique physical properties,including robust mechanical and electrical properties.The as-prepared hydrogels can be further assembled into a high-performance flexible sensor,which can sensitively detect large-scale and small-scale human activities.The simple design concept of this work is believed to provide a new prospect for developing robust nanocomposite hydrogels and flexible devices in the future.

Biobased Furfurylated Poplar Wood for Flame-Retardant Modification with Boric Acid and Ammonium Dihydrogen Phosphate

Furfurylated wood exhibits excellent dimensional stability and corrosion resistance,making it a promising material for constructing buildings,but it is highly flammable.Herein,flame-retardant furfurylated poplar wood was produced via a two-step process utilizing boric acid(BA)and ammonium dihydrogen phosphate(ADP)as flame-retardant components,and biomass-derived furfuryl alcohol(FA)as a modifier.The acidity of BA and ADP allowed them to catalyze the polymerization of FA,which formed a cross-linked network that immobilized BA and ADP inside the wood.The addition of BA/ADP substantially delayed the time to ignition from 10 to 385 s and reduced the total heat release and total smoke release by 58.75%and 77.31%,respectively.Analysis of the pyrolysis process showed that the decomposition products of BA and ADP protected the underlying furfurylated wood and diluted combustible gases.This method significantly improved the fire retardancy and smokeless properties of furfurylated wood,providing promising prospects for its application as an engineering material.

Innovative approach to boosting the chemical stability of AZ31 magnesium alloy using polymer-modified hybrid metal oxides

Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties.However,the integration of polymeric frameworks with MgO/WO_(3) composite layers faces challenges due to the lack of understanding of the formation mechanism and the challenge of determining the impact of self-assembled architecture on anticorrosive properties.In this study,we aimed to enhance the corrosion resistance of the MgO layer produced by plasma electrolysis(PE)of AZ31 Mg alloy by incorporating WO_(3) with partially phosphorated poly(vinyl alcohol)(PPVA).Two types of porous MgO layers were produced using the PE process with an alkaline-phosphate electrolyte,one with and one without WO_(3) nanoparticles,which were subsequently immersed in an aqueous solution of PPVA.Incorporating PPVA into the WO_(3)-MgO layer resulted in hybrids being deposited in a fragmented manner,creating a“laminar reef-like structure”that sealed most of the structural defects in the layer.The PPVA-sealed WO_(3)-based coating exhibited superior corrosion resistance compared to the other samples.Computational analyses were employed to explore the mechanism underlying the formation of PPVA/WO_(3) hybrids on the MgO layer.These findings suggest that PPVA-WO_(3)-MgO hybrid coatings can potentially improve corrosion resistance in various fields.

Highly efficient catalytic valorization of biomass-derived hexoses and furfuryl alcohol in the presence of polymer-based catalysts

The catalytic transformation of furfuryl alcohol and hexose into value-added chemicals have been investigated with a series of polymer-based catalysts including poly(styrenesulfonic acid)(PSS),graphite oxide-doped poly(styrenesulfonic acid)(PSS-GO),and graphite-doped poly(-styrenesulfonic acid)(PSS-C).It is found that the selective conversion of furfuryl alcohol to methyl levulinate(MLE)was successfully performed with PSS as the catalyst,in which a 96.4%yield is attained in methanol solvent.Moreover,the efficient dehydration of D-fructose to produce 5-hydroxymethylfurfural(HMF)has also been achieved using PSS-GO as the catalyst,where a 76.5%yield of HMF was obtained in Nmethylpyrrodinone solvent.The effects of reaction temperature,time and solvent were investigated.Furthermore,the used catalysts have been respectively characterized by XRD,TG,FTIR,SEM and TEM techniques to reveal the physical properties and structures of these polymeric catalytic materials.

DFT Study of Poly Furfuryl Alcohol-Rhodamine B Blend

A theoretical study of poly furfuryle alcohol (PFA), rhodamine B (Rh B) dye and their blends (PFA-Rh B) is carried out by using the density functional theory (DFT). Electronic states and opto-electronic properties are investigated. The electronic states indicate that the oligomers of FA are insulators and Rh B is a wide band gap semiconductor. Their blends have a narrow band gap of about 0.75 eV. The optoelectronic properties are studied using TDDFT, which indicates that the chain length of poly furfuryl alcohol is an effective parameter to control both energies and intensities of absorption in which longer chain causes absorption with high intensity within long wavelength. A single broad baned of electron excitations is more like 8-oligomer-RhB case, which centers at wavelengths about 599 nm and 625 nm. This band of absorption covers the whole visible region of spectrum.

Selective hydrogenolysis of biomass-derived furfuryl alcohol into 1,2- and 1,5-pentanediol over highly dispersed Cu-Al_2O_3 catalysts

Cu nanoparticles supported on a variety of oxide supports, including SiO2, TiO2, ZrO2, Al2O3, MgO and ZnO, were investigated for the hydrogenolysis of biomass‐derived furfuryl alcohol to1,2‐pentanediol and 1,5‐pentanediol. A Cu‐Al2O3 catalyst with 10 wt% Cu loading prepared by a co‐precipitation method exhibited the best performance in terms of producing pentanediols compared with the other materials. This catalyst generated an 85.8% conversion and a 70.3% combined selectivity for the target pentanediols at 413 K and 8 MPa H2 over an 8‐h reaction. The catalyst could also be recycled over repeated reaction trials without any significant decrease in productivity. Characterizations with X‐ray diffraction, NH3/CO2‐temperature programmed desorption, N2 adsorption,transmission electron microscopy and N2 O chemisorption demonstrated that intimate and effective interactions between Cu particles and the acidic Al2O3 support in this material greatly enhanced its activity and selectivity. The promotion of the hydrogenolysis reaction was found to be especially sensitive to the Cu particle size, and the catalyst with Cu particles 1.9 to 2.4 nm in size showed the highest turnover frequency during the synthesis of pentanediols.

Controlled delivery of ibuprofen from poly(vinyl alcohol)-poly(ethylene glycol) interpenetrating polymeric network hydrogels

Hydrogels composed of poly(vinyl alcohol)(PVA) and poly(ethylene glycol)(PEG) were synthesized using glutaraldehyde as crosslinker and investigated for controlled delivery of the common anti-inflammatory drug, ibuprofen(IBF). To regulate the drug delivery, solid inclusion complexes(ICs) of IBF in β–cyclodextrin(β–CD) were prepared and added to the hydrogels. The ICs were prepared by the microwave irradiation method, which is more environmentally benign. The formation of IC was confirmed by various analytical techniques and the synthesized hydrogels were also characterized. Controlled release of drug was achieved from the hydrogels containing the ICs in comparison to the rapid release from hydrogels containing free IBF.The preliminary kinetic analysis emphasized the crucial role of β–CD in the drug release process that influences the polymer relaxation, thereby leading to prolonged release. The cytotoxicity assay validated the hydrogels as non-toxic in nature and hence can be utilized for controlled delivery of IBF.

Selective hydrogenolysis of furfuryl alcohol to 1,5-and 1,2-pentanediol over Cu-LaCoO_3 catalysts with balanced Cu^O-CoO sites

Selective hydrogenolysis of biomass‐derived furfuryl alcohol(FFA)to 1,5‐and 1,2‐pentanediol(PeD)was conducted over Cu‐LaCoO3 catalysts with different Cu loadings;the catalysts were derived from perovskite structures prepared by a one‐step citrate complexing method.The catalytic performances of the Cu‐LaCoO3 catalysts were found to depend on the Cu loading and pretreatment conditions.The catalyst with 10 wt%Cu loading exhibited the best catalytic performance after prereduction in 5%H2‐95%N2,achieving a high FFA conversion of 100%and selectivity of 55.5%for 1,5‐pentanediol(40.3%)and 1,2‐pentanediol(15.2%)at 413 K and 6 MPa H2.This catalyst could be reused four times without a loss of FFA conversion but it resulted in a slight decrease in pentanediol selectivity.Correlation between the structural changes in the catalysts at different states and the simultaneous variation in the catalytic performance revealed that cooperative catalysis between Cu0 and CoO promoted the hydrogenolysis of FFA to PeDs,especially to 1,5‐PeD,while Co0 promoted the hydrogenation of FFA to tetrahydrofurfuryl alcohol(THFA).Therefore,it is suggested that a synergetic effect between balanced Cu0 and CoO sites plays a critical role in achieving a high yield of PeDs with a high 1,5‐/1,2‐pentanediol selectivity ratio during FFA hydrogenolysis.

Compatibility and Properties of Biodegradable Blend Films with Gelatin and Poly(vinyl alcohol)

The blend films with gelatin and poly（vinyl alcohol） （PVA） were prepared by a solution casting method. The compatibility between gelatin and PVA in the blend films was investigated. The transmittance, Fourier-transform infrared spectroscopy （FTIR）, x-ray diffraction （XRD）, thermogravimetry analysis （TG）, and differential scanning calorimetry （DSC） were employed to characterize the resultant blend films. According to optic result, the opacity of the blend film at the ratio of 20/80 （w/w, Gel to PVA） was the lowest, indicating the best compatibility between Gel and PVA at the ratio. The results oflR, XRD, DSC, and TG revealed an intensive interaction and good compatibility between them in the blend film at the ratio. The mechanical properties and solubility showed that PVA content in the blend films obviously affected the elongation at break and solubility. The mechanical properties and water resistance of gelatin film may be improved by the introduetion of PVA.

A Hybrid Membrane of Poly(vinyl alcohol) and Phosphotungstic Acid for Fuel Cells

Proton conducting membranes composed of phosphotungstic acid (PWA) and poly(vinyl alcohol) (PVA)were prepared. Conductivity and Fourier transform infrared spectrometer(FTIR) measurements show that most ofthe acid embedded are stable in the PVA matrix when the membrane is immerged in water or methanol solution atroom temperature. Conductivity of the composite membranes scatters around 10-3 S.cm-1 at room temperature.The methanol crossover through the membranes is about an order of magnitude lower than that through Nafion117 membrane.

One-pot cascade conversion of xylose to furfuryl alcohol over a bifunctional Cu/SBA-15-SO3H catalyst

The conversion of hemicellulose-derived xylose to furfuryl alcohol is a practical procedure for producing value-added chemicals from biomass.In this study,a bifunctional Cu/SBA-15-SO3 H catalyst was employed for the one-pot catalytic conversion of xylose to furfuryl alcohol with a yield of up to 62.6% at the optimized conditions of 140℃,4 MPa,and for 6 h in a biphasic water/n-butanol solvent.A high reaction temperature resulted in further hydrogenation to 2-methyl furan,while a high hydrogen pressure led to a side hydrogenation reaction to xylitol.The biphasic solvent allowed xylose solvation as well as furfuryl product extraction.The acidic-SO3 H sites and Cu sites co-existed,maintained a balance,and cooperatively catalyzed the cascade conversion.Excessive acidic sites and large pores could promote the xylose conversion,although a low furfuryl alcohol yield was obtained.This catalytic system could be potentially applied to the one-pot synthesis of furfuryl alcohol from hemicellulose-derived xylose.

Low-cost synthesis of nanoaggregate SAPO-34 and its application in the catalytic alcoholysis of furfuryl alcohol

Silicoaluminophosphate-34(SAPO-34) molecular sieves have important applications in the petrochemical industry as a result of their shape selectivity and suitable acidity. In this work, nanoaggregate SAPO-34 with a large external surface area was obtained by dissolving pseudoboehmite and tetraethylorthosilicate in an aqueous solution of tetraethylammonium hydroxide and subsequently adding phosphoric acid. After hydrolysis in an alkaline solution, the aluminum and silicon precursors exist as Al(OH)4-and SiO2(OH)-, respectively;this is beneficial for rapid nucleation and the formation of nanoaggregates in the following crystallization process. Additionally, to study the effect of the external surface area and pore size on the catalytic performance of different SAPO-34 structures, the alcoholysis of furfuryl alcohol to ethyl levulinate(EL) was chosen as a model reaction. In a comparison with the traditional cube-like SAPO-34, nanoaggregate SAPO-34 generated a higher yield of 74.1% of EL, whereas that with cube-like SAPO-34 was only 19.9%. Moreover, the stability was remarkably enhanced for nanoaggregate SAPO-34. The greater external surface area and larger number of external surface acid sites are helpful in improving the catalytic performance and avoiding coke deposition.

SYNTHESIS OF POLYMER-STABILIZED RUTHENIUM COLLOIDS BY LOW BOILING POINT ALCOHOL REDUCTION

Stable and well-dispersed poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloidal clusters wereprepaxed via the reduction of ruthenium(III) chloride by refluxing with low boiling point alcohols. Investigation of the size ofRu colloids by transmission electron microscopy (TEM) indicated that the average diametes could be controlled in the rangeof 1.2-1.6 nm with relative standard deviations of less than 0.33 by changing the molar ratio of PVP to Ru. The X-rayphotoelectron spectroscopy (XPS) characterization verified the formation of elemental ruthenium colloids.

Emission of BTEX and PAHs from molding sands with furan cold setting resins containing different contents of free furfuryl alcohol during production of cast iron

At present, furan resin is the largest selling no-bake system of moulding sands. The most commonly used furan no-bake binders(FNB) are condensation products of furfuryl alcohol(FA) urea, formaldehyde and phenol. They are generally cured by exposure to organic sulfonic acids. FNB provide excellent mold and core strength, cure rapidly and allow the sand to be reclaimed at fairly high yields, generally 75%-80%, especially in applications where due allowance is made for the need to keep total sulfur content below 0.1%. However, due to probable carcinogenic properties of furfuryl alcohol, the EU Directive limits the content of this substance(in a monomer form in resin) to 25%. The classification of furfuryl alcohol and the resulting furan resin products has changed from "harmful" to "toxic by inhalation". The aim of this study was to determine the effect of free furfuryl alcohol content in the resin on the emission of harmful substances from the BTEX(Benzene Toluene Ethylbenzene & Xylene) and PAHs(polycyclic aromatic hydrocarbon) group exposed to high temperature and how it affects the emissions allowance of reclaimed sand in the matrix. Three resins from a leading manufacturer were examined, which contain a free furfuryl alcohol content of 71%-72%, about 50% and < 25%, respectively. The hardener for each resin was 65% aqueous solution of paratoluenesulfonic acid. Tests were carried out in semi-industrial conditions where liquid cast-iron was poured into sample sand mold at 1,350 °C. The matrix of the studied sands was reclaimed in the amount of 0, 50%, 100%, respectively.With the increase of free furfuryl alcohol content, the volume of evolved gases decreased. For all resins the main component from the BTEX group dominating in the emitted gases was benzene; however toluene also appeared in the amount of a few percentages. In contrast, ethylbenzene and xylenes occurred only in the gases emitted from resin-bonded sands with the largest furfuryl alcohol content. The increase in the share of reclaimed sands resulted in very significant increase in the volume of gas generated and participation of benzene in these gases. In terms of emission of compounds from the PAHs group virtually for all resins, the total content of these substances was comparable(within the limits of error). The main components were: fluoranthene, pyrene and benzo(a) anthracene.

Research on the Long Time Swelling Properties of Poly (vinyl alcohol)/Hydroxylapatite Composite Hydrogel

Poly(vinyl alcohol)/hydroxylapatite(PVA/HA)composite hydrogel was prepared by repeated freezing and thawing.The water loss properties of the resultant hydrogel were investigated by using optical microscope.Long time immersion tests of PVA/HA composite hydrogel were carried out in the diluted calf serum solution to study the change laws of swelling properties with the freezing-thawing cycles and HA content.The micro-morphologies of PVA/HA composite hydrogel after long time immersion were observed by means of the high-accuracy 3D profiler.The results show that the swelling process of PVA/HA composite hydrogel is the converse process of its water loss.Long time swelling ratio curves of PVA/HA composite hydrogel in the calf serum solution are manifested as four stages of quick increase,decrease,slow decrease and stable balance,and its equilibrium swelling ratio decreases with the increase of freezing-thawing cycles and HA content.It is revealed that the network structure of the composite hydrogel immersed for a long period is significantly improved with the increase of HA content. Perfect network structures of PVA/HA composite hydrogel as well as full and equilibrium tissues after swelling equilibrium are obtained when the HA content is 3% and the number of freezing-thawing cycles is 7.

Preparation and Swelling Behavior of Physically Crosslinked Hydrogels Composed of Poly(vinyl alcohol) and Chitosan

The physically crosslinked poly（vinyl alcohol）/chitosan （CS） composite hydrogels were prepared by cyclic freezing/thawing techniques, and the microstructure and swelling behavior of the hydrogels in the simulated gastric （pH 1.0） and intestinal （pH 7.4） media were investigated. The experimental results of infrared spectra （IR）, scanning electron microscope （SEM） and differential scanning calorimetry （DSC） demonstrated that poly（vinyl alcohol） and chitosan had good miscibility in the composite hydrogels, and the addition of chitosan perturbed the formation of poly（vinyl alcohol） crystallites. The swelling kinetics results indicated that the composite hydrogels had good pH sensitive properties to the acidic environments, and with the increase of chitosan content in the blend, the maximum swelling degreed and the swelling rate both increased, but it led to more dissolution at pH 1.0. And the composite hydrogels also exhibited good reversible swelling behavior with pH value of the swelling medium altering between 1.0 and 7.4. In addition, the higher freezing/thawing cycle times resulted in the lower swelling rate. Therefore, the swelling behavior of the composite hydrogels could be adjusted by changing the chitosan contents and the freezing/thawing cycle times.