Blend films of natural wool and cellulose prepared from an ionic liquid

Natural wool/cellulose blends were prepared in an ionic liquid green solvent, 1-butyl-3-methylimidazolium chloride (BMIMCl) and the films were formed subsequently from the coagulated solutions. The wool/cellulose blend films show significant improvement in thermal stability compared to the coagulated wool and cellulose. Moreover, the blend films exhibited an increasing trend of tensile strength with increase in cellulose content in the blends which could be used for the development of wool-based materials with improved mechanical properties, and the elongations of the blends were considerably improved with respect to the coagulated films of wool and cellulose. It was found that there was hydrogen bonding interaction between hydroxyl groups of wool and cellulose in the coagulated wool/cellulose blends as determined by Fourier transform infrared (FTIR) spectroscopy. The ionic liquid was completely recycled with high yield and purity after the blend film was prepared. This work presents a green processing route for development of novel renewable blended materials from natural resource with improved properties.

Evaluation of cassava peel waste as lowcost biosorbent for Ni-sorption : equilibrium, kinetics, thermodynamics and mechanism

The feasibility of cassava peel waste for Ni-sorption is evaluated in this work. The biosorbents are characterized by Boehm titration, Fourier transform-infra red (FTIR) spectroscopy, Nitrogen sorption, scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis (e.g. elemental mapping) and X-ray photoelectron spectroscopy (XPS). Adsorption experiments are performed in batch mode at 30 °C (303.15 K), 45 °C (318.15 K) and 60 °C (333.15 K). The performance of several temperature dependence forms of isotherm models e.g. Langmuir, Freundlich, Sips and Toth to represent the adsorption equilibrium data is evaluated and contrasted. Sips model demonstrates the best fitting with the maximum uptake capacity for Ni(II) ions of 57 mg/g (0.971 mmol/g) at pH 4.5. For kinetic data correlation, pseudo-second order model shows the best representation. The chemisorption mechanism and thermodynamics aspect are also discussed.

Influence of emulsification on the properties of styrene-butadiene-styrene chemically modified bitumens

The effect of emulsification on the styrene-butadiene-styrene (SBS) chemically modified bitumens (CMBs) is studied by conventional tests, differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) spectroscopy. Compared to CMBs, modified bitumen emulsion residues (MBERs) exhibit higher temperature susceptibility, inferior resistant to cracking and deformation, lower elastic recovery and storage stability whereas these properties are improved substantially relative to base bitumens. DSC results show that the thermostability of CMBs decreased slightly after emulsification which indicate the emulsification exerts very little effect on the thermal property of CMBs. The FTIR results do not indicate any chemical reaction exists on CMBs during the emulsification.

Reducing the pilling propensity of wool knits with a three-step plasma treatment

A three-step plasma treatment, including surface activation with argon, surface functionalization with oxygen and then thin film deposition using a pulsed plasma polymerization of hexamethyldisiloxane (HMDSO), was used in low-pressure plasma to improve the pilling resistance of knitted wool fabric. The pilling propensity of the treated samples was investigated and compared with the pilling propensity of untreated, argon activated and oxygen functionized samples and argon and oxygen plasma-treated samples that were afterwards subject to continuous wave plasma polymerization of HMDSO. With the three-step treatment, a pilling grade of four was achieved for the treated wool fabric, while that of untreated and other plasma-treated was two and three, respectively. For the three-step plasma-treated sample, a uniform HMDSO polymer coating of 300 nm thickness was obtained; X-ray photoelectron spectroscopy (XPS) showed the presence of the silicone element, and Fourier transform infrared (FTIR) spectroscopy confirmed the chemical structure of the coating. No apparent differences were found in the whiteness index between the treated and untreated wool knits, but there was deterioration in the bursting strength and handle of the plasma-treated wool samples.

Synthesis and characterization of surface-enhanced Raman-scattered gold nanoparticles

In this paper, we report a simple, rapid, and robust method to synthesize surface-enhanced Raman-scattered gold nanoparticles (GNPs) based on green chemistry. Vitis vinifera L. extract was used to synthesize noncytotoxic Raman-active GNPs. These GNPs were characterized by ultraviolet-visible spectroscopy, dynamic light-scattering, Fourier-transform infrared (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The characteristic surface plasmon-resonance band at ~528 nm is indicative of spherical particles, and this was confirmed by TEM. The N–H and C–O stretches in FTIR spectroscopy indicated the presence of protein molecules. The predominant XRD plane at (111) and (200) indicated the crystalline nature and purity of GNPs. GNPs were stable in the buffers used for biological studies, and exhibited no cytotoxicity in noncancerous MIO-M1 (Müller glial) and MDA-MB-453 (breast cancer) cell lines. The GNPs exhibited Raman spectral peaks at 570, 788, and 1,102 cm-1. These new GNPs have potential applications in cancer diagnosis, therapy, and ultrasensitive biomarker detection.

Protonated melonate Ca[HC6N7(NCN)3]·7H2O – synthesis, crystal structure, and thermal properties

Calcium hydrogenmelonate heptahydrate Ca[HC6N7(NCN)3]·7H2O was obtained by metathesis reaction in aqueous solution. The structure of the molecular salt was elucidated by single-crystal X-ray diffraction. The crystal structure consists of alternating layers of planar monopronated melonate ions, Ca2+ and crystal water molecules. The anions of adjacent layers are staggered so that no π–π stacking occurs. The melonate entities are interconnected by hydrogen bonds within and between the layers. Ca[HC6N7(NCN)3]·7H2O was investigated by solid-state NMR and FTIR spectroscopy, TG and DTA measurements.

Poly(triazine imide) with intercalation of Lithium and ChlorideiIons [(C3N3)2(NHxLi1−x)3⋅LiCl]: A Crystalline 2D Carbon Nitride network

Poly(triazine imide) with intercalation of lithium and chloride ions (PTI/Li+Cl−) was synthesized by temperature-induced condensation of dicyandiamide in a eutectic mixture of lithium chloride and potassium chloride as solvent. By using this ionothermal approach the well-known problem of insufficient crystallinity of carbon nitride (CN) condensation products could be overcome. The structural characterization of PTI/Li+Cl− resulted from a complementary approach using spectroscopic methods as well as different diffraction techniques. Due to the high crystallinity of PTI/Li+Cl− a structure solution from both powder X-ray and electron diffraction patterns using direct methods was possible; this yielded a triazine-based structure model, in contrast to the proposed fully condensed heptazine-based structure that has been reported recently. Further information from solid-state NMR and FTIR spectroscopy as well as high-resolution TEM investigations was used for Rietveld refinement with a goodness-of-fit (χ2) of 5.035 and wRp=0.05937. PTI/Li+Cl− (P63cm (no. 185); a=846.82(10), c=675.02(9) pm) is a 2D network composed of essentially planar layers made up from imide-bridged triazine units. Voids in these layers are stacked upon each other forming channels running parallel to [001], filled with Li+ and Cl− ions. The presence of salt ions in the nanocrystallites as well as the existence of sp2-hybridized carbon and nitrogen atoms typical of graphitic structures was confirmed by electron energy-loss spectroscopy (EELS) measurements. Solid-state NMR spectroscopy investigations using 15N-labeled PTI/Li+Cl− proved the absence of heptazine building blocks and NH2 groups and corroborated the highly condensed, triazine-based structure model.

Evaluation of bread crumbs as a potential carbon source for the growth of Thraustochytrid species for oil and omega-3 production

The utilization of food waste by microorganisms to produce omega-3 fatty acids or biofuel is a potentially low cost method with positive environmental benefits. In the present study, the marine microorganisms Thraustochytrium sp. AH-2 and Schizochytrium sp. SR21 were used to evaluate the potential of breadcrumbs as an alternate carbon source for the production of lipids under static fermentation conditions. For the Thraustochytrium sp. AH-2, submerged liquid fermentation with 3% glucose produced 4.3 g/L of biomass and 44.16 mg/g of saturated fatty acids after seven days. Static fermentation with 0.5% and 1% breadcrumbs resulted in 2.5 and 4.7 g/L of biomass, and 42.4 and 33.6 mg/g of saturated fatty acids, respectively. Scanning electron microscopic (SEM) studies confirmed the growth of both strains on breadcrumbs. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy for both strains were consistent with the utilization of breadcrumbs for the production of unsaturated lipids, albeit at relatively low levels. The total lipid yield for static fermentation with bread crumbs was marginally lower than that of fermentation with glucose media, while the yield of unsaturated fatty acids was considerably lower, indicating that static fermentation may be more appropriate for the production of biodiesel than for the production of omega-3 rich oils in these strains.

Biodegradable polyethylene glycol-based ionic liquids for effective inhibition of shale hydration

A series of ionic liquids based on polyethylene glycol (PEG) with different molecular weights were prepared for inhibiting shale hydration and swelling. The antiswelling ratio was measured to investigate the effect of different PEG-based ionic liquids on bentonite volume expansion, and it has shown that the ionic liquid based PEG200, i.e. PEG with molecular weight of 200, exhibited superior inhibition. The structures of the PEG200-based ionic liquids were characterized by ¹H NMR studies. The XRD results indicated that the PEG200-based ionic liquids intercalated into sodium montmorillonite (Na-MMT) reducing the water uptake by the clay. The formation of complexes of Na-MMT and PEG200-based ionic liquids was also verified by FTIR spectroscopy. Thermal degradation analysis suggested that the PEG200-based ionic liquids accessed the interlamellar spaces of Na-MMT and reduced the water content of the complexes obtained. Moreover, no breaks and collapse were observed on the shale samples after immersion in PEG200-based ionic liquid solutions. All the PEG200-based ionic liquids showed biodegradability and potential application in effective inhibition for clay hydration.

A highly conductive porous graphene electrode prepared via in situ reduction of graphene oxide using Cu nanoparticles for the fabrication of high performance supercapacitors

Herein, a new graphene/Cu nanoparticle composite was prepared via the in situ reduction of GO in the presence of Cu nanoparticles which was then utilized as a sacrificing template for the formation of flexible and porous graphene capacitor electrodes by the dissolution of the intercalated Cu nanoparticle in a mixed solution of FeCl3 and HCl. The porous RGO electrode was characterized by atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). The as-prepared graphene/Cu nanoparticle composite and the pure graphene film after removal of Cu nanoparticles possessed high conductivity of 3.1 × 10³ S m^-1 and 436 S m^-1 respectively. The porous RGO can be used as the electrode for the fabrication of supercapacitors with high gravimetric specific capacitances up to 146 F g^-1, good rate capability and satisfactory electrochemical stability. This environmentally friendly and efficient approach to fabricating porous graphene nanostructures could have enormous potential applications in the field of energy storage and nanotechnology.

Ionic transport through a composite structure of N-ethyl-N-methylpyrrolidinium tetrafluoroborate organic ionic plastic crystals reinforced with polymer nanofibres

The incorporation of polyvinylidene difluoride (PVDF) electrospun nanofibres within N-ethyl-N-methylpyrrolidinium tetrafluoroborate, [C2mpyr][BF4] was investigated with a view to fabricating self-standing membranes for various electrochemical device applications, in particular lithium metal batteries. Significant improvement in mechanical properties and ionic conduction was demonstrated in a previous study, which also demonstrated the remarkably high performance of the lithium-doped composite material in a device. We now seek a fundamental understanding of the role of fibres within the matrix of the plastic crystal, which is essential for optimizing device performance through fine-tuning of the composite material properties. The focus of the current study is therefore a thorough investigation of the phase behaviour and conduction behaviour of the pure and the lithium-doped (as LiBF4) plastic crystal, with and without incorporation of polymer nanofibres. Analysis of the structure of the plastic crystal, including the effects of lithium ions and the incorporation of PVDF fibres, was conducted by means of synchrotron XRD. Ion dynamics were evaluated using VT solid-state NMR spectroscopy. ATR-FTIR spectroscopy was employed to gain insights into the molecular interactions of doped lithium ions and/or the PVDF nanofibres in the matrix of the [C2mpyr][BF4] composites. Preliminary measurements using PALS were conducted to probe structural defects within the pure materials. It was found that ion transport within the plastic crystal was significantly altered by doping with lithium ions due to the precipitation of a second phase in the structure. The incorporation of the fibres activated more mobile sites in the systems, but restricted ion mobility with different trends being observed for each ion species in each crystalline phase. In the presence of the fibres a strong interaction observed between the Li ion and the pyrrolidinium ring disappeared and formation of the second phase was prevented. As a result, an increased number of mobile lithium ions are released into the solid solution structure of the matrix, simultaneously removing the blocking effect of the second phase. Thus, ion conduction was remarkably improved within the Li-doped composite compared to the neat Li-doped plastic crystal.

Capsular polypyrrole hollow nanofibers: an efficient recyclable adsorbent for hexavalent chromium removal

Capsular polypyrrole hollow nanofibers (PPy-HNFs) were fabricated via in situ polymerization of pyrrole on an organic-inorganic template, followed by acid etching. Their application in removing hexavalent chromium (Cr(vi)) from aqueous solution was then investigated. The morphologies of the capsular PPy-HNFs were studied by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which showed that the PPy-HNFs had a capsular structure in the walls of hollow nanofibers. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) data confirmed the adsorption of Cr on capsular PPy-HNFs. The adsorption capacity increased with reduced pH of the initial solution and the adsorption process can be described using the pseudo-second-order model. These capsular PPy-HNFs showed a high Cr(vi) adsorption capacity up to 839.3 mg g-1. This adsorption capacity was largely retained even after five adsorption/desorption cycles. Electrostatic attraction between Cr and PPy-HNFs was studied using a proposed adsorption mechanism. The capsular PPy-HNFs formed a flexible membrane, which allowed easy handling during application. This study has demonstrated the possibilities of using this capsular PPy-HNF membrane for heavy metal removal from aqueous solution.

Plasma assisted finishing of cotton fabric with chitosan

Chitosan is a natural and non-toxic polymer which can be used as a multifunctional, e.g. antimicrobial or anti-wrinkle, agent on cotton fabrics. However, due to the lack of strong bonding forces between two polysaccharides, chitosan coating on cotton has poor durability. To provide efficient and irreversible chitosan adsorption on cotton substrate, it is required to build appropriate binding sites and to activate the substrate material properly. For this purpose, plasma treatment can be a promising method as it can activate the surface of the cotton fabric and improve the adsorption of chemicals in a completely harmless procedure. In this study, we investigated the effect of atmospheric pressure plasma treatment on adsorption of chitosan onto the cotton fabric. The purpose of the study was to investigate to which extent adsorption of chitosan on cotton can be improved by helium plasma treatment. Fibre surface and adsorption of chitosan were characterized by X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared (FTIR) spectroscopy. Changes in hydrophobicity of fabric`s surface and fibre morphology were evaluated using contact angle method and scanning electron microscopy (SEM), respectively. The results from XPS showed an increase in the C=O bonds on cotton fabrics oxydised by helium plasma treatmnets, confirming the formation of aldehyde groups in cellulose. The characteristic absorbance band of chitosan, amide II (N-H bending vibration) showed an enlargement for all fabrics treated with helium and chitosan, as assesed by FTIR. The absorbance peaks of CH2 stretching vibrations, which confirm chitosan existence, were stronger for all treated fabrics compared to the untreated control. While the plasma only treated fabric surface was very hydrophilic, the surface became hydrophobic after chitosan coating.

Synergistic corrosion inhibition of mild steel in aqueous chloride solutions by an imidazolinium carboxylate salt

Mild steel infrastructure is constantly under corrosive attack in most environmental and industrial conditions. There is an ongoing search for environmentally friendly, highly effective inhibitor compounds that can provide a protective action in situations ranging from the marine environment to oil and gas pipelines. In this work an organic salt comprising a protic imidazolinium cation and a 4-hydroxycinnamate anion has been shown to produce a synergistic corrosion inhibition effect for mild steel in 0.01 M NaCl aqueous solutions under acidic, neutral, and basic conditions; an important and unusual phenomenon for one compound to support inhibition across a range of pH conditions. Significantly, the individual components of this compound do not inhibit as effectively at equivalent concentrations, particularly at pH 2. Immersion studies show the efficacy of these inhibitors in stifling corrosion as observed from optical, SEM, and profilometry experiments. The mechanism of inhibition appears to be dominated by anodic behavior where dissolution of the steel, and in particular the pitting process, is stifled. FTIR spectroscopy provides confirmation of a protective interfacial layer, with the observation of interactions between the steel surface and 4-hydroxycinnamate.