Eco-friendly Nanocomposites Research Articles

Eco-friendly nanocomposites derived from geranium oil and zinc oxide in one step approach

Nanocomposites offer attractive and cost-effective thin layers with superior properties for antimicrobial, drug delivery and microelectronic applications. This work reports single-step plasma-enabled synthesis of polymer/zinc nanocomposite thin films via co-deposition of renewable geranium essential oil-derived polymer and zinc nanoparticles produced by thermal decomposition of zinc acetylacetonate. The chemical composition, surfaces characteristics and antimicrobial performance of the designed nanocomposite were systematically investigated. XPS survey proved the presence of ZnO in the matrix of formed polymers at 10 W and 50 W. SEM images verified that the average size of a ZnO nanoparticle slightly increased with an increase in the power of deposition, from approximately 60 nm at 10 W to approximately 80 nm at 50 W. Confocal scanning laser microscopy images showed that viability of S. aureus and E.coli cells significantly reduced on surfaces of ZnO/polymer composites compared to pristine polymers. SEM observations further demonstrated that bacterial cells incubated on Zn/Ge 10 W and Zn/Ge 50 W had deteriorated cell walls, compared to pristine polymers and glass control. The release of ZnO nanoparticles from the composite thin films was confirmed using ICP measurements, and can be further controlled by coating the film with a thin polymeric layer. These eco-friendly nanocomposite films could be employed as encapsulation coatings to protect relevant surfaces of medical devices from microbial adhesion and colonization.

Fabrication and electrical properties of regenerated cellulose-loaded exfoliated graphene nanoplatelet composites

Low cost and scalable manufacturing of highly doped cellulose for enhanced multifunctional applications is still an issue. In this work, eco-friendly nanocomposites were fabricated by incorporating regenerated cellulose (RC) of 10, 30, and 50 wt% into an exfoliated graphene nanoplatelets (GNPs), resulting in the intercalation of GnPs. The thermal and electrical properties of hybrid nanocomposites were investigated. The structural property was conducted through scanning electron microscope and X-ray diffraction analyses. Strong frequency-dependent dielectric response was found due to the change of the permittivity and the loss tangent of nanocomposites by different content of RC, which is associated with the polarizations behavior. Non-elastic relaxation at the GNPs–RC chains interfacial areas in an alternating field was identified as the main cause of polarization losses among others. Detailed ferroelectric measurements provided the evidence of the ideal resistive behavior of the nanocomposites, which are confirmed by the resistivity measurements along the out-of-plane direction of the nanocomposite sheets.

Green and eco-friendly nanocomposite for the removal of toxic Hg(II) metal ion from aqueous environment: Adsorption kinetics & isotherm modelling

Magnetic bio-composite was fabricated using curcumin and Fe3O4 nanoparticles. The structure and morphology of the resin (CG) and the curcumin based magnetic nanocomposite (CMNC) was analyzed by several techniques. The CMNC was applied as an adsorbent which revealed outstanding abilities for the adsorption of Hg(II) ions. The equilibrium data coincided with the Langmuir adsorption isotherm indicating the maximum adsorption capacity of CMNC 144.9 mg/g for Hg(II). The adsorption kinetic was well-defined by the pseudo-first-order. The thermodynamic results showed that the adsorption process was spontaneous and exothermic at the studied temperatures. The cycling adsorption/desorption tests were made by using 0.1 mol/L hydrochloric acid solution which revealed that CMNC had good reusable ability up to four cycles. It can be suggested from the results that CMNC could be easily and efficiently used for the removal of Hg(II) from aqueous solution.

Effect of NiO/SiO2 nanofluids on the ultra interfacial tension reduction between heavy oil and aqueous solution and their use for wettability alteration of carbonate rocks

One of the important factors in enhanced oil recovery (EOR), which leads to better oil flow in reservoirs and increases the recovery efficiency of the reservoirs, is the reduction of surface tension (S.T) and interfacial tension (IFT). The effect of NiO and SiO2 nanoparticles and their nanocomposites as NiO/SiO2 on the reduction of oil/water interfacial tension was investigated for the heavy oil of Soroush field located in Iran with a density of 0.965 g/cm3 and viscosity of 1310 cP at 22 °C. NiO and SiO2 nanoparticles were produced by sol-gel-hydrothermal process and NiO/SiO2 nanocomposites were synthesized by co-precipitation-hydrothermal method. The interfacial tension of water/Soroush oil was measured to be 29.02 mN/m, as the reference, in the absence of nanoparticles. Water-based nanofluid of 30 wt% NiO/SiO2 and 28 wt% Fe@ NiO/SiO2 nanocomposites that benefits the synergism of the Fe promotor, decreased the IFT to 1.28 mN/m and less than 1 mN/m, respectively. In addition, the key factors such as concentration, aging time and salinity affect were studied in variation of S.T and IFT. It was found that 8 v/v% of the 30 wt% NiO/SiO2 diluted in water had the best efficiency in reducing the S.T and IFT, while preheating time of nanofluids and salinity of water that the nanofluid dissolved in had negligible impacts on surface and interfacial tension. Moreover, as the 30 wt% NiO/SiO2 nanocomposites were essentially hydrophobic, novel hydrophilic and eco-friendly nanocomposites of 30 wt% NiO/SiO2 were also synthesized through smart surface modifications by polyethylene glycol (PEG 6000) and polydimethylsiloxane. It was shown that the surface-modified nanocomposites could reduce the S.T and IFT significantly and alter the wettability of a strong oil-wet carbonate rock to water-wet condition.

Magnetic mesoporous MCM-41 supported boric acid: A novel, efficient and ecofriendly nanocomposite

A novel magnetic mesoporous MCM-41 supported boric acid [Fe3O4@MCM-41-OB(OH)2] is prepared, characterized and its catalytic application is investigated. The Fe3O4@MCM-41-OB(OH)2 was prepared through modification of magnetic iron oxide nanoparticles with MCM-41 silica followed by treatment with boric acid. This nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM). The Fe3O4@MCM-41-OB(OH)2 was used as effective nanocatalyst in the one-pot Biginelli condensation of aldehydes with urea and alkylacetoacetates at 50 °C under ultrasonic conditions. The corresponding products were obtained in high yields (88–96%) at short times (15–30 min). The designed catalyst was successfully reused and recovered at least nine times without significant decrease in its stability and efficiency.

Treatment of wastewater from cationic dye using eco-friendly nanocomposite: Characterization, adsorption and kinetic studies

This investigation intended to the treatment of wastewater from cationic dyes utilizing economical eco-friendly nanocomposites arranged by green strategy. For this reason, Graphene oxide was set up and trapped in Arginine/Chitosan (Arg/Cs) hydrogel to perform Arg/Cs/GO nanocomposite. The magnetic nanocomposite Arg/Cs/GO-mag additionally arranged in situ to be receptive to a magnetic field. Characterization of Arg/Cs/GO, and Arg/Cs/GO-mag was performed. The impacts of different working conditions like starting pH, connect time, and starting dye dose on the sorption of methylthioninium chloride (MB) have been researched and pseudo-second order formula demonstrated much portrayed the sorption of MB. The thermodynamic variables were ascertained to anticipate the sorption kind.

In Situ Coprecipitation Formed Highly Water-Dispersible Magnetic Chitosan Nanopowder for Removal of Heavy Metals and Its Adsorption Mechanism

The requirement for enhanced, less expensive, and eco-friendly nanocomposites as an adsorbent is highly preferred for removal of heavy metals and in the major applications of environmental remediat...

In vitro molecular study of wound healing using biosynthesized bacteria nanocellulose/silver nanocomposite assisted by bioinformatics databases

BackgroundIn recent years, bacterial nanocellulose (BNC) based nanocomposites have been developed to promote healing property and antibacterial activity of BNC wound dressing. Molecular study can help to better understanding about interaction of genes and pathways involved in healing progression.ObjectivesThe aim of this study was to prepare bacterial nanocellulose/silver (BNC/Ag) nanocomposite films as ecofriendly wound dressing in order to assess their physical, cytotoxicity and antimicrobial properties. The in vitro molecular study was performed to evaluate expression of genes involved in healing of wounds after treatment with BNC/Ag biofilms.Study design, materials, and methodsSilver nanoparticles were formed by using Citrullus colocynthis extract within new isolated bacterial nanocellulose (BNC) RM1. The nanocomposites were characterized using X-ray diffraction, Fourier transform infrared, and field emission scanning electron microscopy. Besides, swelling property and Ag release profile of the nanocomposites were studied. The ability of nanocomposites to promote wound healing of human dermal fibroblast cells in vitro was studied. Bioinformatics databases were used to identify genes with important healing effect. Key genes which interfered with healing were studied by quantitative real time PCR.ResultsSpherical silver nanoparticles with particle size ranging from 20 to 50 nm were synthesized and impregnated within the structure of BNC. The resulting nanocomposites showed significant antibacterial activities with inhibition zones ranging from 7±0.25 to 16.24±0.09 mm against skin pathogenic bacteria. Moreover, it was compatible with human fibroblast cells (HDF) and could promote in vitro wound healing after 48h. Based on bioinformatics databases, the genes of TGF-β1, MMP2, MMP9, CTNNB1, Wnt4, hsa-miR-29b-3p and hsa-miR-29c-3p played important role in wound healing. The nanocomposites had an effect in expression of the genes in healing. Thus, the BNC/Ag nanocomposite can be used to heal wound in a short period and simple manner.ConclusionThis eco-friendly nanocomposite with excellent antibacterial activities and healing property confirming its utility as potential wound dressings.

Fabrication and characterization of an eco-friendly antibacterial nanocomposite of galactomannan/ZnO by in situ chemical co-precipitation method

The present study concerns the methodology for the successful synthesis of galactomannan/ZnO (GM/ZnO) nanocomposite using an in situ chemical co-precipitation route utilizing galactomannan as a nanoreactor. The galactomannan was isolated using a hydrothermal extraction from mezquite (Prosopis spp.) seeds, in which the tree represents a valuable resource for the habitants of arid and semiarid zones of Mexico. The GM/ZnO was synthesized at room temperature. The effects of changing the galactomannan concentration in the nanocomposite over the antibacterial activity against Escherichia coli and Staphylococcus aureus were investigated by microdilution broth method. The GM/ZnO with greatest antibacterial activity was the one with the lowest amount of galactomannan and it was characterized. The ZnO nanoparticles that were observed by SEM and TEM, showed the formation of ZnO nanoparticles, with flake/petal shape and wurtzite structure. The synthesis of nanocomposite was confirmed by FTIR, with strong interactions between the primary alcohol of the galactomannan and ZnO. The thermal stability and decomposition was determined by TGA and DSC, finding a greater thermal stability and an increase of the degradation temperature. A mechanism for the synthesis of GM/ZnO, as well as the formation model of the ZnO with the assistance of the galactomannan are proposed.

Molecular study of wound healing after using biosynthesized BNC/Fe3O4 nanocomposites assisted with a bioinformatics approach.

BackgroundMolecular investigation of wound healing has allowed better understanding about interaction of genes and pathways involved in healing progression.ObjectivesThe aim of this study was to prepare magnetic/bacterial nanocellulose (Fe3O4/BNC) nanocomposite films as ecofriendly wound dressing in order to evaluate their physical, cytotoxicity and antimicrobial properties. The molecular study was carried out to evaluate expression of genes involved in healing of wounds after treatment with BNC/Fe3O4 films.Study design, materials, and methodsMagnetic nanoparticles were biosynthesized by using Aloe vera extract in new isolated bacterial nanocellulose (BNC) RM1. The nanocomposites were characterized using X-ray diffraction, Fourier transform infrared, and field emission scanning electron microscopy. Moreover, swelling property and metal ions release profile of the nanocomposites were investigated. The ability of nanocomposites to promote wound healing of human dermal fibroblast cells in vitro was examined. Bioinformatics databases were used to identify genes with important healing effect. Key genes which interfered with healing were studied by quantitative real time PCR.ResultsSpherical magnetic nanoparticles (15–30 nm) were formed and immobilized within the structure of BNC. The BNC/Fe3O4 was nontoxic (IC50>500 μg/mL) with excellent wound healing efficiency after 48 hours. The nanocomposites showed good antibacterial activity ranging from 6±0.2 to 13.40±0.10 mm against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. The effective genes for the wound healing process were TGF-B1, MMP2, MMP9, Wnt4, CTNNB1, hsa-miR-29b, and hsa-miR-29c with time dependent manner. BNC/Fe3O4 has an effect on microRNA by reducing its expression and therefore causing an increase in the gene expression of other genes, which consequently resulted in wound healing.ConclusionThis eco-friendly nanocomposite with excellent healing properties can be used as an effective wound dressing for treatment of cutaneous wounds.

Fabricating eco-friendly nanocomposites of SiC with morphologically-different nano-carbonaceous phases

A route based on aqueous colloidal processing followed by liquid-phase assisted spark-plasma-sintering (SPS) is described for fabricating eco-friendly nanocomposites of SiC with nano-carbonaceous phases (nanotubes, nanoplatelets, or nanoparticles). To this end, the conditions optimizing the aqueous colloidal co-dispersion of SiC nanoparticles, Y3Al5O12 nanoparticles (acting as sintering additives), and carbon nanotubes (CNTs), graphene oxide (GO) nanoplatelets, or carbon black (CB) nanoparticles were first identified. Next, homogeneous powder mixtures were prepared by freeze-drying, and densified by liquid-phase assisted SPS, thus obtaining nanocomposites of SiC with CNTs, reduced GO (rGO) nanoplatelets, or pyrolized + graphitized CB (p + gCB) nanoparticles. It is also shown that these nanocomposites are dense and have a high hardness of ∼20 GPa regardless of the nano-carbonaceous phase chosen, but are markedly tougher with CNTs and rGO (i.e., with high aspect ratio nano-carbonaceous phases). Finally, arguments are provided for the appropriate choice of nano-carbonaceous phases for engineering ceramic nanocomposites.

Soy protein isolate nanocomposites reinforced with nanocellulose isolated from licorice residue: Water sensitivity and mechanical strength

The cellulose-rich residues of licorice are usually discarded as waste in many medicine factories, resulting in serious wastage of biomass. In this work, nanocellulose was extracted from licorice residue and the microstructure, particle size, crystallinity, and stability were investigated. The prepared licorice residue nanocellulose (LNC) was incorporated to soy protein isolate (SPI) for the production of eco-friendly nanocomposites. The effects of LNC content (0, 2, 4, 6, and 8 wt%) on the water sensitivity, mechanical and barrier properties of SPI films were characterized. The results revealed that LNC had a short rod-like structure (100–400 nm in length and 10–35 nm in diameter) and had high stability in aqueous media. LNC had a higher crystallinity degree than licorice residue cellulose. The addition of LNC significantly improved the properties of SPI films, especially at 6 wt%. At 6 wt% LNC, tensile strength and contact angle of SPI films increased by 35.4% and 20.3%, respectively, and monolayer moisture content, water vapor permeability, and oxygen permeability decreased by 44.4%, 27.2%, and 55.5%, respectively.

Eco-friendly polyvinyl alcohol (PVA)/bamboo charcoal (BC) nanocomposites with superior mechanical and thermal properties

Carbon-based nanofillers, such as carbon nanotubes (CNTs) and graphene sheets are considered as effective nanoreinforcements due to their unique structures and material performance. However, the utilisation of such nanofillers can be hindered owing to a high level of nanotoxicity via human inhalation and high material cost for CNTs, as well as the tendency to form agglomerates of graphene sheets in polymer matrices. Bamboo charcoals (BCs) are eco-friendly and sustainable carbon-based particles, which possess good affinity with polyvinyl alcohol (PVA), one of popular water soluble biopolymers, to achieve excellent properties of PVA/BC nanocomposites. In particular, porous structures of BC particles enable polymeric molecules to easily penetrate with the strong internal bonding. In this study, fully eco-friendly PVA/BC nanocomposite films were successfully fabricated using a simple solution casting method to achieve the high dispersibility of BCs. With the inclusion of only 3 wt% BCs, tensile modulus and tensile strength of PVA/BC nanocomposite films were enhanced by 70.2 and 71.6%, respectively, when compared with those of PVA films. Better thermal stability is manifested for resulting nanocomposite films as opposed to that of pristine PVA, which is evidenced by the maximum increase of 17.8% in the decomposition temperature at the weight loss of 80%. It is anticipated that BCs can compete against conventional carbon-based nanofillers with a great potential to be developed into eco-friendly nanocomposites used for thin-film packaging application.

Waterborne polyurethane-urea dispersion with chain extension step in homogeneous medium reinforced with cellulose nanocrystals

Waterborne polyurethane-urea (WBPUU) dispersions have gained attention towards environmentally-friendly synthesis routes. Differing from the conventional WBPUU synthesis route where the diamine chain extension is performed in heterogeneous medium in the surface of the already formed particles, in this case the chain extension was carried out in homogeneous medium, prior to WBPUU nanoparticles formation. Thus, stable WBPUU dispersion with small particle sizes and narrow distribution was synthesized. Furthermore, cellulose nanocrystals (CNC) were isolated for the preparation of eco-friendly nanocomposites just by mixing. Nanocomposites with different CNC contents were prepared and extensively characterized in terms of physicochemical, thermal, thermomechanical and mechanical properties, hydrophilic behavior and morphology.

Eco-friendly nanocomposites between carboxylated acrylonitrile–butadiene rubber (XNBR) and graphene oxide or graphene at low content with enhanced mechanical properties

ABSTRACTA crucial step in rubber nanocomposites is the homogenous dispersion of the nanofillers within the elastomer matrix. Herein, a green and modified latex co-coagulation strategy was conducted to develop high-performance nanocomposite materials based on carboxylated acrylonitrile-butadiene rubber (XNBR) latex with graphene oxide (GO) or reduced graphene oxide (RGO). Aqueous solutions with different concentrations of GO or RGO were mixed with XNBR rubber latex under vigorous magnetic stirring. The incorporation of graphene-derivative fillers in the XNBR matrix provided significant improvements in the rheological and mechanical properties compared to the unfilled rubber. Indeed, with increasing fillers loading, the maximum torque, tensile strength and crosslink density of obtained nanocomposites were found to increase. These results were correlated to the better dispersion of fillers through the matrix and, thus, to stronger interactions between the oxygen-containing functional groups of fillers and the carboxyl ones in XNBR matrix.

Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces.

Biohybrid materials based on the intercalation of zein, the major storage protein in corn, into sodium-exchanged montmorillonite were prepared following two synthesis strategies. The first one made use of zein dissolved in 80% (v/v) ethanol/water solution, the usual solvent for this protein, while the second method is new and uses a sequential process that implies the previous separation of zein components in absolute ethanol. This treatment of zein with ethanol renders a soluble yellow phase and an agglomerate of insoluble components, which are able to intercalate the layered silicate when an aqueous dispersion of montmorillonite is added to the ethanol medium containing both phases. The diverse steps in this second route were investigated individually in order to understand the underlying mechanism that drives to the intercalation of this complex hydrophobic biomacromolecule into the hydrophilic interlayer space of sodium-exchanged montmorillonite. In addition to physicochemical characterization of the resulting materials, these biohybrid interfaces were also evaluated as biofillers in the preparation of diverse ecofriendly nanocomposites.

Removal of lead ion and oil droplet from aqueous solution by lignin-grafted carbon nanotubes

Water contamination is one of the most serious problems afflicting people throughout the world, innovation of nanomaterials with eco-friendliness is important for a greener environment. Here, an eco-friendly nanocomposite based on lignin grafted carbon nanotubes (L-CNTs) is reported as a new type of adsorbent for water remediation. By integrating the tridimensional structure, oxygen-containing functional groups and eco-friendliness of lignin with the high surface area and mechanical stability of CNTs, the as-prepared nanocomposite not only possesses a good water-dispersibility and eco-friendliness, but also exhibits an excellent adsorption capability for lead ion and oil droplet. It shows a high distribution coefficient for lead ion (Kd=3.6×105mL/g) that is comparable to some benchmark materials, including mesoporous carbon and metal-organic frameworks. The large surface area and tridimensional structure also endows L-CNTs with a high removal efficiency for oil droplet from water. Moreover, the cost of the nanocomposite has been minimized by incorporation of the low cost lignin. These results demonstrate the as-obtained nanocomposite with a natural polymer layer has advanced adsorption capability, low-in cost and eco-friendliness, and accordingly is an ideal candidate for water cleanup.

Eco-Friendly Electromagnetic Interference Shielding Materials from Flexible Reduced Graphene Oxide Filled Polycaprolactone/Polyaniline Nanocomposites

ABSTRACTHybrid nanocomposites have the unique ability of enhancing material properties due to the existing synergistic effect of the fillers. In this study, the authors report such an eco-friendly hybrid nanocomposite comprising of polyaniline and reduced graphene oxide in polycaprolactone. The conducting polyaniline improved the processability of polycaprolactone, and the final composites were prepared by incorporating graphene oxide reduced at 200 and 600°C temperatures to the polycaprolactone–polyaniline blend. Polyaniline, polyaniline/reduced graphene oxide200, and polyaniline/reduced graphene oxide600 imparted good electrical conductivity to polycaprolactone, and the fabricated flexible polycaprolactone–polyaniline/reduced graphene oxide nanocomposites exhibited good mechanical property, increased thermal stability, and excellent electromagnetic interference shielding up to 42 dB at 13 GHz.

Photobiosynthesis of metal/graphene nanocomposites: new materials for water desalination and purification

Ultra-pure water, free from metals and micro-organisms, has been easy obtained from Red seawater (Jeddah, KSA) by plasmonic-graphene hybrid nanocomposites that green synthesized using Baker’s yeast (Saccharomyces cerevisiae) extract under visible light irradiation. Gas chromatography mass spectroscopy (GC/MS) analysis of aqueous yeast extract indicates the presence of significant biomolecules; butane-2,3-diol, glucose, undecanoic acid, and indole-3-acetic acid that can act under visible light as reducing and capping agent for the growth of (Ag, Au, and Ag/Au) plasmonic nanoparticles and graphene-based plasmonic nanocomposites. These nanocomposites able to absorb sunlight very strongly and converting it very efficiently into heat energy that enhancing the seawater evaporation. Bimetallic Ag/Au/reduced graphene-oxide nanocomposites show the highest gain of temperature and highest stability after three times of recycling processes. These eco-friendly nanocomposites are smart alternatives in water desalination and purification technique by taking the advantages of their excellent photothermal conversion, its energy-saving, cost-effective, and ease recyclability.

Synthesis and characterization of bifunctional lipophilic and basic mesoporous organosilica supported palladium nanoparticles as an efficient and ecofriendly nanocomposite in aqueous Heck reaction

In the present study, a highly ordered mesoporous organosilica nanocomposite having modified pore channels with both lipophilic and basic units, SBA-R/Im-NH2, was synthesized through surfactant-templated sol–gel methodology and post modification process.