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Active food packaging incorporated with natural plant extracts as food preservatives, which will totally replace chemical preservatives gradually, are of major interest. Sequentially to our and other scientists’ previous work, in this paper we present the results of a study on the development of a novel active food packaging film based on the incorporation of a natural-halloysite/carvacrol-extract nanohybrid with the commercially used low-density polyethylene. The corona-treatment procedure was employed to incorporate a natural preservative on to the optimum final film. Packaging films are formatted with and without incorporation of natural-halloysite/carvacrol-extract nanohybrid and are coated externally, directly or via corona-treatment, with carvacrol essential oil. Mechanical, physicochemical, and preservation tests indicated that the low-density polyethylene incorporated perfectly with a natural-halloysite/carvacrol-extract nanohybrid. The extra external coating of the film with pure carvacrol extract using the corona-treatment technique led to approximately 100% higher Young Modulus values, slightly decreased ultimate strength by 20%, and exhibited almost stable elongation at break properties. The water vapor and oxygen properties were increased by 45 and 43%, correspondingly, compared to those of pure low-density polyethylene film. Finally, the antioxidant activity of the corona-treated film increased by 28% compared to the untreated film coated with carvacrol because of the controlled release rate of the carvacrol.

Aluminum-coated plastics, such as CDs and snack bags, are widely used and consumed around the world. Since millions of CDs and trillions of snack bags end up in landfills and oceans as plastic waste every year, we suggest here an easy, fast, and cost-effective method for transforming this significant volume of garbage into added-value carbon using microwave technology. The proposed method differs from existing time- and energy-consuming pyrolytic processes employed in the traditional carbonization of this sort of waste. Conceptually, direct irradiation of the aluminum-coated plastic items in a domestic microwave oven heats up the metallic coating, thus triggering carbonization of the plastic substrate. The resulting carbon, which is characterized by means of X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques, has structural similarities to carbons produced from CDs and snack bags using pyrolytic methods. In other words, the microwave technique produces similar effect, but it is faster and more energy efficient. We finally demonstrate some practical uses of the derived materials in gunpowder production, carbothermal production of metals and grey paint formulations.

This work presents the development of novel gypsum board composites for advanced thermal energy storage (TES) and electromagnetic interference (EMI) shielding applications. Activated carbon (AC) derived from spent coffee with a high surface area (SBET = 1372 m2/g) was used as a shape stabilizer, while the commercial paraffin, RT18HC, was used as organic encapsulant phase change material (PCM). The AC showed a remarkable encapsulation efficiency as a shape stabilizer for PCM, with ~120.9 wt% (RT18HC), while the melting enthalpy (ΔHm) of the shape-stabilized PCM was 117.3 J/g. The performance of this PCM/carbon nanocomposite as a thermal energy storage material was examined by incorporating it into building components, such as gypsum wallboards. The microstructure of these advanced panels, their density, and their dispersion of additives were examined using X-ray microtomography. Their thermal-regulated performance was measured through a self-designed room model with a similar homemade environmental chamber that was able to create a uniform temperature environment, surrounding the test room during heating and cooling. The measurements showed that the advanced panels reduce temperature fluctuations and the indoor temperature of the room model, in comparison with normal gypsum panels, by a range of 2–5%. The investigated gypsum board composite samples showed efficient electromagnetic shielding performance in a frequency range of 3.5–7.0 GHz, reaching an EMI value of ~12.5 dB, which is adequate and required for commercial applications, when filled with PCMs.

Developing materials for efficient energy storage and effective electromagnetic interference (EMI) shielding is crucial in modern technology. This study explores the synthesis and characterization of carbonaceous shape-stabilized octadecane/MWCNT (multi-walled carbon nanotube) composites, utilizing activated carbon, expanded graphite or ceramic carbon foam, as shape stabilizers for phase change materials (PCMs) to enhance thermal energy storage and EMI shielding, for energy-efficient and advanced applications. The integration of octadecane, a phase change material (PCM) with carbonaceous stabilizers ensures the material’s stability during phase transitions, while MWCNTs contribute to improved thermal storage properties and EMI shielding capabilities. The research aims to develop novel composites with dual functionality for thermal storage and EMI shielding, emphasizing the role of carbon matrices and their MWCNT composites. SEM and CT microtomography analyses reveal variations in MWCNT incorporation across the matrices, influenced by surface properties and porosity. Leaching tests, infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) confirm the composite’s stability and high latent heat storage. The presence of nanotubes enhances the thermal properties of octadecane and ΔH values almost reached their theoretical values. EMI shielding effectiveness measurements indicate that the composites show improved electric properties in the presence of MWCNTs.

There is a rising demand for energy-efficient and low-carbon buildings that is driven by the energy consumption in the building sector, global population growth, and high standards of comfort. Integrating contemporary energy-efficient technologies is crucial for tackling this issue. In this study, thermal energy storage (TES) technologies are investigated, particularly phase change materials (PCMs), by using them in buildings and in order to improve energy efficiency. Paraffin-based PCMs are the main focus and are known for their advanced thermal storage capacity and compatibility with building materials. The work focuses on embedding these PCMs into building components such as roofs and walls in order to maximize energy efficiency. Key data, including thermal conductivity (varying from 0.063 W/mK to 0.175 W/mK) and solar reflectance (ranging from 42.7% to 70.31%), were taken with a Hot Disc TPS1500 and a UV-Vis-NIR spectrophotometer and used as inputs for EnergyPlus calculations. The results show that PCM-enhanced materials greatly increase thermal regulation and energy efficiency. Gypsum boards 30% PCM-enhanced used in buildings achieved up to 12.8% annual energy consumption reductions (106.1 kWh/m2) and 22.3% net annual energy consumption savings (52.2 kWh/m2) when compared to baseline scenarios. The study indicates that PCM integration can significantly cut energy usage while improving indoor thermal comfort, underlining its potential for widespread use in sustainable building design.

Non-toxic carbon-based hybrid nanomaterials based on carbon nanodisks were synthesized and assessed as novel antibacterial agents. Specifically, acid-treated carbon nanodisks (oxCNDs), as a safe alternative material to graphene oxide, interacted through covalent and non-covalent bonding with guanidinylated hyperbranched polyethyleneimine derivatives (GPEI5K and GPEI25K), affording the oxCNDs@GPEI5K and oxCNDs@GPEI25K hybrids. Their physico-chemical characterization confirmed the successful and homogenous attachment of GPEIs on the surface of oxCNDs, which, due to the presence of guanidinium groups, offered them improved aqueous stability. Moreover, the antibacterial activity of oxCNDs@GPEIs was evaluated against Gram-negative E. coli and Gram-positive S. aureus bacteria. It was found that both hybrids exhibited enhanced antibacterial activity, with oxCNDs@GPEI5K being more active than oxCNDs@GPEI25K. Their MIC and MBC values were found to be much lower than those of oxCNDs, revealing that the GPEI attachment endowed the hybrids with enhanced antibacterial properties. These improved properties were attributed to the polycationic character of the oxCNDs@GPEIs, which enables effective interaction with the bacterial cytoplasmic membrane and cell walls, leading to cell envelope damage, and eventually cell lysis. Finally, oxCNDs@GPEIs showed minimal cytotoxicity on mammalian cells, indicating that these hybrid nanomaterials have great potential to be used as safe and efficient antibacterial agents.

Chitosan and fish gelatin, two natural polymers, coupled with glycerol, were used to develop hydrogel membranes. The membrane properties of the prepared membranes, have been improved after heat treatment, leading to materials with ameliorated mechanical performance and lower degradation rate. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and x-ray diffraction (XRD) tests were conducted to study the interactions between the biopolymers and the plasticizer. Biopolymers and plasticizer interact via secondary interactions with all plasticized materials being amorphous. Scanning electron microscopy (SEM) was used to evaluate the morphology of the materials and showed that increase in fish gelatin concentration leads to rougher surface morphologies. Dynamic mechanical analysis (DMA) measurements and tensile testing, indicated that increase in fish gelatin concentration leads to improved mechanical performance and in particular in terms of maximum strain at break as well as stress at break. Water absorption and degradation rates were found to be fully dependent on fish gelatin concentration as expected. Antimicrobial testing via the measurement of an inhibition zone, as well as ,endothelial cell attachment and proliferation results (in vitro endothelial cell colonization tests) indicate that the hydrogel membranes show promising potential for use in wound healing/care applications (protection against bacteria, providing a moist environment, etc.).

Three-dimensional (3D) printing has gained increasing attention for its unique ability to create geometrically complex designs, which not only can be used for mass manufacturing but also has environmental and economic benefits. Additionally, as far as the food industry is concerned, this emerging technology has the potential to personalize products in terms of shape and/or nutritional requirements creating a wide range of food items with specially made shapes, colors, textures, tastes, and even nutrition using suitable raw materials/food components. In the future, 3D food printing could make complex food models with special interior design. This review gives attention to intelligent food packaging. Point-of-use machinery for manufacturing smart packaging, with a 3D printing approach, enables the use of multifunctional smart components and is self-identifying and highly sensitive, while using biocompatible non-toxic materials is cheaper than traditional manufacturing methods. This would create smart food packaging and in turn prevent customers from purchasing unsuitable food and thus reduce food waste. Future studies can make the process more compatible and efficient with a wide variety of materials that could be used to improve the 3D printing process.

Nowadays, the scientific interest is focused more and more on the development of new strategies in recycling of waste products as well as on the development of clean technologies due to the increased environmental pollution. In this work we studied the valorization of an expired cheese-tomato flavor corn snack, which is polysaccharide food product, by producing advanced hybrid magnetic materials for environmental remediation purposes. The carbonization-chemical activation of this snack using potassium hydroxide leads to a microporous activated carbon with high surface area (SgBET ~800 m2/g). The magnetic hybrid material was synthesized via an in-situ technique using iron acetate complex as the precursor to produce iron based magnetic nanoparticles. The resulting material retains a fraction of the microporous structure with surface area SgBET ~500 m2/g. Such material consists, of homogenously dispersed magnetic isolated zero valent iron nanoparticles and of iron carbides (Fe3C), into the carbon matrix. The magnetic carbon exhibited high adsorption capacity in Cr(VI) removal applications following a pseudosecond order kinetic model. The maximum adsorption capacity was 88.382 mgCr(VI)/gAC at pH = 3. Finally, oxidation experiments, in combination with FT-IR, Mössbauer, and VSM measurements indicated that the possible Cr6+ removal mechanism involves oxidation of iron phases and reduction of Cr6+ to Cr3+.

Hypergolic reactions have emerged as a new synthetic approach enabling the rapid production of a diverse set of materials at ambient conditions. While hypergolic reactions bear several similarities to the well-established flame spray pyrolysis (FSP), the former has only recently been demonstrated as a viable approach to materials synthesis. Here we demonstrate a new pathway to 2D materials using hypergolic reactions and expand the gallery of nanomaterials synthesized hypergolically. More specifically, we demonstrate that ammonia borane complex, NH _3 BH _3 , or 4-fluoroaniline can react hypergolically with fuming nitric acid to form hexagonal boron nitride/fluorinated carbon nanosheets, respectively. Structural and chemical features were confirmed with x-ray diffraction, infrared, Raman, XPS spectroscopies and N _2 porosimetry measurements. Electron microscopy (SEM and TEM) along with atomic force microscopy (AFM) were used to characterize the morphology of the materials. Finally, we applied Hansen affinity parameters to quantify the surface/interfacial properties using their dispersibility in solvents. Of the solvents tested, ethylene glycol and ethanol exhibited the most stable dispersions of hexagonal boron nitride (h-BN). With respect to fluorinated carbon (FC) nanosheets, the suitable solvents for high stability dispersions were dimethylsulfoxide and 2-propanol. The dispersibility was quantified in terms of Hansen affinity parameters ( δ _d , δ _p , δ _h ) = (16.6, 8.2, 21.3) and (17.4, 10.1, 14.5) MPa ^1/2 for h-BN and FC, respectively.

Biomass exploitation is a global trend due to the circular economy and the environmentally friendly spirit. Numerous applications are now based on the use of biomass-derived products. Hydrogen sulfide (H2S) is a highly toxic and environmentally hazardous gas which is emitted from various processes. Thus, the efficient removal of this toxic hazardous gas following cost-effective processes is an essential requirement. In this study, we present the synthesis and characterization of biomass-derived activated carbon/zinc oxide (ZnO@AC) composites from different biomass sources as potential candidates for H2S sorption. The synthesis involved a facile method for activated carbon production via pyrolysis and chemical activation of biomass precursors (spent coffee, Aloe-Vera waste leaves, and corncob). Activated carbon production was followed by the incorporation of zinc oxide nanoparticles into the porous carbon matrix using a simple melt impregnation method. The synthesized ZnO@AC composites were characterized using X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and nitrogen porosimetry. The H2S removal performance of the ZnO@AC composites was evaluated through sorption experiments using a handmade apparatus. Our findings demonstrate that the Aloe-Vera-, spent coffee-, and corncob-derived composites exhibit superior H2S sorption capacity up to 106 mgH2S/gads., 66 mgH2S/gads., and 47 mgH2S/gads., respectively.

Chondroitin sulfate (ChS), chitosan (Chi), and fish gelatin (FG), which are byproducts of a fish-treatment small enterprise, were incorporated with glycerol (Gly) to obtain dense hydrogel membranes with reduced brittleness, candidates for dressing in wound healing applications. The mechanical properties of all samples were studied via Dynamic Mechanical Analysis (DMA) and tensile tests while their internal structure was characterized using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray Diffraction (XRD) instruments. Their surface morphology was analyzed by ThermoGravimetric Analysis (TGA) method, while their water permeability was estimated via Water Vapor Transmission Rate (WVTR) measurements. Wettability and degradation rate measurements were also carried out. Characterization results indicated that secondary interactions between the natural polymers and the plasticizer create the hydrogel membranes. The samples were amorphous due to the high concentration of plasticizer and the amorphous nature of the natural polymers. The integration of ChS led to decreased decomposition temperature in comparison with the glycerol-free sample, and all the materials had dense structures. Finally, the in vitro endothelial cell attachment studies indicate that the hydrogel membranes successfully support the attachment and survival of primary on the hydrogel membranes and could be appropriate for external application in wound healing applications as dressings.

Additive manufacturing, also known as 3D-printing, has been successfully employed to create novel bioactive scaffolds incorporating carbon dots for bioimaging purposes. Fused filament fabrication technique (FFF) was used to print a hybrid poly-lactic acid (PLA)-based filament bearing bioactive material, suited for hydroxyapatite (HAp) development, as well as carbon dots which by virtue of their strong luminescence could support an optical characterization of the composite, thus, its regenerative stages. This technique using FFF biodegradable PLA can be used to create the exact custom-made scaffold depending on the user needs (i.e. shape of a bone fracture), whereas the bioactive material (bioglass® 45S5) assists bone regeneration by HAp development. On the other hand, biocompatible red emissive boron-doped carbon dots could allow for monitoring of the procedure. Scaffolds were tested for their in vitro bioactivity by soaking in simulated body fluid (SBF) solution. In addition, in vitro cytotoxicity testing confirmed the low toxicity of the composite materials used for creating the scaffolds. Degradation of the PLA scaffold initiated immediately providing space for bone regeneration. HAp development was confirmed by scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM/EDS) and infrared spectroscopy (IR). Ultraviolet visible and photoluminescence spectroscopies were used to evaluate the properties of the carbon dots as well as composite materials. Results indicate that this is a promising technique for confronting asymmetric or irregular-shaped bone fractures with simultaneous monitoring of the healing process through bioimaging.

Currently, food saving, a circular economy, and zero environmental fingerprints are of major interest. Scientific efforts for enhanced food preservation using “green” methods have been intensified. Even though chemicals could achieve such targets effectively, the global trend against the “greenhouse effect” suggests the use of environmentally friendly biobased materials for this purpose. In this study, the promising biopolymer chitosan is incorporated with the promising biodegradable polymer polyvinyl alcohol to produce an improved biopolymeric matrix. This biodegradable biopolymer was further mixed homogeneously with 15% thymol/nano-zeolite nanohybrid material. The properties of the final developed film were improved compared to the relevant values of chitosan/polyvinyl alcohol film. The mechanical properties were enhanced significantly, i.e., there was a 34% increase in Young’s modulus and a 4.5% increase in the ultimate tensile strength, while the antioxidant activity increased by 53.4%. The antibacterial activity increased by 134% for Escherichia coli, 87.5% for Staphylococcus aureus, 32% for Listeria monocytogenes, and 9% for Salmonella enterica. The water vapor diffusion coefficient and the oxygen permeability coefficient decreased to −51% and −74%, respectively, and thus, the water vapor and oxygen barrier increased significantly. The active pads were used in strawberries, and the antimicrobial activity evaluation against the mold of fungi was carried out. The visual evaluation shows that the active pads could extend the shelf life duration of strawberries.

Developing materials for efficient energy storage and effective electromagnetic interference (EMI) shielding is crucial in modern technology. This study explores the synthesis and characterization of carbonaceous shape-stabilized octadecane/MWCNT (multi-walled carbon nanotube) composites, utilizing activated carbon, expanded graphite or ceramic carbon foam, as shape stabilizers for phase change materials (PCMs) to enhance thermal energy storage and EMI shielding, for energy-efficient and advanced applications. The integration of octadecane, a phase change material (PCM) with carbonaceous stabilizers ensures the material's stability during phase transitions, while MWCNTs contribute to improved thermal storage properties and EMI shielding capabilities. The research aims to develop novel composites with dual functionality for thermal storage and EMI shielding, emphasizing the role of carbon matrices and their MWCNT composites. SEM and CT microtomography analyses reveal variations in MWCNT incorporation across the matrices, influenced by surface properties and porosity. Leaching tests, infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) confirm the composite's stability and high latent heat storage. The presence of nanotubes enhances the thermal properties of octadecane and ΔH values almost reached their theoretical values. EMI shielding effectiveness measurements indicate that the composites show improved electric properties in the presence of MWCNTs. [ABSTRACT FROM AUTHOR]

Active food packaging incorporated with natural plant extracts as food preservatives, which will totally replace chemical preservatives gradually, are of major interest. Sequentially to our and other scientists' previous work, in this paper we present the results of a study on the development of a novel active food packaging film based on the incorporation of a natural-halloysite/carvacrol-extract nanohybrid with the commercially used low-density polyethylene. The corona-treatment procedure was employed to incorporate a natural preservative on to the optimum final film. Packaging films are formatted with and without incorporation of natural-halloysite/carvacrol-extract nanohybrid and are coated externally, directly or via corona-treatment, with carvacrol essential oil. Mechanical, physicochemical, and preservation tests indicated that the low-density polyethylene incorporated perfectly with a natural-halloysite/carvacrol-extract nanohybrid. The extra external coating of the film with pure carvacrol extract using the corona-treatment technique led to approximately 100% higher Young Modulus values, slightly decreased ultimate strength by 20%, and exhibited almost stable elongation at break properties. The water vapor and oxygen properties were increased by 45 and 43%, correspondingly, compared to those of pure low-density polyethylene film. Finally, the antioxidant activity of the corona-treated film increased by 28% compared to the untreated film coated with carvacrol because of the controlled release rate of the carvacrol. [ABSTRACT FROM AUTHOR]

There is a rising demand for energy-efficient and low-carbon buildings that is driven by the energy consumption in the building sector, global population growth, and high standards of comfort. Integrating contemporary energy-efficient technologies is crucial for tackling this issue. In this study, thermal energy storage (TES) technologies are investigated, particularly phase change materials (PCMs), by using them in buildings and in order to improve energy efficiency. Paraffin-based PCMs are the main focus and are known for their advanced thermal storage capacity and compatibility with building materials. The work focuses on embedding these PCMs into building components such as roofs and walls in order to maximize energy efficiency. Key data, including thermal conductivity (varying from 0.063 W/mK to 0.175 W/mK) and solar reflectance (ranging from 42.7% to 70.31%), were taken with a Hot Disc TPS1500 and a UV-Vis-NIR spectrophotometer and used as inputs for EnergyPlus calculations. The results show that PCM-enhanced materials greatly increase thermal regulation and energy efficiency. Gypsum boards 30% PCM-enhanced used in buildings achieved up to 12.8% annual energy consumption reductions (106.1 kWh/m2) and 22.3% net annual energy consumption savings (52.2 kWh/m2) when compared to baseline scenarios. The study indicates that PCM integration can significantly cut energy usage while improving indoor thermal comfort, underlining its potential for widespread use in sustainable building design. [ABSTRACT FROM AUTHOR]

This article explores the cutting-edge advancement of gypsum or cement building boards infused with shape-stabilized n-octadecane, an organic phase change material (PCM). The primary focus is on improving energy efficiency and providing electromagnetic interference (EMI) shielding capabilities for contemporary buildings. This research investigates the integration of these materials into construction materials, using red-mud carbon foam (CCF) as a stabilizer for n-octadecane (OD@CCF). Various analyses, including microstructural examination, porosity, and additive dispersion assessment, were conducted using X-ray microtomography and density measurements. Thermal conductivity measurements demonstrated the enhancement of composite boards as the OD@CCF content increased, while mechanical tests indicated an optimal additive content of up to 20%. The thermally regulated capabilities of these advanced panels were evaluated in a custom-designed room model, equipped with a homemade environmental chamber, ensuring a consistent temperature environment during heating and cooling cycles. The incorporation of OD@CCF into cement boards exhibited improved thermal energy storage properties. Moreover, the examined composite boards displayed efficient electromagnetic shielding performance within the frequency range of 3.2–7.0 GHz, achieving EMI values of approximately 18 and 19.5 dB for gypsum and cement boards, respectively, meeting the minimum value necessary for industrial applications. [ABSTRACT FROM AUTHOR]

This study presents, the development of a green method to produce rich in thymol natural zeolite (TO@NZ) nanostructures. This material was used to prepare sodium-alginate/glycerol/xTO@NZ (ALG/G/TO@NZ) nanocomposite active films for the packaging of soft cheese to extend its shelf-life. Differential scanning calorimetry (DSC), X-ray analysis (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) instruments were used for the characterization of such nanostructures and films, to identify the thymol adsorbed amount, to investigate the thermal behaviour, and to confirm the dispersion of nanostructure powder into the polymer matrix. Water vapor transmission rate, oxygen permeation analyzer, tensile measurements, antioxidant measurements, and antimicrobial measurements were used to estimate the film’s water and oxygen barrier, mechanical properties, nanostructure’s nanoreinforcement activity, antioxidant and antimicrobial activity. The findings from the study revealed that ALG/G/TO@NZ nanocomposite film could be used as an active packaging film for foods with enhanced, mechanical properties, oxygen and water barrier, antioxidant and antimicrobial activity, and it is capable of extending food shelf-life.

The global turn from the linear to the circular economy imposes changes in common activities such as food packaging. The use of biodegradable materials such as polyvinyl alcohol, natural raw materials such as clays, and food byproducts such as chitosan to develop novel food packaging films attracts the interest of industrial and institutional research centers. In this study, novel hybrid nanostructures were synthesized via the growth of zinc oxide nanorods on the surface of two nanoclays. The obtained nanostructures were incorporated with chitosan/polyvinyl alcohol composite either as nanoreinforcement or as an active agent to develop packaging films. The developed films were characterized via XRD, FTIR, mechanical, water-vapor diffusion, water sorption, and oxygen permeability measurements. Antimicrobial activity measurements were carried out against four different pathogen microorganisms. XRD indicated the formation of an intercalated nanocomposite structure for both types of nanoclays. Furthermore, improved tensile, water/oxygen barrier, and antimicrobial properties were recorded for all films compared to the pure chitosan/polyvinyl alcohol film. Overall, the results indicated that the use of the bio-based developed films led to an extension of food shelf life and could be used as novel active food packaging materials. Among them, the most promising film was the 6% wt. ZnO@halloysite.

Sodium polyacrylate is the superabsorbent waterlock polymer used in disposable diapers, which are the third largest single consumer item in landfills. As diapers are difficult to recycle, their use produces an incredible amount of environmental waste. In the present article, we present a reliable and facile approach to transform sodium polyacrylate, the main constitute in the used diapers, in a carbon-based magnetic sorbent material, capable for use in environmental applications. A nanoporous carbon magnetic hybrid material was prepared by reacting NaPA with iron acetate species under chemical activation conditions. Analysis of the characterization results revealed, the creation of a nanoporous structure, with high specific surface area value (SgBET = 611 m2/g), along with the formation of nanosized zero valent iron nanoparticles and iron carbide (Fe3C), inside the carbon pore system. 57Fe Mössbauer spectroscopy verified also the existence of these two main iron-bearing phases, as well as additional minor magnetic phases, such as Fe3O4 and γ-Fe2O3. Vibrating sample magnetometry (VSM) measurements of the obtained hybrid confirmed its ferromagnetic/ferrimagnetic behavior. The hybrid material demonstrated a rapid sorption of Cr(VI) ions (adsorption capacity: 90 mg/g, 24 h, pH = 3). The results showed highly pH-dependent sorption efficiency of the hybrids, whereas a pseudo-second-order kinetic model described their kinetics.

Today, the use of natural biodegradable materials in the production processes is more and more adopted by industry to achieve cyclic economy targets and to improve environmental and human health indexes. Active packaging is the latest trend for food preservation. In this work, nanostructures were prepared by incorporation of thyme oil with natural natrium-montmorillonite and organo-montmorillonite with two different techniques, direct impregnation and the green evaporation–adsorption process. Such nanostructures were mixed with poly-L-lactic-acid for the first time via an extrusion molding process to develop a new packaging film. Comparisons of morphological, mechanical, and other basic properties for food packaging were carried out via XRD, FTIR, TG, SEM/EDS, oxygen and water vapor permeation, and antimicrobial and antioxidant activity for the first time. Results showed that poly-L-lactic-acid could be modified with clays and essential oils to produce improved active packaging films. The final product exhibits food odor prevention characteristics and shelf-life extension capabilities, and it could be used for active packaging. The films based on OrgMt clay seems to be more promising, while the thyme oil addition improves their behavior as active packaging. The PLLA/3%TO@OrgMt and PLLA/5%TO@OrgMt films were qualified between the tested samples as the most promising materials for this purpose.

More than 14 billion pencils are manufactured and used globally every year. On average, a pencil is discarded after 60% of its original length has been depleted. In the present work we propose a simple and affordable way of converting this non-neglectable amount of waste into added value carbon product. In particular, we demonstrate the microwave synthesis of carbon from the wood pencil with and without chemical activation. This could be a process stage before the final recycling of the expensive graphite core. In the latter case, irradiation of the wood pencil in a domestic microwave oven heats up the pencil’s graphite core, thus inducing carbonization of its wood casing. The carbonized product consists of amorphous carbon nanosheets having relatively low surface area. However, if the wood pencil is soaked in 50% KOH aqueous solution prior to microwave irradiation, a significantly higher surface area of carbon is obtained, consisting of irregular-shaped porous particles. Consequently, the obtained carbon can easily decolorize a methylene blue aqueous solution, can be used to make pocket warmers or gunpowder, and lastly, serves as an excellent adsorbent towards Cr(VI) removal from water, showing a maximum adsorption capacity of 70–75 mg/g within 24 h at 23 °C, pH = 3.

Hypergolic materials synthesis is a new preparative technique in materials science that allows a wide range of carbon or inorganic solids with useful properties to be obtained. Previously we have demonstrated that metallocenes are versatile reagents in the hypergolic synthesis of inorganic materials, such as γ-Fe2O3, Cr2O3, Co, Ni and alloy CoNi. Here, we go one step further by using metallocene dichlorides as precursors for the hypergolic synthesis of additional inorganic phases, such as photocatalytic titania. Metallocene dichlorides are closely related to metallocenes, thus expanding the arsenal of organometallic compounds that can be used in hypergolic materials synthesis. In the present case, we show that hypergolic ignition of the titanocene dichloride–fuming nitric acid pair results in the fast and spontaneous formation of titania nanoparticles at ambient conditions in the form of anatase–rutile mixed phases. The obtained titania shows good photocatalytic activity towards Cr(VI) removal (100% within 9 h), with the latter being dramatically enhanced after calcination of the powder at 500 °C (100% within 3 h). Notably, this performance was found to be comparable to that of commercially available P25 TiO2 under identical conditions. The cases of zirconocene, hafnocene and molybdocene dichlorides are discussed in this work, which aims to show the wider applicability of metallocene dichlorides in the hypergolic synthesis of inorganic materials (ZrO2, HfO2, MoO2).

The creation of a hierarchical interface between the carbon fiber (CF) and the epoxy resin matrix of fiber-reinforced polymer (CFRP) composites has become an effective strategy for introducing multifunctional properties. Although the efficacy of many hierarchical interfaces has been established in lab-scale, their production is not amenable to high-volume, continuous, cost effective fiber production, which is required for the large-scale commercialization of composites. This work investigates the use of commercially available CO2 laser as a means of nano-structuring the surface of carbon fiber (CF) tows in an incessant throughput procedure. Even though the single carbon fiber tensile strength measurements showed a decrease up to 68% for the exposed CFs, the electrical conductivity exhibited an increment up to 18.4%. Furthermore, results on laminates comprised of irradiated unidirectional CF cloth, demonstrated an enhancement in out of plane electrical conductivity up to 43%, while preserved the Mode-I interlaminar fracture toughness of the composite, showing the potential for multifunctionality. This work indicates that the laser-induced graphitization of the CF surface can act as an interface for fast and cost-effective manufacturing of multifunctional CFRP composite materials.