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Plant-derived carbon dots (P-CDs) are gaining attention in environmental remediation due to their cost-effectiveness, availability, and lower toxicity compared with chemically synthesized carbon dots. This review comprehensively examines the recent advancements in the synthesis and application of P-CDs, with a particular emphasis on their efficacy in the sensing of heavy metals, which are among the most pervasive environmental contaminants. A detailed comparative analysis is presented by evaluating the performance of P-CDs against their chemically synthesized counterparts based on key parameters, such as optimal operating conditions and detection limits. Furthermore, sensing the potential of P-CDs towards every heavy metal ion has been discussed with in-depth mechanistic insights. Additionally, this review explores the industrial applications and future directions of P-CDs. This review provides a comprehensive analysis of -P-CDs for heavy metal sensing, aiming to enhance their sensitivity and selectivity toward heavy metal ions.

Silver nanoparticles (NPs) have become highly promising agents in the field of biomedical science, offering wide therapeutic potential due to their unique physicochemical properties. The unique characteristics of silver NPs, such as their higher surface-area-to-volume ratio, make them ideal for a variety of biological applications. They are easily processed thanks to their large surface area, strong surface plasmon resonance (SPR), stable nature, and multifunctionality. With an emphasis on the mechanisms of action, efficacy, and prospective advantages of silver NPs, this review attempts to give a thorough overview of the numerous biological applications of these particles. The utilization of silver NPs in diagnostics, such as bioimaging and biosensing, as well as their functions in therapeutic interventions such as antimicrobial therapies, cancer therapy, diabetes treatment, bone repair, and wound healing, are investigated. The underlying processes by which silver NPs exercise their effects, such as oxidative stress induction, apoptosis, and microbial cell membrane rupture, are explored. Furthermore, toxicological concerns and regulatory issues are discussed, as well as the present difficulties and restrictions related to the application of silver NPs in medicine.

Recently, silver nanoparticles (NPs) have attracted significant attention for being highly desirable nanomaterials in scientific studies as a result of their extraordinary characteristics. They are widely known as effective antibacterial agents that are capable of targeting a wide range of pathogens. Their distinct optical characteristics, such as their localized surface plasmon resonance, enlarge their utilization, particularly in the fields of biosensing and imaging. Also, the capacity to control their surface charge and modify them using biocompatible substances offers improved durability and specific interactions with biological systems. Due to their exceptional stability and minimal chemical reactivity, silver NPs are highly suitable for a diverse array of biological applications. These NPs are produced through chemical, biological, and physical processes, each of which has distinct advantages and disadvantages. Chemical and physical techniques often encounter issues with complicated purification, reactive substances, and excessive energy usage. However, eco-friendly biological approaches exist, even though they require longer processing times. A key factor affecting the stability, size distribution, and purity of the NPs is the synthesis process selected. This review focuses on how essential it is to choose the appropriate synthesis method in order to optimize the characteristics and use of silver NPs.

The green synthesis of ZnO NPs is becoming increasingly valued for its cost-effectiveness and environmental benefits. This study successfully synthesized hexagonal ZnO NPs using a combination of clove (Syzygium aromaticum) and Thymus capitatus extracts. The use of both extracts significantly improved the antibacterial and antioxidant properties of the ZnO NPs. By optimizing synthesis conditions, including ZnCl2 and extract concentrations, hexagonal wurtzite ZnO NPs were produced at room temperature with only drying at 80 °C without high-temperature annealing. The synthesized ZnO NPs exhibited a hexagonal morphology with an average particle size of 160 nm and a crystallite size of 30 nm. Energy-dispersive X-ray spectroscopy (SEM-EDX) confirmed the elemental composition of the ZnO NPs, showing a high carbon content (63.9 wt.%), reflecting the presence of phytochemicals from the extracts coated the ZnO NPs surface. The UV–Vis spectrum revealed an absorption peak at 370 nm and a bandgap energy of 2.8 eV due to lattice defects caused by organic impurities. The ZnO NPs demonstrated exceptional antioxidant activity, with a DPPH radical scavenging rate of 95.2%. They also exhibited strong antibacterial activity against both Gram-positive and Gram-negative bacteria, with inhibition zones of 25 mm against Bacillus subtilis, 26 mm against Escherichia coli, 24 mm against Salmonella typhimurium, 22 mm against Klebsiella pneumoniae, 21 mm against Staphylococcus aureus, 20 mm against Staphylococcus hominis, and 18 mm against Bacillus subtilis at 200 ppm. Furthermore, significant antifungal activity was observed against Candida albicans, with an inhibition zone of 35 mm at the same concentration. These findings underscore the effectiveness of using combined plant extracts for producing ZnO NPs with controlled morphology and enhanced biological properties, highlighting their potential for various biomedical applications.

This study explored the therapeutic efficacy of Helianthemum lippii and silver nanoparticles (Ag NPs) synthesized using a H. lippii extract to alleviate cadmium-induced nephrotoxicity in Wistar rats. Sub-acute toxicity assessments of H. lippii (100 mg/kg, 1000 mg/kg, and 4000 mg/kg) and Ag NPs (2 mg/kg and 10 mg/kg) did not find any significant difference, compared with untreated control rats (n = 3 animals/group). Then, the adult Wistar rats were divided into one control (untreated/unexposed) and six experimental groups (n = 5/group): Ag NPs alone, H. lippii alone, exposure to 50 mg/kg CdCl2 in drinking water for 35 days, exposure to CdCl2 for 35 days followed by treatment with 0.1 mg/kg/day Ag NPs (intraperitoneal injection) and/or 100 mg/kg/day H. lippii by gavage for 15 days. In the CdCl2-exposed group, body weight decreased; urea, creatinine, and uric acid concentrations increased (p < 0.05 vs. control), indicative of nephrotoxicity, antioxidant defenses (SOD, GSH, and CAT) were reduced, and malondialdehyde concentration increased. Moreover, the kidney’s architecture in CdCl2-exposed rats was altered: fibrosis, inflammatory cell infiltration, glomerular destruction, and tubular dilatation. Treatment with H. lippii and/or Ag NPs after CdCl2 exposure improved some of the renal function and architecture alterations induced by CdCl2, and also increased body weight. This study underscores the potential therapeutic applications of H. lippii and Ag NPs to decrease oxidative stress and promote xenobiotic detoxification, in line with the growing emphasis on environmentally conscious practices in scientific research and healthcare.

Seagrasses are marine angiosperms that inhabit tropical and subtropical regions around the world. They play a vital role in marine biodiversity and the ecosystem by providing habitats and food for several marine organisms, stabilizing sediments, and improving water quality. Halodule uninervis from the family Cymodoceaceae has been used in traditional folk medicine for the treatment of many ailments. Additionally, several identified bioactive metabolites have been shown to contribute to its pharmacological activities, including anticancer, anti-inflammatory, and antioxidant. As such, H. uninervis could contribute to the development of novel drugs for various diseases. This review aims to compile the phytochemical composition and pharmacological activities of H. uninervis. Furthermore, details about its botanical characteristics and ecological significance are also discussed. By providing valuable insights into the role of H. uninervis in both the marine ecosystem and biomedicine, this review helps to highlight its potential as a therapeutic agent for future drug discovery and development.

Plants are being researched as potential sources of novel drugs, which has led to a recent acceleration in the discovery of new bioactive compounds. Research on tissue culture technology for the synthesis and processing of plant compounds has skyrocketed, surpassing all expectations. These plants can be bought either raw or as extracts, where some of the chemicals are extracted by mashing the plant in water, alcohol, or another solvent. The use of herbal medicine may open new chances for reducing the onset of infections and treating different diseases including cancer. A perennial plant that blooms in the winter, Cyclamen, is one of the most widely used potted flowers in many nations. Alkaloids, flavonoids, phenols, tannins, saponins, sterols, and glycosides are the main active components of Cyclamen. Analgesic, cytotoxic, antioxidant, antimicrobial, and anti-inflammatory properties have all been demonstrated as potential effects of various extracts of Cyclamen tubers. However, the use of this medicinal plant in official medicine will require further research in the areas of pharmacology. Furthermore, it is necessary to create standard operating procedures for a crude herbal medication. In this regard, this review aims to highlight the key characteristics of the Cyclamen plant, such as its various parts, species, stages of development, and geographic range; pinpoint its intriguing bioactivities, its antioxidant, anti-inflammatory, and its anti-cancerous effects; and ascertain its potential medicinal uses and the main future perspectives.

Driven by concerns over polluted industrial wastewater, particularly heavy metals and dyes, this study explores biosorption using chemically cross-link chitosan derivatives as a sustainable and cost-effective depollution method. Chitosan cross-linking employs either water-soluble polymers and agents like glutaraldehyde or copolymerization of hydrophilic monomers with a cross-linker. Chemical cross-linking of polymers has emerged as a promising approach to enhance the wet-strength properties of materials. The chitosan thus extracted, as powder or gel, was used to adsorb heavy metals (lead (Pb2+) and copper (Cu2+)) and dyes (methylene blue (MB) and crystal violet (CV)). Extensive analysis of the physicochemical properties of both the powder and hydrogel adsorbents was conducted using a range of analytical techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and scanning electron microscopy (SEM), as well as 1H and 13C nuclear magnetic resonance (NMR). To gain a comprehensive understanding of the sorption process, the effect of contact time, pH, concentration, and temperature was investigated. The adsorption capacity of chitosan powder for Cu(II), Pb(II), methylene blue (MB), and crystal violet (CV) was subsequently determined as follows: 99, 75, 98, and 80%, respectively. In addition, the adsorption capacity of chitosan hydrogel for Cu(II), Pb(II), MB, and CV was as follows: 85, 95, 85, and 98%, respectively. The experimental data obtained were analyzed using the Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models. The isotherm study revealed that the adsorption equilibrium is well fitted to the Freundlich isotherm (R2 = 0.998), and the sorption capacity of both chitosan powder and hydrogel was found to be exceptionally high (approximately 98%) with the adsorbent favoring multilayer adsorption. Besides, Dubinin has given an indication that the sorption process was dominated by Van der Waals physical forces at all studied temperatures.

This study focused on testing the antibacterial and antifungal activity of Origanum syriacum (O. syriacum) and Cimbopogon winterianus (C. winterianus) extracts and their essential oils (EOs). The bacteria were isolated from urine samples and identified by a VITEK assay, and the fungi were isolated from spoiled food samples and further identified by MALDI-TOF. The susceptibility of the microbial isolates was assessed by determining the bacteriostatic and bactericidal/fungicidal effects by the minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) broth microdilution assay and time-kill test. The antibiofilm activities were assessed by the antibiofilm screening assays. The bacterial isolates included three Gram-negative isolates (Escherichia coli, Klebsiella pneumonia, and Citrobacter freundii) and two Gram-positive isolates (Staphylococcus aureus and Streptococcus intermedius). The fungal isolates included Candida albicans and Aspergillus niger. The O. syriacum and C. winterianus extracts exhibited bacteriostatic and fungistatic activities (MIC 1.25–2.5 mg/mL for the bacterial isolates and 2.5–5 mg/mL for the fungal isolates). However, their EOs exhibited bactericidal (MBC 5–20%) and fungicidal (MFC 1.25–10%) activities, meaning that the EOs had a better antimicrobial potential than the extracts. The antibiofilm activities of the mentioned extracts and their EOs were relatively weak. The O. syriacum extract inhibited S. aureus, S. intermedius, and K. pneumonia biofilms at a concentration of 0.3125 mg/mL and C. albicans and A. niger biofilms at 0.625 mg/mL. No antibiofilm activity was recorded for C. winterianus extract. In addition, the packaging of grapes with C. winterianus extract preserved them for about 40 days. The results reflect the significant antimicrobial activity of O. syriacum and C. winterianus extracts and their EOs, thus suggesting their potential in food packaging and preservation.

Ammodaucus leucotrichus exhibits promising pharmacological activity, hinting at anti-inflammatory and anti-arthritic effects. This study investigated seed extracts from Ammodaucus leucotrichus using methanol and n-hexane, focusing on anti-inflammatory and anti-arthritic properties. The methanol extract outperformed the n-hexane extract and diclofenac, a reference anti-inflammatory drug, in trypsin inhibition (85% vs. 30% and 64.67% at 125 μg/mL). For trypsin inhibition, the IC50 values were 82.97 μg/mL (methanol), 202.70 μg/mL (n-hexane), and 97.04 μg/mL (diclofenac). Additionally, the n-hexane extract surpassed the methanol extract and diclofenac in BSA (bovine serum albumin) denaturation inhibition (90.4% vs. 22.0% and 51.4% at 62.5 μg/mL). The BSA denaturation IC50 values were 14.30 μg/mL (n-hexane), 5408 μg/mL (methanol), and 42.30 μg/mL (diclofenac). Gas chromatography–mass spectrometry (GC–MS) revealed 59 and 58 secondary metabolites in the methanol and n-hexane extracts, respectively. The higher therapeutic activity of the methanol extract was attributed to hydroxyacetic acid hydrazide, absent in the n-hexane extract. In silico docking studies identified 28 compounds with negative binding energies, indicating potential trypsin inhibition. The 2-hydroxyacetohydrazide displayed superior inhibitory effects compared to diclofenac. Further mechanistic studies are crucial to validate 2-hydroxyacetohydrazide as a potential drug candidate for rheumatoid arthritis treatment.

Certain plants like Rosemarinus officinalis, Lavandula angustifolia and Origanum vulgare have been used in the food industry for centuries. Cymbopogon winterianus (Java Citronella plant) is one of the most significant plants. The objective of this study is to screen for secondary metabolites by phytochemical screening, evaluate the antioxidant contents of extracts and investigate the use of the Java Citronella plant in food preservation and as an insecticide. Java Citronella powder was added to bread and evaluated for its moisture content, and a visual and sensory analysis was performed. Sitophilus granarius (L.) weevils were exposed to Java Citronella essential oil (JCEO). The phytochemical screening revealed that the extracts were abundant in secondary metabolites. The JCEO had a yield of 0.75%. The aqueous extract had a higher total phenolic content of 49.043 ± 0.217 mg GAE/g than the ethanolic extract, which was 24.478 ± 1.956 mg GAE/g. The aqueous extract had a total flavonoids content 27,725.25 ± 54.96 µg RE/g higher than the ethanolic extract, with 24,263 ± 74 µg RE/g. The ethanolic extract had stronger antioxidant activity, with anIC50 = 196.116 μg/mL higher than the aqueous extract at 420 μg/mL. The 2% Java Citronella powder in the bread was preferred by consumers, and had a shelf life of 6 days. JCEO killed all the weevils with a high dose of 10% after 48 h. The Java Citronella showed insecticidal and food preservative activity. The results should help in future research to enhance the applications of Java Citronella in various domains, from food technology to insecticides.

With the global population continuing to increase, the demand for food and energy has escalated, resulting in severe environmental pressures. Traditional methods of food and energy production have left a significant footprint on the environment, primarily due to the emission of greenhouse gases and a notable surge in waste production. Nevertheless, scientists have recently focused on developing sustainable solutions by managing biomass waste and converting it into useful products. Various biomass conversion technologies, including pyrolysis, gasification, and fermentation, have emerged to transform waste materials into valuable commodities like biofuels, fertilizers, and chemicals. These technologies present an alternative to conventional energy production methods and decrease reliance on non-renewable resources. Furthermore, the by-products generated through biomass conversion, such as biochar, possess utility as valuable soil amendments. This review emphasizes the potential of biomass conversion technologies in providing sustainable solutions for waste management, food and energy production, and reducing negative environmental impacts while providing valuable by-products for agricultural use. The focus is on Lebanon, which is facing a waste and energy crisis, with an aim to encourage and promote sustainable practices by highlighting different green waste management technologies. Focusing on the application of biochar in soil, our goal is to provide cost-effective and eco-friendly solutions to various agricultural and environmental challenges in Lebanon. This includes using biochar from biomass waste as a soil amendment to boost crop yields, remediate soil pollution, reduce soil drought stress, and address other related issues.

Catalytic transfer hydrogenation has emerged as a pivotal chemical process with transformative potential in various industries. This review highlights the significance of catalytic transfer hydrogenation, a reaction that facilitates the transfer of hydrogen from one molecule to another, using a distinct molecule as the hydrogen source in the presence of a catalyst. Unlike conventional direct hydrogenation, catalytic transfer hydrogenation offers numerous advantages, such as enhanced safety, cost-effective hydrogen donors, byproduct recyclability, catalyst accessibility, and the potential for catalytic asymmetric transfer hydrogenation, particularly with chiral ligands. Moreover, the diverse range of hydrogen donor molecules utilized in this reaction have been explored, shedding light on their unique properties and their impact on catalytic systems and the mechanism elucidation of some reactions. Alcohols such as methanol and isopropanol are prominent hydrogen donors, demonstrating remarkable efficacy in various reductions. Formic acid offers irreversible hydrogenation, preventing the occurrence of reverse reactions, and is extensively utilized in chiral compound synthesis. Unconventional donors such as 1,4-cyclohexadiene and glycerol have shown a good efficiency in reducing unsaturated compounds, with glycerol additionally serving as a green solvent in some transformations. The compatibility of these donors with various catalysts, substrates, and reaction conditions were all discussed. Furthermore, this paper outlines future trends which include the utilization of biomass-derived hydrogen donors, the exploration of hydrogen storage materials such as metal-organic frameworks (MOFs), catalyst development for enhanced activity and recyclability, and the utilization of eco-friendly solvents such as glycerol and ionic liquids. Innovative heating methods, diverse base materials, and continued research into catalyst-hydrogen donor interactions are aimed to shape the future of catalytic transfer hydrogenation, enhancing its selectivity and efficiency across various industries and applications.

Polysulfone (PSF) is one of the most used polymers for water treatment membranes, but its intrinsic hydrophobicity can be detrimental to the membranes’ performances. By modifying a membrane’s surface, it is possible to adapt its physicochemical properties and thus tune the membrane’s hydrophilicity or porosity, which can achieve improved permeability and antifouling efficiency. Atomic layer deposition (ALD) stands as a distinctive technology offering exceedingly even and uniform layers of coatings, like oxides that cover the surfaces of objects with three-dimensional (3D) shapes, porous structures, and particles. In the context of this study, the focus was on titanium dioxide (TiO2), zinc oxide (ZnO), and alumina (Al2O3), which were deposited on polysulfone hollow fiber (HF) membranes via ALD using TiCl4, diethyl zinc (DEZ), and trimethylamine (TMA), respectively, and H2O as precursors. The morphology and mechanical properties of membranes were changed without damaging their performances. The deposition was confirmed mainly by energy-dispersive X-ray spectroscopy (EDX). All depositions offered great performances with a maintained permeability and BSA retention and a 20 to 40° lower water contact angle (WCA) than the raw PSF HF membrane. The deposition of TiO2 offered the best results, showing an enhancement of 50% for the water permeability and 20% for the fouling resistance of the PSF HF membranes.

The many pollutants detected in water represent a global environmental issue. Emerging and persistent organic pollutants are particularly difficult to remove using traditional treatment methods. Electro-oxidation and sulfate-radical-based advanced oxidation processes are innovative removal methods for these contaminants. These approaches rely on the generation of hydroxyl and sulfate radicals during electro-oxidation and sulfate activation, respectively. In addition, hybrid activation, in which these methods are combined, is interesting because of the synergistic effect of hydroxyl and sulfate radicals. Hybrid activation effectiveness in pollutant removal can be influenced by various factors, particularly the materials used for the anode. This review focuses on various organic pollutants. However, it focuses more on pharmaceutical pollutants, particularly paracetamol, as this is the most frequently detected emerging pollutant. It then discusses electro-oxidation, photocatalysis and sulfate radicals, highlighting their unique advantages and their performance for water treatment. It focuses on perovskite oxides as an anode material, with a particular interest in calcium copper titanate (CCTO), due to its unique properties. The review describes different CCTO synthesis techniques, modifications, and applications for water remediation.

Halloysite nanotubes (HNTs) are clay minerals with a tubular structure that can be used for many different applications in place of carbon nanotubes. Indeed, HNTs display low/non-toxicity, are biocompatible, and can be easily prepared. Moreover, the aluminum and silica groups present on HNTs’ inner and outer surfaces facilitate the interaction with various functional agents, such as alkalis, organosilanes, polymers, surfactants, and nanomaterials. This allows the deposition of different materials, for instance, metal and non-metal oxides, on different substrate types. This review article first briefly presents HNTs’ general structure and the various applications described in the last 20 years (e.g., drug delivery, medical implants, and energy storage). Then, it discusses in detail HNT applications for water purification (inorganic and organic pollutants). It focuses particularly on HNT-TiO2 composites that are considered very promising photocatalysts due to their high specific surface area and adsorption capacity, large pore volume, good stability, and mechanical features.

In this study, we combined electrospinning of a large amount of halloysite (HNT, 95%) with nitriding to produce N-HNT-TiO2 composite nanofibers (N-H95T5 hereafter) to be used for acetaminophen (ACT) photodegradation. Investigation of the morphological and structural properties of the obtained materials did not highlight any significant difference in their morphological features and confirmed that nitrogen was evenly distributed in the samples. Photocatalytic tests under visible light showed that acetaminophen photodegraded faster in the presence of samples with nitrogen (N-H95T5) than without (H95T5 nanofibers). Moreover, the N-H95T5 nanocomposite photocatalytic activity did not change after repeated utilization (five cycles). The addition of scavengers during photocatalytic tests showed the key implication of OH•−, O2•− and h+ radicals in acetaminophen degradation. These results indicated that N–H95T5 composite nanofibers could be considered a cheap multifunctional material for photodegradation and could open new prospects for preparing tunable photocatalysts.

High-performance hybrid polymer blends can be prepared by blending different types of polymers to improve their properties. However, most polymer blends exhibit phase separation after blending. In this study, polymethylmethacrylate/polyethylene glycol (PMMA/PEG) polymer blends (70/30 and 30/70 w/w) were prepared by solution casting with and without ZnO nanoparticles (NPs) loading. The effect of loading ZnO nanoparticles on blend morphology, UV blocking, glass transition, melting, and crystallization were investigated. Without loading ZnO NP, the PMMA/PEG blends showed phase separation, especially the PEG-rich blend. Loading PMMA/PEG blend with ZnO NPs increased the miscibility of the blend and most of the ZnO NPs dispersed in the PEG phase. The interaction of the ZnO NPs with the blend polymers slightly decreased the intensity of infrared absorption of the functional groups. The UV-blocking properties of the blends increased by 15% and 20%, and the band gap energy values were 4.1 eV and 3.8 eV for the blends loaded with ZnO NPs with a PMMA/PEG ratio of 70/30 and 30/70, respectively. In addition, the glass transition temperature (Tg) increased by 14 °C, the crystallinity rate increased by 15%, the melting (Tm) and crystallization(Tc) temperatures increased by 2 °C and 14 °C, respectively, and the thermal stability increased by 25 °C compared to the PMMA/PEG blends without ZnO NP loading.

Bio-based ceramic membranes were elaborated from kaolinite clays, coconut husks and eggshells to retain E. coli bacteria present in water intended for human consumption. Their characterization and removal performances are investigated in this work. These bio-ceramic membranes were obtained by heating the formulation containing 75% clay, 15% coconut husk and 10% eggshell at 900 °C or 1000 °C, at different temperature rates, to give S1, S2 and S3 materials. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), mercury porosimetry and scanning electron microscopy (SEM) were used to characterize these membranes. Water flux density, bacterial removal and biofouling were also assessed. Water flux density was shown to depend on material porosity. Bacteria retention was 90% (with 1 log-removal) for S1, 80% (with 0.7 log-removal) for S2 and 100% (with 3.3 log-removal) for S3. Membranes S1 and S2 presented reversible biofouling, while no fouling was evidenced for S3 in the tested conditions. This work shows that the best bio-ceramic membrane in terms of bacterial removal and flux density was S3. Its water flux density was 2123 ± 72 L/h/m2 at an initial pressure of 0.2 bar. This material is particularly interesting because its production protocol is quite simple, fast and without the addition of chemical additives. Moreover, it can be used to efficiently remove bacteria from drinking water.

Nanomaterials are materials with one or more nanoscale dimensions (internal or external) (i.e., 1 to 100 nm). The nanomaterial shape, size, porosity, surface chemistry, and composition are controlled at the nanoscale, and this offers interesting properties compared with bulk materials. This review describes how nanomaterials are classified, their fabrication, functionalization techniques, and growth-controlled mechanisms. First, the history of nanomaterials is summarized and then the different classification methods, based on their dimensionality (0–3D), composition (carbon, inorganic, organic, and hybrids), origin (natural, incidental, engineered, bioinspired), crystal phase (single phase, multiphase), and dispersion state (dispersed or aggregated), are presented. Then, the synthesis methods are discussed and classified in function of the starting material (bottom-up and top-down), reaction phase (gas, plasma, liquid, and solid), and nature of the dispersing forces (mechanical, physical, chemical, physicochemical, and biological). Finally, the challenges in synthesizing nanomaterials for research and commercial use are highlighted.

Combating antimicrobial resistance (AMR) is an on-going global grand challenge, as recognized by several UN Sustainable Development Goals. Silver nanoparticles (Ag NPs) are well-known for their efficacy against antimicrobial resistance, and a plethora of green synthesis methodologies now exist in the literature. Herein, this review evaluates recent advances in biological approaches for Ag NPs, and their antimicrobial potential of Ag NPs with mechanisms of action are explored deeply. Moreover, short and long-term potential toxic effects of Ag NPs on animals, the environment, and human health are briefly discussed. Finally, we also provide a summary of the current state of the research and future challenges on a biologically mediated Ag-nanostructures-based effective platform for alleviating AMR.

The majority of proposed exotic applications employing 3D topological insulators require high-quality materials with reduced dimensions. Catalyst-free, PVD-grown Bi2Se3 nanoribbons are particularly promising for these applications due to the extraordinarily high mobility of their surface Dirac states, and low bulk carrier densities. However, these materials are prone to the formation of surface accumulation layers; therefore, the implementation of surface encapsulation layers and the choice of appropriate dielectrics for building gate-tunable devices are important. In this work, all-around ZnO-encapsulated nanoribbons are investigated. Gate-dependent magnetotransport measurements show improved charge transport characteristics as reduced nanoribbon/substrate interface carrier densities compared to the values obtained for the as-grown nanoribbons on SiO2 substrates.

Additive manufacturing of Polymer-Derived Ceramics (PDCs) is regarded as a disruptive fabrication process that includes several technologies such as light curing and ink writing. However, 3D printing based on material extrusion is still not fully explored. Here, an indirect 3D printing approach combining Fused Deposition Modeling (FDM) and replica process is demonstrated as a simple and low-cost approach to deliver complex near-net-shaped cellular Si-based non-oxide ceramic architectures while preserving the structure. 3D-Printed honeycomb polylactic acid (PLA) lattices were dip-coated with two preceramic polymers (polyvinylsilazane and allylhydridopolycarbosilane) and then converted by pyrolysis respectively into SiCN and SiC ceramics. All the steps of the process (printing resolution and surface finishing, cross-linking, dip-coating, drying and pyrolysis) were optimized and controlled. Despite some internal and surface defects observed by topography, 3D-printed materials exhibited a retention of the highly porous honeycomb shape after pyrolysis. Weight loss, volume shrinkage, roughness and microstructural evolution with high annealing temperatures are discussed. Our results show that the sacrificial mold-assisted 3D printing is a suitable rapid approach for producing customizable lightweight highly stable Si-based 3D non-oxide ceramics.

Nanomaterials are becoming important materials in several fields and industries thanks to their very reduced size and shape-related features. Scientists think that nanoparticles and nanostructured materials originated during the Big Bang process from meteorites leading to the formation of the universe and Earth. Since 1990, the term nanotechnology became very popular due to advances in imaging technologies that paved the way to specific industrial applications. Currently, nanoparticles and nanostructured materials are synthesized on a large scale and are indispensable for many industries. This fact fosters and supports research in biochemistry, biophysics, and biochemical engineering applications. Recently, nanotechnology has been combined with other sciences to fabricate new forms of nanomaterials that could be used, for instance, for diagnostic tools, drug delivery systems, energy generation/storage, environmental remediation as well as agriculture and food processing. In contrast with traditional materials, specific features can be integrated into nanoparticles, nanostructures, and nanosystems by simply modifying their scale, shape, and composition. This article first summarizes the history of nanomaterials and nanotechnology. Followed by the progress that led to improved synthesis processes to produce different nanoparticles and nanostructures characterized by specific features. The content finally presents various origins and sources of nanomaterials, synthesis strategies, their toxicity, risks, regulations, and self-aggregation.

Nanotechnology is a broad area integrating different research disciplines, including but not limited to material science, engineering, physics, chemistry, polymer science, optics, electronics, robotic, metallurgy, pharmacology, pharmacy and medicine [...]

In the last few decades, the vast potential of nanomaterials for biomedical and healthcare applications has been extensively investigated. Several case studies demonstrated that nanomaterials can offer solutions to the current challenges of raw materials in the biomedical and healthcare fields. This review describes the different nanoparticles and nanostructured material synthesis approaches and presents some emerging biomedical, healthcare, and agro-food applications. This review focuses on various nanomaterial types (e.g., spherical, nanorods, nanotubes, nanosheets, nanofibers, core-shell, and mesoporous) that can be synthesized from different raw materials and their emerging applications in bioimaging, biosensing, drug delivery, tissue engineering, antimicrobial, and agro-foods. Depending on their morphology (e.g., size, aspect ratio, geometry, porosity), nanomaterials can be used as formulation modifiers, moisturizers, nanofillers, additives, membranes, and films. As toxicological assessment depends on sizes and morphologies, stringent regulation is needed from the testing of efficient nanomaterials dosages. The challenges and perspectives for an industrial breakthrough of nanomaterials are related to the optimization of production and processing conditions.

Flow capacitive deionization is a water desalination technique that uses liquid carbon-based electrodes to recover fresh water from brackish or seawater. This is a potential second-generation water desalination process, however it is limited by parameters such as feed electrode conductivity, interfacial resistance, viscosity, and so on. In this study, titanium oxide nanofibers (TiO2NF) were manufactured using an electrospinning process and then blended with commercial activated carbon (AC) to create a well distributed flow electrode in this study. Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray (EDX) were used to characterize the morphology, crystal structure, and chemical moieties of the as-synthesized composites. Notably, the flow electrode containing 1 wt.% TiO2NF (ACTiO2NF 1 wt.%) had the highest capacitance and the best salt removal rate (0.033 mg/min·cm2) of all the composites. The improvement in cell performance at this ratio indicates that the nanofibers are uniformly distributed over the electrode’s surface, preventing electrode passivation, and nanofiber agglomeration, which could impede ion flow to the electrode’s pores. This research suggests that the physical mixture could be used as a flow electrode in capacitive deionization.

Nanocelluloses are promising bio-nano-materials for use as water treatment materials in environmental protection and remediation. Over the past decades, they have been integrated via novel nanoengineering approaches for water treatment processes. This review aims at giving an overview of nanocellulose requirements concerning emerging nanotechnologies of waster treatments and purification, i.e., adsorption, absorption, flocculation, photocatalytic degradation, disinfection, antifouling, ultrafiltration, nanofiltration, and reverse osmosis. Firstly, the nanocellulose synthesis methods (mechanical, physical, chemical, and biological), unique properties (sizes, geometries, and surface chemistry) were presented and their use for capturing and removal of wastewater pollutants was explained. Secondly, different chemical modification approaches surface functionalization (with functional groups, polymers, and nanoparticles) for enhancing the surface chemistry of the nanocellulose for enabling the effective removal of specific pollutants (suspended particles, microorganisms, hazardous metals ions, organic dyes, drugs, pesticides fertilizers, and oils) were highlighted. Thirdly, new fabrication approaches (solution casting, thermal treatment, electrospinning, 3D printing) that integrated nanocelluloses (spherical nanoparticles, nanowhiskers, nanofibers) to produce water treatment materials (individual composite nanoparticles, hydrogels, aerogels, sponges, membranes, and nanopapers) were covered. Finally, the major challenges and future perspectives concerning the applications of nanocellulose based materials in water treatment and purification were highlighted.

Carbon nanomaterials (CNMs) have received tremendous interest in the area of nanotechnology due to their unique properties and flexible dimensional structure. CNMs have excellent electrical, thermal, and optical properties that make them promising materials for drug delivery, bioimaging, biosensing, and tissue engineering applications. Currently, there are many types of CNMs, such as quantum dots, nanotubes, nanosheets, and nanoribbons; and there are many others in development that promise exciting applications in the future. The surface functionalization of CNMs modifies their chemical and physical properties, which enhances their drug loading/release capacity, their ability to target drug delivery to specific sites, and their dispersibility and suitability in biological systems. Thus, CNMs have been effectively used in different biomedical systems. This review explores the unique physical, chemical, and biological properties that allow CNMs to improve on the state of the art materials currently used in different biomedical applications. The discussion also embraces the emerging biomedical applications of CNMs, including targeted drug delivery, medical implants, tissue engineering, wound healing, biosensing, bioimaging, vaccination, and photodynamic therapy.

We developed free-standing nitrogen-doped carbon nanofiber (CNF) electrodes incorporating Co/CoOx nanoparticles (NPs) as a new cathode material for removing Acid Orange 7 (AO7; a dye for wool) from wastewater by the heterogeneous electro-Fenton reaction. We produced the free-standing N-doped CNF electrodes by electrospinning a polyacrylonitrile (PAN) and cobalt acetate solution followed by thermal carbonation of the cobalt acetate/PAN nanofibers under a nitrogen atmosphere. We then investigated electro-Fenton-based removal of AO7 from wastewater with the free-standing N-doped-CNFs-Co/CoOx electrodes, in the presence or not of Fe2+ ions as a co-catalyst. The electrochemical analysis showed the high stability of the prepared N-doped-CNF-Co/CoOx electrodes in electrochemical oxidation experiments with excellent degradation of AO7 (20 mM) at acidic to near neutral pH values (3 and 6). Electro-Fenton oxidation at 10 mA/cm2 direct current for 40 min using the N-doped-CNF-Co/CoOx electrodes loaded with 25 wt% of Co/CoOx NPs led to complete AO7 solution decolorization with total organic carbon (TOC) removal values of 92.4% at pH 3 and 93.3% at pH 6. The newly developed N-doped-CNF-Co/CoOx electrodes are an effective alternative technique for wastewater pre-treatment before the biological treatment.

The yield and morphology (length, width, thickness) of stoichiometric Bi2Se3 nanoribbons grown by physical vapor deposition is studied as a function of the diameters and areal number density of the Au catalyst nanoparticles of mean diameters 8–150 nm formed by dewetting Au layers of thicknesses 1.5–16 nm. The highest yield of the Bi2Se3 nanoribbons is reached when synthesized on dewetted 3 nm thick Au layer (mean diameter of Au nanoparticles ~10 nm) and exceeds the nanoribbon yield obtained in catalyst-free synthesis by almost 50 times. The mean lengths and thicknesses of the Bi2Se3 nanoribbons are directly proportional to the mean diameters of Au catalyst nanoparticles. In contrast, the mean widths of the Bi2Se3 nanoribbons do not show a direct correlation with the Au nanoparticle size as they depend on the contribution ratio of two main growth mechanisms—catalyst-free and vapor–liquid–solid deposition. The Bi2Se3 nanoribbon growth mechanisms in relation to the Au catalyst nanoparticle size and areal number density are discussed. Determined charge transport characteristics confirm the high quality of the synthesized Bi2Se3 nanoribbons, which, together with the high yield and tunable morphology, makes these suitable for application in a variety of nanoscale devices.

In this report, lanthanum strontium manganite at different Sr2+ ion concentrations, as well as Gd3+ or Sm3+ ion substituted La0.5−YMYSr0.5MnO3 (M = Gd and Sm, y = 0.2), have been purposefully tailored using a sol gel auto-combustion approach. XRD profiles confirmed the formation of a monoclinic perovskite phase. FE-SEM analysis displayed a spherical-like structure of the La0.8Sr0.2MnO3 and La0.3Gd0.2Sr0.2MnO3 samples. The particle size of the LSM samples was found to decrease with increased Sr2+ ion concentration. For the first time, different LSM concentrations were inspected for their cytotoxic activity against CACO-2 (intestinal carcinoma cells) and HepG-2 (human hepatocellular carcinoma cells). The cell viability for CACO-2 and HepG-2 was assayed and seen to decrease depending on the Sr2+ ion concentration. Half maximal inhibitory concentration IC50 of CACO-2 cell and HepG-2 cell inhibition was connected with Sr2+ ion ratio. Low IC50 was noticable at low Sr2+ ion content. Such results were correlated to the particle size and the morphology. Indeed, the IC50 of CACO-2 cell inhibition by LSM at a strontium content of 0.2 was 5.63 ± 0.42 µg/mL, and the value increased with increased Sr2+ ion concentration by up to 0.8 to be = 25 ± 2.7 µg/mL. Meanwhile, the IC50 of HepG-2 cell inhibition by LSM at a strontium content of 0.2 was 6.73 ± 0.4 µg/mL, and the value increased with increased Sr2+ ion concentration by up to 0.8 to be 31± 3.1 µg/mL. All LSM samples at different conditions were tested as antimicrobial agents towards fungi, Gram positive bacteria, and Gram negative bacteria. For instance, all LSM samples were found to be active towards Gram negative bacteria Escherichia coli, whereas some samples have presumed antimicrobial effect towards Gram negative bacteria Proteus vulgaris. Such results confirmed that LSM samples possessed cytotoxicity against CACO-2 and HepG-2 cells, and they could be considered to play a substantial role in pharmaceutical and therapeutic applications.

In this paper, we are relating a significant improvement of the SERS effect achieved with assembled Au/ZnO nano-urchins. This improvement is realized thanks to an excellent capacity of adsorption (denoted K) for thiram molecules on these plasmonic nano-urchins, which is a key point to be taken into account for obtaining a SERS spectrum. Moreover, this outlook may be employed for different types of plasmonic substrates and for a wide number of molecules. We studied the capacity of the assembled Au/ZnO nano-urchins to be sensitive to the pesticide thiram, which adsorbs well on metals via the metal–sulfur bond. For the thiram detection, we found a limit concentration of 10 pM, a value of this capacity of adsorption (K) of 9.5 × 106 M−1 and a factor of analytical enhancement equal to 1.9 × 108.

This study presents the microsphere-based fiber-optic sensor with the ZnO Atomic Layer Deposition coating thickness of 100 nm and 200 nm for temperature measurements. Metrological properties of the sensor were investigated over the temperature range from 100 °C to 300 °C, with a 10 °C step. The interferometric signal was used to monitor the integrity of the microsphere and its attachment to the connecting fiber. For the sensor with a 100 nm coating, a spectrum shift of the reflected signal and the optical power of the reflected signal were used to measure temperature, while only the optical power of the reflected signal was used in the sensor with a 200 nm coating. The R2 coefficient of the discussed sensors indicates a linear fit of over 0.99 to the obtained data. The sensitivity of the sensors, investigated in this study, equals 103.5 nW/°C and 19 pm/°C or 11.4 nW/°C for ZnO thickness of 200 nm and 100 nm, respectively.

Levofloxacin (LF) is a medically important antibiotic drug that is used to treat a variety of bacterial infections. In this study, three highly sensitive and selective carbon paste electrodes (CPEs) were fabricated for potentiometric determination of the LF drug: (i) CPEs filled with carbon paste (referred to as CPE); (ii) CPE coated (drop-casted) with ion-selective PVC membrane (referred to as C-CPE); (iii) CPE filled with carbon paste modified with a plasticizer (PVC/cyclohexanone) (referenced as P-CPE). The CPE was formulated from graphite (Gr, 44.0%) and reduced graphene oxide (rGO, 3.0%) as the carbon source, tricresyl phosphate (TCP, 47.0%) as the plasticizer; sodium tetrakis[3,5-bis(trifluoromethyl)phenyl] borate (St-TFPMB, 1.0%) as the ion exchanger; and levofloxacinium-tetraphenylborate (LF-TPB, 5.0%) as the lipophilic ion pair. It showed a sub-Nernstian slope of 49.3 mV decade−1 within the LF concentration range 1.0 × 10−2 M to 1.0 × 10−5 M, with a detection limit of 1.0 × 10−5 M. The PVC coated electrode (C-CPE) showed improved sensitivity (in terms of slope, equal to 50.2 mV decade−1) compared to CPEs. After the incorporation of PVC paste on the modified CPE (P-CPE), the sensitivity increased at 53.5 mV decade−1, indicating such improvement. The selectivity coefficient (log KLF2+,Fe+3pot.) against different interfering species (Na+, K+, NH4+, Ca2+, Al3+, Fe3+, Glycine, Glucose, Maltose, Lactose) were significantly improved by one to three orders of magnitudes in the case of C-CPE and P-CPE, compared to CPEs. The modification with the PVC membrane coating significantly improved the response time and solubility of the LF-TPB within the electrode matrix and increased the lifetime. The constructed sensors were successfully applied for LF determination in pharmaceutical preparation (Levoxin® 500 mg), spiked urine, and serum samples with high accuracy and precision.

Capacitive deionization is a second-generation water desalination technology in which porous electrodes (activated carbon materials) are used to temporarily store ions. In this technology, porous carbon used as electrodes have inherent limitations, such as low electrical conductivity, low capacitance, etc., and, as such, optimization of electrode materials by rational design to obtain hybrid electrodes is key towards improvement in desalination performance. In this work, different compositions of mixture of reduced graphene oxide (RGO) and activated carbon (from 5 to 20 wt% RGO) have been prepared and tested as electrodes for brackish water desalination. The physico-chemical and electrochemical properties of the activated carbon (AC), reduced graphene oxide (RGO), and as-prepared electrodes (AC/RGO-x) were characterized by low-temperature nitrogen adsorption measurement, scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red (FT-IR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Among all the composite electrodes, AC/RGO-5 (RGO at 5 wt%) possessed the highest specific capacitance (74 F g−1) and the highest maximum salt adsorption capacity (mSAC) of 8.10 mg g−1 at an operating voltage ∆E = 1.4 V. This shows that this simple approach could offer a potential way of fabricating electrodes of accentuated carbon network of an improved electronic conductivity that’s much coveted in CDI technology.

Medical textiles have played an increasingly important protection role in the healthcare industry. This study was aimed at improving the conventional cotton gauze for achieving advanced biomedical specifications (coloration, UV-protection, anti-inflammation, and antimicrobial activities). These features were obtained by modifying the cotton gauze fabrics via in-situ precipitation of hydroxyapatite nanoparticles (HAp NP), followed by in-situ photosynthesis of silver (Ag) NPs with ginger oil as a green reductant with anti-inflammation properties. The HAp-Ag NPs coating provides good UV-protection properties. To further improve the HAp and Ag NPs dispersion and adhesion on the surface, the cotton gauze fabrics were modified by cationization with chitosan, or by partial carboxymethylation (anionic modification). The influence of the cationic and anionic modifications and HAp and Ag NPs deposition on the cotton gauze properties (coloration, UV-protection, antimicrobial activities, and water absorption) was thoroughly assessed. Overall, the results indicate that chemical (anionic and cationic) modification of the cotton gauze enhances HAp and Ag NPs deposition. Chitosan can increase biocompatibility and promotes wound healing properties of cotton gauze. Ag NP deposition onto cotton gauze fabrics brought high antimicrobial activities against Candida albicans, Gram-positive and Gram-negative bacteria, and improved UV protection.

Capacitive deionization is an emerging brackish water desalination technology whose principle lies in the utilization of porous electrodes (activated carbon materials) to temporarily store ions. Improving the properties of carbon material used as electrodes have been the focus of recent research, as this is beneficial for overall efficiency of this technology. Herein, we have synthesized a composite of activated carbon/graphene oxide electrodes by using a simple blending process in order to improve the hydrophilic property of activated carbon. Graphene oxide (GO) of different weight ratios was blended with commercial Activated carbon (AC) and out of all the composites, AC/GO-15 (15 wt.% of GO) exhibited the best electrochemical and salt adsorption performance in all operating conditions. The as prepared AC and AC/GO-x (x = 5, 10, 15 and 20 wt.% of GO) were characterized by cyclic voltammetry and their physical properties were also studied. The salt adsorption capacity (SAC) of AC/GO-15 at an operating window of 1.0 V is 5.70 mg/g with an average salt adsorption rate (ASAR) of 0.34 mg/g/min at a 400 mg/L salt initial concentration and has a capacitance of 75 F/g in comparison to AC with 3.74 mg/g of SAC, ASAR of 0.23 mg/g/min and a capacitance of 56 F/g at the same condition. This approach could pave a new way to produce a highly hydrophilic carbon based electrode material in CDI.

In this paper, the application of a microsphere-based fiber-optic sensor with a 200 nm zinc oxide (ZnO) coating, deposited by the Atomic Layer Deposition (ALD) method, for temperature measurements between 100 and 300 °C, is presented. The main advantage of integrating a fiber-optic microsphere with a sensing device is the possibility of monitoring the integrity of the sensor head in real-time, which allows for higher accuracy during measurements. The study has demonstrated that ZnO ALD-coated microsphere-based sensors can be successfully used for temperature measurements. The sensitivity of the tested device was found to be 103.5 nW/°C when the sensor was coupled with a light source of 1300 nm central wavelength. The measured coefficient R2 of the sensor head was over 0.99, indicating a good fit of the theoretical linear model to the measured experimental data.

In recent years, numerous studies have been conducted to develop biopolymer-based membranes, highlighting the challenges to prepare porous structures with control porosity. In this paper an innovative method that relies on the generation of Pickering emulsions was developed to prepare porous membranes from gelatin for filtration purpose. Hexagonal boron nitride nanosheets (h-BNNS) were used to stabilize micro-droplets of castor oil in a continuous homogeneous gelatin solution. Two steps in the membrane preparation process strongly influenced the porous structure. Specifically, the duration of the drying time after emulsion casting and the duration of the cross-linking step affected membrane pore size, hydrophobicity, water swelling, and water permeability. By controlling these two steps, membranes could be designed with pore size between 0.39 and 1.60 μm and display pure water permeability between 150 and 506 L h−1 m−2 bar−1. These membranes have been tested for complexation–ultrafiltration experiments in which iron ions were removed from aqueous solutions with/without poly (acrylic acid) (PAA). Without PAA, the removal of free iron (II) ions was low (not more than 14%). The addition of PAA (200 ppm) allowed obtaining high removal rates (97%) at pH ≥ 5 with 3 bars of transmembrane pressure.

Electrochemical water desalination has been a major research area since the 1960s with the development of capacitive deionization technique. For the latter, its modus operandi lies in temporary salt ion adsorption when a simple potential difference (1.0–1.4 V) of about 1.2 V is supplied to the system to temporarily create an electric field that drives the ions to their different polarized poles and subsequently desorb these solvated ions when potential is switched off. Capacitive deionization targets/extracts the solutes instead of the solvent and thus consumes less energy and is highly effective for brackish water. This paper reviews Capacitive Deionization (mechanism of operation, sustainability, optimization processes, and shortcomings) with extension to its counterparts (Membrane Capacitive Deionization and Flow Capacitive Deionization).

As organic dyes are a major source of pollution, it is important to develop novel and efficient heterogeneous catalysts with high activity for their degradation. In this work, two innovative techniques, atomic layer deposition and electrospinning, were used to prepare palladium nanoparticles (Pd NPs) supported on carbon nanofibers (CNFs). The sample morphology was investigated using scanning and transmission electron microscopy. This showed the presence of nanofibers of several micrometers in length and with a mean diameter of 200 nm. Moreover, the size of the highly dispersed Pd NPs was about 7 nm. X-ray photoelectron spectroscopy visually validated the inclusion of metallic Pd. The prepared nano-catalysts were then used to reduce methyl orange (MO) in the presence of sodium borohydride (NaBH4). The Freundlich isotherm model was the most suitable model to explain the adsorption equilibrium for MO onto the Pd/CNF catalysts. Using 5 mL MO dye-solution (0.0305 mM) and 1 mL NaBH4 (0.026 mM), a 98.9% of catalytic activity was achieved in 240 min by 0.01 g of the prepared nano-catalysts Pd/C (0.016 M). Finally, no loss of catalytic activity was observed when such catalysts were used again. These results represent a promising avenue for the degradation of organic pollutants and for heterogeneous catalysis.

Microfibrillar and droplet morphology of polypropylene (PP) phase dispersed in polypropylene (PS) was fabricated by using melt-extrusion. This morphology was obtained by introducing isotactic PP (20 wt.%) with different viscosity in the PS matrix (80 wt.%). Furthermore, the rheological properties of the blend investigated as a function of the viscosity ratio K. The variations in blend morphology were related to crystallization, melting properties, and viscoelasticity. The blends with K >> 1 develop a fine morphology with PP microfibrils along the flow direction, while diameters of the dispersed PP droplets gradually increase with lower values of K = 1, or K << 1. Crystallinity of the prepared blends significantly decreases compared to neat PP, while the microfibrillar morphology induces homogeneous crystallization with small crystallites. This is reflected in a decrease of the crystallization temperature, small loss in the crystallinity, and lower melting temperature of the PS80/PP20 blend compared to neat PP. The storage moduli, loss moduli, and complex viscosity are highest for the microfibrillar morphology that presents retarded relaxation. The rheological properties are dominated by the dispersed phase (K > 1), or matrix (K < 1). The variation in blend properties with microfibrillar morphology can be clearly distinguished from heterogeneous blends containing PP droplets, providing an efficient tool to create a binary blend with unique properties.

Improving the selectivity of gas sensors is crucial for their further development. One effective route to enhance this key property of sensors is the use of selective nanomembrane materials. This work aims to present how metal-organic frameworks (MOFs) and thin films prepared by atomic layer deposition (ALD) can be applied as nanomembranes to separate different gases, and hence improve the selectivity of gas sensing devices. First, the fundamentals of the mechanisms and configuration of gas sensors will be given. A selected list of studies will then be presented to illustrate how MOFs and ALD materials can be implemented as nanomembranes and how they can be implemented to improve the operational performance of gas sensing devices. This review comprehensively shows the benefits of these novel selective nanomaterials and opens prospects for the sensing community.

Rapid urbanization proportionally increases the waste products which force humankind to find a suitable waste management system. This study aims at identifying the possibility of using toner waste powder (TWP) as a filler for fabricating polymer composites for enhanced electrical conductivity of polymer blends. TWP was successfully incorporated into a polymer blend of low-density polyethylene/high impact polystyrene (LDPE/HIPS) at a high loading percentage of up to 20 wt %. Elemental analysis (SEM-EDS and XRF) showed that the main constituents of TWP are carbon and iron with traces of other metals such as Ca, Cs, Ti, Mn, Si. The electrical conductivity of LDPE/HIPS is significantly enhanced by loading the TWP into the polymer blend. The addition of TWP to LDPE/HIPS blend decreases the electrical resistivity of the LDPE/HIPS/TWP composite to ~2.9 × 107 Ohm.cm at 10 wt % of TWP, which is several orders of magnitude lower than that of the neat blend with maintaining the thermal stability of the polymer composite. The prepared polymer composite is lightweight and shows electrical conductivity, thus it can have potential applications in electronic materials and automotive industries.

Catalytic electrodes were prepared via carbonization of MIL-53(Fe) on the surface of porous carbon felt electrodes (CF) for use in wastewater treatment by the heterogeneous electro-Fenton (EF) process. The best results were obtained when the carbon felt was pretreated with nitric acid, enhancing the affinity of the MIL-53(Fe) for the surface. Following a series of optimization experiments, carbonization conditions of 800 °C for 5 h were used to form Fe-nanoporous carbon (MOFs@CF). The as-prepared electrodes were used as both cathode and heterogeneous catalyst in the EF process for the mineralization of exemplar dye Acid Orange 7 (AO7). Total organic carbon (TOC) removal of 46.1% was obtained within 8 h of electrolysis at around neutral pH (6.5) and the electrode retained over 80% of its original efficiency over five treatment cycles.

We report the fabrication of a novel fiber-optic sensor device, based on the use of a microsphere conformally coated with a thin layer of zinc oxide (ZnO) by atomic layer deposition (ALD), and its use as a refractive index sensor. The microsphere was prepared on the tip of a single-mode optical fiber, on which a conformal ZnO thin film of 200 nm was deposited using an ALD process based on diethyl zinc (DEZ) and water at 100 °C. The modified fiber-optic microsphere was examined using scanning electron microscopy and Raman spectroscopy. Theoretical modeling has been carried out to assess the structure performance, and the performed experimental measurements carried out confirmed the enhanced sensing abilities when the microsphere was coated with a ZnO layer. The fabricated refractive index sensor was operating in a reflective mode of a Fabry⁻Pérot configuration, using a low coherent measurement system. The application of the ALD ZnO coating enabled for a better measurement of the refractive index of samples in the range of the refractive index allowed by the optical fiber. The proof-of-concept results presented in this work open prospects for the sensing community and will promote the use of fiber-optic sensing technologies.

Rapid progress in the performance of organic devices has increased the demand for advances in the technology of thin-film permeation barriers and understanding the failure mechanisms of these material systems. Herein, we report the extensive study of mechanical and gas barrier properties of Al2O3/ZnO nanolaminate films prepared on organic substrates by atomic layer deposition (ALD). Nanolaminates of Al2O3/ZnO and single compound films of around 250 nm thickness were deposited on polyethylene terephthalate (PET) foils by ALD at 90 °C using trimethylaluminium (TMA) and diethylzinc (DEZ) as precursors and H2O as the co-reactant. STEM analysis of the nanolaminate structure revealed that steady-state film growth on PET is achieved after about 60 ALD cycles. Uniaxial tensile strain experiments revealed superior fracture and adhesive properties of single ZnO films versus the single Al2O3 film, as well as versus their nanolaminates. The superior mechanical performance of ZnO was linked to the absence of a roughly 500 to 900 nm thick sub-surface growth observed for single Al2O3 films as well as for the nanolaminates starting with an Al2O3 initial layer on PET. In contrast, the gas permeability of the nanolaminate coatings on PET was measured to be 9.4 × 10−3 O2 cm3 m−2 day−1. This is an order of magnitude less than their constituting single oxides, which opens prospects for their applications as gas barrier layers for organic electronics and food and drug packaging industries. Direct interdependency between the gas barrier and the mechanical properties was not established enabling independent tailoring of these properties for mechanically rigid and impermeable thin film coatings.

The thermal and mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate, PHBV) composites filled with boron nitride (BN) particles with two different sizes and shapes were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), thermal gravimetric analysis (TGA) and mechanical testing. The biocomposites were produced by melt extrusion of PHBV with untreated BN and surface-treated BN particles. Thermogravimetric analysis (TGA) showed that the thermal stability of the composites was higher than that of neat PHBV while the effect of the different shapes and sizes of the particles on the thermal stability was insignificant. DSC analysis showed that the crystallinity of the PHBV was not affected significantly by the change in filler concentration and the type of the BN nanoparticle but decreasing of the crystallinity of PHBV/BN composites was observed at higher loadings. BN particles treated with silane coupling agent yielded nanocomposites characterized by good mechanical performance. The results demonstrate that mechanical properties of the composites were found to increase more for the silanized flake type BN (OSFBN) compared to silanized hexagonal disk type BN (OSBN). The highest Young’s modulus was obtained for the nanocomposite sample containing 1 wt.% OSFBN, for which increase of Young’s modulus up to 19% was observed in comparison to the neat PHBV. The Halpin⁻Tsai and Hui⁻Shia models were used to evaluate the effect of reinforcement by BN particles on the elastic modulus of the composites. Micromechanical models for initial composite stiffness showed good correlation with experimental values.

The ability to prepare controllable nanocatalysts is of great interest for many chemical industries. Atomic layer deposition (ALD) is a vapor phase technique enabling the synthesis of conformal thin films and nanoparticles (NPs) on high surface area supports and has become an attractive new route to tailor supported metallic NPs. Virtually all the studies reported, focused on Pd NPs deposited on carbon and oxide surfaces. It is, however, important to focus on emerging catalyst supports such as boron nitride materials, which apart from possessing high thermal and chemical stability, also hold great promises for nanocatalysis applications. Herein, the synthesis of Pd NPs on boron nitride (BN) film substrates is demonstrated entirely by ALD for the first time. X-ray photoelectron spectroscopy indicated that stoichiometric BN formed as the main phase, with a small amount of BNxOy, and that the Pd particles synthesized were metallic. Using extensive transmission electron microscopy analysis, we study the evolution of the highly dispersed NPs as a function of the number of ALD cycles, and the thermal stability of the ALD-prepared Pd/BN catalysts up to 750 °C. The growth and coalescence mechanisms observed are discussed and compared with Pd NPs grown on other surfaces. The results show that the nanostructures of the BN/Pd NPs were relatively stable up to 500 °C. Consequent merging has been observed when annealing the samples at 750 °C, as the NPs’ average diameter increased from 8.3 ± 1.2 nm to 31 ± 4 nm. The results presented open up exciting new opportunities in the field of catalysis.