Search Results (978)

Heavy metal wastewater, characterized by high toxicity, poor biodegradability, and strong bioaccumulation potential, poses a serious threat to the ecological environment and human health. Conventional chemical treatment methods are costly and prone to secondary pollution. In contrast, using solid waste to prepare environmental functional materials for “waste control by waste” has emerged as a research hotspot in the field of synergistic water pollution control and resource recovery. This review systematically consolidates the sources, physicochemical properties, and compositional characteristics of typical industrial solid wastes—including red mud, electroplating sludge, fly ash, copper slag, and blast furnace slag—and elucidates how compositional variations constrain the selection of functionalization pathways. On this basis, key preparation techniques, namely hydrothermal synthesis, surface modification/impregnation, thermal treatment, geopolymerization, and sol–gel/polymerization, are critically reviewed and compared in terms of product structural regulation, process complexity, and engineering scale-up potential. Subsequently, the adsorption performance of the resultant materials toward heavy metals such as Pb²⁺, Cu²⁺, Cr(VI), As(VI), Cd²⁺, Ni^2+, and Zn²⁺ is discussed, with particular emphasis on the pronounced effects of pH, temperature, initial concentration, coexisting ions, and adsorbent dosage on adsorption capacity. Notably, Pb²⁺ exhibits the highest adsorption capacity, whereas the removal of Cr(VI) and As(V) is strongly governed by the positive charge density and reduction efficiency of the material surface. In quinary heavy metal competitive systems, marked differences in the affinity of adsorption sites toward distinct metal ions have been observed. Mechanistic analysis identifies ion exchange, surface complexation, electrostatic attraction, and redox reactions as the predominant removal pathways. This review further incorporates engineering-oriented assessments, including multi-component competitive adsorption, fixed-bed column operation, and regeneration stability, and identifies the critical bottlenecks currently impeding the transition from laboratory-scale research to practical implementation—namely, performance instability arising from feedstock variability, attenuation of adsorption capacity during prolonged operation (with a 10–40% decline over 5–10 cycles), underdeveloped regeneration and recovery routes, and a systemic deficiency in techno-economic analysis and life-cycle assessment data. Finally, future research directions are proposed, emphasizing the development of low-carbon and energy-efficient preparation technologies, the promotion of synergistic valorization of multiple solid wastes alongside critical metal recovery, and the advancement of this field toward engineering applications through artificial intelligence-assisted design and life-cycle assessment, thereby furnishing theoretical references and technical support for the integrated management of industrial solid waste resource utilization and heavy metal wastewater treatment. Full article

In the present work, thin TiO₂ films were obtained by the sol–gel spin-coating method on glass and ITO-covered glass substrates. The crystallization evolution of the thin films was studied by the X-ray Diffraction (XRD) technique. The results indicate that the films’ crystalline structure was greatly affected by substrate type. X-ray photoelectron spectroscopy (XPS) revealed the chemical states of the TiO₂ films and proved the formation of TiO₂ on ITO substrates. Field Emission Scanning Electron Microscopy (FESEM) showed that the TiO₂ films deposited on the ITO glass possessed a uniform and homogeneous surface morphology. The influence of optical properties (transmittance, reflectance, and optical band gap) on substrate type, the number of layers and annealing temperatures was determined. Spectroscopic data confirmed high transparency of the TiO₂ films obtained on ITO substrates as the transmittance in the visible spectral range was close to 85%. The obtained results reveal that thin TiO₂ films on ITO substrates can be an excellent candidate for photovoltaic and optoelectronic applications. Full article

Lithium-ion batteries (LIBs) are essential for current technological infrastructure, driving the development of portable electronics, electric vehicles or grid-scale energy storage. The performance and sustainability of LIBs are critically dependent on their anode materials. This comprehensive review analyzes the evolution and characteristics of key anode materials, highlighting the specific properties they confer to the final battery products. Beyond material properties, the synthesis methods employed for these materials, from conventional techniques (such as solid-state reactions, sol–gel, hydrothermal/solvothermal, co-precipitation, etc.) to innovative and greener approaches (like electrospinning and a novel induction furnace-oxidation hybrid method for complex oxides), are a crucial part in the development of sustainable materials. While these methods offer different advantages, the challenges in achieving optimal electrochemical performance, including issues related to material stability, capacity retention and scalability, remain significant for both research and manufacturing industries. Furthermore, a significant focus is placed on strategies for mitigating the environmental impact associated with anode material production, emphasizing the importance of unconventional and sustainable synthesis routes. Ultimately, the sustainable evolution of LIB technology to achieve future energy demands hinges on overcoming existing limitations. This necessitates integrated research combining advanced material modeling and design, scalable and environmentally conscious synthesis techniques and in-depth electrochemical characterization. Full article

Hollow glass microspheres, as demonstrated in recent studies, have shown significant importance in the field of composite materials and have emerged as transformative materials in biomedical applications. This is necessitated by their ability to provide a physicochemical gradient, a desirable tool for complex tissues and biological interfaces, through the spatiotemporal release of bioactive factors and nanophase ceramics. HGMs are structures with diameters ranging from 1 to 1000 µm that can be used as support for cell growth, either in the form of a scaffold or a drug delivery system. In this review, we describe the various methods for HGM fabrications, synthesis (e.g., flame spraying, sol-gel processes, spray drying, etc.), structural characterizations, and chemical and physical properties (e.g., densities ranging from 0.1 to 0.6 g/cm³ and compressive strength ranging from 10 MPa to 30 MPa for low and high densities, respectively), highlighting how these methods influence their drug delivery, tissue engineering, bone implants, and nanocarrier abilities. Furthermore, a comprehensive list of other materials and their various biomedical uses is reported. Some of the limitations of existing techniques and future investigations into how HGM can perform as a biomedical material are discussed. Full article

Metal oxide nanoparticles have been the subject of intense research interest because of their remarkable physicochemical properties, such as their high surface area, particle size tunability, outstanding chemical stability, optical activity, catalytic efficiency, and antimicrobial behavior. These properties make them very useful in environmental, biomedical, energy, sensing, agricultural and industrial applications. The chosen synthesis method is important in controlling the morphology, crystallinity, surface charge, band gap and overall performance of metal oxide nanoparticles. They have been prepared using various physical, chemical and biological means, such as sol–gel, co-precipitation, hydro/solvothermal, microwave-assisted, sonochemical, combustion and green synthesis. Of these, green synthesis is gaining more interest as it employs plant extracts, microorganisms, and other biological materials as reducing agents, stabilizing and capping agents that make the process more eco-friendly and cost-effective. Recent advancements in the synthesis and application of metal oxide nanoparticles are discussed. There is an emphasis on the major synthesis routes, the main factors that influence the formation of nanoparticles, the characterization techniques used, and the structure–property relationships uncovered. A special focus is given to the influence of synthesis parameters, such as the type of precursor and the pH, temperature, reaction time, solvents and capping agents, on the properties of nanoparticles. In addition, the uses of metal oxide nanoparticles in photocatalysis, wastewater treatment, antimicrobial activity, drug delivery, biosensing, energy storage, gas sensing, and agriculture are also included. Finally, present challenges, toxicity issues, the problems of large-scale production, and future research directions are discussed to support the practical and sustainable uses of metal oxide nanoparticles. Full article

Functional coatings have evolved from their early role as passive barriers against corrosion and wear into engineered interfaces that actively mediate the interaction between a bulk material and its environment. This review traces the evolution of coating technologies from traditional macroscopic protective layers to nanoscale and multifunctional systems, and finally to smart and stimuli-responsive architectures. Advanced deposition and surface modification techniques are examined, including atomic layer deposition, physical vapor deposition, electrochemical and sol–gel approaches. The discussion is structured around two complementary application domains: extreme energy environments, focusing on coatings developed for advanced nuclear systems, and modern medical implants, including bioactive and antimicrobial surfaces and drug-delivery interfaces. The review highlights that, despite the differences between reactor and biomedical environments, both sectors share a common set of design principles and challenges, including interfacial adhesion, mechanical durability, the dual role of nanostructuring, and the trade-off between architectural complexity and operational reliability. Long-term stability, scalability, and standardized validation remain key barriers to deployment, while data-driven design and the deliberate integration of multiple functions emerge as the principal directions for future development. Full article

Tungsten trioxide (WO₃) is the most widely studied cathodic electrochromic (EC) material, serving as the core component of energy-efficient smart windows, displays, and optical modulation devices. Post-deposition annealing, as a critical post-processing technique, precisely regulates the microstructure, crystallinity, oxygen vacancy concentration, and electronic structure of WO₃ thin films, thereby directly determining their EC performance. This review summarizes the research progress of annealing effects on WO₃ films, focusing on the synergistic regulation of annealing temperature, atmosphere, and dwell time. It elaborates on the fundamental EC mechanisms of amorphous and crystalline WO₃, including polaron hopping and free-electron Drude behavior, and analyzes the influence of different deposition methods (magnetron sputtering, sol–gel, electrodeposition, etc.) on the annealing response of films. The optimal annealing windows for balancing optical modulation, coloration efficiency, switching speed, and cycling stability are clarified: moderate temperatures (200–350 °C) and inert/air atmospheres yield mixed amorphous–nanocrystalline structures with optimal oxygen vacancy content. Current challenges such as the inherent contrast–stability trade-off and thermal budget limitations of flexible substrates are discussed, and future directions including spatially resolved annealing, interface co-design, and machine learning-assisted optimization are prospected. This work provides a theoretical reference and process guidance for the development of high-performance WO₃-based EC devices. Full article

Adsorption therapies in hemodialysis have emerged as an innovative approach for removing protein-bound uremic toxins (PBUTs). The present work focuses on the enhancement of the adsorption capacity of hemodialysis membranes through the incorporation of Metal–Organic Frameworks (MOFs). The removal capacity of PBUT p-cresyl sulfate by cellulose acetate (CA)/silica (SiO₂)/MOF mixed matrix membranes was investigated with two types of MOFs, UiO-66 which synthesis and characterization has been previously reported, and UiO-66-NH₂. The UiO-66-NH₂ MOFs were synthesized and characterized by infrared spectroscopy, X-ray diffraction, nitrogen adsorption–desorption equilibrium at −196 °C, and thermogravimetry analysis. Both mixed matrix membranes were synthesized by coupling the phase inversion technique with the sol–gel method and with casting solutions incorporating the MOF dispersions. The two membrane types of MOFs were characterized in terms of hydraulic permeability, molecular weight cut-off, and rejection coefficients to pCS and bovine serum albumin (BSA). The mixed matrix membranes CA/SiO₂/UiO-66-NH₂ exhibited lower permeability and molecular weight cut-off when compared to the CA/SiO₂/UiO-66 ones. In permeation tests simulating a hemodialysis session with a feed solution of 100 ppm pCS and 35 g/L BSA, it is shown the improved performance of MOFs membranes as the rejection coefficients of free pCS is 0.2% for the CA22/SiO₂/UiO-66 membrane with 1.5% of MOF and 2.6% for the CA22/SiO₂/UiO-66-NH₂ membrane with 2% of MOF. The capacity of these MOF membranes in removing pCS bound to BSA was addressed through the development of a new methodology to quantify the pCS free and bound to BSA. The CA22/SiO₂/UiO-66 membrane with 1.5% of MOF has a removal capacity of 99.8% and the CA22/SiO₂/UiO-66-NH₂ membrane with 2% of MOF 95.9%. Based on these results, it is concluded that the mixed matrix membranes CA22/SiO₂/UiO-66 and CA22/SiO₂/UiO-66-NH₂ are promising candidates for PBUTs removal in hemodialysis. Full article

Polymer-derived ceramics (PDCs) technology has been established for over five decades as a versatile route for the fabrication of advanced bioceramic materials. However, conventional processing routes for bioceramics, such as melt-quenching and sol–gel methods, still present significant limitations, including high processing temperatures, limited compositional flexibility, long processing times, and difficulties in fabricating complex and highly porous structures required for biomedical applications. In this context, increasing attention has been devoted to polymer-derived ceramics as an alternative approach for the fabrication of bioceramic materials. In this approach, preceramic polymers are converted into ceramic phases through thermal treatment in air or inert atmosphere (e.g., nitrogen), enabling low-temperature processing, high compositional flexibility, and precise control over phase evolution and microstructure. These features make the polymer-derived Ceramic route particularly attractive for the fabrication of complex and functional bioceramic architectures. This review provides an overview of the polymeric precursors employed for the synthesis of Polymer Derived Ceramic-based bioceramics, with particular emphasis on inorganic polymers, typically characterized by a siloxanic backbone, and the mechanisms governing their ceramization behavior. Special attention is given to emerging trends, including the integration of polymer-derived ceramics with additive manufacturing techniques and the development of functional systems for biomedical applications. Full article

In the present research, lanthanum ferrite nanoparticles (LaFeO₃ NPs) and lanthanum ferrite polypyrrole (LaFeO₃/PPy) nanocomposites were synthesized and evaluated for electrochemical sensing of TNZ in biological and pharmaceutical samples. LaFeO₃ NPs were synthesized using the sol–gel auto-combustion method, whereas LaFeO₃/PPy nanocomposites were produced through an in situ chemical oxidative polymerization process. The obtained materials were subjected to comprehensive characterization by multiple analytical techniques, including XRD, which confirms an orthorhombic crystal structure; SEM micrographs of LaFeO₃ NPs and LaFeO₃/PPy nanocomposites exhibit a highly agglomerated structure with non-uniform particle distribution and a more homogeneous, smoother surface morphology, respectively, with an average size of <70 nm. The LaFeO₃/PPy nanocomposites exhibited an electron-transfer process governed by diffusion, as evidenced by cyclic voltammetry (CV) analysis. Using differential pulse voltammetry (DPV), the sensor achieved quantitative detection across a linear concertation range of 0.1–230 µM (R² = 0.997), with a detection limit (0.023 µM). The developed sensor demonstrated excellent stability, remarkable sensitivity, and high reproducibility, confirming reliability and suitability (RSD% < 4.0) for the quantitative determination of TNZ in both biological and pharmaceutical matrices. Full article

In this research work, Ag-doped and undoped TiO₂ nanocomposites were prepared through a sol–gel method, using diethanolamine as a solvent. From the evolution of various characterized techniques (XRD, FT-IR, SEM and TGA analysis), it was found that Ag-TiO₂ nanocomposites have a mixture of rutile and anatase phases of titania. The catalytic performance of the Ag-TiO₂ nanocomposites was evaluated for Eriochrome Black T (EBT) photodegradation. To determine the photocatalytic efficiency of the nanocomposites, different factors including pH (2–12), catalytic dose (2–12 mg), reaction time (0–180 min) and concentration (2–10 mg/L) were investigated. The calcined Ag-TiO₂ showed high degradation (94%) for EBT at a low pH for 0.01 g of catalyst using 10 mg/L of dye solution. The kinetic study revealed that the photocatalytic degradation process obeys pseudo second-order kinetics. To investigate antibacterial effects, different bacteria such as Enterococcous, Staph Avrius, serritia and Escherichia E. coli were utilized. A total of 200 mg of calcined Ag-TiO₂ nanocomposite showed optimum activities against bacterial strains. Full article

The need for sustainable and cost-effective thermoelectric materials has brought attention to earth-abundant and mineral compounds, like Cu₂ZnSnS₄ (CZTS). In this work, CZTS nanoparticles (NPs) were synthesized via the sol–gel method using environmentally friendly solvents based on water and ethanol mixtures. The resulting CZTS NPs were then processed into inks through ball milling to produce a thin-film thermoelectric generator (TEG). Structural and microstructural properties were investigated via X-ray diffraction and Raman spectroscopy, confirming the kesterite CZTS phase upon sintering. The chalcogenide exhibited p-type semiconductor behaviour, with a Seebeck coefficient reaching ~69 µV/K at 385 K. Van-der-Pauw measurements of conductivity confirmed a non-degenerate semiconducting behaviour, achieving ~1.77 S/cm at 323 K. A two-leg CZTS thin-film TEG reaching a maximum power output of 32(3) nW at a ΔT ~160 K was used, measured with a home-made setup. The volume-specific power of the generator reached $4\times {10}^{-4}$μW cm⁻³ K⁻². These results point to an effective use of sol–gel-based techniques to produce a functional thermoelectric generator, providing a costless and environmentally friendly approach to CZTS NPs. Full article

CuO thin layers were synthesized using the sol–gel method and deposited onto glass substrates through the dip-coating technique. The impact of annealing temperatures on the structural, optical, and electrical characteristics of the developed CuO thin layers was comprehensively assessed through X-ray diffraction, UV–visible spectrophotometry, and four-point techniques, respectively. X-ray diffraction analysis revealed the formation of CuO thin layers with a distinctive monoclinic tenorite phase structure. The UV–visible spectrophotometer results demonstrated a decrease in transmittance from approximately 30% to about 7% as the annealing temperature increased from 200 °C to 400 °C. The semiconducting properties exhibited temperature-dependent variations, with the band gap narrowing from 1.70 to 1.48 eV as the temperature increased from 200 to 400 °C. Additionally, the electrical conductivity of the CuO layers exhibited a significant increase from 48 to 61 S.m⁻¹ over the same temperature range. Collectively, the findings suggest that an annealing temperature of 400 °C is optimal for achieving well-crystallized CuO layers with desirable characteristics, including high absorbance, low transmittance, a reduced energy band gap, and enhanced electrical conductivity. These results underscore our ability to manipulate CuO properties, offering insights for tailoring them to meet specific requirements, particularly in the context of gas sensor applications. Full article

Self-powered photodetectors have attracted widespread attention in Internet of Things applications due to their low power consumption and high sensitivity. In this study, plasmonic self-powered poly(3-hexylthiophene)/zinc oxide (P3HT/ZnO) heterojunction photodetectors incorporating silver triangular nanoplates (AgTNPs) were fabricated using sol–gel and spin-coating techniques. The experimental results demonstrate that the incorporation of AgTNP nanostructures significantly enhances the photoelectric conversion efficiency of the plasmonic P3HT/AgTNPs/ZnO photodetectors across both the ultraviolet and visible spectral regions. The responsivity enhancement ratio of the plasmonic devices reached its maximum under illumination at a wavelength of 525 nm. Compared with the reference P3HT/ZnO device, the responsivity values of the P3HT/AgTNPs-1/ZnO and P3HT/AgTNPs-2/ZnO devices increased by factors of 3.24 and 4.21, respectively. The optimal P3HT/AgTNPs-2/ZnO device exhibited responsivity values of 9.49, 10.80, and 10.47 mA/W under irradiation at wavelengths of 440 nm, 460 nm, and 525 nm, respectively. The mechanism of performance enhancement induced by the plasmonic AgTNPs is also discussed. This work demonstrates that embedding triangular plasmonic metal nanoplates within semiconductor heterojunctions constitutes an effective strategy for performance enhancement, providing new insights for the rational design of high-performance optoelectronic devices. Full article

Mg-doped ZnO (Zn_1−xMg_xO, x = 0.00–0.05) thin films were successfully grown on glass substrates with a c-axis orientation at 600 °C using the sol–gel dip-coating technique. The structural features, defect-related photoluminescence, and optical constants of the films were systematically investigated as a function of Mg concentration. X-ray diffraction (XRD) patterns confirmed a single-phase hexagonal wurtzite structure with a preferential (₀₀₂) orientation for all compositions, indicating the successful substitution of Mg²⁺ ions into the ZnO lattice. The crystallite size (D₀₀₂) was found to vary between 28.49 and 41.18 nm, while microstrain and stress exhibited non-monotonic behavior depending on Mg content. This behavior reveals a transition from compressive to tensile stress due to lattice distortion and defect formation. Photoluminescence (PL) spectra showed a dominant near-band-edge (NBE) ultraviolet emission, along with broad visible emissions extending from violet to red. Optical constants were accurately extracted using a double-facet-coated substrate (DFCS) model, combined with nonlinear curve fitting using the Nelder–Mead optimization algorithm. The films showed a strong absorption edge at about 370 nm and exceptional optical transparency (≈60–80%) in the visible spectrum. The systematic blue shift in the extinction coefficient with increasing Mg content confirms bandgap engineering in Zn_1−xMg_xO thin films. The refractive index dispersion was successfully modeled using the Cauchy relation, demonstrating composition-dependent tunable optical properties. Depending on the Mg content, the optical bandgap values ranged from approximately 3.265 to 3.315 eV. The band-edge states and optical constants are strongly affected by the combined effects of defect development, Mg-induced lattice distortion, and changes in optical dispersion. These results indicate that sol–gel-derived Mg-doped ZnO thin films with composition-dependent stress states, defect states, and tunable optical properties are promising candidates for UV photodetectors, optical coatings, and transparent optoelectronic devices. Full article