Search Results (1,543)

Hybrid conductive materials have attracted increasing attention due to their combined electrical conductivity, mechanical flexibility, and sustainability. In this work, new hybrid materials based on polyaniline (PANI)-wrapped multi-walled carbon nanotubes (MWCNTs) and microfibrous cellulosic substrates were developed and assessed for photocatalytic degradation of a model dye pollutant. First, in situ oxidative polymerization of aniline in formic acid (FA) was conducted in the presence of MWCNTs to afford stable dispersions of carboxylated polyaniline-wrapped carbon nanotubes (c-PANI/MWCNTs). Next, the dispersions were used for affordable impregnation of microfibrous cellulosic filter paper. The influence of the initiator type—potassium peroxodisulfate (KPS) and hydrogen peroxide—on polymer–nanotube interactions, stabilization and surface deposition was emphasized. The structural, surface, morphological and thermal properties of the obtained dispersions and cellulose nanocomposites were systematically investigated using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermal gravimetric analysis. The results revealed strong interfacial interactions between c-PANI and the pristine MWCNTs, resulting in improved dispersion stability and effective and even surface deposition of the conductive c-PANI/MWCNT hybrids into the cellulose fiber mesh. The photocatalytic degradation of 5 ppm methylene blue (MB) dye in the presence of the developed nanocomposite materials under UV-A illumination was studied. The results showed that the c-PANI@MWCNT-impregnated cellulose substrates exhibited enhanced photocatalytic ability (up to 83% degree of degradation of MB dye) in comparison with the pure c-PANI. Full article

The ultrasound-guided erector spinae plane (ESP) block is a locoregional anesthesia technique primarily aimed at providing analgesia to structures innervated by the dorsal branches of the spinal nerves (DBSN). While this block has been widely studied in dogs, evidence in cats is limited, and only a few cadaveric studies have addressed the lumbar region. The aim of this study was to compare the injectate distribution and staining of the DBSN following ultrasound-guided lumbar ESP blocks performed using either a longitudinal or transverse approach in feline cadavers. A total of 15 feline cadavers were included, with 3 used for anatomical dissection and 12 for ultrasound-guided injections (24 sides). Injections were performed at the level of the third lumbar vertebra (L3) using a mixture of methylene blue, lidocaine, and iopromide (0.4 mL kg⁻¹ per side). Needle placement and injectate spread were guided and confirmed by ultrasonography, followed by computed tomography (CT) and anatomical dissection to evaluate contrast and dye distribution. CT images revealed longitudinal spread of the contrast in all injections, with the transverse approach producing exclusively longitudinal distribution and the longitudinal approach showing occasional ventral spread beneath the transverse processes (25% of sides). Dissections demonstrated staining of a median of 2 DBSN per side for both approaches, predominantly L2–L3, with rare partial staining of ventral branches (VBSN) observed only with the longitudinal approach. The sympathetic trunk was not stained in any injection. No statistically significant differences were observed between approaches, except for L1 DBSN staining, which was identified significantly more frequently with the transverse approach (p = 0.033). These findings indicate that ultrasound-guided lumbar ESP block is anatomically feasible in feline cadavers and that both longitudinal and transverse approaches can result in injectate distribution to the DBSN. Full article

The pressing issues of organic pollutants contamination of aquatic ecosystems challenges current research. Herein, we prepared three melamine-based POFs, to remove organic dyes from water. Melamine was polymerized with 1,4-dibromobutane (POF-1,4), terephthalaldehyde (POF-TerA) and trimesic acid (POF-TriA), obtaining POFs of different structural order degree and aromaticity. POFs were characterized using FT-IR spectroscopy, thermal gravimetric analysis, BET, powder X-ray diffraction and scanning electron microscopy. They were employed to remove cationic (Rhodamine B, RhB and Methylene Blue, MB) and anionic dyes (Methyl Orange, MO and Eosin Yellow, EY), using UV-vis investigation. The adsorption process was studied from the kinetic and thermodynamic points of view and reusing the best adsorbent was also considered. Data collected evidence that adsorption capacity depends on the POF structure, with maximum adsorption capacity, according to Langmuir isotherm model, of 329 mg/g for POF-1,4/MO and 472 mg/g for POF-TerA/RhB. Interactions involved in the adsorption were also elucidated. Comparison with reported data demonstrates that our materials show comparable performance to some previously reported systems. Furthermore, POF-TriA, is effective for dye mixtures and reusable three times without performance loss, after washing with methanol, avoiding harsh acidic/basic treatments. Results obtained systematically relate the adsorption efficiency to structural features of melamine-based POFs, representing useful support in designing such materials to remove selected classes of contaminants. Full article

The objective of this study is to develop a nanosized, visible-light-responsive photocatalyst with magnetic separability and recyclability for repeated use. Spinel ferrite nanoparticles, which are environmentally friendly, are promising candidates for achieving this goal. Spinel ferrite nanoparticles were synthesized via a low-temperature hydrothermal method to investigate their microstructural characteristics, magnetic properties, and photocatalytic performance. Initially, four ternary spinel ferrite (MFe₂O₄, where M = Mg, Mn, Co, and Zn) nanoparticles were compared in terms of their physical properties and photodegradation efficiencies of organic dye methylene blue (MB). Among them, the MgFe₂O₄ and ZnFe₂O₄ samples exhibited superior photocatalytic activity compared to the MnFe₂O₄ and CoFe₂O₄ samples. Subsequently, a systematic investigation of the Zn–Mg ferrite system (Zn_1−xMg_xFe₂O₄, x = 0 to 0.8 in increments of 0.2) was carried out. The results revealed that the x = 0.8 samples achieved the highest photodegradation efficiency of 99 for a 10 MB aqueous solution under visible-light irradiation for 90 min. This improved performance is attributed to formation of a heterojunction of Zn–Mg nanoferrite/Fe₂O₃, which promotes light harvesting and prevents photogenerated charge recommendation, thus significantly improving photocatalytic activity. Full article

MgCr₂O₄ nanospinel samples were synthesized using a modified Pechini method, followed by controlled calcination. The resulting materials were evaluated in terms of crystal structure, particle morphology, and optical and electronic properties. Their oxidative activity towards the degradation of organic dyes was investigated via photocatalysis, Fenton-like, and photon-Fenton-like processes. Various analytical techniques were employed to characterize the samples, including X-ray diffraction (XRD) with Rietveld refinements, infrared (IR) spectroscopy, UV–Vis spectroscopy, colorimetry, and transmission and high-resolution transmission electron microscopy (TEM/HRTEM). Structural characterization revealed that MgCr₂O₄ crystallized after calcination at 600 °C, and Rietveld refinements confirmed cubic Fd-3m symmetry. IR spectra confirmed the short-range order through the presence of vibrational modes assigned to CrO₆^2- octahedra. UV–Vis spectroscopy indicated mixed Cr valences (Cr³+/Cr⁶+) for samples calcined at temperatures below 900 °C, with Cr⁶+ eliminated at higher temperatures, confirmed by electron paramagnetic resonance (EPR) spectroscopy. This suggests that an oxidation reaction occurred due to oxygen vacancies in the lattice. Optical bandgap (Eg) increased with temperature. Samples calcined at low temperatures were dark green and became more saturated at temperatures above 900 °C, suggesting photoresponse to visible light, as indicated by the Eg values. The oxidative activity of the nanospinels in degrading the dyes methylene blue (MB) and rhodamine B (RhB) under visible light depended on the nature of the dye, the catalyst concentration, and the use of H₂O₂ in the process to improve the formation of hydroxyl radicals (•OH), as confirmed by photohydroxylation of terephthalic acid (TA). The highest degradation rate was observed in the photo-Fenton-like process, with 96% and 97% degradation of RhB and MB dyes in 60 min, reaching a kinetic rate constant (${\mathit{K}}_{app}$) of 0.055 min⁻¹ and 0.051 min⁻¹, respectively. This study highlights the importance of controlling various parameters to promote the formation of reactive oxygen species (ROS) required for oxidative degradation by nanospinels. Full article

This study investigates the potential of several sustainable agricultural by-products—including olive stones, cork, and almond shells, which are locally available in Alentejo, Portugal—as low-cost adsorbents for the removal of methylene blue (MB) from synthetic wastewater. The biomass residues were evaluated both in their raw form and after conversion into activated carbons (ACs) through chemical activation with KOH at 973 K. The produced ACs exhibited well-developed surface areas (760–1103.5 m² g⁻¹) and porous structures (0.31–0.51 cm³ g⁻¹). The adsorbents were characterised in terms of their chemical and textural properties. Raw biomass materials presented acidic surface groups, whereas the ACs presented neutral or basic groups. Batch adsorption experiments were conducted to assess the effects of adsorbent particle size, solution pH, initial MB concentration, stirring speed, contact time, and temperature on dye removal efficiency. Among all tested materials, the ACs achieved superior MB adsorption capacities, ranging from 244.2 to 317.6 mg g⁻¹, compared to the untreated biomass adsorbents, which showed capacities between 34.1 and 46.4 mg g⁻¹. The adsorption data were best described by the Langmuir isotherm model, while the kinetic data closely followed the pseudo-second-order (PSO) model. Thermodynamic analysis revealed that MB adsorption was spontaneous and endothermic; however, the relatively low enthalpy values indicated that physical interactions contributed significantly, particularly in the case of the raw biomass adsorbents. This suggests that the PSO model may also be applicable when physical adsorption is the dominant mechanism. This work demonstrates the novel use of cork, olive stone, and almond shell biomasses and their derived ACs as sustainable adsorbents, highlighting an integrated approach that simultaneously promotes efficient wastewater treatment, waste valorisation, and circular economy-driven socio-economic development. Full article

In this work, ZnO nanoparticles were synthesized via a plant-mediated green route using Prosopis tamaulipana extract as a reducing and stabilizing agent and subsequently modified with silver to obtain Ag-modified ZnO powders. Structural and morphological characterization techniques confirmed the formation of nanocrystalline ZnO with a hexagonal wurtzite structure, submicrometric agglomerates composed of nanosized primary particles and a high degree of phase purity, indicating the effectiveness of the synthesis approach. The photocatalytic performance of the Ag-modified ZnO materials was evaluated under natural solar irradiation using methylene blue as a model organic contaminant in aqueous solution. Visual observations, together with absorbance, temperature and electrical conductivity measurements, demonstrated an effective and progressive degradation of the dye over a 5 h irradiation period. The observed increase in electrical conductivity under illumination was associated with enhanced charge carrier generation and improved separation efficiency, as well as the formation of reactive oxygen species, promoted by the presence of Ag as an electron sink. These results confirm that green-synthesized Ag-modified ZnO nanoparticles exhibit enhanced photocatalytic activity and are promising multifunctional materials for sustainable water sanitation applications. Full article

In this work, monodisperse carbon microspheres with an average diameter of approximately 900 nm were successfully synthesized via a hydrothermal method. To further tailor their surface properties, the layer-by-layer (LbL) self-assembly technique was employed, where the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) and the anionic polyelectrolyte poly(styrene sulfonate) (PSS) were alternately deposited on the microsphere surface, forming two and four bilayer assemblies, respectively. The resulting composite microspheres exhibited remarkable adsorption performance toward representative dyes in water solution, such as rhodamine B (RhB) and methylene blue (MB). Experimental results demonstrated that the incorporation of a single bilayer significantly reduced the specific surface area but introduced additional active adsorption sites, thereby enhancing dye removal efficiency. However, when the number of bilayers was further increased to two, partial pore coverage and blockage occurred, leading to a reduced surface area and consequently diminished adsorption capacity. These findings highlight that in LbL surface modification, more layers do not necessarily yield better performance, but rather an optimal assembly thickness exists. This insight provides valuable guidance for the rational design of advanced adsorbent materials for wastewater treatment. Full article

Geopolymers, alkali-activated aluminosilicate materials, have gained increasing attention as sustainable adsorbents for wastewater treatment due to their low-temperature synthesis, cost-effectiveness, and ease of shaping into mechanically robust structures. Their intrinsic negatively charged framework promotes the adsorption of cationic species; however, pristine geopolymers typically exhibit moderate performance, with adsorption capacities generally below ~70 mg g⁻¹ for dyes such as methylene blue (MB) and in the range of 20–100 mg g⁻¹ for divalent metal ions. To overcome these limitations, different strategies have been developed to tailor their pore structure and surface chemistry. In particular, foaming approaches enable the production of highly porous materials with tunable pore architecture, improving mass transfer and accessibility of active sites. Moreover, functionalization with carbon-based materials (e.g., activated carbon, graphene derivatives, biochar) or zeolitic phases significantly enhances adsorption performance, with reported capacities exceeding 500 mg g⁻¹ for Pb²⁺ and up to 450 mg g⁻¹ for organic dyes in optimized systems. This review provides a comprehensive overview of recent advances in geopolymer synthesis, pore engineering, and functionalization strategies, highlighting the relationships between composition, structure, and adsorption performance. Particular attention is devoted to the comparison between carbon-based and zeolitic modifications, as well as to the role of material shaping in enabling practical applications. Overall, the combination of tunable porosity, chemical versatility, and structural integrity positions functionalized geopolymers as promising candidates for the development of scalable and multifunctional adsorbents for wastewater remediation. Full article

Semiconductor photocatalysis technology is a simple, efficient, and low-cost method for environmental pollution remediation. As a promising photocatalyst for oxidative degradation, titanium dioxide (TiO₂) demonstrates the capability to address energy shortages and environmental pollution issues. In this study, orange peel was used as the raw material to synthesize a (TiO₂-CdS-C₃N₄-CDs) TCCC composite photocatalyst containing natural green carbon dots via a one-pot hydrothermal method for the first time. This catalyst was applied to the catalytic degradation of multiple dye molecules (Rhodamine B, Methylene Green, Reactive Brilliant Blue KN-R) and quinolone antibiotic (Ciprofloxacin, CIP) as well as tetracycline antibiotic (Tetracycline, THC). Meanwhile, it provides more adsorption sites for target pollutants and loads electron reservoirs (CDs) on the TCC surface, promoting the separation of photogenerated carriers in pure TiO₂, thereby enhancing the visible light utilization and photocatalytic activity of the material. This work expands the application scope of semiconductor photocatalysis technology and TiO₂-based photocatalytic active substrates. Full article

Background: Lateral epicondylopathy is commonly approached as a tendinopathic disorder of the common extensor origin; however, persistent lateral elbow pain may also involve a superficial sensory nerve component related to the posterior antebrachial cutaneous nerve (PABCN). This proof-of-concept cadaveric anatomical feasibility study evaluated whether a single-window, humerus-parallel ultrasound-guided injectate pathway could simultaneously reach the superficial PABCN-related fascial plane and the common extensor origin. Methods: One fresh-frozen male cadaveric donor was used, and both elbows were injected under real-time ultrasound guidance. With the elbow flexed and the forearm pronated, the transducer was aligned parallel to the long axis of the humerus over the lateral epicondylar region. A 23-gauge, 6 cm needle was advanced in plane from distal to proximal over the common extensor aponeurosis, and 10 mL of 1% methylene blue was injected into each elbow. Layer-by-layer anatomical dissection was then performed by an anatomist who was not involved in the injection procedure. Gross linear dye spread was measured directly during dissection using the distal needle entry point as the reference point, and ruler-containing photographs were additionally reviewed using ImageJ software for supportive image-assisted assessment. Results: In both elbows, methylene blue stained the superficial PABCN-related fascial plane, including the anterior and posterior branches of the PABCN, and concomitantly covered the common extensor aponeurosis and lateral epicondylar enthesis. Dye spread measured approximately 10 cm proximally, 5 cm distally, and 4 cm anteriorly. No gross intra-articular dye deposition or focal intramuscular pooling was observed. Conclusions: This proof-of-concept cadaveric study demonstrates the anatomical plausibility of a single-window, enthesis-centered ultrasound-guided injectate pathway that includes both the superficial PABCN-related plane and the common extensor origin. These findings should be interpreted as descriptive anatomical feasibility observations and do not establish reproducibility across anatomical variants, clinical efficacy, safety, or procedural superiority. Full article

This work reports the synthesis, characterization, and photocatalytic performance of multifunctional spheres based on AgNP-doped TiO₂-Fe₃O₄ embedded in an alginate–chitosan biopolymeric matrix for the removal of organic contaminants from water. The composite powders exhibited a nanocrystalline structure composed of anatase TiO₂ (~20 nm) and magnetite (~25 nm), with homogeneously dispersed Ag nanoparticles, as observed by SEM. The spheres presented a mainly submicrometric particle size distribution (0.55–0.92 µm), favoring high surface area and colloidal stability. Under simulated solar irradiation, the material achieved efficient photocatalytic degradation of methylene blue, with a pseudo-first-order rate constant of 0.112 h⁻¹ and ~46% decolorization after 5 h. UV-Vis spectra showed progressive attenuation of the dye absorption band without accumulation of intermediates. Magnetic recovery tests confirmed rapid separation and reuse without performance loss. The enhanced activity is attributed to the synergistic interaction among plasmonic Ag, photocatalytic TiO₂, redox-active Fe₃O₄, and the adsorptive carbon–biopolymer matrix. The material exhibited strong antibacterial activity, achieving over 90% removal of fecal coliforms after 5 h of irradiation. Therefore, the developed AgNP-doped TiO₂-Fe₃O₄ spheres represent a sustainable, reusable, and efficient material for solar-assisted water sanitation. Full article

Increasing volumes of dye-containing wastewater generated by the textile industry have become a serious environmental issue, particularly in Indonesia, where textile production contributes substantially to industrial activity. Among synthetic dyes, methylene blue (MB) is widely used because of its low cost and high solubility in water; however, its persistence, toxicity, and potential carcinogenicity make its removal from wastewater highly important. Conventional treatment methods are often limited by incomplete degradation and secondary waste generation. In this study, iron oxide nanoparticles (IONPs) were synthesized through a green route using Psidium guajava leaf extract as both a reducing and stabilizing agent. Characterization by PSA, UV-Vis, SEM-EDX, and XRD confirmed the formation of magnetite-like iron oxide particles with sizes ranging from 209.2 to 291.4 nm. Photocatalytic experiments showed high MB degradation efficiency (94.7–99.0%) under UV irradiation, highlighting the potential of guava leaf-mediated IONPs as low-cost, sustainable photocatalysts for wastewater treatment. Full article

The development of high-performance adsorbents for treating dye-laden wastewater necessitates a deep understanding of structure–property relationships. This study presents a systematic investigation into the role of carbon material dimensionality (0D biochar, BC; 1D carbon nanotubes, CNT; 2D graphene oxide, GO) in modulating the properties of a dual physically crosslinked sodium alginate/polyacrylamide (SA/PAM) hydrogel for methylene blue (MB) adsorption. A series of composite hydrogels was fabricated via a sequential physical crosslinking strategy. Comprehensive characterization confirmed the successful incorporation and dispersion of carbon materials within the dual network. The three hydrogels showed good mechanical properties. Under the conditions of 25 °C, an initial MB concentration of 100 mg/L, and pH 10–11, the incorporation of carbon materials enhanced the adsorption capacity, with maximum adsorption capacities of 411.5, 410.6, and 422.8 mg/g for BC-H, GO-H, and CNT-H, respectively. Coexisting constituents in real water samples reduce adsorption capacity via competitive adsorption and interfacial interference. After five consecutive adsorption–desorption cycles, the adsorption capacities of BC-H, GO-H, and CNT-H decreased to 57.7%, 67.2%, and 61.7% of their initial values, respectively. Adsorption isotherm and kinetic studies revealed that the process followed the Langmuir model and pseudo-second-order kinetics, indicative of monolayer chemisorption. Mechanistic analysis identified synergistic contributions from electrostatic attraction, π-π stacking, and physical entrapment. Physical structural changes and chemical site occupation are the main reasons for the decrease in the adsorption performance of hydrogels during cyclic use. This work provides a rational design strategy for advanced adsorbents and a theoretical foundation for efficient dye wastewater remediation. Full article

In this study, manganese ferrite was grown on the surface of a low-cost powder substrate of a guava leaf using the co-precipitation method. The resulting material was characterized using various spectroscopic and microscopic techniques. The composite was formed through the electrostatic and non-electrostatic interactions between the manganese ferrite nanoparticles, and the functional groups present on the guava leaf substrate; consequently, a high content of functional groups was observed in the synthesized composite through the Fourier transform infrared spectroscopy. The average size of the nanoparticles grown on the guava leaf substrate was determined to be between 3 and 5 nanometers. The synthesized composite material was utilized for adsorption applications, employing Methylene blue dye as a model adsorbate. Methylene blue was removed from the aqueous solutions under various conditions—including variations in the pH, contact time, temperature, and concentration. Under optimal conditions, it was observed that an adsorbent dosage of 2 g L⁻¹ was capable of removing approximately 99% of the dye from a 10 mg L⁻¹ dye solution at pH 7. The dye removal efficiency (%) decreased with the increasing temperature, indicating an exothermic process; this was further confirmed by the thermodynamic parameter analysis (specifically, the change in enthalpy, or ΔH), which yielded a negative value. Gibbs Free Energy (ΔG) also yielded a negative value, signifying the feasibility and spontaneity of the adsorption process. In this study, the adsorption process followed the Freundlich isotherm model, with the value of ‘n’ falling between 1 and 10, which is indicative of heterogeneous adsorption. The adsorption kinetics were determined to follow a pseudo-second-order model, and the overall rate-limiting step of the process was identified as intraparticle diffusion. To assess the sustainability and stability of the adsorbent, regeneration and reusability experiments were conducted. The results revealed that the modified guava leaf performed effectively for up to five cycles, achieving an adsorption efficiency of approximately 24% after the final cycle. Thus, the developed adsorbent proved to be an effective material for the removal of Methylene blue dye. Full article