Search Results (152)

Nanofiltration membranes have emerged as a crucial class of pressure-driven separation materials, positioned between ultrafiltration and reverse osmosis in terms of selectivity, permeance, operating pressure, and energy consumption. Their ability to remove fine contaminants—including multivalent ions, organic micropollutants, dyes, and macromolecules—has made them essential in water and wastewater treatment, pharmaceutical processing, and various industrial applications. In spite of their growing relevance, the performance of polymeric nanofiltration membranes, such as polyamide, polysulfone, polyethersulfone, polyvinylidene fluoride, and polyimide, is still constrained by weak hydrophilicity and a strong susceptibility to fouling, which collectively decrease permeance, increase operational costs, and shorten membrane lifespan. In recent years, substantial research efforts have focused on designing and engineering the surface chemistry and structural characteristics of nanofiltration membranes to improve water permeance, reduce foulant adhesion, and improve long-term stability. This review provides a comprehensive and comparative assessment of the most recent modification techniques applied to polymer-based nanofiltration membranes. Strategies such as polymer blending, nanoparticle incorporation, physical surface coating, plasma treatment, chemical attachment, layer-by-layer assembly, and interfacial polymerization are critically examined with respect to their effectiveness and practical limitations supported by recent research examples. Special attention is given to how these modification methods affect membrane morphology, hydrophilicity, permeance, and antifouling properties. Eventually, the review highlights emerging ideas and forward-looking design directions that may guide the next generation of nanofiltration membranes toward higher efficiency, improved durability, and broader industrial applicability. Full article

The contamination of water bodies with organic pollutants has emerged as one of the most pressing environmental and public health challenges of the modern era. The continuous discharge of dyes, pesticides, agricultural runoff, and pharmaceutical residues into the aquatic ecosystem degrades water quality. Long-term exposure to these organic pollutants poses a severe risk to human and aquatic life. ZnO and TiO₂ have emerged as promising photocatalysts, particularly for degrading organic waste in wastewater. However, their photocatalytic activity is limited to the UV region due to their wide band gaps. To improve nanoparticle efficiency, polydopamine (PDA) is incorporated as a modifying agent. PDA-modified ZnO and TiO₂ nanocomposites exhibit enhanced photocatalytic activity in the degradation of various organic pollutants under visible light, compared with their unmodified counterparts. Furthermore, they exhibit improved antibacterial activity against a variety of waterborne pathogens; this is advantageous as wastewater contains both chemical pollutants and microorganisms. Thus, the combined photocatalytic and antibacterial properties of PDA-modified ZnO and TiO₂ make them promising materials for next-generation wastewater treatment. Full article

Magnetic polymer nanocomposites (MPNCs) have attracted considerable attention as advanced multifunctional materials for water purification due to their high adsorption capacity, magnetic recoverability, and excellent reusability. This review presents a comprehensive overview of recent developments in the synthesis, characterization, and environmental applications of MPNCs for wastewater treatment. Particular emphasis is placed on the principal synthesis strategies, including in situ and ex situ approaches, and their influence on nanoparticle dispersion, interfacial interactions, and the physicochemical properties of the resulting nanocomposites. The review covers the most widely investigated magnetic nanomaterials, such as Fe₃O₄, γ-Fe₂O₃, CoFe₂O₄, ZnFe₂O₄, and other ferrites, incorporated into natural and synthetic polymer matrices including chitosan, cellulose, alginate, polyaniline, polypyrrole, poly(vinyl alcohol), and polystyrene. Advanced characterization techniques, including X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and superconducting quantum interference device (SQUID) measurements, are discussed to evaluate the structural, chemical, thermal, and magnetic properties of these hybrid materials. The adsorption performance and underlying mechanisms of MPNCs for the removal of heavy metals, dyes, pharmaceutical compounds, organic pollutants, and oil contaminants are critically analyzed, highlighting the roles of polymer functionalization, nanocomposite architecture, and magnetic separation in enhancing treatment efficiency and reusability. In addition, the contribution of density functional theory (DFT) to understanding adsorption mechanisms and guiding the rational design of high-performance adsorbents is reviewed. Finally, current challenges and future perspectives, including green synthesis, multifunctional and stimuli-responsive materials, scalable manufacturing, and industrial implementation, are discussed. This review provides a comprehensive framework for the design and development of next-generation magnetic polymer nanocomposites for sustainable water remediation applications. Full article

Silica aerogel films are highly promising matrices for advanced optical applications, yet balancing ultra-high transmittance with structural stability during functionalization remains a critical challenge. Directly incorporating organic dyes often leads to aggregation and severe photodegradation, necessitating a robust host–guest encapsulation strategy. Herein, we report the fabrication of ultra-transparent, fluorescent silica aerogel films via precisely tailored acid/base two-step sol–gel kinetics and dip-coating. The optimized pure silica matrix achieves a peak visible transmittance of 97.4% and sub-nanometer surface smoothness (RMS = 276.7 pm). By utilizing this pristine network, Rhodamine 6G (Rh6G) and Rhodamine B (RhB) dyes were effectively confined within the amorphous mesoporous pores. Notably, RhB exhibited superior matrix integration, indicated by an H4 hysteresis loop transition and a significantly reduced pore volume (0.019 cm³/g). This mesoporous confinement successfully suppressed dye quenching, prolonging the fluorescence lifetimes to 5.22 ns and 5.36 ns for Rh6G and RhB, respectively. Crucially, we elucidate that the electrostatic and hydrogen-bonding interactions between the silica pore walls and the dye’s xanthene rings elevate the excited-state energy, inducing a distinct matrix-driven emission blue shift. This work provides a scalable pathway for high-performance optical coatings and offers deep insights into host–guest interfacial coupling in gel networks. Full article

Objectives: Fluorescence-guided surgery (FGS) targeting prostate-specific membrane antigen (PSMA) holds promise for improving surgical precision in prostate cancer. Since conjugation of fluorescent dyes to targeting vectors can substantially alter pharmacokinetic properties, we systematically evaluated a library of fluorescent dyes conjugated to a PSMA-617-derived scaffold incorporating sarcosine-based spacers to identify candidates with favorable biodistribution and optical profiles for clinical translation. Methods: Nineteen fluorescent dyes spanning NIR, large Stokes shift, and STED-compatible categories were conjugated to a dual-labeled PSMA-617-derived precursor (Glu-urea-Lys-2Nal-TXA-Sar₁₀-Lys(DOTA)-Sar₅-βAla; hereafter DP). Compounds were radiolabeled with ⁶⁸Ga or ¹⁷⁷Lu and characterized for serum stability, lipophilicity, binding affinity, and internalization in LNCaP^PSMA+ cells. In vivo pharmacokinetics were assessed in LNCaP xenograft-bearing BALB/c nu/nu mice by µPET/MRI (1 and 2 h p.i., 500 pmol ⁶⁸Ga), organ distribution (0.5, 1, and 2 h p.i., 60 pmol ¹⁷⁷Lu), and clinical-grade endoscopic fluorescence imaging. Results: All conjugates retained hydrophilic character (logD: −3.72 to −1.79), low nanomolar binding affinity (K_i: 18–87 nM), and high serum stability (94–100% intact at 24 h). Despite comparable in vitro properties, dye conjugation markedly influenced in vivo pharmacokinetics: tumor uptake at 2 h p.i. ranged from 1 to 23%ID/g and kidney accumulation from 3 to 82%ID/g. Visible-range dyes exhibited faster renal washout within the imaging window and higher tumor-to-background contrast than NIR fluorophores. Fluorescence signal intensity did not correlate with radiotracer-derived uptake, underscoring the importance of dye-specific photophysical properties. Conclusions: DP-12 (SulfoCy5), DP-15 (Alexa Fluor 647), and DP-18 (Tide Fluor 5WS) were identified as lead candidates combining favorable pharmacokinetics with strong fluorescence contrast, warranting further evaluation toward fluorescence-guided prostate cancer surgery. Full article

Third-generation photovoltaic (PV) technologies, such as dye-sensitized solar cells (DSSCs), organic solar cells (OSCs), quantum-dot solar cells (QDSSCs), and perovskite solar cells (PSCs), are characterized by properties that enable applications beyond conventional silicon-based devices. However, despite remarkable progress in third-generation solar cells, significant challenges related to efficiency, stability, scalability, and commercialization remain significant. The purpose of this review work was to summarize recent developments in third-generation photovoltaic technologies, including component materials design, configurations, performance data, limitations, and future research directions. The reported studies demonstrated crucial improvements in power conversion efficiency, which exceeded 15% for DSSC, 20% for OSC, 12% for QDSSC, and 26% for PSC. The key challenges to commercialization include further improvements in efficiency, better stability, and meeting the environmental requirements. Although important technological and environmental challenges remain, third-generation solar cells are expected to contribute to future sustainable energy systems due to their high efficiency potential, low-cost fabrication, and possible incorporation of environmentally friendly materials in the structure of the cells. The photovoltaic performance under indoor conditions and the aspect of a sustainable approach were identified as recent research trends. Full article

Wastewater containing heavy metals and dyes poses serious environmental risks. This study developed a multifunctional composite by coating polyurethane foam (PUF) with milled activated carbon (mAC) and a zirconium-based metal–organic framework (Zr-MOF) for the simultaneous removal of hexavalent chromium (Cr(VI)) and Congo red (CR). The composite was synthesized using a hydrothermal method to grow Zr-MOF on the surface. The SEM analysis confirmed the successful incorporation of mAC and surface modification with Zr-MOF, which resulted in increased surface roughness and porous morphology. XRD and FTIR confirmed the presence of organic ligands connected to the metal structure and the functional groups of each component in composite materials. The optimum conditions for Zr-MOF/mAC/PUF adsorption (nearly 100% removal) in the binary Cr(VI)/CR solution (50 mg/L each) were 25 °C, pH 9, and 150 rpm for 24 h. The Zr-MOF/mAC/PUF was hydrophilic with a swelling ratio of 2.64 g/g. The thermodynamic investigation of Zr-MOF/mAC/PUF resulted in 141.6218 kJ/mol for Cr(VI) and 166.111 kJ/mol for CR of ΔH° (rapid adsorption), negative ΔG° (spontaneous adsorption), a high positive value of ΔS° (disorder structure) and low activation energy (approximately 2.5 to 2.8 kJ/mol). After analyzing the isotherm and reaction kinetics, the possible mechanism could be endothermic physicochemical adsorption and pseudo-second-order kinetic behavior, with electrostatic attraction and diffusion control. The study of 6-times-reused Zr-MOF/mAC/PUF adsorption identified as a decrease of 7.55 percentage point without changing notable morphology and functional groups, based on SEM and FTIR. Full article

Wastewater contamination with synthetic organic dyes is a significant environmental challenge. Zinc oxide (ZnO) has attracted considerable attention as a non-toxic, multifunctional material for electronics, optics, piezoelectric devices, and photocatalysis, where its performance is strongly governed by morphology. In this work, we investigate the effect of hexamethylenetetramine (HMTA) on the formation and photocatalytic behavior of ZnO nanostructures synthesized from different zinc precursors, namely zinc acetate and zinc nitrate, via a one-step sol–gel process at low temperature without any post-treatment. All samples crystallize in the hexagonal wurtzite phase without detectable impurities, and the incorporation of HMTA leads to smaller, more uniform rod- and flake-like nanostructures. Although ZnO derived from zinc acetate without HMTA exhibits the highest specific surface area, ZnO synthesized in the presence of HMTA shows more favorable crystallinity, morphology, and pore connectivity, which together enhance charge separation and reactive oxygen species generation. As a result, ZnO samples synthesized with HMTA exhibit improved photocatalytic degradation of rhodamine B under UV irradiation. Full article

Photocatalytic degradation of organic pollutants has emerged as a promising approach for wastewater treatment due to its environmental friendliness and high efficiency under mild conditions. This study focuses on evaluating materials for the decolorization of methylene blue (MB) and methyl orange (MO), which are commonly used cationic and anionic dyes, respectively, known for their persistence and toxicity in aquatic environments. The research investigates the synthesis of a Mott–Schottky junction at the interface of two materials using MXene as a dopant. We synthesized three MXene-containing Porous Organic Polymers (POP-2MX, POP-6MX, and POP-10MX), incorporating 2%, 6%, and 10% MXene, respectively. UV–Vis spectroscopy tests revealed that all polymers exhibited high degradation efficiency; however, POP-6MX demonstrated the best overall activity. Under illumination of a 500 W Xenon lamp (λ > 420 nm) with a catalyst loading of 1 mg/mL, POP-6MX achieved complete adsorption-corrected degradation of MB and MO within 10 and 45 min, respectively. This research also investigated the influence of pH on photocatalytic performance under homogeneous aqueous conditions, revealing that neutral pH provides the optimal environment for degradation activity. The photocatalytic mechanism follows a reactive oxygen species (ROS)-dominated pathway, primarily driven by superoxide radicals (•O₂⁻) and hydroxyl radicals generated through photochemical reactions. These results demonstrate the potential of POP-1/MXene composites as efficient and recyclable photocatalysts for sustainable dye wastewater treatment applications. Full article

Solar-driven interfacial water evaporation has been recognized as an effective measure to address freshwater scarcity. Photothermal materials lie at the core of this process and have been extensively studied. However, conventional carbon-based materials typically suffer from high thermal emissivity, leading to significant heat loss. Here, we report a tungsten carbide/carbon composite polyvinyl alcohol hydrogel evaporator (PWC) for solar-driven interfacial seawater evaporation. Specifically, a tungsten carbide/carbon (WC/C) composite was synthesized via a straightforward one-step molten salt coating method and exhibited a remarkable photothermal conversion efficiency of 67.1%, attributed to the plasmon resonance absorption effect of WC nanoparticles. When incorporated into a polyvinyl alcohol (PVA) hydrogel via a physical-chemical dual-crosslinking strategy, the resulting PWC evaporator achieved a high evaporation rate of 2.99 kg m⁻² h⁻¹ and a conversion efficiency of 90.9% in a 5 wt% NaCl solution under 1 kW m⁻² illumination. In addition, the evaporator can purify seawater and effectively remove a variety of organic dyes. This study provides a viable strategy for a sustainable freshwater supply. Full article

Carbon quantum dots (CQDs) and stimuli-responsive hydrogels are advanced functional materials whose hybridization yields CQD-enhanced stimuli-sensitive hydrogels, opening new interdisciplinary avenues for smart material applications. This review systematically summarizes the latest advances in these composites, focusing on synthetic strategies, structure–property modulation mechanisms, and practical applications. Distinct from existing reviews that either investigate CQDs or hydrogels independently or discuss their composites in a single research field, this work features core novelties in integration strategy, application scope and critical analysis: it systematically compares the advantages, limitations and applicable scenarios of three typical CQD–hydrogel integration approaches (physical entrapment, in situ synthesis, covalent conjugation), comprehensively covers the multi-field application progress of the composites and conducts in-depth cross-field analysis of their common scientific issues and technical bottlenecks. By incorporating CQDs, the composites achieve remarkable performance optimizations: 40% improved mechanical toughness, sub-ppm-level heavy metal-sensing sensitivity, and over 80% organic dye photocatalytic degradation efficiency, addressing pure hydrogels’ inherent limitations of insufficient strength and single functionality. These enhancements enable sophisticated applications in biomedical field (real-time biosensing, controlled drug delivery), environmental remediation (pollutant detection/degradation), energy storage, and flexible electronics. The synergistic interplay between CQDs and hydrogels facilitates precise single/multi-stimulus responsiveness (pH, temperature, light), a pivotal advance for precision medicine and intelligent environmental monitoring. Despite promising progress, the large-scale practical application of CQD–hydrogel composites still faces prominent challenges: the difficulty in scalable fabrication with the uniform dispersion of CQDs in hydrogel matrices, poor long-term stability of most composites under physiological cyclic stress (service life < 6 months in practical tests), and low accuracy in discriminating multi-stimuli in complex real-world matrices. Future research should prioritize biomass-based eco-friendly CQD synthesis, machine learning-aided multimodal responsive systems, and 3D bioprinting for scalable manufacturing. Full article

In this study, the in situ solvothermal synthesis of a copper-based metal–organic framework (Cu-BTC MOF) into two porous ceramic substrates with a 10 cm diameter and 2 cm thickness was reported. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, diffuse reflectance spectroscopy (DRS), Tauc plot analysis, optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were the techniques that were utilized to verify the formation and incorporation of the MOF into ceramics (two samples, with different SiO₂ particles; 500 µm (Ceramic 1), and 150 µm (Ceramic 2)). The synthesized Cu-MOF exhibited a crystalline structure. Both the composites and the Cu-MOF exhibited visible-light absorption, with optical band gaps of 2.5 eV and 2.4 eV, respectively, as determined by DRS. TEM images demonstrated that crystalline MOF domains were successfully included inside the ceramics. Methyl orange (MO), Congo red (CR), and methylene blue (MB) were used to assess the composites’ ability to remove dyes. Catalytic hydrogenation, powered by in situ hydrogen production from NaBH₄ hydrolysis, demonstrated high removal efficiencies of 91–97% after 60 min. Adsorption, on the other hand, was ineffective. Despite undergoing four consecutive cycles without performance degradation, the materials demonstrated remarkable recyclability. Cu-MOF@ceramic composites are effective, durable, and practically applicable for improved wastewater treatment. Full article

The increasing discharge of recalcitrant organic dyes from the textile industry necessitates the development of efficient and sustainable wastewater treatment technologies. This study reports the successful eco-friendly fabrication of magnetically separable cerium–manganese ferrite (Ce-MnFe₂O₄) nanocatalysts via a one-pot green synthesis route, utilizing an aqueous extract of Brachychiton populneus leaves. The structural, morphological, magnetic, and optical properties of the synthesized nanocatalysts were systematically investigated. X-ray diffraction (XRD) analysis confirmed the formation of a phase-pure cubic spinel structure, with evidence of Ce³⁺ ion incorporation leading to lattice expansion and the formation of beneficial oxygen vacancies. The composite material exhibited superparamagnetic behavior with a high saturation magnetization of 38.7 emu/g, which facilitates efficient magnetic separation and recovery. Optical studies revealed a direct bandgap of 2.33 eV, enabling significant photocatalytic activity under visible light irradiation. The Ce-MnFe₂O₄ nanocatalyst demonstrated superior performance, achieving degradation efficiencies of 96% for methylene blue and 98% for Congo Red within 90 min. Furthermore, the catalyst demonstrated good operational stability, maintaining 62% of its initial degradation efficiency for CR and 51% for MB after five consecutive reuse cycles. These results underscore the potential of this green-synthesized, magnetically recoverable nanocatalyst as a highly effective and sustainable solution for the remediation of dye-contaminated industrial effluents. Full article

The rapid increase in global population and industrial activities has intensified the discharge of toxic organic pollutants—including antibiotics, dyes, phenolic compounds, and pesticides—into the environment, posing critical threats to both ecosystems and human health. Conventional treatment technologies remain largely inadequate for their complete removal, particularly for pollutants with complex structures and high persistence. Among advanced approaches, photocatalytic systems have emerged as a sustainable and environmentally friendly technology, capable of mineralizing organic pollutants into harmless end products. However, their large-scale application is hindered by inherent limitations such as restricted visible-light activity, low quantum efficiency, and rapid recombination of charge carriers. This mini-review critically examines recent advances aimed at overcoming these bottlenecks, including band gap engineering, metal and non-metal doping, and the incorporation of carbon-based nanomaterials (e.g., CNTs, GO, CQDs). Special emphasis is placed on strategies that enhance photocatalytic activity under visible light, as well as the emerging potential of waste-derived carbon-based photocatalysts for sustainable applications. Finally, key research gaps—such as scalability, long-term stability, and techno-economic feasibility—are discussed to provide future perspectives on the rational design of next-generation photocatalysts. Full article

This review explores the integration of Boron-Dipyrromethene (BODIPY) dyes within Metal–Organic Frameworks (MOFs), highlighting their combined potential in various applications. MOFs, with their high porosity and structural versatility, provide an ideal platform to enable applications with BODIPYs, which otherwise remain challenging in the solid state. The article discusses different strategies for incorporating BODIPYs into MOFs, including their use as monodentate, bidentate, and tridentate ligands, as well as covalent attachment and non-coordinating encapsulation. The resulting hybrid materials exhibit enhanced properties suitable for applications in the luminescent materials/light harvesting, photodynamic therapy, sensing, and photocatalysis areas. The review emphasizes the importance of synthetic conditions, characterization techniques, and the quantification of BODIPY loading to ensure the integrity and functionality of the MOF structures. Full article