Search Results (592)

The emerging demand for water pollution control has driven a significant interest in advanced porous materials for sustainable and effective wastewater treatment technologies. Metal–organic frameworks (MOFs) have been employed as promising substrates due to their versatile properties, especially their high surface area, tunable properties, and chemical functionality. However, their practical applications are often limited by poor aqueous stability, instability during recovery, and high production costs. Lignocellulosic biomass (LCB) is an abundant, low-cost, and renewable resource, primarily composed of cellulose, hemicellulose, and lignin, offering a sustainable solution for these challenges. This review critically examines the recent advances in design and applications of LCB-MOF materials for wastewater remediation. Several synthesis strategies, including in situ growth, ex situ impregnation, and post-synthetic modification, are systematically discussed in relation to their significance in enhancing stability, recyclability, and dispersibility of MOFs. The key, structural, morphological, and physicochemical properties of these LCB-MOFs were analyzed, along with their performance in removing organic dyes and heavy metal ions. Current drawbacks in long-term stability, scalability, and real-world wastewater performance are highlighted. Overall, LCB-MOFs demonstrate a promising class of sustainable materials that align with the principles of the circular economy and green chemistry, making them ideal for next-generation wastewater remediation technologies. Full article

Alginate fiber has been widely recognized in the field of sustainable development due to its environmental friendliness, non toxicity, flame retardancy, biodegradability, good biocompatibility, abundant raw material sources, and the fact that its production process is not limited by arable land resources. However, in the application of textile and apparel, desizing efficiency and economic performance have constrained the application and development of alginate/cotton fiber shuttle-woven fabrics. To resolve the desizing problem of alginate/cotton blended fabrics in a green and effective manner, this study focuses on the catalytic decomposition of hydrogen peroxide by aluminates and their crosslinking modification effect in enhancing the chemical corrosion resistance of alginate fibers; the catalytic effect of aluminates on hydrogen peroxide was investigated and applied to the oxidative decomposition of textile sizing agents, followed by a study of the oxidative desizing process. The results indicate that aluminum salts have excellent catalytic activity towards hydrogen peroxide; after adding aluminate and hydrogen peroxide to the simulated desizing starch slurry, the decomposition rate of starch reached 44.20%. Compared to traditional oxidation desizing processes, this treatment causes slight damage to the strength of alginate fibers, alginate fiber blended yarns, and pure cotton fabrics, with a loss rate of only 3.55 ± 0.08% for alginate fibers in the fabric. The application of this technology can provide important theoretical and practical support for the sustainable development of textiles and the green dyeing and finishing of alginate fibers. Full article

Hexagonal boron nitride (h-BN) is a chemically stable two-dimensional material whose wide band gap and low surface reactivity limit its performance in adsorption and photocatalysis, motivating strategies to tailor its structure. In this work, a mechanochemical approach combining high-energy ball milling with NaOH-assisted treatment was used to induce simultaneous exfoliation and hydroxylation of h-BN, promoting defect generation, reduced crystallinity, interlayer expansion, and incorporation of oxygen-containing groups (B-OH and B-O). These modifications led to band gap narrowing, increased surface polarity, and improved dispersion, enabling the formation of heterogeneous active sites. The hydroxylated material (BN-OH) exhibited high adsorption capacities of 248 mg/g for methylene blue (MB) and 215 mg/g for rhodamine 6G (R6G), following Freundlich behavior, indicative of heterogeneous adsorption governed by electrostatic interactions, π–π stacking, hydrogen bonding, and defect-mediated sites. Under solar irradiation, BN-OH achieved up to 99% degradation of both dyes, following predominantly pseudo-first-order kinetics and outperforming pristine BN; additionally, the kinetic behavior under solar conditions was successfully described using the Behnajady–Modirshahla–Ghanbary (BMG) model, which accurately predicts the two-stage degradation process. Scavenger experiments revealed that ⦁OH radicals dominate MB degradation, while ⦁OH, O₂⦁⁻, and h⁺ contribute to R6G removal. Overall, defect engineering and hydroxyl functionalization synergistically enhance photocatalytic performance, providing a scalable strategy for wastewater treatment. Full article

Titanium-based perovskites have garnered significant attention for photocatalytic applications, particularly in the field of environmental remediation through the degradation of synthetic dyes and pharmaceuticals in aqueous solutions. This review paper aims to explore the synthesis methods, crystal structures, photoactivity, and photocatalytic performance of titanium-based perovskites in degrading synthetic dye and pharmaceutical effluents in water. The unique advantages of titanium-based perovskites as photocatalysts, associated with their high redox potentials and excellent optical and electrical properties, are highlighted. Their limitations in visible light absorption and photocatalytic efficiency due to rapid charge carrier recombination are also discussed. Several strategies to overcome these limitations, such as surface modifications of the photocatalysts, metal and non-metal doping, the introduction of structure defects, the formation of heterojunctions with electron-accepting materials, and the deposition of plasmonic metal nanoparticles are systematically examined. This review also provides an overview of the photocatalytic degradation of dyes and pharmaceuticals as emerging contaminants, utilizing titanium-based perovskites as photocatalysts, to highlight their efficiency and potential for real-word applications. By covering research findings, current knowledge, and future perspectives, this review aims to stimulate advancements in the design and application of titanium-based perovskite photocatalysts. Full article

Background/Objectives: Investigating the modified derivatives of known cell-penetrating peptides can highlight the important residues in the peptide sequence and help understand the cellular uptake mechanism better. Moreover, comparing peptides with different fluorescent-dye positions can highlight the importance of the conjugation site. Earlier, it was demonstrated that the fluorescence quencher 4-((4-(dimethylamino)phenyl)azo)benzoyl (Dabcyl) group can enhance the internalization efficiency of highly cationic oligoarginine peptides. However, its effect in the case of arginine-rich penetratin, a secondary amphipathic cationic CPP, remains undiscovered. Methods: Here, several penetratin derivatives were studied in which the aromatic residues were substituted and the effect of Dabcyl modification was also studied on the cellular uptake of peptides by flow cytometry. Results: The triple Nal-substituted penetratin and dodeca-penetratin with N-terminally positioned carboxyfluoresein (Cf) dye demonstrated remarkable internalization efficiency compared to penetratin. Moreover, almost all the Dabcyl-modified peptides were superior to penetratin except two peptides with C-terminal Cf-labelling. This result highlights the importance of the structure of the conjugate. The position of the cargo molecule may have a high impact on internalization ability. The relatively low cellular uptake of the Trp48 residue-substituted Dabcyl-Pen12 points to the importance of this residue in the cellular uptake of dodeca-penetratin. The confocal microscopic studies revealed that, besides the greater penetration efficiency of Dabcyl penetratin derivatives, these peptides enter the cytoplasm of cells in an increased manner. Conclusions: We identified several intriguing derivatives and expanded the applicability of Dabcyl, while also highlighting its limitations. Additionally, the critical role of Trp48 in the penetratin sequence was reaffirmed, along with the importance of the fluorescent molecule’s position. Full article

Developing practical low-cost adsorbents for dye-contaminated wastewater remains a critical challenge, especially for persistent cationic dyes such as crystal violet (CV). Here, raw rockmelon skin (RMS), an abundant fruit-processing residue, and its NaOH-modified derivative (NaOH-RMS) were investigated as adsorbents for CV adsorption. Alkaline treatment altered the biomass’s characteristics and affected its adsorption behaviour. Equilibrium was reached within 120 min, and the kinetic data were best fit by the pseudo-second-order model. Equilibrium analysis showed that the Freundlich model best described RMS. In contrast, NaOH-RMS was better represented by the Langmuir model, indicating that alkaline treatment altered the adsorption behaviour of the biomass surface. The Langmuir-derived maximum adsorption capacities were 343.7 mg g⁻¹ for RMS and 295.2 mg g⁻¹ for NaOH-RMS, indicating that NaOH modification did not increase the maximum adsorption capacity. Adsorption was spontaneous across 298–343 K, and both materials retained satisfactory removal performance over five regeneration cycles, particularly under basic desorption conditions. Overall, NaOH treatment altered the adsorption behaviour from heterogeneous adsorption on RMS to a more Langmuir-type adsorption pattern on NaOH-RMS, despite not increasing the maximum adsorption capacity. These findings support the valorisation of fruit-processing residues as practical adsorbents for dye-contaminated wastewater. Full article

In line with circular economy principles, raw spent yerba mate (Ilex paraguariensis) waste (YMs) was transformed into a high-value aminated adsorbent (AYMs) for the removal of anionic dyes, namely Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84). The modification involved a two-step process using epichlorohydrin and aqueous ammonia, and the adsorbents were characterized via FTIR, BET, C/N elemental analysis, and pH_PZC. Batch experiments evaluated pH effects, kinetics (PFO, PSO, and intraparticle diffusion), and equilibrium isotherm analysis (single- and dual-site Langmuir models and Freundlich models). The results confirmed successful functionalization of the biomass with amino groups, shifting the point of zero charge (pH_PZC) from 4.74 (YMs) to 8.73 (AYMs). The optimal adsorption pH was 2.0 for YMs and 3.0 for AYMs. Kinetic data were best described by the pseudo-second-order model, while equilibrium data followed the dual-site Langmuir model, indicating energetic heterogeneity of the AYMs surface. The maximum adsorption capacity of AYMs reached 62.81 mg·g⁻¹ for RB5 and 61.78 mg·g⁻¹ for RY84, representing a fivefold and threefold increase over the YMs, respectively. These findings demonstrate that AYMs is a high-performance, sustainable alternative to commercial activated carbons, providing a scalable waste-to-value solution for industrial effluent treatment. Full article

This research evaluates the feasibility of using a lignocellulosic biosorbent prepared from mature leaves of Asplenium scolopendrium (produced through simple mechanical processing of the leaves, without applying any chemical modification or heat treatment) for the removal of methylene blue from water. Before and after adsorption the material was characterized using SEM technique and color analysis. Subsequently, the adsorption behavior was analyzed by examining equilibrium, kinetic, and thermodynamic aspects of the process. The equilibrium data were best represented by the Sips isotherm model, while the adsorption rate followed the Avrami model. Thermodynamic evaluation indicated that the retention of the dye occurs predominantly through a physical adsorption mechanism, while a minor contribution from chemisorption may be present, slightly enhancing the overall dye uptake. Process optimization was performed using the Taguchi experimental design, which also allowed the identification of the most significant operational variable. In addition, analysis of variance (ANOVA) was applied to quantify the contribution of each factor affecting dye removal efficiency. Among the investigated variables, time showed the strongest influence (72.65%), whereas temperature had a negligible effect (1.33%). The maximum adsorption capacity reached 174.1 mg/g, surpassing the performance of several comparable biosorbents reported in the literature. Overall, the findings demonstrate that Asplenium scolopendrium (hart’s-tongue fern) leaves represent an inexpensive, sustainable, and efficient material for eliminating methylene blue from aqueous solutions. Full article

Textile industry wastewater poses a significant environmental challenge due to the presence of persistent dyes. Cationic dyes are characterized by resistance to the conventional coagulation method. The appropriate properties and combination of chemicals guarantee an effective removal process. This study explains the effect of modification of methylene blue solution by the addition of a natural biopolymer—hydrolyzed tannic acid (TA). The study assumed that a combination of tannic acid, methylene blue and polyaluminum chloride would provide a synergistic effect and significantly improve the coagulation and sediment filtration process. Coagulation tests were carried out for a range of methylene blue concentrations. The optimal arrangement of solution components and coagulant doses was selected and tested. Over 95% dye removal efficiency was achieved. The maximum dye removal efficiency was determined to be 5 mg/mg Al at pH = 5.0. Based on the analysis of UV-VIS spectroscopy, FTIR and electrokinetic potential, changes in the solutions of tannin-modified dyes and their effect on the precipitation of flocs and the nature of sorption were determined. The main phenomena affecting the removal mechanism are discussed. The results indicate that tannic acid can serve as a sustainable coagulant aid, supporting the development of technologies for treating cationic-dye-laden wastewater. Full article

Hydrothermal carbonization (HTC) of agricultural waste is a promising waste management technique. However, the use of different raw materials may produce hydrochars with varying efficiencies, both in yield and application, and environmental impacts, due to differences in composition and required processing conditions. To understand the influence of biomass type and acid-assisted HTC conditions, this study used sugarcane and agave bagasse to produce functionalized hydrochars and evaluated them for the removal of Reactive Orange 84; an azo dye used in the textile industry. Material characterization was performed using FT-IR, TGA, BET, and XRD analyses. In addition, a life cycle assessment was conducted to evaluate environmental impacts associated with hydrochars produced using H₂SO₄ at concentrations of 0.2 and 0.5 M. TGA and XRD results indicate that agave bagasse hydrochars (HBA) retain more crystalline lignocellulosic structures, whereas sugarcane bagasse hydrochars (HBS) exhibit predominantly amorphous structures after HTC. FT-IR analysis confirmed the presence of –SO₃H functional groups; however, HBA samples showed greater availability of these groups with increasing acid concentration. Adsorption experiments and LCA results demonstrated that the most favorable treatment, in terms of emission reduction and dye removal, was agave bagasse functionalized with 0.5 M H₂SO₄, achieving 75.7% mass yield and 94.5% dye removal. Full article

Photocatalysts have emerged as a promising approach for the treatment of contaminated water, particularly for the removal of dyes and pharmaceutical residues that pose risks to human health. In addition, they can be employed for the generation of chemical fuels such as H₂ and oxidizers such as H₂O₂, which have been proposed as sustainable energy carriers to reduce reliance on fossil fuels. The first part of this brief review provides a detailed overview of the fundamental concepts of photocatalysis, including reaction pathways and reported mechanisms. The second part explores the main design strategies for enhancing photocatalytic performance, including morphology control and structural modification. Then, the third section highlights the benefits of theoretical modeling, including first-principles calculations and molecular simulations. The document culminates with a section on challenges and future perspectives, highlighting major issues in photocatalyst development such as large-scale synthesis, material stability, and reusability. This brief review is intended to provide young researchers with a concise understanding of the most effective strategies for enhancing photocatalytic performance, as well as the mechanisms influencing morphology and structural parameters. This work presents an integrated framework linking synthesis strategies, particle growth mechanisms, multidimensional nanostructures, in situ and operando characterization, and computational modeling to guide the rational design of next-generation photocatalysts. Full article

With the development of the information society, display technologies are evolving toward greater flexibility and advanced performance. Dye-based polyvinyl alcohol (PVA) complex films have gained widespread attention for their excellent resistance to high temperature and humidity. This review systematically summarizes the research progress of dye-based polarizers using PVA as the substrate, focusing on their preparation principles, film properties, and impacts on optical performance. Strategies to enhance optical properties and durability are discussed, including dye molecular optimization, formulation design, control of the dyeing process, and PVA substrate film modification. Notably, improving interfacial interactions between dyes and PVA enhances molecular orientation and stability, while PVA modification improves mechanical properties, water resistance, thermal stability, and flame retardancy. By demonstrating these enhanced comprehensive properties, this review highlights the potential of PVA–based films to serve as high-performance platforms for the development of next-generation multifunctional optical and display materials. Finally, the challenges and development directions of dye-based PVA complex films for optical applications in harsh environments are prospected. This review provides a theoretical basis and technical pathway for the design and development of next-generation high-performance composite polarizers. Full article

Agricultural waste management is a strategic priority for reducing greenhouse gas emissions and transitioning to a circular bioeconomy. The thermochemical conversion of residual biomass into biochar offers a dual solution: waste recovery and the production of high-value functional materials. This narrative review summarizes the relationships among the composition of agricultural biomass, the conversion process parameters, and the structural properties of biochar, highlighting advanced modification strategies: controlled pyrolysis, physical and chemical activation, surface functionalization, and hybrid composite formation. Fundamental adsorption mechanisms, redox processes, and photocatalytic behavior are discussed, with a focus on applications in water treatment (heavy metals, dyes, emerging contaminants). The article proposes an integrative structure–property–performance framework and explores emerging concepts such as sequential use and post-use valorization of saturated biochar. Challenges related to reproducibility, industrial scaling, life cycle assessment, and carbon accounting are analyzed. Finally, a SWOT analysis is presented that highlights the potential of modified biochar as a strategic material in the circular economy. Full article

Hypochlorous acid (HClO) is widely used as a low-cost and effective disinfectant; however, its instability under heat and light necessitates simple and reliable monitoring methods. Herein, we report a morphology-evolving thin-film colorimetric sensor that enables intuitive visual detection of HClO through simultaneous color and pattern transitions. The sensor integrates two polymer films with distinct charge-state response behaviors, patterned in X-shaped and circular geometries on a single substrate. Upon exposure to HClO, chlorine-induced modification of amide and amine groups alters the surface charge states, thereby switching the adsorption preference for anionic and cationic dyes. This mechanism results in a pronounced transformation from a blue X-shaped motif to a red circular pattern, enabling direct visual discrimination between different HClO concentrations. Quantitative analysis of RGB values confirmed semi-quantitative detection in the sub-millimolar to millimolar range. The sensor exhibited a linear response in the range of 0–3 mM (R² > 0.979) with a limit of detection of 0.103 mM. The sensor further demonstrated practical applicability by tracking photodecomposition of a commercial disinfectant. This work demonstrates pattern-coupled colorimetric sensing as a straightforward, user-friendly approach for HClO monitoring. Full article

Light-based diagnostic and therapeutic approaches are increasingly important in modern biomedicine, with organic dyes emerging as versatile optical agents due to their tunable photophysical properties. Precise control over absorption and emission characteristics has enabled their application in fluorescence, photoacoustic, and Raman imaging, as well as in photodynamic and photothermal therapies. However, challenges related to biocompatibility, aqueous stability, and in vivo performance remain critical for clinical translation. Organic dyes that absorb in the near-infrared region are particularly attractive because of their deeper tissue penetration and reduced background interference. This review highlights key structure property relationships of organic dyes and summarizes current design strategies, including chromophore modification, peripheral functionalization for water solubility, and self-assembled nanotheranostic systems. Recent biomedical applications in cancer diagnosis and therapy, bacterial detection, and imaging-guided treatment are discussed, along with future directions for advancing dye-based technologies in healthcare. Full article