Search Results (84)

This study examines the use of a1 mm-diameter tubular microreactor submerged in a temperature-controlled water bath to activate potassium persulfate (KPS) via thermal, Fe²⁺-catalyzed, and combined thermo-catalytic processes for degrading the persistent textile dye Safranin O (SO). The efficiency of these methods was evaluated under varying conditions, including KPS, dye, and Fe^2⁺ flow rates, solution pH, reactor length, and water matrix quality (deionized water, tap water, seawater, and secondary effluent from a wastewater treatment plant (SEWWTP)) across bath temperatures of 30–80 °C. Total organic carbon (TOC) analysis validated the results. Maximum dye conversion (up to 89%) occurred at 70 °C, with no improvement beyond this temperature, mainly due to radical-radical recombination. Longer reactors (2–6 m) enhanced conversion, though this effect diminished at higher temperatures due to efficient thermal activation. Increasing dye flow rates reduced removal efficiency, particularly above 50 °C, highlighting kinetic and mass transfer limitations. Persulfate flow rate increases improved conversion, but a plateau emerged at 80 °C. At lower temperatures (30–40 °C), Fe²⁺ addition significantly boosted SO conversion in deionized water. Between 40 and 50 °C, conversion rose from 30.27% (0 mM Fe²⁺) to 85.91% (0.2 mM Fe²⁺) at 50 °C. At higher temperatures (60–80 °C), conversion peaked at 70 °C for lower Fe²⁺ concentrations (100% for 0.01–0.05 mM Fe²⁺), but higher Fe²⁺ levels (0.1–0.2 mM) caused a decline above 60 °C, dropping to 68.44% for 0.2 mM Fe²⁺ at 80 °C. Deionized, tap, and mineral water showed similar performance, while river water, secondary effluent, and seawater inhibited SO conversion at lower temperatures (30–60 °C). At 70–80 °C, all matrices achieved efficiencies comparable to deionized water for both thermal and thermo-catalytic activation. The thermo-catalytic system achieved >50% TOC reduction, indicating significant organic matter mineralization. The results were comprehensively analyzed in relation to thermal and kinetic factors influencing the performance of continuous-flow reactors. Full article

The periodate/hydrogen peroxide (PI/H₂O₂) system is a recently developed advanced oxidation process (AOP) characterized by its rapid reaction kinetics, making it highly suitable for continuous-flow applications compared to conventional batch systems. Despite its potential, no prior studies have investigated its performance under flowing conditions. This work presents the first application of the PI/H₂O₂ process in a tubular microreactor, a promising technology for enhancing mass transfer and process efficiency. The degradation of textile dyes (specifically Basic Yellow 28 (BY28)) was systematically evaluated under various operating conditions, including reactant concentrations, flow rates, reactor length, and temperature. The results demonstrated that higher H₂O₂ flow rates, increased PI dosages, and moderate dye concentrations (25 µM) significantly improved degradation efficiency, achieving complete mineralization at 2 mM PI and H₂O₂ flow rates of 80–120 µL/s. Conversely, elevated temperatures negatively impacted the process performance. The influence of organic and inorganic constituents was also examined, revealing that surfactants (SDS, Triton X-100, Tween 20, and Tween 80) and organic compounds (sucrose and glucose) acted as strong hydroxyl radical scavengers, substantially inhibiting dye oxidation—particularly at higher concentrations, where nearly complete suppression was observed. Furthermore, the impact of water quality was assessed using different real matrices, including tap water, seawater, river water, and secondary effluents from a municipal wastewater treatment plant (SEWWTP). While tap water exhibited minimal inhibition, river water and SEWWTP significantly reduced process efficiency due to their high organic content competing with reactive oxygen species (ROS). Despite its high salt content, seawater remained a viable medium for dye degradation, suggesting that further optimization could enhance process performance in saline environments. Overall, this study highlights the feasibility of the PI/H₂O₂ process in continuous-flow microreactors and underscores the importance of considering competing organic and inorganic constituents in real wastewater applications. The findings provide valuable insights for optimizing AOPs in industrial and municipal wastewater treatment systems. Full article

To fulfil the goals of the circular economy, the treatment of textile wastewater should be focused on the recovery of valuable components. Monovalent anion-selective electrodialysis (MASED) was applied for the separation of reactive dyes from mineral salts. Standard cation-exchange membranes (CM membranes) and monovalent selective anion-exchange membranes (MVA membranes) were used in the electrodialysis (ED) stack. The separation efficiency was evaluated for model solutions of various reactive dyes (varying in molecular weight and chemical reactivity) containing NaCl. In the course of MASED, the mineral salt was successfully removed from the dye solutions with an efficacy of 97.4–99.4%, irrespectively of the composition of the treated solution. The transport of dye molecules through the ion-exchange membranes (IEMs) from diluate to concentrate compartments was irrelevant. Nonetheless, a significant adsorption of dye particles on the membranes was observed. Around 11–40% of the initial dye mass was deposited in the ED stack. Dye adsorption intensity was significantly affected by dye reactivity. This study showed the potential of the MASED process for the separation of the reactive dye from the mineral salt on condition that antifouling membrane properties are improved. The obtained streams (the concentrate rich in mineral salt and the diluate containing the reactive dye) can be reused in the dye-house textile operations; however, some loss of dye mass should be included. Full article

Textile dyes pose a major environmental threat due to their toxicity, persistence in water bodies, and resistance to conventional wastewater treatment. To address this, researchers have explored biological and physicochemical degradation methods, focusing on microbial, photolytic, and nanoparticle-mediated approaches, among others. Microbial degradation depends on fungi, bacteria, yeasts, and algae, utilizing enzymatic pathways involving oxidoreductases like laccases, peroxidases, and azoreductases to breakdown or modify complex dye molecules. Photolytic degradation employs hydroxyl radical generation and electron-hole pair formation, while nanoparticle-mediated degradation utilizes titanium dioxide (TiO₂), zinc oxide (ZnO), and silver (Ag) nanoparticles to enhance dye removal. To improve efficiency, microbial consortia have been developed to enhance decolorization and mineralization, offering a cost-effective and eco-friendly alternative to physicochemical methods. Photocatalytic degradation, particularly using TiO₂, harnesses light energy for dye breakdown. Research advancements focus on shifting TiO₂ activation from UV to visible light through doping and composite materials, while optimizing surface area and mesoporosity for better adsorption. Nanoparticle-mediated approaches benefit from a high surface area and rapid adsorption, with ongoing improvements in synthesis, functionalization, and reusability, particularly through magnetic nanoparticle integration. These emerging technologies provide sustainable solutions for dye degradation. The primary aim of this review is to comprehensively evaluate and synthesize current research and advancements in the degradation of azo dyes through microbial methods, photolytic processes, and nanotechnology-based approaches. The review also provides detailed information on salient mechanistic aspects of these methods, efficiencies, advantages, challenges, and potential applications in industrial and environmental contexts. Full article

The objective of this study is to utilize a simulation employing advanced oxidation processes (AOPs) from photodegradation to examine the treatment of textile effluents. The selection of textile effluents as the material to be degraded is justified by the significant volume of water containing dyes, such as methylene blue (MB), generated daily by the textile industry. Often, this water is discarded without undergoing effective treatment. The purification of textile effluents would enable the reuse of water within the textile production cycle, thereby promoting sustainability. This study focuses on AOPs, which are extensively utilized in photocatalytic processes. The catalytic precursor material consists of two types of clay: a commercial clay and a natural clay. The natural clay is pillared with Al and impregnated with Ce, while the commercial clay is also pillared with Al and impregnated with Ce. Both clays are also pillared with a mixed pillar of Al and Ce. This results in three comparable materials. These clays are characterized by the presence of montmorillonite as their predominant mineral component. The selected clays were commercial bentonite and natural clay (FCN). Photocatalytic performance validation tests were conducted using UV-Vis spectroscopy. Material characterization methods included crystallographic analysis (by X-Ray diffraction (XRD)), chemical composition (by X-Ray fluorescence (XRF)), morphological studies (by scanning electron microscopy (SEM)) and textural property analysis (by N₂ adsorption). The outcomes of these investigations offer signification insights into the potential applications of these materials in the treatment of textile effluents and the development of more sustainable processes within the textile industry. Furthermore, the results contribute to the advancement of photocatalytic material design. Full article

Egypt’s average share of global carbon dioxide emissions has been rising from mid-1990s to date. This motivates the present study to identify industries that drive carbon dioxide emissions (as direct emitters and as total emitters with high emission multiplier effects). Environmental input–output analysis is applied to Egypt’s 2017–2018 input–output table to measure sectoral emissions. The industries identified as high emitters are linked to Egypt’s achievement of Sustainable Development Goals, namely, Goals 7, 8, 9, 12, and 13. The findings indicate that ten industries qualify as environmentally degrading (dirty), having the highest emission multiplier effects (in descending order): electricity, gas, and water; non-metallic mineral products; basic metals; rubber and plastic products; chemicals and chemical products; paper and paper products; food products; hotels and restaurants; transportation and storage; and textiles. Eight of these industries also have high output multiplier effects. This underscores that although potential investment in and the growth of these industries will generate output multiplier effects, they will also be coupled with emission multiplier effects. Five other industries had high emission multipliers, as follows: water and sewerage; beverages; coke and refined petroleum products; extraction of crude petroleum; and mining of metal ores. The growth of these industries would not be in favor of the achievement of SDGs. Policy measures are recommended. Full article

This paper presents the results of an experimental investigation on a steel-reinforced polyurethane (SRPU) composite system with a mineral interlayer, designed for the protection of existing structures. The composite SRPU was reinforced with unidirectional steel textile embedded in polyurethane matrix PS. In the study, SRPU was applied to a brick substrate via a layer of lime- or cement-based mortar of a thickness of 3 mm, 6 mm, or 10 mm. Single-lap shear tests (SLSTs) were carried out on specimens with and without a mortar interlayer. The reference specimens without a mineral interlayer carried higher loads than the specimens with an interlayer. An increase in the interlayer thickness reduced the shear bond strength. The stiffness of the bond under shear of the tested systems was unaffected by the presence of the mineral interlayer. The mechanical properties of the applied mortars influenced the observed failure modes. The tested SRPU system demonstrated notable efficiency in monotonic testing, outperforming previously reported results. Full article

The article presents research on the evaluation of the use of two four-layer textile composites with ZrO₂/Al coatings of different thicknesses (deposited by magnetron sputtering PVD) with potential use in thermally insulating protective gloves designed for steelworkers, welders, or miners. The structure of the composites was analyzed using high-resolution X-ray micro-CT. The assessment of the safety of the glove user was conducted using methods in which the composites were exposed to contact heat, radiant heat, and flame heat. The results showed that both four-layer textile composites equipped with ZrO₂/Al coatings provide effective protection against contact heat, radiant heat, and flame heat and can be successfully used in the construction of metallurgical protective gloves. Both composites achieved the first performance level (for contact heat method, for contact temperature 100 °C), the fourth performance level (for radiant heat), and the third performance level (for flame heat). Full article

Fibrous by-products, including defective or double cocoons, are obtained during silk processing. These cocoons primarily contain fibroin and sericin (SS) proteins along with minor amounts of wax and mineral salts. In conventional textile processes, SS is removed in the production of smooth, lustrous silk threads, and is typically discarded. However, SS has garnered attention for its antioxidant, antibacterial, biocompatible, and anticancer properties as well as its excellent moisture absorption, making it a promising polymer for biomedical applications. Owing to its functional groups (carboxyl, amino, and hydroxyl), SS can blend and crosslink with other polymers, thereby improving the mechanical properties of sericin-based materials. This study explored the effects of different SS/polyvinyl alcohol (PVA) ratios on porous scaffolds fabricated via freeze-drying, focusing on the mechanical stability, water absorption, and protein release in phosphate-buffered saline (PBS). The scaffold morphology revealed reduced porosity with higher SS content, while increased PVA content led to material folding and layering. A greater PVA content enhanced water absorption, mechanical properties, and thermal stability, although SS release decreased. These results demonstrate that scaffold properties can be tailored by optimizing the SS/PVA ratio to suit specific biomedical applications. Full article

Fungi, which are widely distributed across the Earth, have successfully managed to colonize cold environments (e.g., polar regions, alpine ecosystems, and glaciers) despite the challenging conditions for life. They are capable of living in extremely harsh environments due to their ecological versatility and morphological plasticity. It is also believed that lower eukaryotes are the most adapted to life at low temperatures among microorganisms that thrive in cold environments. They play important ecological roles, contributing to nutrient recycling and organic matter mineralization. These highly specialized microorganisms have developed adaptation strategies to overcome the direct and indirect harmful influences of low temperatures. They have evolved a wide range of complex and cooperative adaptations at various cellular levels, including modifications to the cell envelope and enzymes, the production of cryoprotectants and chaperones, and the development of new metabolic functions. Adaptation to cold environments has made fungi an exciting source for the discovery of new cold-adapted enzymes (e.g., proteinases, lipases) and secondary metabolites (e.g., pigments, osmolytes, polyunsaturated fatty acids) for widespread use in biotechnology, food technology, agriculture, pharmaceutics, molecular biology, textile industry, and environmental bioremediation in cold climates. This review aims to provide a comprehensive overview of the adaptive strategies employed by psychrophilic yeasts and fungi, highlighting their ecological roles and biotechnological potential. Understanding these adaptive mechanisms not only sheds light on microbial life in extreme environments but also paves the way for innovative applications in the food industry and agriculture. Full article

Introducing lignocellulosic fibers as the matrix reinforcement in composites is an opportunity for weight reduction and also for the use of by-products and biomass waste from other systems, such as agriculture and textiles. In the case of nautical applications, biofouling, meaning damage during service by marine organisms, represents a significant issue. To address this problem, a number of measures can be taken: these include the introduction of various types of fillers, mainly mineral, in composites, tailored treatment of fibers, and hybrid approaches, including a number of different modifications, such as matrix or fiber grafting. This review reports the state of the art in the various studies carried out to elucidate the performance of natural fiber composites and hybrids as regards water absorption and more specifically exposure to seawater for a prolonged time so as to simulate service conditions. The perspectives on the use of natural fiber composites (NFCs) in aquatic environments will be discussed with respect to the possible onset of degradation by biofouling. Full article

Sprouts, microgreens, and baby leaves are plant-based functional foods that have recently gained popularity for use in human diets as novel foods due to their high nutraceutical value. Microgreens, harvested shortly after germination with one true leaf, include vitamins and minerals with potential health benefits. Achieving high yields, robust growth, and maximum nutrient accumulation requires optimal cultivation, especially when selecting the appropriate growing medium. This study assessed the effectiveness of six different growing media for the cultivation of microgreens, specifically black radish (Raphanus sativus L. var. niger), broccoli (Brassica oleracea var. italica), and red beet (Beta vulgaris L.). The growing media tested included vermiculite, perlite, a peat-based medium, filter paper, cotton textile, and agril. The results revealed that vermiculite and the peat-based medium led to the highest yields. The phenolic content ranged from 110.77 mg GA·100 g⁻¹ FW in red beet to 169.96 mg GA·100 g⁻¹ FW in broccoli. The flavonoid content varied between 17.99 mg RU·100 g⁻¹ FW in black radish and 120.36 mg RU·100 g⁻¹ FW in red beet. Agril and filter paper media yielded the highest SPAD–chlorophyll values (47.34 and 44.36, respectively). The protein content peaked at 3.03 g·100 g⁻¹ FW in black radish grown on filter paper, while the vitamin C content reached a maximum of 29.75 mg·100 g⁻¹ FW in black radish grown in agril. The findings suggest that while the optimal conditions vary by species, the choice of growing medium plays a crucial role in determining microgreens’ quality and nutrient content. Full article

This study aims to evaluate the electrochemical oxidation of real textile wastewater using boron-doped diamond (BDD) and different titanium-based mixed metal oxide (Ti/MMO) commercial anodes, namely Ti/RuO₂-TiO₂, Ti/IrO₂-Ta₂O₅, Ti/IrO₂-RuO₂, and Ti/RuO₂/IrO₂-Pt. Experiments were conducted in batch mode, with stirring, at different applied current densities. The results showed that BDD attained the best results, followed by Ti/RuO₂-TiO₂, which achieved total color removal, a chemical oxygen removal of 61% with some mineralization of organic compounds, and a similar specific energy consumption to BDD. The worst performance was observed for Ti/IrO₂-Ta₂O₅, with a specific energy consumption four times superior to BDD due to a negligible organic load removal. Full article

In this study, hydrogel films of biocomposite comprising bacterial cellulose (BC) and silk (S) were successfully fabricated through a simple, facile, and cost-effective method via biosynthesis by Acetobacter xylinum in a culture medium of coconut skim milk/mature coconut water supplemented with the powders of thin-shell silk cocoon (SC). Coconut skim milk/mature coconut water and SC are the main byproducts of coconut oil and silk textile industries, respectively. The S/BC films contain protein, carbohydrate, fat, and minerals and possess a number of properties beneficial to wound healing and tissue engineering, including nontoxicity, biocompatibility, appropriate mechanical properties, flexibility, and high water absorption capacity. It was demonstrated that silk could fill into a porous structure and cover fibers of the BC matrix with very good integration. In addition, components (fat, protein, etc.) in coconut skim milk could be well incorporated into the hydrogel, resulting in a more elastic structure and higher tensile strength of films. The tensile strength and the elongation at break of BC film from coconut skim milk (BCM) were 212.4 MPa and 2.54%, respectively, which were significantly higher than BC film from mature coconut water (BCW). A more elastic structure and relatively higher tensile strength of S/BCM compared with S/BCW were observed. The films of S/BCM and S/BCW showed very high water uptake ability in the range of 400–500%. The presence of silk in the films also significantly enhanced the adhesion, proliferation, and cell-to-cell interaction of Vero and HaCat cells. According to multiple improved properties, S/BC hydrogel films are high-potential candidates for application as biomaterials for wound dressing and tissue engineering. Full article

Pollution in ecosystems has increased, especially in water, due to the pollutant agents that alter their chemical, physical and biological characteristics. This requires actions to resolve or at least reduce the harmful effects generated on the environment and people’s health. Many of the contaminants present in water come from the industrial sector, with the textile industry being one of the most impactful as it uses mostly synthetic dyes, which are characterized as being recalcitrant and toxic, so they cannot be degraded by conventional water treatment methods. Advanced oxidation processes have a great potential for application, especially those that use heterogeneous photocatalysis. The present research evaluates the efficiency in the adsorption and degradation of the triazoic Direct Blue 71 dye in aqueous mediums at concentrations of 600 ppm by the heterogeneous photocatalysis method. The photocatalysts used are layered double hydroxides (LDHs) with a Mg/Al = 3 ratio and are thermally activated and doped with Fe at 1, 3 and 5% w/w. The most efficient materials achieved removal percentages greater than 80% by means of a second-order kinetic model with a DB71 half-life decolorization of less than one hour; as shown by an HPLC study, the absence of intermediate products would confirm the mineralization of the dye. Full article