Search Results (780)

This study investigates the competitive dynamics of reducing sugar production and degradation during the subcritical water processing (SWP) of lyophilized grape pomace (LGP), with the goal of optimizing sugar yield. Under the SWP conditions tested (150 °C, 150 bar, pH 7, S/F of 30 g water g⁻¹ LGP, and a flow rate of 5 mL min⁻¹), we achieved a reducing sugar yield of 296.0 mg sugars g⁻¹ LGP, effectively balancing sugar production and degradation. Sugar yield decreased as the temperature increased from 150 °C to 210 °C, due to the degradation of monosaccharides into by-products like furfural and 5-HMF. A first-order reaction model was developed to better understand the kinetic competition between sugar formation and degradation at varying temperatures. The highest sugar yield occurred at 150 °C, where sugar production was maximized, and degradation was minimized. These findings offer valuable insights for subcritical water processing in the valorization of LGP into fermentable sugars while minimizing the formation of undesirable by-products. Full article

N-Nitrosodimethylamine (NDMA) is a widely recognized disinfection by-product that poses significant carcinogenic risks in drinking water. Conventional methods for NDMA removal, such as nanofiltration and reverse osmosis membranes, have limited efficacy due to NDMA’s small molecular weight and polar properties. Advanced oxidation processes (AOPs) have shown promise, but traditional Fenton processes often fall short due to the chemical structure of nitrosamines in NDMA. This study proposes a novel, cost-effective approach using a one-step carbonization method to synthesize a catalyst from ferric ammonium citrate (FAC). The resulting FAC-600 integrates zero-valent iron and iron carbide with carbon-based functional groups, enhancing catalytic and electron transport activities. Our experiments demonstrated that the FAC-600/persulfate (PS) AOP system achieves over 90% NDMA removal across a wide concentration range (50 μg L⁻¹ to 1000 μg L ⁻¹) with a limited dosage of 0.5 g L⁻¹. Mechanistic insights revealed that superoxide and hydroxyl radicals dominate NDMA degradation, facilitated by the presence of dissolved oxygen and PS. This study underscores the potential of the FAC-600/PS AOP system as a robust and efficient solution for NDMA removal, promising safer drinking water through practical application. Full article

Since the publication of the 12 principles of green chemistry in 1998 by Paul Anastas and John Warner, the green synthesis of metal and metal oxide nanoparticles has emerged as an eco-friendly and sustainable alternative to conventional chemical methods. Plant-based synthesis utilizes natural extracts as reducing and stabilizing agents, minimizing harmful chemicals and toxic by-products. Ag nanoparticles (Ag-NPs) exhibit strong antibacterial activity; Au nanoparticles (Au-NPs) are seen as a promising carrier for drug delivery and diagnostics because of their easy functionalization and biocompatibility; and ZnO nanoparticles (ZnO-NPs), on the other hand, produce reactive oxygen species (ROS) that kill microorganisms effectively. These nanoparticles also demonstrate antioxidant properties by scavenging free radicals, reducing oxidative stress, and preventing degenerative diseases. Green syntheses based on plant extracts enhance biocompatibility and therapeutic efficacy, making them suitable for antimicrobial, anticancer, and antioxidant applications. Applying a similar “green synthesis” for advanced nanostructures like graphitic carbon nitride (GCN) is an environmentally friendly alternative to the traditional ways of doing things. GCN exhibits exceptional photocatalytic activity, pollutant degradation efficiency, and electronic properties, with applications in environmental remediation, energy storage, and biomedicine. This review highlights the potential of green-synthesized hybrid nanocomposites combining nanoparticles and GCN as sustainable solutions for biomedical and environmental challenges. The review also highlights the need for the creation of a database using a machine learning process that will enable providing a clear vision of all the progress accomplished till now and identify the most promising plant extracts that should be used for targeted applications. Full article

Photochemical degradation is a major removal pathway for pharmaceutical pollutants in water, and dissolved organic matter (DOM) in water is an important factor affecting this process. This study investigates the differential effects of seasonally-varied dissolved organic matter (DOM) from Songhua River and Liao River on the photodegradation of pharmaceutical pollutants, using levofloxacin (LFX), sulfamethoxazole (SMZ), and ibuprofen (IBP) as target compounds. The results demonstrated that summer and autumn DOM inhibited the photodegradation of LFX and SMZ through light screening and dynamic quenching effects, with inhibition rates of 35.1% and 55.5%, respectively, whereas winter DOM enhanced degradation through photo-oxidation mechanisms. DOM from Songhua River and Liao River significantly promoted the photodegradation of IBP. Quenching experiments showed differences in the contributions of photochemically reactive intermediates (PPRIs) to the photodegradation of different target pollutants, with hydroxyl radicals (•OH) dominating LFX photodegradation (48.79% contribution), excited triplet states of DOM (³DOM*) dominating SMZ photodegradation (85.20% contribution), and singlet oxygen (¹O₂) dominating IBP photodegradation (79.89% contribution). The photodegradation pathways were elucidated by measuring the photodegradation by-products of the target pollutants: LFX mainly underwent piperazine ring cleavage and oxidative decarboxylation, SMZ underwent isoxazole ring opening and deamination during photodegradation, and IBP underwent photodecarboxylation and oxidation reactions. Under the influence of the DOM from the Songhua River and Liao River, the generation of multiple photodegradation by-products led to an increasing trend in the acute toxicity of target pollutants to luminescent bacteria. This investigation elucidates the dual regulatory mechanisms of natural aquatic DOM on both photo-induced degradation pathways and toxicity evolution dynamics of pharmaceutical contaminants, which is of great significance for understanding the photochemical transformation behavior and risk assessment of pharmaceutical pollutants in aquatic environments. Full article

The objective of the present study was to investigate the potential effects of biofillers derived from fruit waste, a byproduct of the food-processing industry, on the degradation of ethylene–norbornene (EN) copolymers under the controlled conditions of laboratory composting. This manuscript provides a comprehensive analysis of the influence of waste biofillers on the biological degradation of EN-based materials, thereby filling a gap in the existing literature on the subject. The concept of this work encompasses the enhancement of the degradability of synthetic EN through the incorporation of bioadditives. Waste apple and chokeberry pomace were added to EN as biofillers in amounts of 5, 10, and 15 phr (parts per hundred rubber). The polymeric materials were composted for 3 and 6 months under laboratory conditions. We assessed the susceptibility of the samples to the growth of microorganisms, as well as the mass loss of the polymeric materials after composting. The findings indicated that the bioadditives increased the compostability of the materials, as evidenced by the elevated carbonyl indices observed for the samples containing biofillers. Furthermore, the elevated polar component of the surface energy exhibited by the samples containing biofillers suggested a heightened susceptibility to composting processes, attributable to their augmented hydrophilicity, in comparison to the reference EN. Fruit pomace is a promising additive for increasing the compostability of synthetic polymeric materials. Full article

Although algae possess a high capacity for carbon sequestration, the recalcitrant multilayered cell wall structure and residual microcystin toxicity associated with Microcystis aeruginosa significantly hinder the efficient recovery of algal biomass resources. This study developed a synergistic ozone-ultrasonication (O₃-US) pretreatment strategy, systematically comparing its cell-disruption efficacy with standalone O₃ or US, using harvested algal biomass from natural aquatic systems dominated by Microcystis aeruginosa. The synergistic effects revealed were: (1) O₃-mediated oxidation of extracellular polymeric substances and cell wall matrices, (2) the release of ultrasound-induced cavitation-enhancing intracellular components, and (3) an improvement in the O₃ mass transfer by hydrodynamic shear forces. Through response surface methodology optimization, the O₃-US process achieved maximal performance at 0.14 gO₃/gTSS, with a 4 W/mL ultrasonic intensity, and a 20 min duration. Remarkably, the released protein was 289.2 mg/gTSS, which was 4.3-fold and 1.9-fold, respectively, more than that released in O₃ pretreatment and US pretreatment, while the polysaccharide was 87.5 mg/gTSS, increased by 2.4-fold and 3.1-fold respectively, compared to O₃ alone and US alone. The released solubilized chemical oxygen demand (SCOD) was 1037.1 mg/gTSS, increased by 43.3% and 216.1%, respectively, relative to O₃ alone and US alone. DNA quantification further validated the synergistic cell disruption caused by O₃-US. Fluorescence excitation-emission matrix (EEM) spectroscopy identified biodegradable aromatic proteins (Regions I-II) and soluble microbial byproducts (Region IV) as dominant organic fractions, demonstrating enhanced bioavailability. The hybrid process reduced energy consumption by 33.3% in ultrasonic intensity and 60% in duration versus US alone, while achieving 94.5% microcystin-LR (MC-LR) degradation, which showed a 96.6% risk reduction compared to ultrasonic treatment. This work establishes an efficient, low-energy, and safe pretreatment technology for algal resource recovery, synergistically enhancing intracellular resource release while mitigating cyanotoxin hazards in algal biomass valorization. Full article

Sulfamethoxazole (SMX), a widely used antibiotic, persists in aquatic environments due to its resistance to conventional wastewater treatments. This work examined the breakdown of SMX in both purified water and urban wastewater through the application of electron beam irradiation (EBI). Experiments were conducted across doses of 0.5–3.0 kGy and varying pHs (2.70, 6.13, 9.00 and 11.10) and initial concentrations (5, 10, 15, 20 and 30 mg/L), and the role of reactive species was investigated with the help of scavengers. The results showed that SMX degradation followed pseudo-first-order kinetics and was most efficient at lower pH and concentrations. The scavenger experiments confirmed hydroxyl radicals as the dominant oxidizing agents responsible for SMX degradation, while wastewater constituents slightly inhibited the process. Nevertheless, over 99% SMX degradation was achieved at higher doses (1.5–3.0 kGy). TOC analysis revealed the partial mineralization of SMX, indicating the persistence of intermediate by-products despite high degradation efficiency. LC-MS analysis revealed multiple transformation products including hydroxylated sulfonamides and nitro-substituted derivatives, reflecting diverse degradation pathways. These results demonstrate that EBI is a highly effective laboratory-scale method for degrading SMX from water and wastewater, with promising potential for practical application. Full article

This study explored mycelium-based composites (MBCs) as a sustainable alternative to conventional materials, focusing on the role of lignocellulosic substrates in optimizing their physical, mechanical, and biodegradability properties. It also addressed the valorization of agroforestry by-products, particularly European hazelnut shells (HZ) and radiata pine sawdust (SW), in an effort to reduce waste and minimize environmental impacts. The MBCs were obtained using two formulations (HZ100 and HZ75-SW25) of local agroforestry by-products bound together with natural growth of fungal mycelium from Ganoderma sp. We examined the physical and mechanical properties of these novel materials, including the density, shrinkage, water absorption, hydrophobicity, moduli of rupture and elasticity, and internal bond strength. Additionally, we assessed the biodegradability of the MBCs in soil to estimate the time required for complete degradation. The results clearly indicated differences in performance between the MBCs from HZ100 and HZ75-SW25. In general, HZ75-SW25 demonstrated superior mechanical performance compared to HZ100. Water absorption was low in both cases, suggesting a degree of hydrophobicity on the surface. The biodegradation results indicated that the fabricated MBCs could fully decompose in less than one year when buried in soil, confirming that these biocomposites are entirely biodegradable. Full article

This paper applies a semi-quantitative approach to review the diversity, environmental controls, detection methods, human health risks, and mitigation of cyanotoxins in drinking water systems (DWSs). It discusses the environmental factors controlling the occurrence of cyanotoxins, presents the merits and limitations of emerging methods of their detection (qPCR, liquid chromatography–mass spectrometry, and electrochemical biosensors), and outlines the human exposure pathways and health outcomes with identification of high-risk groups and settings. High-risk groups include (1) communities relying on untreated drinking water from unsafe, polluted water sources and (2) low-income countries where cyanotoxins are not routinely monitored in DWSs. The fate and behavior processes are discussed, including removing cyanotoxins in DWSs based on conventional and advanced treatment processes. The available methods for cyanotoxin removal presented in this paper include (1) polymer-based adsorbents, (2) coagulation/flocculation, (3) advanced oxidation processes, (4) ultra- and nanofiltration, and (5) multi-soil layer systems. Future research should address (1) detection and fate in storage and conveyance facilities and at the point of consumption, (2) degradation pathways and toxicity of by-products or metabolites, (3) interactive health effects of cyanotoxins with legacy and emerging contaminants, (4) removal by low-cost treatment techniques (e.g., solar disinfection, boiling, bio-sand filtration, and chlorination), (5) quantitative health risk profiling of high-risk groups, and (6) epidemiological studies to link the prevalence of human health outcomes (e.g., cancer) to cyanotoxins in DWSs. Full article

A new brazing process for thin-walled stainless steel was proposed by combining green and efficient Ni-Cr-P electrodeposition with brazing technology. Novel information was attained by analyzing the electrodeposited Ni-Cr-P interlayers and the brazed joints and characterizing them using a combination of advanced techniques. The incorporation mechanisms of impurities (i.e., oxygen and carbon) in the Ni-Cr-P interlayers electrodeposited from a Cr(III)–glycine solution were revealed. The oxygen mainly came from the Cr(III)–hydroxy complexes formed by the hydrolysis and olation between Cr(III) complexes and OH⁻ ions near the cathode. Glycine did not directly participate in the cathode reactions but decomposed on the anode surface. These byproducts (carbonyl compounds) were directly incorporated into the interlayers in a molecular pattern, forming a weak link to the metallic chromium. Brazing test results showed that a certain amount of Cr₂O₃ powder, formed by the decomposition of chromium hydroxides in the interlayers under high-temperature catalysis, would cause the degradation of the brazed joints. Using the step-wise brazing method, the brazing sheets were first annealed to eliminate the impurities by utilizing the strong reducing effect of hydrogen and the weak link characteristics between carbonyl compounds and metallic chromium atoms. An excellent joint with a shear strength of 63.0 MPa was obtained by subsequent brazing. The microstructural analysis showed that the brazed seam was mainly composed of a Ni-Fe-Cr solid solution, the Ni₃P eutectic phase, and small quantities of the Ni₅P₂ phase scattered in the Ni₃P eutectic phase. Fracture mode observations showed that the cracks extended along the interface between the brittle P-containing phase and the primary phase, resulting in fracture. Full article

Geopolymer recycled aggregate concrete (GRAC) is an eco-friendly material utilizing industrial byproducts (slag, fly ash) and substituting natural aggregates with recycled aggregates (RA). Incorporating steel-polypropylene hybrid fibers into GRAC to produce hybrid-fiber-reinforced geopolymer recycled aggregate concrete (HFRGRAC) can bridge cracks across multi-scales and multi-levels to synergistically improve its mechanical properties. This paper aims to investigate the mechanical properties of HFRGRAC with the parameters of steel fiber (SF) volume fraction (0%, 0.5%, 1%, 1.5%) and aspect ratio (40, 60, 80), polypropylene fiber (PF) volume fraction (0%, 0.05%, 0.1%, 0.15%), and RA substitution rate (0%, 25%, 50%, 75%, 100%) considered. Twenty groups of HFRGRAC specimens were designed and fabricated to evaluate the compressive splitting tensile strengths and flexural behavior emphasizing failure pattern, load–deflection curve, and toughness. The results indicated that adding SF enhances the specimen ductility, mechanical strength, and flexural toughness, with improvements proportional to SF content and aspect ratio. In contrast, a higher percentage of RA substitution increased fine cracks and reduced mechanical performance. Moreover, the inclusion of PF causes cracks to exhibit a jagged profile while slightly improving the concrete strength. The significant synergistic effect of SF and PF on mechanical properties of GRAC is observed, with SF playing a dominant role due to its high elasticity and crack-bridging capacity. However, the hydrophilic nature of SF combined with the hydrophobic property of PF weakens the bonding of the fiber–matrix interface, which degrades the concrete mechanical properties to some extent. Full article

Over the years, the frequent and continuous use of drugs has led to a high presence of emerging micropollutants in wastewater, increasing environmental and health concerns. Among these chemicals, Indomethacin (IND), a widely used anti-inflammatory drug, has been detected up to 150 ng/L in water bodies. Its presence in aquatic environments causes increasing concerns due to its high persistence, limited biodegradability, and resistance to conventional treatment processes. This study examined the degradation of IND via oxidation with sodium hypochlorite (NaClO) and the characterization of the degradation byproducts (DPs) generated by this process. Based on NMR spectroscopy studies and mass spectrometry analysis, thirteen DPs were identified, seven of which were previously unpublished (DP1: 2-(3-Chloro-1-(4-chlorobenzoyl)-2-hydroxy-5-methoxy-2-methylindolin-3-yl)acetic acid, DP3: 2-(3,4-Dichloro-1-(4-chlorobenzoyl)-2-hydroxy-5-methoxy-2-methylindolin-3-yl)acetic acid, DP5: (3-Chloro-5-methoxy-2-methyl-1H-indol-1-yl)(4-chlorophenyl)methanone, DP6: (4-Chlorophenyl)(5-methoxy-3-(methoxymethyl)-2-methyl-1H-indol-1-yl)methanone, DP7: 2-(2-(4-Chlorobenzamido)-5-methoxyphenyl)-2- oxoethyl acetate, DP8: 2-(5-Methoxy-2-methyl-1H-indol-3-yl)acetic acid, DP9: 4-Chloro-N-(4-methoxyphenyl)benzamide), and a degradation mechanism was proposed. These results show how the degradation of Indomethacin leads to the generation of new byproducts that may persist in the environment, obtaining DP1 in far larger quantities than the other byproducts. Given Indomethacin’s degradation rate of over 90% but not its complete mineralization, it is fundamental to study not only IND but also the byproducts generated to assess their potential environmental impact. Full article

Kelp (Laminaria japonica) is renowned for its rich content of flavor-enhancing amino acids and nucleotides; however, approximately 40% of kelp, including the thin edges and root areas, is discarded during its processing due to its inferior taste. To recycle these kelp byproducts, we have cultivated a functional microbial consortium through continuous enrichment. Analysis via 16S rRNA sequencing has shown that during the three fed-batch fermentation stages of kelp waste, the microbial community was predominantly and consistently composed of three phyla: Halanaerobiaeota, Bacteroidota, and Proteobacteria. At the genus level, Halanaerobium emerged as the dominant player, exhibiting a trend of initial increase followed by a decline throughout the fermentation process. Enzymes such as alginate lyases and both acidic and neutral proteases were found to play crucial roles in the degradation of kelp residues into sauces. Notably, electronic tongue analysis revealed that the fermented kelp sauce demonstrated strong umami characteristics. Furthermore, four novel umami peptides, EIL, STEV, GEEE, and SMEAVEA, from kelp were identified for the first time, with their umami effect largely attributed to strong hydrogen bond interactions with the T1R1–T1R3 umami receptors. In conclusion, this study proposed a sustainable method for kelp by-product utilization, with implications for other seaweed processing. Full article

This study researches the impact of diclofenac (DCF) oxidation via UV/H₂O₂ on water quality, focusing on aromaticity and color changes. The process effectively degrades DCF and its intermediates through hydroxyl radical attack on the aromatic structure, leading to the formation of oxidized by-products. Initially, chromophoric compounds such as quinones and conjugated intermediates cause a yellow coloration, which diminishes as mineralization progresses. Turbidity remains below 1 NTU, aligning with European water quality standards. Aromaticity initially increases due to the stable intermediates (e.g., catechols and hydroquinones) but decreases as advanced oxidation cleaves aromatic rings. Kinetic modeling shows that DCF degradation follows first-order kinetics, while aromatic intermediates degrade via fractional-order kinetics (~0.3), indicating a non-linear relationship with concentration. The formation of chromophore compounds follows first-order kinetics, whereas their degradation transitions to zero-order kinetics when hydroxyl radicals are abundant. The study highlights the environmental relevance of these transformations, as aromatic intermediates like anilines and phenols, which contribute to water toxicity, are ultimately converted into less hazardous compounds (e.g., carboxylic acids and inorganic ions). Experimental validation confirms that degradation kinetics depend on hydrogen peroxide concentration, underscoring the potential of UV/H₂O₂ for water purification and pollutant removal. Full article

Antimicrobial fragrances, commonly found in household and personal care products, are frequently detected in water bodies, yet their environmental fate and transformation mechanisms remain inadequately explored. This study investigates the photochemical transformation of cinnamaldehyde (CA), a representative antimicrobial fragrance, and its consequence for toxicological effects. The results showed that under UV irradiation, 94.6% CA was eliminated within 60 min, with a degradation rate of 0.059 min⁻¹. Laser flash photolysis, quenching experiments, and electron paramagnetic resonance spectra identified O₂^•− and ³CA^* as the important species, contributing 29.4% and 33.6%, respectively, to the transformation process. Additionally, singlet oxygen (¹O₂), hydroxyl radicals (^•OH), and solvated electrons (e_aq⁻) were involved in mediating the oxidation reactions. These species facilitated photoionization and oxidation, resulting in the formation of five major transformation products, including cis-cinnamyl aldehyde, cinnamic acid, styrene, 1aH-indeno [1,2-b]oxirene), and 1-Oxo-1H-indene. Most of these products were persistent, and exhibited considerable ecotoxicological risks. Specifically, the cinnamic acid and 1-Oxo-1H-indene caused severe skin irritation, while cinnamic acid induced significant eye irritation. Notably, the transformation products demonstrated sensitizing effects on human skin. This study underscores the overlooked ecotoxicological risks associated with the photochemical transformation of antimicrobial fragrances, revealing their potential to generate potent allergens and other harmful byproducts. Full article