Search Results (374)

An innovative ultrasound-assisted deep eutectic solvent-based three-phase partitioning (UA-DES-TPP) system was developed for the sustainable extraction of Ficus carica polysaccharide (FCP). Using a hydrophobic DES composed of dodecanoic acid and octanoic acid (1:1 molar ratio), a phase behavior-driven separation mechanism was established. The system was systematically optimized through single-factor experiments and response surface methodology (RSM), achieving a maximum FCP yield of 9.22 ± 0.20% under optimal conditions (liquid–solid ratio 1:24.2 g/mL, top/bottom phase volume ratio 1:1.05 v/v, ammonium sulfate concentration 25.8%). Structural characterization revealed that FCP was a heteropolysaccharide primarily composed of glucose and mannose with α/β-glycosidic linkages and a loose fibrous network. Remarkably, the DESs demonstrated excellent recyclability over five cycles. Furthermore, FCP exhibited significant concentration-dependent antioxidant activities: 82.3 ± 3.8% DPPH radical scavenging at 8 mg/mL, 76.8 ± 0.8% ABTS⁺ scavenging, and ferric ion reducing power of 45.53 ± 1.07 μmol TE/g. This study provides a new path for the efficient and sustainable extraction of bioactive macromolecules. Full article

Background and Objectives: The cultivation of Humulus lupulus has been encouraged in Brazil, despite the country’s climate generally being unfavorable for its development. This study aimed to evaluate the chemical composition, antioxidant activity, and photoprotective potential of four H. lupulus varieties, Cascade, Columbus, Comet, and Nugget, cultivated in the northwestern region of Paraná State, Brazil. Methods: The varieties were grown in experimental plots. Crude extracts (CEs) of cones and leaves were obtained through dynamic maceration with solvent renewal (96% ethanol), followed by concentration in a rotary evaporator. Assays for sun protection factor (SPF), total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), 2.2-diphenyl-1-picrylhydrazyl (DPPH^•) radical scavenging activity, and 2.2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^•⁺) were performed to assess antioxidant activity. Chemical profiling was performed using UHPLC-MS/MS. Results: UHPLC-MS/MS analysis revealed the presence of phenolic and organic acids, flavonoids, phenolic aldehydes, alkaloids, and α-benzopyrone-type lactones, with high concentrations of rutin (>500 µg/g) in both cones and leaves. Total phenolic content ranged from 69.70 to 95.95 µg gallic acid equivalent/mg CE; flavonoids from 170.53 to 696.67 µg quercetin equivalent/mg CE; DPPH^• EC₅₀ values ranged from 1.34 to 3.13 mg/mL; FRAP from 1.19 to 2.52 µM ferrous sulfate/mg; ABTS^•⁺ from 5.11 to 22.60 mM Trolox/mg CE; and SPF ranged from 16.02 to 39.48 in the CE of H. lupulus cones and leaves. Conclusions: These findings demonstrate that the cultivated varieties possess antioxidant and photoprotective properties, encouraging further studies to explore their potential applications. Full article

Disinfection by ultrasound and carbon nanotubes (CNTs) provides attractive alternatives to conventional methods for water and wastewater treatment. This study explored the inactivation of Escherichia coli (E. coli) by 5 mg/L pristine short and long multi-walled CNTs (MWCNTs) and 20 kHz ultrasound individually or in combinations in DI water, Suwannee River natural organic matter (SRNOM), and sodium dodecyl sulfate (SDS) solution, respectively. The results indicated that the dispersity of MWCNTs was the single most important factor determining the inactivation rate of E. coli. The dispersity of short MWCNTs in solutions increased in the order of DI water <10 mgC/L SRNOM < 2 mM SDS. Correspondingly, the greatest log inactivation of E. coli was achieved in SDS when short MWCNTs were used alone (0.67 ± 0.12) and combined with ultrasound (1.80 ± 0.02) for 10 min. Short MWCNTs alone had a slightly greater inactivation (0.29 ± 0.07) in SRNOM solution than in DI water (0.18 ± 0.05). However, long MWCNTs had a slightly higher inactivation in DI water (0.24 ± 0.03) than short ones (0.18 ± 0.05), because of better dispersity in DI. The observed synergistic inactivation when ultrasound and short MWCNTs were used together in 2 mM SDS shows that ultrasound energized the MWCNTs more effectively when they were well dispersed, although SDS and MWCNTs can occupy the reaction sites at the cavitational bubble–water interfacial regions and scavenge •OH radicals. The results suggest that sonophysical effects are more important to inactivate E. coli than sonochemical effects. Ultrasound inactivates E. coli and/or energizes MWCNTs through the mechanisms of acoustic streaming, microstreaming, microstreamers, transient cavitation collapse-generated shock waves and microjets (transitional forms), and localized hot temperatures. The results of this study indicate that the cytotoxicity of CNTs includes impinging bacterial cells and/or direct contact with the bacteria. Full article

Advanced oxidation processes (AOPs) utilizing peroxymonosulfate (PMS) have emerged as a promising technology for organic pollutant degradation due to their distinct environmental advantages. In this study, copper–iron bimetallic oxide catalysts with varying ratios were synthesized via a co-precipitation method to activate PMS for degrading simulated tetracycline hydrochloride wastewater. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The effects of key parameters—including the PMS concentration, catalyst dosage, initial pH, and tetracycline hydrochloride concentration—on the degradation efficiency were systematically investigated. The results demonstrated that the CuFe(2)/PMS system exhibited the highest degradation efficiency. Under optimal conditions (20 mg/L tetracycline hydrochloride, 0.4 mM PMS, 0.5 g/L CuFe(2) catalyst, and pH 3), this system achieved a 94.12% degradation rate of tetracycline hydrochloride within 120 min. The electron paramagnetic resonance (EPR) tests and radical quenching experiments identified sulfate radicals (SO₄·⁻) as the predominant reactive species. Furthermore, the XPS analysis elucidated the persulfate activation mechanism, while the liquid chromatography–mass spectrometry (LC-MS) identified the potential degradation pathways and intermediate products of tetracycline hydrochloride. Full article

The increasing presence of tetracycline antibiotics (TCs) in water sources poses significant environmental and public health risks, necessitating effective treatment technologies. This study investigates the degradation of three types of TCs in water—Tetracycline (TC), Oxytetracycline (OTC), and Chlortetracycline (CTC)—using nonthermal plasma (NTP) coupled with the persulfate (PS) process. The combined NTP/PS system was optimized for various operational parameters, including PS concentration, pH, and reaction time, to achieve maximum degradation and mineralization efficiency. The results showed that the NTP/PS system achieved over 90% degradation of all TCs under optimal conditions, outperforming plasma alone treatment. The degradation kinetics followed a pseudo-first-order model, indicating a rapid initial breakdown of TCs. The degradation mechanism was elucidated through the identification of intermediate byproducts using liquid chromatography-mass spectrometry (LC-MS/MS). Free radicals, such as sulfate (SO₄^•−) and hydroxyl (^•OH) radicals, were identified as the primary reactive species responsible for TCs degradation. This study demonstrates the potential of the NTP/PS system as an efficient and sustainable solution for the removal of antibiotic contaminants from water. Further research on the scalability and application in real wastewater conditions is recommended. Full article

The practical application of powdered photocatalysts is significantly hindered by challenges in recyclability and structural instability. This work proposes a sustainable immobilization strategy by integrating BiVO₄ nanoparticles into a sodium alginate (SA) aerogel scaffold through a facile freeze-drying approach. The abundant hydroxyl/carboxyl groups of SA enable uniform dispersion of BiVO₄ within the porous network, while the aerogel architecture enhances light-harvesting efficiency and mass transfer kinetics. Innovatively, peroxymonosulfate (PMS) was introduced to synergistically couple photocatalysis with sulfate radical-based advanced oxidation processes (SR-AOPs), where the photogenerated electrons from BiVO₄ effectively activate PMS to yield high-activity ·SO₄⁻ radicals. The optimized BiVO₄/SA aerogel achieves nearly complete removal of Rhodamine B within 2 h under visible light, which is competitive to pure BiVO₄ powders. In addition, the mechanically robust aerogel exhibits exceptional reusability, retaining ~90% efficiency after five cycles without structural collapse. This work provides a paradigm for designing recyclable photocatalyst carriers with dual oxidation pathways, demonstrating significant potential for industrial wastewater treatment. Full article

Sulfate radical-based advanced oxidation processes (AOPs) are effective for removing organic pollutants from wastewater. In this study, transition metal-doped cobalt oxyhydroxide (CoOOH) was synthesized as an efficient peroxymonosulfate (PMS) activator for the decolorization of rhodamine B. Doping CoOOH with transition metals enhanced its PMS activation performance compared with that of pure CoOOH. Notably, the reaction rate constant in the Ni-CoOOH/PMS system was approximately 4.3 times higher than that in the CoOOH/PMS system. The presence of multiple metals in the catalyst facilitated efficient Co²⁺/Co³⁺ redox cycling, resulting in improved PMS activation and more effective organic pollutant removal. This study highlights the potential of CoOOH-based materials for use in environmental remediation technologies utilizing PMS. Full article

With the increasing severity of global water pollution, traditional wastewater treatment methods have gradually revealed limitations in dealing with complex and refractory pollutants. Advanced oxidation processes (AOPs) have emerged as a promising alternative due to their ability to generate highly reactive radicals (such as hydroxyl and sulfate radicals) that can effectively degrade a wide range of pollutants. This review provides a detailed overview of various AOP technologies, including Fenton processes, ozone-based AOPs, persulfate-based AOPs, photocatalytic AOPs, electrochemical AOPs, and sonochemical AOPs, focusing on their fundamental principles, reaction mechanisms, catalyst design, and application performance in treating different types of wastewater. The research results show that the improved Fenton process can achieve a chemical oxygen demand (COD) removal rate of up to 85% when treating pharmaceutical wastewater. Photocatalytic AOP technology demonstrates higher degradation efficiency when treating industrial wastewater containing refractory pollutants. In addition to effectively degrading refractory pollutants and reducing dependence on traditional biological treatment methods, these advanced oxidation processes can also significantly reduce secondary pollution generated during the treatment process. Moreover, by optimizing AOP technologies, the deep mineralization of harmful substances in wastewater can be achieved, reducing the potential pollution risks to groundwater and soil while also lowering energy consumption during the treatment process. Additionally, this review discusses the challenges faced by AOPs in practical applications, such as high energy consumption, insufficient catalyst stability, and secondary pollution. This review summarizes the research progress and application trends of catalytically driven AOPs in the field of wastewater treatment over the past five years. It aims to provide a comprehensive reference for researchers and engineering professionals on the application of AOPs in wastewater treatment, promoting the further development and practical implementation of these technologies. Full article

Petroleum hydrocarbon (PH) contamination in groundwater necessitates sustainable remediation solutions. This study develops a novel co-encapsulated composite by embedding steel slag (SS) and sodium persulfate (SPS) within an ethyl cellulose (EC) matrix ((SS + SPS)/EC) for permeable reactive barrier applications. The EC matrix enables controlled release of SPS oxidant and gradual leaching of alkaline components (Ca²⁺/OH⁻) and Fe²⁺/Fe³⁺ activators from SS, synergistically sustaining radical generation while buffering pH extremes. Optimized at a 10:7 SS:SPS mass ratio, the composite achieves 66.3% PH removal via dual pathways: (1) sulfate radical (${\mathrm{S}\mathrm{O}}_4^{-}$•) oxidation from Fe²⁺-activated persulfate (S₂${\mathrm{O}}_8^{2-}$ + Fe²⁺→${\mathrm{S}\mathrm{O}}_4^{-}$• + ${\mathrm{S}\mathrm{O}}_4^{2-}$ + Fe³⁺), and (2) direct electron transfer by surface-bound Fe³⁺. In situ material evolution enhances functionality—nitrogen physisorption reveals a 156% increase in surface area and 476% pore volume expansion, facilitating contaminant transport while precipitating stable sulfate minerals (Na₂SO₄, Na₃Fe(SO₄)₃) within pores. Crucially, the composite maintains robust performance under groundwater-relevant conditions: 54% removal at 15 °C (attributed to pH-buffered activation) and >55% efficiency with common interfering anions (Cl⁻, ${\mathrm{H}\mathrm{C}\mathrm{O}}_3^{-}$, 50 mg·L⁻¹). This waste-derived design demonstrates a self-regulating system that concurrently addresses oxidant longevity (≥70 h), geochemical stability (pH 8.5→10.4), and low-temperature activity, establishing a promising strategy for sustainable groundwater remediation. Continuous-flow column validation (60 d, 5 mg·L⁻¹ gasoline) demonstrates sustained >80% removal efficiency and systematically stable effluent pH (9.8–10.2) via alkaline leaching. Full article

The continuous occurrence of steroidal pharmaceutical dexamethasone (DXM) in aqueous environments indicates the need for an efficient removal technology. The frequent detection of DXM in surface water could be substantially reduced by the application of photo-induced advanced oxidation technology. In the present study, Fe²⁺ and UVA-light activated peroxo compounds were applied for the degradation and mineralization of a glucocorticoid, 25.5 µM DXM, in ultrapure water (UPW). The treatment efficacies were validated in real spring water (SW). A 120 min target pollutant degradation followed pseudo first-order reaction kinetics when an oxidant/Fe²⁺ dose 10/1 or/and UVA irradiation were applied. Acidic conditions (a pH of 3) were found to be more favorable for DXM oxidation (≥99%) regardless of the activated peroxo compound. Full conversion of DXM was not achieved, as the maximum TOC removal reached 70% in UPW by the UVA/H₂O₂/Fe²⁺ system (molar ratio of 10/1) at a pH of 3. The higher efficacy of peroxymonosulfate-based oxidation in SW could be induced by chlorine, bicarbonate, and carbonate ions; however, it is not applicable for peroxydisulfate and hydrogen peroxide. Overall, consistently higher efficacies for HO^•-dominated oxidation systems were observed. The findings from the current paper could complement the knowledge of oxidative removal of low-level DXM in real water matrices. Full article

Pseudo-persistent organic pollutants, such as pharmaceuticals, personal care products (PPCPs), and organic dyes, are a major issue in current environmental engineering. Considering the limitations of traditional wastewater treatment plant methods and degradation technologies for organic pollutants, the search for new technologies more suitable for treating these new types of pollutants has become a research hotspot in recent years. Membrane filtration, adsorption, advanced oxidation, and electrochemical advanced oxidation technologies can effectively treat new organic pollutants. The electro-advanced oxidation process based on sulfate radicals is renowned for its non-selectivity, high efficiency, and environmental friendliness, and it can improve the dewatering performance of sludge after wastewater treatment. Therefore, in this study, octyl methoxycinnamate (OMC) was selected as the target pollutant. A new type of electrochemical filtration device based on the advanced oxidation process of sulfate radicals was designed, and a new type of modified carbon nanotube material electrode was synthesized to enhance its degradation effect. In a mixed system of water and acetonitrile, the efficiency of the electrochemical filtration device loaded with the modified electrode for degrading OMC is 1.54 times that at room temperature. The experimental results confirmed the superiority and application prospects of the self-designed treatment scheme for organic pollutants, providing experience and a reference for the future treatment of PPCP pollution. Full article

This study presents the development of a novel Cu–Co–O-codoped graphitic carbon nitride (g-C₃N₄) catalyst for efficient peroxymonosulfate (PMS) activation to degrade sulfamethoxazole (SMX) in aqueous environments. The synthesized Cu–Co–O-g-C₃N₄ catalyst demonstrated exceptional catalytic performance, achieving 90% SMX removal within 10 min—significantly outperforming pristine g-C₃N₄ (14%) and O-doped g-C₃N₄ (22%)—with a reaction rate constant of 0.63 min⁻¹. The superior activity was attributed to the synergistic effects of Cu-Co bimetallic doping and oxygen incorporation, which enhanced the active sites, stabilized metal ions, and minimized leaching. Mechanistic studies revealed a dual-pathway degradation process: (1) a radical pathway dominated by sulfate radicals (SO₄•⁻) and (2) a non-radical pathway driven by singlet oxygen (¹O₂), with the latter identified as the dominant species through quenching experiments. The catalyst exhibited broad pH adaptability and optimal performance at neutral to alkaline conditions. Characterization techniques (XRD, FTIR, XPS) confirmed successful doping and revealed that oxygen incorporation modified the electronic structure of g-C₃N₄, improving charge carrier separation. This work provides a sustainable strategy for antibiotic removal, addressing key challenges in advanced oxidation processes (AOPs), and highlights the potential of multi-heteroatom-doped carbon nitride catalysts for water purification. Full article

Copper is an essential micronutrient for plants, but excessive levels can induce toxicity and impair physiological functions. This study evaluates the toxic effects of copper sulfate (CuSO₄) on the germination of common wheat (Triticum aestivum), with emphasis on the gas emission dynamics and oxidative stress biomarkers. Seeds were germinated in agar and exposed to CuSO₄ at concentrations of 1 µM, 100 µM, 1 mM, and 10 mM; distilled water served as the control. Ethylene and ammonia emissions were quantified using CO₂ laser photoacoustic spectroscopy, while electron paramagnetic resonance (EPR) spectroscopy was employed to detect free radicals and Cu²⁺ complexes. Exposure to Cu concentrations ≥ 1 mM significantly inhibited germination and biomass accumulation. Enhanced ethylene and ammonia emissions, particularly at 10 mM, indicated stress-related metabolic responses. The EPR spectra confirmed the presence of semiquinone radicals and Cu²⁺ complexes under higher Cu levels. These results demonstrate that photoacoustic and EPR techniques are effective tools for the early detection of metal-induced phytotoxicity and offer a non-invasive approach to environmental toxicity screening and plant stress assessment. Full article

This study investigated the degradation efficacy, kinetics, and mechanism of the ozone (O₃) process and two enhanced O₃ processes (O₃/peroxymonosulfate (O₃/PMS) and O₃/peroxymonosulfate/iron molybdates/biochar composite (O₃/PMS/FeMoBC)), especially the O₃/PMS/FeMoBC process, for the degradation of tetracycline (TC) in water. An FeMoBC sample was synthesized by the impregnation–pyrolysis method. The XRD results showed that the material loaded on BC was an iron molybdates composite, in which Fe₂Mo₃O₈ and FeMoO₄ accounted for 26.3% and 73.7% of the composite, respectively. The experiments showed that, for the O₃/PMS/FeMoBC process, the optimum conditions were obtained at pH 6.8 ± 0.1, an initial concentration of TC of 0.03 mM, an FeMoBC dosage set at 200 mg/L, a gaseous O₃ concentration set at 3.6 mg/L, and a PMS concentration set at 30 μM. Under these reaction conditions, the degradation rate of TC in 8 min and 14 min reached 94.3% and 98.6%, respectively, and the TC could be reduced below the detection limit (10 μg/L) after 20 min of reaction. After recycling for five times, the degradation rate of TC could still reach about 40%. The introduction of FeMoBC into the O₃/PMS system significantly improved the TC degradation efficacy and resistance to inorganic anion interference. Meanwhile, it enhanced the generation of hydroxyl radicals (^•OH) and sulfate radicals (SO₄^•−), thus improving the oxidizing efficiency of TC in water. Material characterization analysis showed that FeMoBC has a well-developed porous structure and abundant active sites, which is beneficial for the degradation of pollutants. The reaction mechanism of the O₃/PMS/FeMoBC system was speculated by the EPR technique and quenching experiments. The results showed that FeMoBC efficiently catalyzed the O₃/PMS process to generate a variety of reactive oxygen species, leading to the efficient degradation of TC. There are four active oxidants in O₃/PMS/FeMoBC system, namely ^•OH, SO₄^•−, ¹O₂, and •O₂⁻. The order of their contribution importance was ^•OH, ¹O₂, SO₄^•−, and •O₂⁻. This study provides an effective technological pathway for the removal of refractory organic matter in the aquatic environment. Full article

As human living standards have improved, the demand for industrial products—such as food, dyes, cosmetics, pharmaceuticals, and others—has significantly increased. This surge in production has, in turn, led to a rise in industrial wastewater (IW) generation, which is often marked by low biodegradability and a high concentration of toxic or refractory compounds. This review highlights the use of coagulation–flocculation–decantation (CFD) and advanced oxidation processes (AOPs) for treating such wastewater. A comprehensive analysis of CFD is provided, covering the underlying mechanisms, types of coagulants (including metal-based, animal-derived, mineral, and plant-based), and the optimal operational conditions required to maximize treatment efficiency. This review discusses the properties and performance of these coagulants in detail. In addition, this paper explores the methods used in AOPs to reduce organic carbon, focusing particularly on the roles of hydroxyl and sulfate radicals. Emphasis is placed on the enhancement of these processes using radiation, chelating agents, and heterogeneous catalysts, along with their effectiveness in IW treatment. Finally, the integration of CFD as a pre-treatment step to improve the efficiency of subsequent AOPs is provided. Full article