Search Results (441)

Artemisia frigida Willd. (A. frigida), a traditional medicinal herb widely distributed in northern China, Mongolia, and Siberia, has garnered increasing scientific interest due to its diverse phytochemical profile and extensive pharmacological potential. Modern studies have identified a wide range of bioactive compounds in A. frigida, including flavonoids, sesquiterpene lactones and phenolic acids. These compounds exhibit various biological activities, such as antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. This review systematically summarizes the research progress on the chemical constituents of A. frigida and their extraction and separation methods, including solvent extraction, ultrasonic-assisted extraction, macroporous resin adsorption, and chromatography-based techniques. By integrating traditional knowledge with modern pharmacological evidence, this review provides a scientific foundation for the further development and utilization of A. frigida in functional food, pharmaceuticals, and ethnomedicine. Full article

Nano-silica is widely used to enhance gel properties, but its size, concentrations, and aggregation behaviors all matter. The influencing rules of these factors remain unclear especially in harsh reservoir conditions. This study presented a comprehensive investigation into the gelation, rheological, and plugging properties of phenolic polymer gels reinforced by modified nano-silica (GSNP) of different sizes and concentrations in harsh reservoir conditions. Specifically, the nano-silica was modified with a highly soluble silane, and gel properties were evaluated through rheological, differential scanning calorimetry (DSC), and sandpack flooding tests. The results showed that the incorporation of GSNP prolonged the gelation time, enhanced gel strength, and improved stability, allowing the gelation solution to enter deeper into the formation while maintaining long-time effectiveness. The optimal gel system was obtained with 0.4 wt.% GSNP-30, under which condition the storage modulus increased by approximately 14 times, and the content of non-freezable bound water more than doubled. This system exhibited plugging efficiency exceeding 80% in formations with permeabilities ranging from 1000 to 6000 millidarcy and enhanced the oil recovery factor by over 25%. The reinforcement mechanisms were attributed to the adsorption of GSNP onto polymer chains and its role in filling the gel matrix, which enhanced polymer hydrophilicity, suppressed polymer aggregation/curling, prevented ion penetration, and promoted the formation of a more uniform gel network. Careful optimization of nanoparticle size and concentration was essential to avoid the detrimental effects due to nanoparticle overfilling and aggregation. The novelty of this study lies in the practicable formulation of thermal and salt-tolerant gel systems with facile modified nano-silica of varying sizes and the systematic study of size and concentration effects. These findings offer practical guidance for tailoring nanoparticle parameters to cater for high-temperature and high-salinity reservoir conditions. Full article

Medicinal and Aromatic Plant (MAP) by-products constitute a vast reservoir of bioactive metabolites with antioxidant and antimicrobial properties, offering potential for the development of high added value natural products. This study focuses on the by-product (tepals) remaining during the process of receiving the stigma of Crocus sativus L. Iridaceae (saffron), which is the commercially exploitable part of the flowers. The tepals are the main part of the flowers (>95%) and are still discarded in the fields during the collection of the stigmas in Kozani, Greece. According to numerous findings, the saffron tepals are rich in flavonoids with notable biological properties, and our aim was to investigate an alternative for their management. Within this context, dry and frozen tepals were extracted at a laboratory scale through microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE), followed by adsorption resin technology (ART) for the preparation of enriched extracts. Furthermore, their HPTLC profiling, the phenolic (TPC) and flavonoid (TFC) content, and the free-radical-scavenging (DPPH) and anti-tyrosinase activity were evaluated. The frozen tepals were further extracted at a pilot scale using MAE and maceration (Mc) techniques, followed by ART treatment to remove the contained sugars. The enriched extract produced at a pilot scale using MAE and ART sequentially is characterized by a high phenolic (147.2 mg GAE/g dry extract) and flavonoid (114.8 mg QUE/g dry extract) load. These findings demonstrate that saffron tepals, traditionally considered waste, can serve as a valuable raw material for producing extracts rich in phenolic derivatives, particularly flavonoids and anthocyanins. Full article

With the increasing severity of cadmium (Cd) contamination in soil and its persistent toxicity, developing efficient remediation methods has become a critical necessity. In this study, sodium borohydride (NaBH₄) and tea polyphenols (TP) were employed as reducing agents to synthesize biochar (BC)-supported nanoscale zero-valent iron (nZVI), denoted as BH₄-nZVI/BC and TP-nZVI/BC, respectively. The effects of dosage, pH, and reaction time on Cd immobilization efficiency were systematically investigated. Both composites effectively stabilized Cd, significantly reducing its mobility and toxicity. Toxicity Characteristic Leaching Procedure (TCLP) results showed that Cd leaching concentrations decreased to 8.23 mg/L for BH₄-nZVI/BC and 4.65 mg/L for TP-nZVI/BC, corresponding to performance improvements of 29.9% and 60.5%. The immobilization process was attributed to the reduction of Cd(II) into less toxic species, together with adsorption and complexation with oxygen-containing groups (-OH, -COOH, phenolic) on biochar. TP-nZVI/BC exhibited superior long-term stability, while maintaining slightly lower efficiency than BH₄-nZVI/BC under certain conditions. Microbial community analysis revealed minimal ecological disturbance, and TP-nZVI/BC even promoted microbial diversity recovery. Mechanistic analyses further indicated that tea polyphenols formed a protective layer on nZVI, which inhibited particle agglomeration and oxidation, reduced the formation of iron oxides, preserved Fe⁰ activity, and enhanced microbial compatibility. In addition, the hydroxyl and phenolic groups of tea polyphenols contributed directly to Cd(II) complexation, reinforcing long-term immobilization. Therefore, TP-nZVI/BC is demonstrated to be an efficient, sustainable, and environmentally friendly amendment for Cd-contaminated soil remediation, combining effective immobilization with advantages in stability, ecological compatibility, and long-term effectiveness. Full article

Phenol and its derivatives in water and wastewater are highly toxic and challenging to degrade, posing serious environmental and health risks. Therefore, this research focuses on the removal of phenol from aqueous solutions using activated carbon made from Catha edulis stems. The activation process involved impregnating the Catha edulis stems with phosphoric acid followed by thermal treatment at 500 °C for 2 h. The resulting adsorbent was extensively characterized using various techniques, including Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area analysis, and proximate analysis. Batch adsorption experiments were designed using a full factorial approach with four factors at two levels, resulting in 16 different experimental conditions. The characterization results showed that the activated carbon has a high surface area of 1323 m²/g, a porous and heterogeneous structure, and an amorphous surface with multiple functional groups. Under optimal conditions of pH 2, a contact time of 60 min, an adsorbent dosage of 0.1 g/100 mL, and an initial phenol concentration of 100 mg/L, the adsorbent achieved a phenol removal efficiency of 99.9%. Isotherm and kinetics analyses revealed that phenol adsorption fits the Langmuir model and pseudo-second-order kinetics, indicating a uniform interaction and chemisorptive process. This study highlights the effectiveness of Catha edulis stem-based activated carbon as a promising material for phenol removal in water treatment applications. Full article

Organic and pharmaceutical pollution of water is a serious problem, particularly when it comes to drinking and groundwater. Although some evaluations indicate that these pollutants are unlikely to be at current exposure levels, they are often detected in aquatic systems and can be harmful to human health. Organic contaminants include hazardous micropollutants, aromatic phenols, pesticides, etc. Pharmaceutical contaminants are sulfamethoxazole, diclofenac, doxycycline, amoxicillin, trimethoprim, ciprofloxacin, norfloxacin, lipid regulators, nonsteroidal anti-inflammatory drugs (NSAIDs), hormones, antidepressants, etc. Hydrogel adsorbents’ distinct structural, chemical, and environmentally benign qualities make them a potential and successful option for environmental remediation, especially in wastewater treatment. In the search for clean water resources, they are an important instrument because of their reusability and capacity to be customized for certain contaminants, such as organic and pharmaceutical pollutants. This review focusses on the present state, adsorption sites and surfaces, different adsorption mechanisms, and the prospects and scope of improvement of effective hydrogels for eliminating dangerous aqueous organic and pharmaceutical contaminants. It offers a thorough summary of the area, highlighting its facets and potential paths forward. Full article

Formo-phenolic-like resins were synthesized by replacing phenol with phloroglucinol, a biobased and biocompatible compound, and using different aldehydes, such as biomass-derived furaldehyde and glyoxal. Studies on the adsorption of rare earth elements from an aqueous organic acid solution indicate that these resins follow the Langmuir isotherm model, with maximum adsorption capacities ranging from 0.38 to 0.75 mmol/g. Adsorption was temperature-independent but strongly influenced by pH, with an up to fourfold increase between pH 2 and 5. Extraction kinetics were rapid, reaching equilibrium within two hours. Complete metal recovery was achieved within ten minutes using a 1 mol/L HCl desorption solution. Selectivity also varied with pH; glyoxal- and furfural-based resins showed superior separation performance at pH 2–3 and 3–4, respectively. The application of this method to real-world samples, including permanent magnet and red mud organic acid leachates, demonstrated effective extraction of rare earth elements and promising selectivity over iron (Fe), cobalt (Co), and nickel (Ni). Full article

This study investigated the effectiveness of palygorskite (Pal) as an adsorbent for removing total phenolic content (TPC), dissolved chemical oxygen demand (d-COD), and color from treated olive wastewater (TOW). Experiments were conducted to evaluate the impact of varying Pal dosages (2.5–20 g/L), initial TPC concentrations (80–400 mg/L), and pH (2–9). The results showed that increasing the Pal dosage improved the removal efficiency of TPC and d-COD, though there were diminishing returns beyond 10 g L⁻¹, which indicates equilibrium adsorption behavior. The maximum TPC and d-COD removal reached 68% and 55%, respectively, while color removal exceeded 95% regardless of dosage. Adsorption was most efficient at lower TPC concentrations and an acidic pH (2–3), with up to 85% TPC removal. This suggests that pH-dependent phenolic ionization enhances Pal adsorption. Color removal remained consistently high across all conditions, highlighting palygorskite’s mesoporosity and affinity for chromophoric compounds. These findings affirm the potential of Pal as a cost-effective and versatile adsorbent for TOW treatment. Full article

The removal of high-concentration m-cresol from industrial wastewater remains a significant challenge due to its toxicity and persistence. In this study, a commercially available functionalized resin with a high BET surface area (1439 m² g⁻¹) and hierarchical pore structure was employed for the adsorption of pure m-cresol at an initial concentration of 20 g L⁻¹, representative of coal-based industrial effluents. Comprehensive characterization confirmed the presence of oxygen-rich functional groups, amorphous polymeric structure, and uniform surface morphology conducive to adsorption. Batch experiments were conducted to evaluate the effects of resin dosage, contact time, temperature, and equilibrium concentration. Under optimized conditions (0.15 g resin, 60 °C), a maximum adsorption capacity of 556.3 mg g⁻¹ and removal efficiency of 71% were achieved. Kinetic analysis revealed that the pseudo-second-order model best described the adsorption process (R² > 0.99). Isotherm data fit the Langmuir model most closely (R² = 0.9953), yielding a monolayer capacity of 833.3 mg g⁻¹. Thermodynamic analysis showed that adsorption was spontaneous (ΔG° < 0), endothermic (ΔH° = 7.553 kJ mol⁻¹), and accompanied by increased entropy (ΔS° = 29.90 J mol⁻¹ K⁻¹). The good agreement with the PSO model is indicative of chemisorption, as supported by other lines of evidence, including thermodynamic parameters (e.g., positive ΔH° and ΔS°), surface functional group characteristics, and molecular interactions. The adsorption mechanism was elucidated through comprehensive modeling of adsorption kinetics, isotherms, and thermodynamics, combined with detailed physicochemical characterization of the resin prior to adsorption, reinforcing the mechanistic understanding of m-cresol–resin interactions. Full article

Construction and demolition byproducts include substantial amounts of wood panel waste (WPW) that pose environmental challenges. They also create opportunities for sustainable resource recovery. This study investigates the potential of WPW-derived biochar as an efficient adsorbent for phenol removal from aqueous solutions. Biochar was produced via pyrolysis at 450 °C and subsequent activation at 750, 850, and 950 °C. The biochar’s physicochemical properties, including surface area, pore volume, and elemental composition, were characterized using advanced methods, including BET analysis, elemental analysis, and adsorption isotherm analysis. Activated biochar demonstrated up to nine times higher adsorption capacity than raw biochar, with a maximum of 171.9 mg/g at 950 °C under optimal conditions: pH of 6 at 25 °C, initial phenol concentration of 200 mg/L, and biochar dosage of 1 g/L of solution for 48 h. Kinetic and isotherm studies revealed that phenol adsorption followed a pseudo-second-order model and fit the Langmuir isotherm, indicating chemisorption and monolayer adsorption mechanisms. Leaching tests confirmed the biochar’s environmental safety, with heavy metal concentrations well below regulatory limits. Based on these findings, WPW biochar offers a promising, eco-friendly solution for wastewater treatment in line with circular economy and green chemistry principles. Full article

Due to its lightweight and superior adsorption properties, carbon foam is frequently employed for the removal of heavy metal pollutants from aqueous solutions. In this study, a novel modified carbon foam (M-CF) was successfully synthesized for the effective removal of Pb²⁺ and Cd²⁺ from water. The synthesis involved partially substituting phenol with the liquefaction product of bamboo powder, followed by modification with a silane coupling agent (KH560) and foaming with n-hexane-loaded activated carbon (H/AC). The prepared carbon foam was comprehensively characterized, and its adsorption performance and mechanism for Pb²⁺ and Cd²⁺ in aqueous solution were investigated. The results showed that M-CF possessed a uniform and well-developed spherical pore structure and demonstrated excellent removal capacity for Cd²⁺ and Pb²⁺. The adsorption process conformed to the Sips isotherm model and the pseudo-second-order kinetic equation, with maximum adsorption capacities of 22.15 mg·g⁻¹ and 61.59 mg·g⁻¹ for Cd²⁺ and Pb²⁺, respectively. Mechanistic analysis revealed that the removal of Cd²⁺ and Pb²⁺ was a result of the synergistic effect of physisorption and chemisorption, accompanied by complexation. Furthermore, precipitates formed during the adsorption process were found to be mainly composed of hydroxides, carbonates, and PbS. This research demonstrates the efficacy of carbon foam prepared from bamboo powder waste as a partial phenol substitute for the efficient removal of Pb²⁺ and Cd²⁺ from water, thus expanding the preparation pathways for novel heavy metal adsorption materials. Full article

Reducing the application of chemical fertilizers and remediating heavy metal pollution in soil are important directions in current agricultural research. Utilizing the plant-growth-promoting and remediation capabilities of bacteria can provide more environmentally friendly assistance to agricultural production. In this study, the Burkholderia alba YIM B08401 strain was isolated and identified from rhizospheric soil, subjected to whole-genome sequencing and analysis, and its Cd²⁺ adsorption efficiency and characteristics were confirmed using multiple experimental methods, including atomic absorption spectrometry (AAS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). The results showed that the genome of strain YIM B08401 has a total length of 7,322,157 bp, a GC content of 66.39%, and predicts 6504 protein-coding sequences. It contains abundant functional genes related to nutrient conversion (phosphate solubilization, sulfur metabolism, zinc solubilization, siderophore production), plant hormone regulation (indole-3-acetic acid secretion, ACC deaminase production), phenolic acid degradation, root colonization, heavy metal tolerance, pathogen antagonism, and the production of antagonistic secondary metabolites. Additionally, strain YIM B08401 can specifically bind to Cd²⁺ through various functional groups on the cell surface, such as C-O-C, P=O, and O-H, enabling biosorption. In conclusion, strain YIM B08401 is an excellent strain with plant-growth-promoting, disease-resistant, and bioremediation capabilities, warranting further development as a biofertilizer for agricultural applications to promote green and sustainable agricultural development. Full article

Nejayote (Nej), an effluent from nixtamalization process, has an alkaline pH and contains a high load of organic matter in suspension and dissolution, which makes it a highly polluting waste when discharged directly into the environment. However, the sustainable reuse of this effluent is relevant since it contains high-value compounds (ferulic acid (FA)) with appropriate activity for the ecological synthesis of silver nanoparticles (AgNPs). This study explores the synthesis of AgNPs using Nej as a reducing and stabilizing agent and evaluates the antibacterial effectiveness of AgNPs against Escherichia coli (E. coli). The AgNPs under study possess excellent optical (UV-Vis) and structural properties (XRD). HR-TEM images show predominantly spherical particles, with an average size of 20 nm. FTIR spectroscopy identified functional groups, including phenols and flavonoids, on the nanoparticle surface, acting as stabilizing agents. HPLC supports the existence of FA in the AgNPs. Biogenic AgNPs exhibit enhanced antibacterial activity due to the adsorption of these functional groups onto their surface, which contributes to bacterial membrane disruption. Finally, no hemolytic or cytotoxic activity was observed, suggesting that the AgNPs exert antimicrobial activity without potentially harmful doses (biocompatibility). The study highlights the potential of Nej as a sustainable source for use in nanoparticle synthesis, promoting the recycling of agro-industrial waste and the production of materials with technological applications. Full article

Antibiotic resistance has been recognized as a global threat to human health. Therefore, it is urgent to develop effective strategies to address the contamination of water environments caused by antibiotics. In this study, Fe/Mn bimetallic-modified biochar (FMBC) was synthesized through a one-pot oxidation/reduction-hydrothermal co-precipitation method, demonstrating an exceptional photocatalytic-Fenton degradation performance for oxytetracycline (OTC). Characterization techniques including FTIR, SEM, XRD, VSM, and N₂ adsorption–desorption analysis confirmed that the Fe/Mn bimetals were successfully loaded onto the surface of biochar in the form of Fe₃O₄ and MnFe₂O₄ mixed crystals and exhibited favorable paramagnetic properties that facilitate magnetic recovery. A key innovation is the utilization of biochar’s inherent phenol/quinone structures as reactive sites and electron transfer mediators, which synergistically interact with the loaded bimetallic oxides to significantly enhance the generation of highly reactive ·OH radicals, thereby boosting catalytic activity. Even after five recycling cycles, the material exhibited minimal changes in degradation efficiency and bimetallic crystal structure, indicating its notable stability and reusability. The photocatalytic degradation experiment conducted in a Fenton-like reaction system demonstrates that, under the conditions of pH 4.0, a H₂O₂ concentration of 5.16 mmol/L, a catalyst dosage of 0.20 g/L, and an OTC concentration of 100 mg/L, the optimal degradation efficiency of 98.3% can be achieved. Additionally, the pseudo-first-order kinetic rate constant was determined to be 4.88 min⁻¹. Furthermore, this study elucidated the detailed degradation mechanisms, pathways, and the influence of various ions, providing valuable theoretical insights and technical support for the degradation of antibiotics in real wastewater. Full article

This study evaluated the odor mitigation potential of rice husk biochar in a simulated dairy bedded pack over 21 days. Biochar was incorporated into a dairy manure–sawdust mixture at 5% and 10% dry weight. Emissions of key odorous compounds—ammonia (NH₃), sulfur compounds, volatile fatty acids, phenol, p-cresol, and indole—were evaluated. Odor units were assessed to determine perceived odor reduction. Biochar significantly reduced NH₃ and dimethyl sulfide (DMS) emissions: NH₃ by 27% and 43%, and DMS by 53% and 75%, at 5% and 10% application, respectively. The NH₃ reduction was attributed to ammoniacal nitrogen adsorption, while the DMS reduction likely resulted from enhanced air permeability suppressing anaerobic bacterial activity. The 5% biochar treatment, achieving 63% and 70% of the NH₃ and DMS reductions attained by the 10% treatment, respectively, offers a more practical and cost-effective option. Other odorous compounds were not significantly affected. A temporary reduction in odor units was observed on day 7. Rice husk biochar contains 14.5% atomic Si, primarily as silica, which supports structural stability but hinders pore development, reducing adsorption efficiency. These findings demonstrate the importance of biochar’s physicochemical properties in odor mitigation. Future research should evaluate long-term field performance, microbial interactions, and silica modification strategies. Full article