Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Environ Sci Pollut Res Int ; 31(22): 32614-32636, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38656718

RESUMEN

The water treatment depends exclusively on the identification of residues containing toxic chemical elements accumulated in NPs (nanoparticles), and ultrafine particles sourced from waste piles located at old, abandoned sulfuric acid factories containing phosphogypsum requires global attention. The general objective of this study is to quantify and analyze the hazardous chemical elements present in the leachate of waste from deactivated sulfuric acid factories, coupled in NPs and ultrafine particles, in the port region of the city of Imbituba, Santa Catarina, Brazil. Samples were collected in 2020, 2021, and 2022. Corresponding images from the Sentinel-3B OLCI satellite, taken in the same general vicinity, detected the levels of absorption coefficient of Detritus and Gelbstoff (ADG443_NN) in 443 m-1, chlorophyll-a (CHL_NN (m-3)), and total suspended matter (TSM_NN (g m-3) at 72 points on the marine coast of the port region. The results of inductively coupled plasma atomic-emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) demonstrate that the leaching occurring in waste piles at the port area of Imbituba was the likely source of hazardous chemical elements (e.g., Mg, Sr, Nd, and Pr) in the environment. These leachates were formed due to the presence of coal pyrite and Fe-acid sulfates in said waste piles. The mobility of hazardous chemical elements potentiates changes in the marine ecosystem, in relation to ADG443_NN (m-1), CHL_NN (m-3), and TSM NN (g m-3), with values greater than 20 g m-3 found in 2021 and 2022. This indicated changes in the natural conditions of the marine ecosystem up to 30 km from the coast in the Atlantic Ocean, justifying public initiatives for water treatment on a global scale.


Asunto(s)
Monitoreo del Ambiente , Contaminantes Químicos del Agua , Calidad del Agua , Monitoreo del Ambiente/métodos , Brasil , Contaminantes Químicos del Agua/análisis
2.
Artículo en Inglés | MEDLINE | ID: mdl-38526663

RESUMEN

Natural drugs derived from plants are becoming more popular because of their apparent biological efficacy, affordability, and safety. A byproduct of cocoa farms, cocoa pod husk (CPH), is often disregarded yet contains an abundance of phenolic chemicals that have antimicrobial and antioxidant features, which has led to intensive investigation into possible biomedical applications. In order to identify crucial functional groups and phytochemical components, we carefully examined the 80% ethanol and dichloromethane extracts of CPH using gas chromatography-mass spectrometry (GC-MS) and HPLC. The antibacterial and antioxidant properties of such extracts and their impact on cytotoxicity and α-glucosidase were explored. According to our results, the 80% ethanol and dichloromethane extracts contained 19 and 12 phytochemical components, respectively. Interestingly, at 250 µg/mL, all CPH extracts showed strong antibacterial properties that totally prevented the bacterial growth. At 66.6% and 82.7%, respectively, the ethanol and dichloromethane extracts showed impressive antioxidant and DPPH scavenging capabilities where the ethanol extract showed a substantially lower IC50 value of 35.26 µg/mL than the dichloromethane extract, which had an IC50 value of 23.88 µg/mL. Furthermore, the α-glucosidase inhibitory effect of the dichloromethane extract was found to be better, as shown by its IC50 value of 126.5 µg/mL, which was lower than that of the ethanol extract at 151.3 µg/mL. The extracts' compatibility was verified by cytotoxicity tests, which revealed no appreciable alterations in the cell lines. Additionally, novel in silico molecular docking experiments were performed on 25 discovered compounds, providing insight into their possible bioactivity. Broad-spectrum activities of extracts were confirmed by molecular docking investigations aimed at interacting with α-glucosidase proteins. Our thorough analysis makes CPH extracts seem like the excellent candidates for biomedical uses. These results provide new insights into the therapeutic potential of CPH extracts and pave the way for the development of innovative medications and natural remedies.

3.
Environ Sci Pollut Res Int ; 31(7): 10417-10429, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38200192

RESUMEN

There is a growing need to develop new strategies for rare earth element (REE) recovery from secondary resources. Herein, a novel approach to utilize biogenic silica (from rice husk) and metakaolin was employed to fabricate magnetic geopolymer (MGP) by incorporating metallic iron. The fabricated MGP adsorbent material was used to uptake Ce3+, La3+, and Nd3+ from synthetic solutions and real phosphogypsum leachate in batch and column modes. The MGP offers a negatively charged surface at pH above 2.7, and the uptake of REEs rises from pH 3 to 6. The kinetic study validated that the kinetics was much faster for Nd3+, followed by La3+ and Ce3+. A thermodynamic investigation validated the exothermic nature of the adsorption process for all selected REEs. The desorption experiment using 2 mol L-1 H2SO4 as the eluent demonstrated approximately 100% desorption of REEs from the adsorbent. After six adsorption-desorption cycles, the MGP maintained a high adsorption performance up to cycle five before suffering a significant decrease in performance in cycle six. The effectiveness of MGP was also assessed for its applicability in recovering numerous REEs (La3+, Ce3+, Pr3+, Sm3+, and Nd3+) from real leachate from phosphogypsum wastes, and the highest recovery was achieved for Nd3+ (95.03%) followed by Ce3+ (86.33%). The operation was also feasible in the column presenting suitable values of the length of the mass transfer zone. The findings of this investigation indicate that MGP adsorbent prepared via a simple route has the potential for the recovery of REEs from synthetic and real samples in both batch and continuous operations modes.


Asunto(s)
Sulfato de Calcio , Metales de Tierras Raras , Oryza , Fósforo , Adsorción , Fenómenos Magnéticos
4.
Carbohydr Polym ; 114: 65-72, 2014 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-25263865

RESUMEN

Photocatalytic degradation of 2-chlorophenol (2-CP) was studied using the photocatalyst chitosane/CoFe2O4 nanocomposite (CS/CF) under visible light. CS/CF nanocomposites were synthesized via gamma irradiation cross-linking method with the aid of sonication. Physical characteristics of CS/CF were studied using infrared spectrophotometer (IR), scanning electron microscopy (SEM), transmission electron microscope (TEM) and ultraviolet-visible (UV-vis) spectroscopy. Their photocatalytic activity was tested for the degradation of 2-CP in aqueous medium using sunlight. The effect of different parameters such as catalyst concentration, 2-CP concentration and reaction pH on degradation was also examined. It was verified that the 2-CP degradation rate fits a pseudo-first-order kinetics for initial 2-CP concentrations between 25 and 100mg/l, at 30°C. The degradation kinetics fit well Langmuir-Hinshelwood rate law. The degradation of (2-CP) follows pseudo-first-order kinetics. Results showed that after the catalyst had been used 5 times repeatedly, the degradation rate was still above 80%.


Asunto(s)
Quitosano/química , Cobalto/química , Compuestos Férricos/química , Rayos gamma , Nanocompuestos/química , Aguas Residuales/química , Adsorción , Catálisis/efectos de la radiación , Quitosano/metabolismo , Quitosano/efectos de la radiación , Cobalto/metabolismo , Cobalto/efectos de la radiación , Compuestos Férricos/metabolismo , Compuestos Férricos/efectos de la radiación , Fotólisis/efectos de la radiación
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...