Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 78
Filtrar
Más filtros











Intervalo de año de publicación
1.
Turk J Chem ; 48(2): 364-375, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39050493

RESUMEN

A hyperbranched ion-imprinted polymer (IIP) material containing multiple selective adsorption sites was synthesized using halloysite nanotubes, methyl acrylate, and ethylenediamine in the presence of a template ion [i.e. Cd (II) heavy metal]. The successful preparation of the Cd-IIP composition was confirmed by FT-IR, XRD, TEM, TGA, and elemental analysis. The polymers exhibited good adsorption of Cd (II) with a maximum adsorption capacity of 64.37 mg·g-1. The imprinting factor (α) for Cd (II) was 2.62 and the selection factor (ß) was 1.78, indicating a specific adsorption of Cd (II) ion. The selection coefficients of Cd-IIP for Cd (II)/Pb (II), Cd (II)/Cu (II), Cd (II)/Ni (II), Cd (II)/Cr (III), and Cd (II)/Na (I) also indicated an excellent selectivity of the hyperbranched polymers for Cd (II) in the presence of competitive ions. The removal efficiency remained more than 75% after five cycles of desorption/adsorption. We envision that the HNTs based Cd-IIP has promising applications in the removal of Cd (II) from wastewater.

2.
Polymers (Basel) ; 16(12)2024 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-38932105

RESUMEN

The adsorption mechanism of superabsorbent polymer (SAP) can provide theoretical guidance for their practical applications in different environments. However, there has been limited research on the mechanism of attapulgite-sodium polyacrylate. This research aimed to compare the Cd(II) adsorption characteristics and water retention properties of organic-inorganic composite SAP (attapulgite-sodium polyacrylate, OSAP) and organic SAP (polyacrylamide, JSAP). Batch experiments were used to investigate the kinetics of Cd(II) adsorption, as well as the thermodynamic properties and factors influencing these properties. The results show that the Cd(II) adsorption capacity was directly proportional to the pH value. The maximum adsorption capacities of OSAP and JSAP were of 770 and 345 mg·g-1. The Cd(II) adsorption for OSAP and JSAP conformed to the Langmuir and the quasi-second-order kinetic model. This indicates that chemical adsorption is the primary mechanism. The adsorption process was endothermic (ΔH0 > 0) and spontaneous (ΔG0 < 0). The water adsorption ratios of OSAP and SAP were 474.8 and 152.6 in pure water. The ratio decreases with the increase in Cd(II) concentration. OSAP and JSAP retained 67.23% and 38.37% of the initial water adsorption after six iterations of water adsorption. Hence, OSAP is more suitable than JSAP for agricultural and environmental ecological restoration in arid and semi-arid regions.

3.
J Hazard Mater ; 476: 135035, 2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-38941838

RESUMEN

The hydrogen molecule can effectively regulate plant growth and development, improving plant resistance to abiotic stresses. However, studies regarding the optimal concentration of hydrogen and the associated mechanisms of action in organisms are lacking. This study showed that the maximum germination rate of radish seeds decreased from 90 % to 50 % under the stress of cadmium ions (Cd2+), and hydrogen nanobubble (NB) water significantly alleviated the stress effect of Cd2+ on radish seed germination. A hydrogen concentration of 0.8 ppm had the best effect, reducing Cd2+ accumulation in radish seeds by 63.23 % and increasing the maximum germination rate from 50 % to 65 %. At concentrations exceeding 1.2 ppm, the beneficial effect of hydrogen was weakened or even reversed. Consequently, we integrated the concept of the oxidative window into a REDOX balance model and demonstrated that an appropriate hydrogen concentration can effectively maintain the REDOX state within organisms. Transcriptome sequencing analysis revealed that hydrogen NB water modulated Cd2+ absorption and accumulation in seeds by regulating cell wall components, alleviating oxidative stress through oxidoreductase activity, and enhancing nutrient synthesis and metabolism. This collectively alleviated the inhibitory effect of Cd2+ on seed germination. This study is helpful for further understanding the effect of hydrogen concentration on the REDOX balance of seed germination, providing a theoretical basis for selecting hydrogen concentration to improve its effectiveness in agricultural fields.


Asunto(s)
Cadmio , Germinación , Hidrógeno , Oxidación-Reducción , Estrés Oxidativo , Raphanus , Semillas , Germinación/efectos de los fármacos , Hidrógeno/metabolismo , Semillas/efectos de los fármacos , Semillas/crecimiento & desarrollo , Semillas/metabolismo , Cadmio/toxicidad , Estrés Oxidativo/efectos de los fármacos , Raphanus/efectos de los fármacos , Raphanus/crecimiento & desarrollo , Raphanus/metabolismo
4.
Int J Phytoremediation ; 26(10): 1593-1610, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38623998

RESUMEN

Malachite green (MG) dye and cadmium metal ion are toxic pollutants that should be removed from aqueous environment. The recent study aimed to examine the adsorption behavior of MG dye and Cd (II) from wastewater onto low-cost adsorbent prepared by activating corn silk with nitric acid (ACS) and characterized by SEM, FTIR, XRD, BET and TGA. The optimum MG and Cd (II) adsorption was observed at pH 7 and pH 9 and maximum uptake of both pollutants was at 0.5 g dosage, 60 mins contact time and 20 mg/L initial concentration. The retention of dye and metal ion by the studied adsorbent was best fit to Langmuir isotherm and Pseudo-second order kinetics. The maximum monolayer coverage capacity of ACS for MG dye and Cd (II) ion was 18.38 mg/g and 25.53 mg/g, respectively. Thermodynamic studies predicted a spontaneous reaction with exothermic process for MG dye whereas an endothermic and spontaneous process was confirmed for Cd ion based on estimated parameters. The adsorption mechanism of MG dye and Cd (II) uptake was by combination of electrostatic interaction, pore diffusion, ion exchange, pie-pie attraction, hydrogen bonding, and complexation. The adsorbed pollutants were effectively desorbed with significant regeneration efficiency after successive five cycles that proved the potential of low-cost biosorbent for selective sequestration of cationic dye and divalent metal ion from effluents.


The use of nitric acid-modified corn silk has been reported to enhance its adsorption performance over the unmodified cob for pollutants such as cadmium ions and malachite green. Although there may be no recorded data on the adsorption efficiency of acid-treated corn silk for selected pollutants, it can be considered as a prospective bio-sorbent owing to its chemical composition and functional groups for exchange of hydrogen ions for other cations.


Asunto(s)
Cadmio , Colorantes de Rosanilina , Termodinámica , Aguas Residuales , Contaminantes Químicos del Agua , Zea mays , Cadmio/metabolismo , Contaminantes Químicos del Agua/metabolismo , Zea mays/metabolismo , Adsorción , Cinética , Aguas Residuales/química , Colorantes de Rosanilina/química , Biodegradación Ambiental , Eliminación de Residuos Líquidos/métodos , Colorantes/química
5.
Polymers (Basel) ; 16(5)2024 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-38475366

RESUMEN

For the first time, composites of metal-organic framework MOF-5 and conjugated polymer polyaniline (PANI), (MOF-5/PANI), prepared using PANI in its conducting (emeraldine salt, ES) or nonconducting form (emeraldine base, EB) at various MOF-5 and PANI mass ratios, were evaluated as electrode materials for the electrochemical detection of cadmium (Cd2+) and lead (Pb2+) ions in aqueous solutions. Testing of individual components of composites, PANI-ES, PANI-EB, and MOF-5, was also performed for comparison. Materials are characterized by Raman spectroscopy, scanning electron microscopy (SEM) and dynamic light scattering (DLS), and their electrochemical behavior was discussed in terms of their zeta potential, structural, morphology, and textural properties. All examined composites showed high electrocatalytic activity for the oxidation of Cd and Pb to Cd2+ and Pb2+, respectively. The MOF/EB-1 composite (71.0 wt.% MOF-5) gave the highest oxidation currents during both individual and simultaneous detection of two heavy metal ions. Current densities recorded with MOF/EB-1 were also higher than those of its individual components, reflecting the synergistic effect where MOF-5 offers high surface area for two heavy metals adsorption and PANI offers a network for electron transfer during metals' subsequent oxidation. Limits of detection using MOF/EB-1 electrode for Cd2+ and Pb2+ sensing were found to be as low as 0.077 ppm and 0.033 ppm, respectively. Moreover, the well-defined and intense peaks of Cd oxidation to Cd2+ and somewhat lower peaks of Pb oxidation to Pb2+ were observed at voltammograms obtained for the Danube River as a real sample with no pretreatment, which implies that herein tested MOF-5/PANI electrodes could be used as electrochemical sensors for the detection of heavy metal ions in the real water samples.

6.
Water Res ; 253: 121326, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38377928

RESUMEN

Cadmium (Cd) is a widespread and highly toxic environmental pollutant, seriously threatening animal and plant growth. Therefore, monitoring and employing robust tools to enrich and remove Cd from the environment is a major challenge. In this work, by conjugating a fluorescent indicator (CCP) with a functionalized glass slide, a special composite material (CCPB) was constructed to enrich, remove, and monitor Cd2+ in water rapidly. Then Cd2+ could be effectively eluted by immersing the Cd-enriched CCPB in an ethylenediaminetetraacetic acid (EDTA) solution. With this, the CCPB was continuously reused. Its recovery of Cd2+was above and below 100 % after multiple uses by flame atomic absorption spectrometry (FAAS), which was excellent for practical use in enriching and removing Cd2+ in real aqueous samples. Therefore, CCPB is an ideal material for monitoring, enriching, and removing Cd2+ in wastewater, providing a robust tool for future practical applications of Cd enrichment and removal in the environment.


Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Cadmio/análisis , Agua/química , Ácido Edético/química , Aguas Residuales , Contaminantes Ambientales/análisis , Contaminantes Químicos del Agua/análisis , Espectrofotometría Atómica/métodos , Adsorción
7.
Ultrason Sonochem ; 102: 106764, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38219549

RESUMEN

Replacing cadmium ions in cadmium-containing solutions with aluminum powder is beneficial for cadmium resource recycling and environmental protection. However, the conventional aluminum powder replacement method requires harsh temperatures and prolonged conditions. In this study, the effect and mechanism of ultrasound on the replacement of cadmium with aluminum powder were investigated at low temperatures. Ultrasound has been proven to promote the etching of alumina films through the use of TEM and XPS, providing mechanistic support for the superiority of the new process. A degree of Cd replacement as high as 95.08 % is achieved at a low temperature (60 ℃) and in a short time (20 min) when using ultrasonicated aluminum powder replacement, which is 42.17 % higher than that of conventional aluminum powder. Compared with conventional aluminum powder replacement conditions with the same effect, the introduction of ultrasound can reduce the temperature by 30℃ and shorten the replacement time by 2/3, which has significant advantages in reaction efficiency and safety. The strengthening mechanism of ultrasound on the replacement effect of aluminum powder at low temperatures is revealed through detailed discussions on the corrosion of alumina films, agglomeration of aluminum powder, and adhesion of replacement products to the surface of aluminum powder, dissolved oxygen in the solution, and redissolution of cadmium. Therefore, a new approach for replacing aluminum powder in solutions with high Cd2+ concentrations at low temperatures is proposed in this work, which is expected to solve the existing harsh and dangerous problems of industrial aluminum powder replacement.

8.
Food Chem ; 440: 138185, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38100966

RESUMEN

A sensitive electrochemical assay for simultaneously detecting cadmium ion (Cd2+) and mercury ion (Hg2+) with the aptamer as recognition unit was established, in which methylene blue (MB) and target-triggered in-situ generated Ag nanoclusters (Ag NCs) were identified as signal reporters. Multi-walled carbon nanotubes and gold nanoparticles composites were prepared with polyethyleneimine to amplify electrical signals of screen-printed electrodes. Due to the particular base sequences, MB labeled Cd2+ aptamer paired with ssDNA through T-Hg-T structure with Hg2+. Notably, the C-rich structure in ssDNA acted as a template for the generation of Ag NCs, which could induce differential pulse voltammetry signals corresponding to Hg2+ concentrations. This electrochemical aptasensor exhibited detection limits of 94.01 pg/mL and 15.74 pg/mL for Cd2+ and Hg2+, respectively. The developed aptasensor allowed for practical application to tea and vegetable samples with satisfactory accuracy. This work possesses potential in developing biosensing technologies for simultaneous determination of multiple heavy metals.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Mercurio , Nanopartículas del Metal , Nanotubos de Carbono , Oro/química , Cadmio , Nanotubos de Carbono/química , Azul de Metileno/química , ADN de Cadena Simple , Electrodos , Técnicas Electroquímicas , Aptámeros de Nucleótidos/química , Límite de Detección
9.
Polymers (Basel) ; 15(18)2023 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-37765646

RESUMEN

Given the predominantly negative impact of heavy metals on living organisms, the present study proposed to evaluate the adsorption performances under static conditions of Cd (II) from aqueous solutions on unmodified Sarkanda grass lignin compared to the adsorption performances of polysaccharide polymers chemically functionalized, obtained by synthesis and in their native state, but which, although effective, have a cost price that does not allow for large-scale expansion. To improve the retention of Cd (II) on this aromatic component of the biomass resulting from the processing of lignocellulosic materials, different experimental conditions (pH, concentration, dose and contact time) were followed. The Freundlich and Langmuir isotherms were used to describe the equilibrium conditions. Adsorption kinetics were assessed using the Lagergren I and Ho and McKay II kinetic models, furnishing informative insights into the process mechanism. Lignin adsorption capacity was also analyzed by performing biological tests on tomato seeds (Lypercosium esculentum), since heavy metals are known to be a stress factor for seeds by disturbing the osmotic equilibrium. Through the prism of the investigated parameters and under precisely established experimental conditions, unmodified Sarkanda grass lignin-an aromatic biopolymer-can be recommended as a promising adsorbent for the retention of Cd (II) from aqueous solutions, successfully replacing polysaccharide, especially cellulose-based polymers.

10.
Int J Biol Macromol ; 250: 126252, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37562480

RESUMEN

Recently, carboxymethyl chitosan (CMCS) has proved to be an intrinsically fluorescent material with aggregation-induced emission characteristic. In order to elucidate the influence of CMCS's chemical structure and solution behavior on its fluorescent intensity, two series of CMCS with different degrees of carboxymethylation (DCM) are synthesized by adjusting the mass ratio of monochloroacetic acid and sodium hydroxide to chitosan at various reaction temperature and time, and then characterized using Fourier-transform infrared spectroscopy and nuclear magnetic resonance. Their solution behaviors at different pH values are studied via zeta potential and ultraviolet-visible measurements. The data reveal that the isoelectronic point (IEP) of a CMCS decreases with increasing DCM, and all the CMCSs have good water solubility at pH range below their IEPs. Fluorescence spectra indicate that a CMCS shows the highest fluorescent intensity in a slightly acidic environment next to its IEP, and the photoluminescence of a CMCS solution increases significantly after heat treatment above T = 70 °C. Furthermore, we compare for the first time the use of heated CMCS solutions for the fluorescence turn-on detection of cadmium ion in pure and tap water, respectively. The limit of detection is found to be ca. 1 µM for the Cd2+ in pure water.

11.
Ecotoxicol Environ Saf ; 263: 115378, 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37598544

RESUMEN

A detailed understanding the metals binding with algal organic matter (AOM) is essential to gain a deeper insight into the toxicity and migration of metals in algae cell. However, the molecular complexation mechanism of the metals binding with AOM remains unclear. In this study, cadmium ion (Cd2+) binding properties of AOMs from Scenedesmus obliquus, which included extracellular organic matter (EOM) and intracellular organic matter (IOM), were screened. When Cd2+ < 0.5 mg/L, the accumulation of Cd2+ could reach 40%, while Cd2+ > 0.5 mg/L, the accumulation of Cd2+ was only about 10%. EOM decreased gradually (from 8.51 to 3.98 mg/L), while IOM increased gradually (from 9.62 to 21.00 mg/L). The spectral characteristics revealed that IOM was richer in peptides/proteins and had more hydrophilic than EOM. Both EOM and IOM contained three protein-like components (containing tryptophan and tyrosine) and one humic-like component, and their contents in IOM were higher than that in EOM. The tryptophan protein-like substances changed greatly during Cd2+ binding, and that the tryptophan protein-like substances complexed to Cd2+ before tyrosine protein-like substances in IOM was identified. Moreover, the functional groups of N-H, O-H, and CO in AOM played an important role, and the N-H group was priority to interacts with Cd2+ in the complexing process. More functional groups (such as C-O and C-N) were involved in the metals complexing in EOM than in IOM. It could be concluded that Cd2+ stress promoted the secretion of AOM in Scenedesmus obliquus, and proteins in AOM could complex Cd2+ and alleviate its toxicity to algal cell. These findings provided deep insights into the interaction mechanism of AOM with Cd2+ in aquatic environments.


Asunto(s)
Chlorophyceae , Scenedesmus , Cadmio/toxicidad , Triptófano , Tirosina
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 303: 123178, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37499473

RESUMEN

Abiotic stress and oxidative stress are closely related to the health status of plants. Plants will produce oxidative stress under abiotic stress, induce mitochondrial dysfunction, cause programmed cell death, and decrease plant survival rate. It is well known that rice is an essential crop for humans, but its cadmium tolerance is poor. Therefore, it is crucial to determine whether cadmium stress causes oxidative stress in rice in order to guide rice cultivation. Hydrogen peroxide (H2O2), a highly reactive oxygen species (ROS), is one of the most critical signals in corps under oxidative stress. In this work, we adopted a near-infrared (NIR) H2O2 fluorescent probe YFE-1 and a cadmium ion (Cd2+) fluorescent probe SCP to observe the fluctuation of H2O2 in rice roots under Cd2+ co-incubation conditions. Due to the advantages of fast response (within 2 min), a large Stokes shift (181 nm), good selectivity, and a low detection limit (LOD:26.4 nM), YFE-1 achieved the visualization of H2O2 produced by Cd2+ stress in rice roots. This study provides a new idea for assessing the risk of oxidative stress of Cd2+ in rice roots. It is expected to guide the control of Cd2+ in the rice planting industry to improve rice yield.


Asunto(s)
Cadmio , Oryza , Humanos , Cadmio/metabolismo , Peróxido de Hidrógeno/metabolismo , Oryza/metabolismo , Colorantes Fluorescentes/metabolismo , Fluorescencia , Estrés Oxidativo , Antioxidantes/metabolismo , Plantas/metabolismo , Raíces de Plantas/metabolismo
13.
J Agric Food Chem ; 71(29): 11195-11203, 2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37439107

RESUMEN

The detection of heavy metals in food is beneficial to public health. Herein, a new time-resolved fluorescent immunosensor based on the Förster resonance energy transfer (FRET) was proposed to rapidly detect a cadmium ion (Cd2+). After coupling with an antigen and a monoclonal antibody (mAb), respectively, the synthesized europium (III)-chelate-doped polystyrene time-resolved fluorescence microsphere-antigen (Eu-antigen) and gold nanoflowers-mAb (GNFs-mAb) interacted by antigen-antibody combination to quench fluorescence through FRET. Under optimal conditions, the Eu-GNF immunosensing platform provided a quick response to Cd2+ within 30 min. The limit of detection was 0.29 ng/mL with a linear range of 1-500 ng/mL. This immunosensor was further validated via graphite furnace atomic absorption spectrometry and exhibited satisfactory recovery for the detection of Cd2+ in four kinds of tea samples (98.82-108.01%). Thus, this strategy provides a good paradigm for the rapid and high-throughput detection of heavy metals in field testing.


Asunto(s)
Técnicas Biosensibles , Grafito , Nanopartículas del Metal , Transferencia Resonante de Energía de Fluorescencia/métodos , Cadmio , Técnicas Biosensibles/métodos , Inmunoensayo/métodos , Europio/química , Oro/química , Anticuerpos Monoclonales , Límite de Detección , Nanopartículas del Metal/química
14.
J Hazard Mater ; 457: 131748, 2023 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-37267647

RESUMEN

Cadmium (Cd), a widespread and highly toxic environmental contaminant, has seriously impacted the growth of rice and the quality of its products. Hence, it is crucial to monitor and employ robust means to reduce Cd levels in rice, and selenium (Se) has been proven to chelate cadmium ion (Cd2+) in rice with rational use. Herein, for the first time, the reported selenocysteine (Sec) probe NN-Sec and the newly designed Cd2+ probe SCP were chosen as visualization tools to monitor Sec-inhibited Cd2+ uptake in rice. Specifically, reduced fluorescence of rice precultured with Cd2+ was observed by SCP after Se application, while similarly decreased fluorescence of rice pretreated with Se was observed by NN-Sec after Cd2+ addition. The diminished fluorescence indicated the formation of Cd-Se complexes reduced the Cd2+ content in rice. Additionally, it was Cd2+ and Se that entered the rice causing the fluorescence generation, as demonstrated by inductively coupled plasma mass spectrometry (ICP-MS). To conclude, the two probes successfully visualized Se inhibited Cd2+ uptake in rice, which could provide a robust tool for supporting the development of novel organic fertilizers and reagents to reduce Cd2+ content in rice and the environment.


Asunto(s)
Oryza , Selenio , Contaminantes del Suelo , Selenio/química , Cadmio/toxicidad , Cadmio/análisis , Oryza/química , Colorantes Fluorescentes , Contaminantes del Suelo/análisis
15.
Anal Chim Acta ; 1266: 341363, 2023 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-37244660

RESUMEN

Cd2+ is one of the most toxic heavy metal ions that can be easily accumulated in human body via food chain. Thus, the onsite detection of Cd2+ in food is very important. However, present methods for Cd2+ detection either require the use of large equipment, or suffer from the severe interference from other analogical metal ions. This work establishes a facile Cd2+ mediated turn-on ECL method for highly selective detection of Cd2+ via cation exchanging with the nontoxic ZnS nanoparticles, owing to the unique surface-state ECL properties of CdS nanomaterials. The linear range of the calibration curve is from 7.0 × 10-8 to 1.0 × 10-6 M, while other analogical metal ions do not interfere, facilitating the selective detection of Cd2+ in oyster samples. The result agrees well with that obtained using atomic emission spectroscopy, indicating the potential for wider application of this approach.


Asunto(s)
Cadmio , Nanopartículas , Humanos , Luminiscencia , Nanopartículas/química , Sulfuros/química , Iones
16.
Anal Bioanal Chem ; 415(12): 2281-2289, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36952025

RESUMEN

Cadmium ion (Cd(II)) is a pernicious environmental pollutant that has been shown to contaminate agricultural lands, accumulate through the food chain, and seriously threaten human health. At present, Cd(II) monitoring is dependent on centralized instruments, necessitating the development of rapid and on-site detection platforms. Against this backdrop, the present study reports on the development of a fluorometric aptasensor designed to target Cd(II), which is achieved through the integration of strand displacement amplification (SDA) and CRISPR/Cas12a. In the absence of Cd(II), the aptamer initiates SDA, resulting in the generation of a profusion of ssDNA that activates Cas12a, leading to a substantial increase in fluorescence output. Conversely, the presence of Cd(II) curtails the SDA efficiency, culminating in a significant reduction in fluorescence output. The proposed approach has been demonstrated to enable the selective detection of Cd(II) at concentrations of 60 pM, with the performance of the aptasensor validated in real water and rice samples. The proposed platform based on aptamer-target interaction holds immense promise as a signal-amplified and precise method for the detection of Cd(II) and has the potential to transform current hazard detection practices in food samples.


Asunto(s)
Técnicas Biosensibles , Contaminantes Ambientales , Humanos , Sistemas CRISPR-Cas , Cadmio , Agricultura , ADN de Cadena Simple , Oligonucleótidos
17.
Heliyon ; 9(3): e14503, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36967911

RESUMEN

In this study, waste biomass adsorbents produced from mangosteen shells (MGS) were prepared (denoted as MGS500 and MGS1000). The physical and chemical characteristics, such as scanning electron microscopy, thermogravimetric-differential thermal analysis, specific surface area, pore volumes, surface functional groups, and point of zero charge of the prepared MGS samples were determined, and the adsorption capacity of cadmium ions from aqueous media was assessed. The effects of pH, adsorption time, temperature, and coexistence on adsorption were carefully assessed using an inductively coupled plasma optical emission spectrometer under several experimental conditions. The adsorption capacity decreased in the order, MGS < MGS500 < MGS1000. The optimal pH for cadmium ion removal was 5.0. The amount of cadmium ions adsorbed gradually increased with time, and adsorption equilibrium was achieved within 24 h after adsorption. Additionally, the amount of adsorbed cadmium ions increased with increasing adsorption temperature. To elucidate the adsorption mechanism in detail, the elemental distribution and X-ray photoelectron spectra of the prepared adsorbents were analyzed. Finally, desorption solutions such as HNO3, H2O, and NaOH were used to desorb the absorbed cadmium ions from MGS1000. Under our experimental conditions, the desorption percentage of cadmium ions was approximately 98.8% using HNO3. In conclusion, MGS1000 exhibited a good adsorption capacity of 12.0 mg/g for adsorbing cadmium ions from aqueous media and desorption capacity with HNO3 at 1000 mmol/L.

18.
Sci Total Environ ; 865: 161313, 2023 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-36596423

RESUMEN

Cadmium pigments are a group of inorganic pigments used in consumer products. The aggregation behavior and photo-dissolution process of cadmium pigment nanoparticles in aquatic systems control their environmental fate, which is largely unknown. Herein, we investigated the influence of dissolved organic matter (DOM) on the aggregation behavior and photo-dissolution process of CdS nanoparticles in aquatic systems. Bare CdS nanoparticles are prone to aggregation in both NaCl and CaCl2 solutions. DOM can remarkably increase the colloidal stability of CdS nanoparticles owing to the steric hindrance and enhanced electrostatic repulsion. With 10 mg/L Suwannee River natural organic matter (SRNOM), the colloidal stability of CdS nanoparticles is significantly enhanced in NaCl solutions (i.e., the critical coagulation concentration, CCCNa, is 707.2 mM). Suwannee River humic acid (SRHA) has a stronger stabilization effect than SRNOM due to its higher molecular weight and aromaticity. The Ca2+ cations can induce charge neutralization and structural compacting of DOM corona, efficiently reducing the colloidal stability of CdS nanoparticles. The CCCCa is 10.8 mM and 14.9 mM with 10 mg/L SRNOM and SRHA, respectively. Upon solar irradiation, the presence of a low concentration of SRNOM (3 mg/L) can enhance the photo-dissolution of CdS nanoparticles and the consequent Cd2+ leaching. This is caused by the facilitated electron transfer from CdS nanoparticles to O2 induced by SRNOM corona, leading to better electron-hole separation. However, a high concentration of SRNOM inhibited the photo-dissolution of CdS nanoparticles due to the strong inner filter effect and the scavenging of phototransients. The colloidal stability of SRNOM-coated CdS nanoparticles increases in NaCl but decreases in CaCl2 solutions after irradiation owing to the oxidation of SRNOM corona. Our results highlight the decisive role of DOM in the environmental fate of cadmium pigments.

19.
Food Chem ; 402: 134285, 2023 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-36162169

RESUMEN

Scallop is well known for its high accumulation of cadmium. The bioaccessibility and speciation of cadmium in different tissues of scallops during gastrointestinal digestion could influence the evaluation of its biological effects and consumption safety in humans. The bioaccessibility of total Cd ranged from 44.0 % (kidney) to 90.2 % (gonad) for different tissues of scallop Chlamys farreri. Steaming decreased the total Cd bioaccessibility in the mantle, gill, gonad, digestive gland and the muscle. During in vitro digestion, the reactive inorganic Cd2+ could be detected in the digestive juice of five tissues except for the muscle. Steaming process increased the bioaccessible Cd2+ content for the digestive gland, gill and gonad tissues. Based on the bioaccessible total Cd and Cd2+ content, the muscle, gonad, and mantle of the steamed scallops are the safe tissues for human consumption according to the scenarios of Cd intake established by WHO and EFSA.


Asunto(s)
Cadmio , Pectinidae , Animales , Humanos , Alimentos Marinos , Branquias , Digestión
20.
Front Chem ; 10: 1005231, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36247679

RESUMEN

Cadmium (Cd2+) and mercury ions (Hg2+) are essential for the quality control of food samples because of their serious toxicity to human health, but the effective and simple strategy for their parallel detection remains challenging. In this paper, a rapid and simple parallel detection method for Cd2+ and Hg2+ was developed using carbon dots (CDs) as fluorescent sensors. A one-step hydrothermal method with a single precursor l-arginine as both the carbon and nitrogen sources was employed to prepare nitrogen-doped CDs (N-CDs). N-CDs exhibited a uniform particle size and excitation-independent fluorescence emission. The maximum emission wavelength of N-CDs was observed at 354 nm with the excitation wavelength at 295 nm. The quantum yield of N-CDs reached as high as 71.6% in water. By using sodium diphosphate and phytic acid as masking agents, the fluorescent sensor can be quenched by Cd2+ and Hg2+ in the linear range of 0-26.8 µM and 0-49.9 µM within 5 min. Other common ions in farm products showed no significant effect on the fluorescence intensity of the sensing system. The results demonstrated that the sensing system had good selectivity and sensitivity for Cd2+ and Hg2+. The detection limits for Cd2+ and Hg2+ were 0.20 and 0.188 µM, respectively. In addition, the fluorescent sensor had been successfully applied for the detection of Cd2+ and Hg2+ in fruits and vegetables, and the recoveries were 86.44-109.40% and 86.62-115.32%, respectively. The proposed fluorescent sensor provides a rapid, simple, and sensitive detection method for Cd2+ and Hg2+ in food samples and thus a novel quantitative detection method for heavy metal ions in foods.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA