RESUMEN

The present study focuses on the elaboration of magnetic nanocomposites by the in situ incorporation of magnetite (Fe3O4) nanoparticles (NPs) with spherical and nanoflower-like morphologies in graphitic carbon nitride (g-C3N4) sheets using two different synthetic routes. Nanomaterials are characterized by TEM, SEM, XRD, FTIR, BET, zetametry, vibrating sample magnetometry, and UV-vis absorption spectroscopy. The decoration of the carbon nitride matrix with the magnetic NPs enhanced optical and textural properties. The influence of the morphology of the magnetic NPs on the adsorptive and photocatalytic properties of the nanocomposites under different pH conditions (4.5, 6.9, and 10.6) was assessed from batch tests to remove methylene blue (MB) from aqueous solutions. In extreme pH conditions, the nanocomposites exhibited lower or equivalent MB removal capacity compared to the pure g-C3N4. However, at neutral medium, the nanocomposite with incorporated Fe3O4 nanoflowers showed a significantly higher removal efficiency (80.7%) due to the combination of a high adsorption capacity and a good photocatalytic activity in this pH region. The proposed nanocomposite is a promising alternative to remove cationic dyes from water by magnetic assistance, since no pH adjustment of the polluted effluent is required, reducing costs and environmental impact in the dyeing industry.

Asunto(s)

Azul de Metileno , Nanocompuestos , Nitrilos , Contaminantes Químicos del Agua , Azul de Metileno/química , Nanocompuestos/química , Concentración de Iones de Hidrógeno , Contaminantes Químicos del Agua/química , Nitrilos/química , Adsorción , Purificación del Agua/métodos , Colorantes/química , Grafito/química , Compuestos de Nitrógeno

RESUMEN

BACKGROUND: This study aims to provide an academic medical overview of the framework and key outcomes of two mammography quality certification programs in Brazil. METHODS: These programs assess radiation dose and phantom image quality in mammography units through a postal system. Each unit that passes this initial assessment is required to submit a sample of copies of five complete examinations. The quality of the patient images and reports is then reviewed by radiologists and medical physicist experts. Additionally, the number of mammography units and mammography coverage in the target population, were assessed. RESULTS: During the study period, 1007 units applied to the certification programs, and 934 (92.8%) successfully passed the assessment of radiation dose and phantom image quality. Out of these, 556 (59.5%) also passed the review of clinical image quality and reports, earning certification. The main issues related to mammogram and report quality were associated with the performance of radiographers (in terms of positioning) and radiologists (in terms of interpretation). On average, there are more than two mammography units/10,000 women in the target group. The screening mammography coverage in this group is 26.3% for women relying exclusively on the public healthcare and 58.1% for women with private healthcare plans. CONCLUSION: This study demonstrates the suitability of the framework adopted by national mammography quality certification programs in a middle-income country. These programs are carried out by relatively small workforce and at reasonable costs, utilizing postal resources to cover the large number of existing mammographic units and the vast distances within the country. POLICY STATEMENT: All mammography services in Brazil must adhere to the quality requirements for examinations and reference values for radiation dose to women established by the Ministry of Health. This ensures standardized conditions for early detection of breast cancer and minimizes the risk associated with x-rays.

Asunto(s)

Neoplasias de la Mama , Mamografía , Femenino , Humanos , Brasil , Neoplasias de la Mama/diagnóstico , Detección Precoz del Cáncer , Mamografía/métodos , Recursos Humanos

RESUMEN

Nanotechnologies based on magnetic materials have been successfully used as efficient and reusable strategies to remove pharmaceutical residuals from water. This paper focuses on the fabrication, characterization, and application of ferrite-based magnetic nanoparticles functionalized with L-lysine as potential nanoadsorbents to remove acetylsalicylic acid (ASA) from water. The proposed nanomaterials are composed of highly magnetic and chemically stable core-shell nanoparticles covered with an adsorptive layer of L-lysine (CoFe2O4-γ-Fe2O3-Lys). The nanoadsorbents were elaborated using the coprecipitation method in an alkaline medium, leading to nanoparticles with two different mean sizes (13.5 nm and 8.5 nm). The samples were characterized by XRD, TEM, FTIR, XPS, Zetametry, BET, and SQUID magnetometry. The influence of time, pH, and pollutant concentration was evaluated from batch studies using 1.33 g/L of the nanoadsorbents. The Freundlich isotherm best adjusted the adsorption data. The adsorption process exhibited a pseudo-second-order kinetic behavior. The optimal pH for adsorption was around 4-6, with a maximum adsorption capacity of 16.4 mg/g after 150 min of contact time. Regeneration tests also showed that the proposed nanomaterials are reusable. The set of results proved that the nanoadsorbents can be potentially used to remove ASA from water and provide relevant information for their application in large-scale designs.

RESUMEN

The main goal of the present survey was to elaborate, characterize and evaluate the efficiency of ferrite-based nanoparticles modified with cetyltrimethylammonium bromide (CTAB) as potential magnetic nanoadsorbents to remove Remazol Brilliant Blue R (RBBR) from water. It is proposed an innovative nanomaterial architecture based on highly magnetic and chemically stable core@shell nanoparticles covered by an adsorptive surface layer of CTAB (CoFe2O4@γ-Fe2O3@CTAB). Samples of two different mean sizes (7.5 and 14.6 nm) were synthesized using a hydrothermal coprecipitation followed by surface treatment and functionalization. Batch tests were performed to evaluate the influence of contact time, temperature, pH, shaking rate, presence of interferents and mean size on the performance of the proposed nanomaterials. The kinetics of the adsorption process followed the pseudo-second-order model with an equilibrium time of 20 min. The adsorption capacity was estimated by the Langmuir isotherm model and was found to be 56.3 mg/g (smaller size) and 45.6 mg/g (larger size) at pH = 3 and a shaking rate of 400 rpm. The process was spontaneous, exothermic, and showed increased randomness. Sulphate ions negatively impacted the removal of RBBR. The best performance of the nanoadsorbent based on smaller mean sizes can be correlated to its larger surface area. Regeneration and readsorption tests showed that the nanoadsorbents retain more than 80% of their original removal capacity, therefore they can be effectively recycled and reused.