RESUMO
Nanotechnology offers a great opportunity for efficient removal of pollutants and pathogenic microorganisms in water. Copper nanoparticles were synthesized using a polysaccharide bioflocculant and its flocculation, removal efficiency, and antimicrobial properties were evaluated. The synthesized nanoparticles were characterized using thermogravimetry, UV-Visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction, scanning electron microscope (SEM), and transmission electron microscope (TEM). The highest flocculation activity (FA) was achieved with the lowest concentration of copper nanoparticles (0.2 mg/mL) with 96% (FA) and the least flocculation activity was 80% at 1 mg/mL. The copper nanoparticles (CuNPs) work well without the addition of the cation as the flocculation activity was 96% and worked best at weak acidic, neutral, and alkaline pH with the optimal FA of 96% at pH 7. Furthermore, the nanoparticles were found to be thermostable with 91% FA at 100 °C. The synthesized copper nanoparticles are also high in removal efficiency of staining dyes, such as safranin (92%), carbol fuchsine (94%), malachite green (97%), and methylene blue (85%). The high removal efficiency of nutrients such as phosphate and total nitrogen in both domestic wastewater and Mzingazi river water was observed. In comparison to ciprofloxacin, CuNPs revealed some remarkable properties as they are able to kill both the Gram-positive and Gram-negative microorganisms.
Assuntos
Cobre/química , Floculação , Nanopartículas Metálicas/química , Águas Residuárias/química , Purificação da Água/métodos , Antibacterianos/química , Corantes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Microbiologia da ÁguaRESUMO
Cysteine and triethanolamine capped CdTe nanoparticles have been synthesized using a simple aqueous solution based method. This method involves the reaction of tellurium powder with sodium borohydride (NaBH(4)) in water to produce telluride ions (Te(2-)), followed by the simultaneous addition of an aqueous solution of cadmium chloride or other cadmium source (acetate, carbonate and nitrate) and solution of L-cysteine ethyl ester hydrochloride or triethanolamine. The effect of capping agent on the size, structure and morphology of the as-synthesized nanoparticles was investigated. The particles were characterized using optical spectroscopy, transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy.
Assuntos
Compostos de Cádmio/síntese química , Cisteína/síntese química , Etanolaminas/síntese química , Ácido Ascórbico/química , Boroidretos , Cádmio/química , Indicadores e Reagentes , Luminescência , Microscopia Eletrônica de Transmissão , Nanopartículas , Tamanho da Partícula , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Telúrio , Difração de Raios XRESUMO
Cadmium selenide (CdSe) quantum dots have gained increased attention for their potential use in biomedical applications. This has raised interest in assessing their toxicity. In this study, water-soluble, cysteine-capped CdSe nanocrystals with an average size of 15 nm were prepared through a one-pot solution-based method. The CdSe nanoparticles were synthesized in batches in which the concentration of the capping agent was varied with the aim of stabilizing the quantum dot core. The effects of the CdSe quantum dots on DNA stability, aggregation of blood platelets, and reducing activity of iron were evaluated in vitro . DNA damage was observed at a concentration of 200 µg/mL of CdSe quantum dots. Furthermore, the CdSe nanocrystals exhibited high reducing power and chelating activity, suggesting that they may impair the function of haemoglobin by interacting with iron. In addition, the CdSe quantum dots promoted aggregation of blood platelets in a dose dependent manner.
Assuntos
Plaquetas/efeitos dos fármacos , Compostos de Cádmio/toxicidade , DNA/química , Quelantes de Ferro/toxicidade , Ferro/química , Sondas Moleculares/toxicidade , Pontos Quânticos , Compostos de Selênio/toxicidade , Plaquetas/fisiologia , Compostos de Cádmio/síntese química , Cisteína/química , Dano ao DNA , Relação Dose-Resposta a Droga , Humanos , Ferro/metabolismo , Quelantes de Ferro/síntese química , Microscopia Eletrônica de Transmissão , Sondas Moleculares/síntese química , Desnaturação de Ácido Nucleico , Oxirredução , Tamanho da Partícula , Agregação Plaquetária/efeitos dos fármacos , Compostos de Selênio/síntese química , ÁguaRESUMO
A simple method for the preparation of tri-n-octylphosphine oxide (TOPO) and hexadecylamine (HDA) capped CdTe particles have been employed in this study. The method involves the reduction of tellurium in water followed by the addition of the cadmium salt and thermolysis in TOPO and HDA. The influence of the reduction time (2, 4 and 6 h) of tellurium on the optical properties was investigated. The particles were characterised by electron microscopy and X-ray diffraction techniques.
