Synthesis of CdO nanopowders by a simple soft chemical method and evaluation of their antimicrobial activities

Application of green-synthesized cadmium oxide nanofibers and cadmium oxide/graphene nanosheet nanocomposites as alternative and efficient photocatalysts for methylene blue removal from aqueous matrix

For the first time, cadmium oxide (CdO) nanofibers (NFs) and graphene nanosheet (GNS)-doped CdO nanocomposites (NCs) have been synthesized by a simple green route using green tea (Camellia sinensis) extract, for subsequent application as photocatalysts for methylene blue (MB) removal from an aqueous matrix. In addition, the materials were tested as working electrodes for supercapacitors. The prepared samples were analyzed by FESEM, UV-Vis spectroscopy, FTIR, and X-ray diffraction (XRD). FESEM revealed that the obtained NPs and NCs show fiber-shaped nanostructure. FTIR confirmed the presence of biomolecules on CdO and carbon compounds on CdO/GNS, while XRD exhibited the cubic crystalline structure of obtained NPs and NCs. The Rietveld refinement using XRD data was performed to ascertain the crystallographic characteristics of the produced samples and look into lattice imperfections. UV-Vis spectroscopy evaluated the optical bandgap energies of CdO and CdO/GNS NCs. The CdO/GNS NCs demonstrated a fast cleavage of the dye molecule under UV irradiation, resulting in 97% removal in 120 min. In addition, CdO/GNS NCs showed remarkable chemical stability as an electrode material, with a high specific capacitance of 231 F g-1 at a scan rate of 25 mV s-1. These observed NCs characteristics are higher when compared to pristine CdO NPs. Finally, we found that the investigated NCs showed enhanced multifunctional properties, such as photocatalytic and supercapacitor characteristics, which can be useful in practical applications.

Hydrothermal Synthesis of Fe-Doped Cadmium Oxide Showed Bactericidal Behavior and Highly Efficient Visible Light Photocatalysis

Cationic dyes present in industrial effluents significantly reduce the effectiveness of remediation operations. Considering the terrible impact of these pollutants on environment and biodiversity, investigating strategies to remove potentially harmful compounds from water is becoming an increasingly intriguing issue. In this work, we employed a simple hydrothermal technique to synthesize Fe-doped CdO (2, 4, and 6 wt %) nanostructures and assessed their efficacy in degrading methylene blue (MB) dye and inhibiting the growth of Staphylococcus aureus and Escherichia coli, respectively. Structural, morphological, and optical characterization of produced nanomaterials was also performed using X-ray diffraction, TEM, and UV absorption spectra. The photocatalytic decomposition of MB was significantly enhanced (58.8%) by using Fe (6 wt %)-doped CdO catalysts for 80 min under irradiation. In addition, 2.05-5.05 mm inhibitory zones were seen against Gram-positive bacteria (S. aureus), whereas the range for Gram-negative bacteria (E. coli) was 1.65-2.75 mm. These nanostructures were shown to be very effective inhibitors of beta-lactamase, d-alanine-d-alanine ligase B, and fatty acid synthase inhibitor by in silico molecular docking investigations.

Identification of Nano-Metal Oxides That Can Be Synthesized by Precipitation-Calcination Method Reacting Their Chloride Solutions with NaOH Solution and Their Application for Carbon Dioxide Capture from Air-A Thermodynamic Analysis

Several metal oxide nanoparticles (NPs) were already obtained by mixing NaOH solution with chloride solution of the corresponding metal to form metal hydroxide or oxide precipitates and wash-dry-calcine the latter. However, the complete list of metal oxide NPs is missing with which this technology works well. The aim of this study was to fill this knowledge gap and to provide a full list of possible metals for which this technology probably works well. Our methodology was chemical thermodynamics, analyzing solubilities of metal chlorides, metal oxides and metal hydroxides in water and also standard molar Gibbs energy changes accompanying the following: (i) the reaction between metal chlorides and NaOH; (ii) the dissociation reaction of metal hydroxides into metal oxide and water vapor and (iii) the reaction between metal oxides and gaseous carbon dioxide to form metal carbonates. The major result of this paper is that the following metal-oxide NPs can be produced by the above technology from the corresponding metal chlorides: Al₂O₃, BeO, CaO, CdO, CoO, CuO, FeO, Fe₂O₃, In₂O₃, La₂O₃, MgO, MnO, Nd₂O₃, NiO, Pr₂O₃, Sb₂O₃, Sm₂O₃, SnO, Y₂O₃ and ZnO. From the analysis of the literature, the following nine nano-oxides have been already obtained experimentally with this technology: CaO, CdO, Co₃O₄, CuO, Fe₂O₃, NiO, MgO, SnO₂ and ZnO (note: Co₃O₄ and SnO₂ were obtained under oxidizing conditions during calcination in air). Thus, it is predicted here that the following nano-oxides can be potentially synthesized with this technology in the future: Al₂O₃, BeO, In₂O₃, La₂O₃, MnO, Nd₂O₃, Pr₂O₃, Sb₂O₃, Sm₂O₃ and Y₂O₃. The secondary result is that among the above 20 nano-oxides, the following five nano-oxides are able to capture carbon dioxide from air at least down to 42 ppm residual CO₂-content, i.e., decreasing the current level of 420 ppm of CO₂ in the Earth's atmosphere at least tenfold: CaO, MnO, MgO, CdO, CoO. The tertiary result is that by mixing the AuCl₃ solution with NaOH solution, Au nano-particles will precipitate without forming Au-oxide NPs. The results are significant for the synthesis of metal nano-oxide particles and for capturing carbon dioxide from air.

Fabrication of electrospun Mondia whitei/PVA nanofibres: application in the removal of acidic drugs

Novel electrospun Mondia whitei/PVA blend nanofibres were fabricated for potential water treatment applications by blending a natural polymer extracted from Mondia whitei (MW) roots with poly (vinyl alcohol) (PVA). The fabricated nanofibres were shown to have a smooth and uniform morphology with an average diameter of 99 ± 0.025 nm. The FTIR, XPS, XRD, and TGA characterisation results indicated changes in functional groups, crystallinity, and thermal stability of the Mondia whitei/PVA blend nanofibres, as compared to the original material. This finding confirmed that the polymers interacted through hydrogen bonding of MW and hydroxyl groups of PVA. The performance of the fabricated nanofibres was investigated for the removal of acidic drugs from spiked water samples. Factors (concentration of acidic drugs, dosage of the nanofibers and contact time) which affect the removal efficiency of the nanofibres were optimised using ultrapure water. Using the nanofibres, 100% removal efficiency for acidic drugs (aspirin, ketoprofen, fenoprofen, diclofenac, and ibuprofen) was achieved. The removal efficiency of the influent wastewater was 76, 89, 97, 93 and 94% for aspirin, ketoprofen, fenoprofen, diclofenac and ibuprofen, respectively, while the removal efficiency of the effluent was 86, 96, 97, 97 and 95% for aspirin, ketoprofen, fenoprofen, diclofenac and ibuprofen, respectively.

Biosynthesis and characterization of CdO nanostructure and its influence on cancer cells of (HT29)

Due to increased drug potency and lower toxicity in the nano-sized mediated drug delivery model, the environmentally sustainable synthesis of nanoparticles by the bio route from plant extracts has a wide variety of applications in novel science. In this report, our research groups have synthesized stable and cost-effective CdO nanostructure by the Curcuma plant. The biosynthesis of CdO nanostructure by the Curcuma plant extract was confirmed by different analytical methods such as UV-Visible Spectroscopy (UV-Vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffractometer (XRD), Atomic force microscopy AFM and Field emission scanning electron microscopy (FESEM), in addition to MTT assay screening of the synthesized CdO nanostructure for anticancer activity on (HT29). The result was that the biosynthesized CdO nanostructure exhibited strong anticancer cytotoxicity on (HT29). The findings of the MTT shows that at a concentration of 50.81 μ, 50 percent of the cancer cell line was destroyed by the extract.

Removal of Heavy Metal Ions Using Modified Celluloses Prepared from Pineapple Leaf Fiber

Since large amounts of pineapple leaves are abandoned after harvest in agricultural areas, the possibility of developing value-added products from them is of interest. In this work, cellulose fiber was extracted from pineapple leaves and modified with ethylenediaminetetraacetic acid (EDTA) and carboxymethyl (CM) groups to produce Cell-EDTA and Cell-CM, respectively, which were then used as heavy metal ion adsorbents. A solution of either lead ion (Pb²⁺) or cadmium ion (Cd²⁺) was used as wastewater for the purpose of studying adsorption efficiencies. The adsorption efficiencies of Cell-EDTA and Cell-CM were significantly higher than those of the unmodified cellulose in the pH range 1-7. Maximum adsorptions toward Pb²⁺ and Cd²⁺ were, for Cell-EDTA, 41.2 and 33.2 mg g^-1, respectively, and, for Cell-CM, 63.4 and 23.0 mg g^-1, respectively. The adsorption behaviors of Cell-CM for Pb²⁺ and Cd²⁺ fitted well with a pseudo-first-order model, but those of Cell-EDTA for Pb²⁺ and Cd²⁺ fitted well with a pseudo-second-order model. All of the adsorption behaviors could be described using the Langmuir adsorption isotherm. Desorption studies of Pb²⁺ and Cd²⁺ on both adsorbents using 1 M HCl suggested that regenerability of Cell-EDTA was, for both adsorbates, better than that of Cell-CM. Moreover, adsorption measurements in a mixture of Pb²⁺ and Cd²⁺ at various ratios showed that for both adsorbents the adsorption of Pb²⁺ was higher than that of Cd²⁺, while the adsorption selectivity for Pb²⁺ of Cell-CM was greater than that of Cell-EDTA. This study showed that the modified cellulosic adsorbents made from pineapple leaves were able to efficiently adsorb metal ions.