In this study, ZnO-TiO2 nanoparticles were synthesized from three different precursors for ZnO (zinc acetate di-hydrate, zinc nitrate hexahydrate and zinc sulfate heptahydrate) and titanium (IV) isopropoxide for TiO2. The prepared nanomaterials were calcined at 500 °C for 3 h and characterized by various physicochemical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy, combined with energy dispersive X-ray spectroscopy (TEM-EDS). The obtained results showed that the crystalline structure, size and morphology of the ZnO-TiO2 nanoparticles are strongly influenced by the nature of the precursor of ZnO, as well as the ZnO/TiO2 weight ratio. The antibacterial and antifungal activities of the synthesized nanomaterials were evaluated, in the dark, against five multi-resistant of Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella Paratyphi A) bacteria and a fungus (Candida albicans), which are pathogenic for humans. The obtained results showed that pure TiO2 anatase is inactive against the tested strains, while the addition of ZnO to TiO2 improves noticeably the effectiveness of TiO2 nanoparticles, depending on the nature of the precursor of ZnO and the ZnO/TiO2 weight ratio.
The results of 2-chloroaniline (2-CA) immobilization experiments in cement matrices, using an organophilic clay modified with phenolic resins as pre-sorbent, are shown. The 2-CA suspended in water was kept in contact with the organoclay for 24 h, and the slurry obtained was then admixed with ordinary Portland cement (OPC) without additional water, to obtain a firm solid waste. Six cement—clay pastes were prepared with the same water-to-cement ratio (0.50 wt/wt), but with different slurry composition (water-to-organ...
Semiconductor components are made primarily from surface-doped substrates of silicon, gallium arsenide, mercury-cadmium telluride, and other highly refractive metalloid materials. Special lenses and mirrors usually have a specific coating to impart some required optical property (anti-glare, UV-blocking, colorcorrection,
etc).
Polymer films used in packaging and manufacturing are often made to certain thickness specifications. These films can either be pure, single-component plastics, copolymers, or multi-layer...
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Koch Membrane Systems` Henia and Jorge Yacubowicz outline the uses and benefits of nanofiltration.
Modern crossflow filtration technology has principally evolved during the last thirty years, following the significant advancements in polymer chemistry over the same time. Today, a vast majority of crossflow filtration installations utilise polymeric membranes. Virtually all commercial nanofiltration membranes are polymeric.
Nanofiltration (NF) is a crossflow, pressure driven...
Membrane distillation (MD) is a relatively novel membrane technology considered by the researchers as a potential method for seawater desalination. In the first issue of this journal, the possibility of nuclear desalination by MD was discussed comparing various MD configurations. The present paper firstly reviews the membranes used in MD and the methods of their characterisation, among them wet/dry flow method, gas permeation test, scanning electron microscopy, field emission scanning electron microscopy and...
Progress in environmental management relies on innovation. Whether it's novel applications of new technologies, pioneering public policies, or groundbreaking partnerships – innovation leads to advances. Looking toward tomorrow's advances, the theme of A&WMA's 98th Annual Conference & Exhibition is “Exploring Innovative Solutions.” The conference will take place June 21-24, 2005, at the Minneapolis Convention Center in Minneapolis, MN.
As a thriving, dynamic, and increasingly diverse metropolitan area,...
The increasing production of several plastics such as expanded polystyrene, widely used as packaging and building materials, has caused the release of considerable amounts of pentane employed as an expanding agent. Today many microorganisms are used to degrade hydrocarbons in order to minimize contamination caused by several industrial activities. The aim of our work was to identify a suitable microorganism to degrade pentane. We focused our attention on a strain of Arthrobacter sp. which in a shake-flask culture...
The decomposition stage and stabilization of organic matter in biowaste (mixture of yard waste and kitchen waste), originating from an open windrow process, were investigated using Fourier transform infrared (FT-IR) spectroscopy and pyrolysis-field ionization mass spectrometry (Py-FIMS). These investigations provided detailed information about chemical constituents and their behavior during the composting process. The chemical compounds were classified by their molecular signals in Py-FIMS. Multivariate statistical...
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Field studies have
shown that many organic contaminants degrade naturally by microorganisms present
in soil and groundwater. This naturally occurring bioremediation, known as natural
attenuation, has been accepted as a passive remediation process for contaminated
soil and groundwater. When the natural degradation is insufficient to meet remediation
goals protective of human health and the environment, there may be attempts
to increase the degradation rate by...
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Many investigators have been dealing with mold issues the last few years and may have been overlooking bacteria as the underlying microbial problem. Bacteria typically outnumber fungi in the indoor air and may also account for foul odor problems. Bacterial contamination of HVAC systems has also been linked to hypersensitivity pneumonitis in building occupants.
Bacteria are different than all other life forms on earth because they are singlecelled, prokaryotic organisms. "Prokaryo...
There are still a wide range of concerns about air quality in the vicinity of Ground Zero. Many commercial and residential spaces have yet to be re-occupied. In only a few cases has any sort of inspection or testing been done to determine if they are safe to occupy. The greatest concerns are asbestos and the very irritating concrete dust that spread throughout lower Manhattan during the collapse and the days following.
In Lower Manhattan buildings, whether occupied or not, the potential for problems is not over...
Abstract
The paper presents the results obtained for zinc recovery from residual solution resulting from dimetridazol (1,2 dimethyl 5-nitro glyoxaline) fabrication (a drug for animal use) and its reuse in the process. The authors propose a flow-sheet for zinc recovery with efficiency higher than 99% like a complex compound which can be reintroduced in the process with good results. The mother liquor resulted after zinc separation contains 28-30% sodium nitrate and can be used in the treatment of wheat, potatoes...
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