TiO2 Photocatalysis for the Transformation of Aromatic Water Pollutants into Fuels

The growing world energy consumption, with reliance on conventional energy sources and the associated environmental pollution, are considered the most serious threats faced by man-kind. Heterogeneous photocatalysis has become one of the most frequently investigated technolo-gies, due to its dual functionality, i.e., environmental remediation and converting solar energy into chemical energy, especially molecular hydrogen. H2 burns cleanly and has the highest gravimetric gross calorific value among all fuels. However, the use of a suitable electron donor, in what so-called “photocatalytic reforming”, is required to achieve acceptable efficiency. This oxidation half-reaction can be exploited to oxidize the dissolved organic pollutants, thus, simultaneously improving the water quality. Such pollutants would replace other potentially costly electron donors, achieving the dual-functionality purpose. Since the aromatic compounds are widely spread in the environment, they are considered attractive targets to apply this technology. In this review, different aspects are highlighted, including the employing of different polymorphs of pristine titanium dioxide as pho-tocatalysts in the photocatalytic processes, also improving the photocatalytic activity of TiO2 by loading different types of metal co-catalysts, especially platinum nanoparticles, and comparing the effect of various loading methods of such metal co-catalysts. Finally, the photocatalytic reforming of aromatic compounds employing TiO2-based semiconductors is presented

TiO2 Photocatalysis for the Transformation of Aromatic Water Pollutants into Fuels

The growing world energy consumption, with reliance on conventional energy sources and the associated environmental pollution, are considered the most serious threats faced by mankind. Heterogeneous photocatalysis has become one of the most frequently investigated technologies, due to its dual functionality, i.e., environmental remediation and converting solar energy into chemical energy, especially molecular hydrogen. H2 burns cleanly and has the highest gravimetric gross calorific value among all fuels. However, the use of a suitable electron donor, in what so-called “photocatalytic reforming”, is required to achieve acceptable efficiency. This oxidation half-reaction can be exploited to oxidize the dissolved organic pollutants, thus, simultaneously improving the water quality. Such pollutants would replace other potentially costly electron donors, achieving the dual-functionality purpose. Since the aromatic compounds are widely spread in the environment, they are considered attractive targets to apply this technology. In this review, different aspects are highlighted, including the employing of different polymorphs of pristine titanium dioxide as photocatalysts in the photocatalytic processes, also improving the photocatalytic activity of TiO2 by loading different types of metal co-catalysts, especially platinum nanoparticles, and comparing the effect of various loading methods of such metal co-catalysts. Finally, the photocatalytic reforming of aromatic compounds employing TiO2-based semiconductors is presented

The Application of Mediated Biosynthesized Green Silver Nanoparticles by Streptomyces griseorubens in Water Treatment

In the present study, a soil actinomycete was isolated from near the river Nile shoreline, Egypt. The identification of this isolate as Streptomyces griseorubens was performed using 16s rDNA. The sequence has been deposited in the Gene Bank with the accession number LC066679. Factors affecting the biogenesis of AgNPs were optimized by applying the Plackett-Burman factorial design. The maximum silver nanoparticles (AgNPs) biosynthesis (2.76 OD at 400 nm) was achieved in the trial No.9 that contained the following ingredients (g/L): Starch (20); MgSO4 (0.05); K‚ HPO4 (1.0); NaNO3 (2.0); AgNO3 (1.0) mmol/l; PH (7); incubated at temperature 30°C for 72 hr. The biosynthesized nanoparticles were characterized using spectroscopic techniques. AgNPs showed the characteristic UV spectra at a wavelength range 300 - 600 nm and a characteristic absorption peak was recorded at the wavelength of 400 nm. For AgNPs with absorbance height ofH≈2.56 a.u. and peak width at half maximum absorbance (PWHM) H≈120 nm which remained constant over a long period of time indicating its stability. FTIR spectra showed the functional group of the biomaterials capping the AgNPs. EDX confirmed the formation of the metallic silver nanoparticles, indicating the presence of proteinaceous cabbing. TEM micrograph showed spherical AgNPs in shape with an average diameter of 22 nm. The biosynthesized AgNPs showed high stability up-to two weeks. The conjugate (AgNPs/cellulosic fiber (C)) of Luffa aeygptiaca and (AgNPs/activated carbon (AC)) was applied for drinking water treatment, which resulted in fecal Coliform bacteria removal with a success of 99.9% as a water treatment application

Phenotypic and genotypic characterization of Escherichia albertii in chicken and human.

Background:  Escherichia albertii (E. albertii) is a newly identified enteropathogen that affects humans and birds. It is a Gram-negative bacterium frequently mistaken for E. coli. Objective: To isolate E. albertii from chicken feces, products, and patients with diarrhea to assess its role in gastroenteritis and inflammatory bowel disease (IBD), also to assess antimicrobial susceptibility of this pathogen, and to identify it genetically by PCR. Methodology: 225 random samples from Assiut Governorate were tested, representing (100) chicken feces, (50) chicken products and (75) human feces from patients with gastroenteritis and IBD. The fecal samples were cultured on Hektoen enteric agar and xylose lysine deoxycholate plates. Biochemical identification of E-albertii was done by sulfur-indole motility (SIM), Simmonsʼ citrate, urease test, triple-sugar iron (TSI), lysine iron and indole test. Genotypic detection of E. albertii was done by PCR for eae and mdh genes. The isolates were tested for antimicrobial susceptibility. Results: The prevalence of E. albertii was 21.7% by culture, 18.6 % by biochemical tests and 12.8 % by PCR. Escherichia. albertii was identified by PCR in 20% of chicken feces and 9% of human feces. No E. albertii was identified in chicken products. Out of 29 isolates, 65.5 %, 51.7% were resistant to tetracycline, nalidixic acid, respectively, while lower resistance rates were observed to other antibiotics. Conclusion:  Escherichia albertii could be isolated from chicken and human feces, but not from chicken products. High resistance rate was observed for tetracycline, and nalidixic acid. Escherichia. albertii culture should be interpreted carefully and confirmed by PCR

Highly efficient photocatalysis by BiFeO3/α(γ)-Fe2O3 ferromagnetic nano p/n junctions formed by dopant-induced phase separation

International audienc

Highly efficient photocatalysis by BiFeO3/α(γ)-Fe2O3 ferromagnetic nano p/n junctions formed by dopant-induced phase separation

International audienc

Iron-based photocatalytic and photoelectrocatalytic nano-structures: Facts, perspectives, and expectations

The increasing demand for clean renewable energy needed for sustainable industrial progress and population growth is the driving force for the scientific community to achieve a continuous development in the field of photocatalysis and photoelectrochemistry. Nanostructures and nanomaterials have contributed significantly to the field of renewable energy due to their new physicochemical properties. Iron-based nanostructures have considerable advantages like small band gaps, allowing to harvest photons in the visible region of the solar spectrum, abundance, and important physical properties like magnetism and ferroelectricity. But they also have many shortcomings and drawbacks related to stability in the different photocatalytic media, low surface area, conductivity, and fast charge carrier recombination. In this review, the focus is placed on important members of the iron-based photocatalyst family such as, hematite, iron oxy-hydroxide, iron-based perovskites, and spinel ferrites. Also, iron doped titanium dioxide as visible light photocatalysts is covered. Various strategies employed for enhancing the photocatalytic and photoelectrocatalytic performance are discussed. Doping, oxygen vacancies, induced defects and formation of solid solutions seem to be a working strategy to address some of the challenges in photocatalysis and photoelectrocatalysis. Finally, photocatalytic and photoelectrocatalytic applications employing iron-based semiconductors are presented.Fil: AlSalka, Yamen. Leibniz Universitat Hannover.; AlemaniaFil: Granone, Luis Ignacio. Leibniz Universitat Hannover.; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Ramadan, Wegdan. Leibniz Universitat Hannover.; Alemania. Alexandria University; EgiptoFil: Hakki, Amer. University of Aberdeen; Reino UnidoFil: Dillert, Ralf. Leibniz Universitat Hannover.; AlemaniaFil: Bahnemann, Detlef W.. Leibniz Universitat Hannover.; Alemania. Saint Petersburg State University; Rusi

Radiation attenuation properties of chemically prepared MgO nanoparticles/HDPE composites

Abstract Sheets of high-density polyethylene (HDPE) loaded with magnesium oxide in micro and nano were synthesized with different weight percentages of micro-MgO (0,5,10,20 and 30% by weight) and nano-MgO (5 and 30%) and shaped in form of disc and dog bone shape. The morphological, mechanical, and attenuation characteristics of each concentration were determined. The linear attenuation coefficients (LAC) of the prepared discs were calculated using a well-calibrated scintillation detector and five standard gamma-ray point sources (241Am, 133Ba, 137Cs, 60Co and 152Eu). The LAC was theoretically calculated for HDPE/micro-MgO composites using XCOM software. A good agreement between the theoretical and experimental results was observed. The comparison between micro and nano-MgO as a filler in HDPE was evaluated. The results proved that the loaded nano-MgO in different proportions of HDPE produced greater attenuation coefficients than its micro counterpart. The addition of nano MgO with different weight percentage led to a significant improvement in the mechanical properties of HDPE, the ultimate force and ultimate stress increased as the concentration of nano MgO increased, and the young modulus of HDPE also increased with increasing concentration of micro and nano MgO