Health and Safety Concerns: Quantitative Studies of Leaching of Metals from Glazed Surfaces of Traditional Ceramic Potteries

Traditional ceramic wares have been known as a source of heavy metals poisoning. Traditional ceramic potteries may be improperly glazed, and the glaze used to make the pottery may contain over amounts of heavy metals. These over glazed ceramic wares can release deadly metal into foodstuff and constitute health hazards. In this work, Quantitative studies were done according to ASTM C 738.81 (1982) leaching standard test methods for the determination of trace amount of selected metals from glazed surfaces of traditional ceramic potteries by 4% acetic and 2% citric acid standard solutions at different temperatures. Finally, leaching potential has been done using ICP-MS analysis. The capacity of each ceramic tableware sample ranged between 250 and 350ml. The ceramic wares selected randomly from products available in the local markets at Doha (Qatar), Cairo (Egypt) and Gharyan (Libya)

Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16) to longer chain n-alkanes (n-C21–n-C25) and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time.This work was supported by the College of Arts and Sciences and Department of Biological and Environmental Sciences of Qatar University [QUUG-CAS-DEM-12/13-6; QUST-CAS-FALL-12/13-23; and QUST-CAS-FALL-12/13-22]

CoNi Nanoparticles/CNT Composite as Effective Anode for Direct Urea Fuel Cells

CoNi nanoparticles/CNTs composite is introduced as workable anode in the direct urea fuel cells. The proposed anode was prepared by calcination under argon atmosphere of a dried cobalt acetate/nickel acetate/CNTs/ethanol slurry at 850 oC. The composition of the metal nanoparticles was optimized by synthesizing composites having different cobalt contents compared to nickel. The results indicated that the best performance is attributed to the anode containing nanoparticles having 10 wt% Co as the corresponding generated power was 3.95 mW/m2 which is 40 folds compared to that obtained from pristine nickel nanoparticles-containing anode (0.09 mW/m2).This Publication was made possible by NPRP grant # [8-1344-1-246] from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of authors

Applicable anode based on Co3O4–SrCO3 heterostructure nanorods-incorporated CNFs with low-onset potential for DUFCs

Besides the high-current density, lower onset potential of urea electrooxidation is key parameter which influences the direct urea fuel cell performance. In the present article, low-onset potential has been reported for nickel-free (NF) electrocatalyst in urea electrooxidation. The nickel-free electrocatalyst: Co3O4–SrCO3 heterostructure nanorods-incorporated carbon nanofibers (CNFs) were synthesized by electrospinning technique, followed by calcination of electrospun mat composed of strontium acetate, cobalt acetate, and poly(vinyl alcohol) sol–gel in inert environment at 750 °C. Physiochemical characterizations confirmed the formation of Co3O4–SrCO3 heterostructure nanorods-incorporated CNFs. The electrochemical activity of resultant nickel-free electrocatalyst toward the electrooxidation of urea in alkaline medium is evaluated using cyclic voltammetry measurements (CV). Co3O4–SrCO3 heterostructure nanorods-incorporated CNFs reveals high-current density of 21.33 mA/cm2 at low-fuel concentration. Notably, the low-onset potential has been observed, showing a good application prospect in direct urea fuel cells.This Publication was made possible by NPRP grant # [8-1344-1-246] from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of authors

ZnO@C (core@shell) microspheres derived from spent coffee grounds as applicable non-precious electrode material for DMFCs

Although numerous reports have introduced non precious electrocatalysts for methanol oxidation, most of those studies did not consider the corresponding high onset potential which restricts utilization in real fuel cells. In this study, an −90 mV [vs. Ag/AgCl] onset potential non-precious electrocatalyst is introduced as an applicable anode material for the direct methanol fuel cells. Moreover, the proposed material was prepared from a cheap and abundantly existing resource; the spent coffee grounds. Typically, the spent coffee grounds were facilely converted to core@shell (ZnO@C) microspheres through a two-step approach, involving chemical activation and a subsequent calcination at temperature of 700 °C. Activation of the carbon derived from the spent coffee grounds was performed with ZnCl2 which acts as pore-forming agent as well as a precursor for the ZnO. The structure and morphology were characterized by (XRD), (SEM), and (TEM) analyses while the electrochemical characterizations was evaluated by cyclic voltammetry (CV) technique. Besides the comparatively very low onset potential, the introduced microspheres exhibited relatively high current density; 17 mA/cm2. Overall, based on the advantages of the green source of carbon and the good electrocatalytic activity, the spent coffee grounds-derived carbon can be considered a promise anode material for the DMFCs.This Publication was made possible by NPRP grant # [8-1344-1-246] from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of authors

Engineering of magnetically separable ZnFe2O4@ TiO2 nanofibers for dye-sensitized solar cells and removal of pollutant from water

Abstract In this study, magnetic Zinc Ferrite (ZnFe2O4)@TiO2 nanofibers were prepared by low cost and nontoxic route; hydrothermal technique followed by electrospinning process. The prepared magnetic ZnFe2O4@TiO2 nanofibers were morphologically and structurally analyzed by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and thermal gravimetric analysis (TGA). The prepared magnetic ZnFe2O4@TiO2 nanofibers were utilized as photoanode for the fabrication of dye-sensitized solar cells (DSSCs) and presented applicable performance with 4.2% overall conversion efficiency with high short circuit current density (JSC) of 10.16 mA/cm2. The maximum ∼42% incident photo-to-current conversion efficiency (IPCE) value was also recorded at 520 nm. In addition, ZnFe2O4@TiO2 nanofibers were not only possessed the good conversion efficiency, but also shown excellent photocatalytic efficiency with magnetic properties towards the dye remediation. Prepared ZnFe2O4@TiO2 nanofibers can be considered as a promising material for energy conversion and environmental applications

Leaching of Some Essential and Non-Essential Heavy Metals from Modern Glazed Ceramic Crockeries Imported into Qatar from China, India and Spain

In this study, the leaching potential of ceramic crockeries available in Qatar market has been evaluated using inductively coupled plasma mass spectrometry (ICP-MS). Ceramic crockeries decorated with glaze matter containing various essential (Zinc, Iron, and Barium, etc.) and non-essential heavy metals (lead and cadmium) can adulterate the foodstuff and/or can release deadly metals into the food substance. Chines, Indian, and Spanish ceramic crockeries were randomly selected from the products available in the local Qatari market and analyzed to determine the level of leachable essential and non-essential heavy metals. Leaching studies were performed according to the ASTM 738-94 standard test methods for specific metals leaching into 4% acetic acid solutions over 24 hours exposure time. ASTM 738-94 is a precise and standard method and particularly designed for the determination of some heavy metals extracted by acetic acid from the glazed ceramic surface. Results show that all the ceramic crockeries contain both leachable essential and non-essential heavy metals. However, the concentration of these heavy metals is not potentially high to cause any adverse effect on human health

Patulin and patulin producing Penicillium spp. occurrence in apples and apple-based products including baby food

Introduction: Patulin has raised the international attention because of its health risk. In fact, it has mutagenic, neurotoxic, immunotoxic, genotoxic and gastrointestinal effects in animals. In the present work, patulin and patulin-producing Penicillium spp. in apple and apple-based products marketed in Qatar were analysed. Methodology: Sampling was carried out using apple fruits and apple-based products. Fungi were isolated from undamaged apples, apple juice and baby apple food. DNA extraction was carried out with DNeasy Plant Mini Kit (QIAGEN, Valencia, USA). The molecular identification of fungal isolates was carried out using ITS1-ITS4 PCR. PCR products were sequenced and blasted. Patulin was extracted and analyzed by LC/MS/MS, then quantified using Agilent 1290UHPLC coupled to 6460 triple quadruple mass spectrometer. Results: Forty-five samples of undamaged fresh apple fruits, apple juice and apple-based baby food products sold in different markets in Qatar were surveyed for both fungal and patulin contamination using Liquid Chromatography Tandem Mass Spectrometery (LC/MS/MS). Twenty-five Penicillium spp. isolates were selected, including 23 P. expansum and one isolate each of P. brevicompactum and P. commune. All the tested Penicillium spp. isolates produced patulin in vitro (from 40 to 100 μg/g on Malt Yeast Extract agar medium). Patulin was detected in 100% of apple juice samples at levels ranging from 5.27 to 82.21 μg/kg. Only 5 samples contained patulin levels higher than European Union recommended limit (50 μg/kg). The average patulin contamination was 30.67 μg/kg and 10.92 μg/kg in baby apple juice and in baby apple compote, respectively.This publication was made possible by NPRP grant # NPRP 4-259-2-083 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors

Knowledge and Attitude of Saudi Arabian School Teachers with Regards to Emergency Management of Dental Trauma

Injury to both the primary and the permanent dentitions and their supporting structures is one of the most common dental problems seen in children.  School is one of the locations with greatest prevalence of occurrence of traumatic dental injuries.  School teachers play important role in prevention of dental trauma and improving its prognosis. The present study was undertaken to assess knowledge and attitudes regarding emergency management of dental trauma, first aid for avulsed tooth and influence of dental education among school teachers in Abha city. METHODS: The participants were 100 school teachers from Abha city and were interviewed using a questionnaire regarding management of dental trauma.  The completed proformas was collected and the result was statistically analyzed to know the knowledge and attitudes regarding emergency management of dental trauma. CONCLUSIONS: Majority of school staff had little knowledge related to handling of traumatic dental injuries and emergency management of avulsed permanent teeth in school children. Majority of school teachers were eager to have knowledge regarding dental trauma through continues dental education programs and workshops.  First aid training increases knowledge about dental trauma and should be included in the course curriculum of teachers training program

Contaminant metals in costal marine sediment along the Doha Bay, Qatar

Heavy metals pollution in marine environments has become a worldwide problem with the fast industrial development in the east coastal region of Qatar, especially in the Doha bay area. Heavy metals are expected to be presented into the coastal environment and be combined within sediments together with organic matters, clay, oxides, and sulfides. The concentration of heavy metals in the marine environment depends on many factors such as the source of pollution, input, and its speciation, sediment characteristics, adsorptive properties of clay minerals, and others. This study aimed at providing knowledge on the environmental characteristics and properties in the location where many developments are constructed such as residences, marinas, and other facilities within the coast of Doha Bay. The study analysed the concentrations of 25 metals around Doha Bay to evaluate the pollution loading and the magnitude of the impact that the contaminants had on the sediment samples within the area on two sampling durations. Significant differences were observed in metal concentrations between the sampling locations and durations. Higher concentrations were observed in areas where there are a lot of anthropological activities. The distribution of selected metals was presented in contour maps showing the variation between the two periods. In order to further study particle size effect on metals uptake, two different grinding times were administered on four randomly selected samples and the results showed no significant difference on the analysis in the ICP-OES instrument. The overall results of metal analyses were within the international standards criteria and the results were comparable to the previous studies conducted around Qatar.qscienc