1.Some remarks on the microbiological contamination of the food hawking on the street in Thanh Hoa city 2007
Nhat Xuan Trinh ; Quang Huy Tran
Journal of Preventive Medicine 2008;97(5):71-74
Background: Quality, hygiene and food safety are the pressing questions that affects the public. Objectives: To discover some remarks on the microbiological contamination of food selling on the street in Thanh Hoa city and various suitable solutions in management and deployment. Subjects and method: A cross-sectional survey on the microbiological contamination of 310 different samples of food hawking on the street of 11 communes in Thanh Hoa province. Results:310 different samples were collected in Thanh Hoa city in 2007, we found micro biological contamination is still high, the highest rate was spring roll (76,7% contamined), lowest was food prepared from fish and other fish products (43,3%). Conclusion: The contamination rate varies with different organisms. The rate of food contaminated with 2 organisms was high (91.1%).To ensure the health of the public; it is necessary to have the measures to ensure that sellers provide the public with safe and hygienic food. \r\n', u'\r\n', u'\r\n', u'
microbiological contamination of the food selling
2.Melanin-embedded materials effectively remove hexavalent chromium (Cr) from aqueous solution.
An Manh CUONG ; Nguyen Thi LE NA ; Pham Nhat THANG ; Trinh Ngoc DIEP ; Ly Bich THUY ; Nguyen Lai THANH ; Nguyen Dinh THANG
Environmental Health and Preventive Medicine 2018;23(1):9-9
BACKGROUND:
Currently, it is recognized that water polluted with toxic heavy metal ions may cause serious effects on human health. Therefore, the development of new materials for effective removal of heavy metal ions from water is still a widely important area. Melanin is being considered as a potential material for removal of heavy metal from water.
METHODS:
In this study, we synthesized two melanin-embedded beads from two different melanin powder sources and named IMB (Isolated Melanin Bead originated from squid ink sac) and CMB (Commercial Melanin Bead originated from sesame seeds). These beads were of globular shape and 2-3 mm in diameter. We investigated and compared the sorption abilities of these two bead materials toward hexavalent-chromium (Cr) in water. The isotherm sorption curves were established using Langmuir and Freundlich models in the optimized conditions of pH, sorption time, solid/liquid ratio, and initial concentration of Cr. The FITR analysis was also carried out to show the differences in surface properties of these two beads.
RESULTS:
The optimized conditions for isotherm sorption of Cr on IMB/CMB were set at pH values of 2/2, sorption times of 90/300 min, and solid-liquid ratios of 10/20 mg/mL. The maximum sorption capacities calculated based on the Langmuir model were 19.60 and 6.24 for IMB and CMB, respectively. However, the adsorption kinetic of Cr on the beads fitted the Freundlich model with R values of 0.992 for IMB and 0.989 for CMB. The deduced Freundlich constant, 1/n, in the range of 0.2-0.8 indicated that these beads are good adsorption materials. In addition, structure analysis data revealed great differences in physical and chemical properties between IMB and CMB. Interestingly, FTIR analysis results showed strong signals of -OH (3295.35 cm) and -C=O (1608.63 cm) groups harboring on the IMB but not CMB. Moreover, loading of Cr on the IMB caused a shift of broad peaks from 3295.35 cm and 1608.63 cm to 3354.21 cm and 1597.06 cm, respectively, due to -OH and -C=O stretching.
CONCLUSIONS
Taken together, our study suggests that IMB has great potential as a bead material for the elimination of Cr from aqueous solutions and may be highly useful for water treatment applications.
Adsorption
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Chromium
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chemistry
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Kinetics
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Melanins
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chemistry
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Waste Disposal, Fluid
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methods
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Water Pollutants, Chemical
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chemistry
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Water Pollution, Chemical
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prevention & control
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Water Purification
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methods