Entity

Time filter

Source Type


Mohamed A.A.,National Research Center of Egypt | Khalil A.A.,Mubarak City for Scientific Research | El-Beltagi H.E.S.,Cairo University
Grasas y Aceites | Year: 2010

The widespread use of medicinal plants for health purposes has increased dramatically due to their great importance to public health. In this study, the levels of phenolic, flavonoid, β-carotene and lycopene compounds of Anastatica hierochuntica and Hyphaene thebaica were determined. The plant extracts were evaluated for their antioxidant activities using various antioxidant methodologies: (i) scavenging of free radicals using 2, 2-diphenyl-1-picrylhydrazyl, (ii) metal ion chelating capacity, and (iii) scavenging of superoxide anion radical. The antimicrobial activity of both plant extracts was evaluated against a panel of microorganisms using the agar disc diffusion method. The total phenolic content (51.97 and 64.9 mg/g dry weight in A. hierochuntica and H. thebaica, respectively) was significantly (p < 0.05) different. The antioxidant activity increased with an increase in concentration. The plant extracts were more active against Gram-positive bacteria than Gram-negative bacteria. Also, the antimicrobial activity of H. thebaica was higher than that of A. hierochuntica methanolic extracts. This study reveals that the consumption of these plants would exert several beneficial effects by virtue of their antioxidant and antimicrobial activities. Source


Hwang J.-H.,Yonsei University | Choi J.-A.,Yonsei University | Abou-Shanab R.A.I.,Yonsei University | Abou-Shanab R.A.I.,Mubarak City for Scientific Research | And 5 more authors.
Bioresource Technology | Year: 2011

Anaerobic fermentation for hydrogen (H2) production was studied in a two-stage fermentation system fed with different ripened fruit feedstocks (apple, pear, and grape). Among the feedstocks, ripened apple was the most efficient substrate for cumulative H2 production (4463.7mL-H2 L-1-culture) with a maximum H2 yield (2.2mol H2 mol-1 glucose) in the first stage at a hydraulic retention time (HRT) of 18h. The additional cumulative biohydrogen (3337.4mL-H2 L-1-culture) was produced in the second stage with the reused residual substrate from the first stage. The major byproducts in this study were butyrate, acetate, and ethanol, and butyrate was dominant among them in all test runs. During the two-stage system, the energy efficiency (H2 conversion) obtained from mixed ripened fruits (RF) increased from 4.6% (in the first stage) to 15.5% (in the second stage), which indicated the energy efficiency can be improved by combined hydrogen production process. The RF could be used as substrates for biohydrogen fermentation in a two-stage (dark/dark) fermentation system. © 2010 Elsevier Ltd. Source


Mansour M.S.,Alexandria University | Ossman M.E.,Mubarak City for Scientific Research | Farag H.A.,Alexandria University
Desalination | Year: 2011

The ability of Polyaniline coated on saw dust as synthetic adsorbent was investigated for adsorptive removal of Cd (II) ions from aqueous solutions by batch operation. It was found that polyaniline coated on saw dust (PANI/SD) is very easy and simple to prepare and can be used as an effective adsorbent for removal of Cd (II) ions from aqueous solutions. Various physico-chemical parameters such as pH, initial metal ion concentration, and adsorbent dosage level and equilibrium contact time were studied. The adsorption of Cd (II) ions increased with an increase in pH. The optimum solution pH for adsorption of Cd (II) from aqueous solutions was found to be 6. Adsorption was rapid and occurred within 20min for a cadmium concentration range of 10: 40mg L-1. The kinetic process of Cd (II) adsorption onto PANI/SD was found to fit the pseudo-second-order rate equation. The equilibrium adsorption data for Cd (II) were better fitted to the Freundlich adsorption isotherm model. © 2011 Elsevier B.V. Source


Ahn Y.-T.,Yonsei University | Kim H.-C.,Pennsylvania State University | Cho D.-W.,Yonsei University | Abou-Shanab R.A.I.,Mubarak City for Scientific Research | Jeon B.-H.,Yonsei University
Geosystem Engineering | Year: 2012

A zero-valent iron (ZVI) treatment system combined with pH adjustment, aeration, sedimentation and microfiltration processes was developed for the robust removal of nitrate from groundwater. Powdered ZVI dosed at 10 g L-1 removed nitrate by 166 mg L-1, of which 80% were converted to ammonium ion for a given contact time of 125 h. By diffusing gaseous carbon dioxide (CO2) into the ZVI reactor, pH was desirably controlled in the range of 5.5-6.5, and concurrently,< 0.5 mg L-1 dissolved oxygen was consistently maintained during the longer-term of dissolved oxygen ZVI treatment system. The combination of ZVI treatment and CO2 gas bubbling reached up to 35% removal of nitrate and passivation on the surface of ZVI was prevented by diffusing CO2 gas. Soluble Fe (II) concentration of mixed liquor in the ZVI reactor ranged between 0.2 and 7.8 mg L-1 and Fe (II) dissolved in the ZVI-treated water was almost completely removed by subsequent aeration. The overall result shows that the novel ZVI treatment system is significantly promising to remove nitrate in groundwater and therefore to meet the regulatory limit for drinking water. © 2012 Taylor & Francis. Source


Khan M.A.,Yonsei University | Kim S.-W.,Yonsei University | Rao R.A.K.,Aligarh Muslim University | Abou-Shanab R.A.I.,Yonsei University | And 4 more authors.
Journal of Hazardous Materials | Year: 2010

The objective of this work was to compare the effectiveness of four commercially available granular activated carbons (GACs); coconut (CGAC), wood (WGAC), lignite (LGAC) and bituminous (BGAC) for the removal of dichloromethane (DCM) from aqueous solution by batch process. Various parameters such as thermodynamics, kinetics, pH, concentration of adsorbate, dosages of adsorbent and competitive ions effect on DCM adsorption were investigated. Maximum adsorption capacity (45.5. mg/g for CGAC) was observed at pH 6.0-8.0. The kinetics data indicate better applicability of pseudo-second-order kinetics model at 25 and 35°C. Freundlich model was better obeyed on CGAC, WGAC, and BGAC, while LGAC followed Langmuir model. The adsorption process for 100. mg/L initial DCM concentration on CGAC was exothermic in nature. The adsorption of DCM on various adsorbents involves physical adsorption process. The adsorption of DCM over a large range of initial concentration on CGAC and LGAC is effective even in presence of ionic salts. © 2010 Elsevier B.V. Source

Discover hidden collaborations