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دسترسی آزاد مقاله
1 - Kinetic and thermodynamic studies of adsorption of 4-chloro-2-nitrophenol on nano- Ti02
A. Mehrizad K. Zare H. Dashti Khavidaki S. Dastmalchi H. Aghaie P. GharbaniAdsorption capacity of 4-chloro-2-nitrophenol (4C2NP) onto nano-Ti02 from aqueous solutions wasinvestigated in a batch system by considering the effects of various parameters like contact time, nano-TiO2 dosage, initial pH and initial 4C2NP concentration. Optimum condit چکیده کاملAdsorption capacity of 4-chloro-2-nitrophenol (4C2NP) onto nano-Ti02 from aqueous solutions wasinvestigated in a batch system by considering the effects of various parameters like contact time, nano-TiO2 dosage, initial pH and initial 4C2NP concentration. Optimum conditions for 4C2NP adsorptionwere found to be initial pH z 2, nano-TiO2 closer- 0.01 g and equilibrium time 1 h. The adsorptionkinetic data were analyzed using pseudo-first and pseudo-second order models. It was found that thepseudo-second-order kinetic model was the most appropriate model, describing the adsorption kinetics.The thermodynamic parameters such as AG°, MP and AS° were computed from the experimental data.These values show that the adsorption of 4C2NP onto nano-Ti02 is spontaneous and endothermic. پرونده مقاله -
دسترسی آزاد مقاله
2 - Removal of Direct Red Dye 23 from Water and Wastewater Using S2O8 Oxidant Activated by UV Irradiation:An Investigation on the Operational Parameters
Mohammad Hossein Rasoulifard Mohammad Hossein AlidoustThe photo-oxidative decolorization of Direct Red 23 (DR23), a textile dye which is suspected to be carcinogenic was investigated using peroxydisulfate activated by UV irradiation and heat in a batch photo-reactor at experimental conditions. A very simple analytical meth چکیده کاملThe photo-oxidative decolorization of Direct Red 23 (DR23), a textile dye which is suspected to be carcinogenic was investigated using peroxydisulfate activated by UV irradiation and heat in a batch photo-reactor at experimental conditions. A very simple analytical method, direct UV–vis spectrophotometric detection, was utilized for the progress of photo-oxidative decolorization of dye in aqueous medium. The effect of operational parameters namely initial peroxydisulfate concentration, pH and temperature of reaction, additional photo-catalyst on the decolorization rate was truly investigated. The results showed that use of UV/S2 O8 2- system was a highly effective way to remove colored components from contaminated waters. Optimum conditions for maximum degradation was acidic pH (pH=2), temperature of 50°C with 7.5 mM of peroxydisulfate. Also, it was observed that dye degradation was enhanced using nano-TiO2 glass beads as photo-catalyst and peroxydisulfate consumption was significantly reduced to achieve the same percentages of dye degradation which was observed in UV/S2 O8 2- system at the same conditions. پرونده مقاله -
دسترسی آزاد مقاله
3 - Titanium Dioxide Nanoparticles Increase Resistance of L. iberica to Drought Stress due to Increased Accumulation of Protective Antioxidants
Niloufar Shoarian Rashid Jamei Bahman Pasban Eslam Seyed Yahya Salehi LisarThis research was carried out to study the effect of TiO2 and nano-TiO2 on some chemical compounds in a medicinal plant Lallemantia iberica under water deficit conditions. The experiment was conducted as a factorial arrangement in a randomized complete block design with چکیده کاملThis research was carried out to study the effect of TiO2 and nano-TiO2 on some chemical compounds in a medicinal plant Lallemantia iberica under water deficit conditions. The experiment was conducted as a factorial arrangement in a randomized complete block design with three replications. The first factor was the application of external materials as spraying with 3 levels of control, TiO2 and nano-TiO2, and the second factor was 100% (no stress), 75% (moderate stress) and 35% (severe stress) irrigation content. The results of measurements showed moderate stress and the use of nano-TiO2 caused a significant increase in phenolic content, total flavonoid and antioxidant activity; severe drought stress significantly reducing these compounds. The effect of nano-TiO2 on catalase and superoxide dismutase enzyme activity was also significant, and in the treatment of nano-TiO2 and moderate stress, the highest activity level of these two enzymes was observed. Identification of phenolic compounds of the extracts by HPLC indicated the production of vanillic, ferulic acid and syringic acid by nano-TiO2 spray application. Gallic acid was measurable in moderate and severe stress and caffeic acid in severe stress under the influence of nTiO2. The sinapic acid and syringic acid contents increased under moderate stress and severe stress decreased them. Finally, it is concluded that nano-TiO2 in comparison with TiO2 reduces the effects of drought stress on L. iberica and can be used to produce this plant in water-deficit areas. پرونده مقاله -
دسترسی آزاد مقاله
4 - Effect on Germination and Early Growth Characteristics in Wheat Plants (Triticumaestivum L.) Seeds Exposed to TiO2 Nanoparticles
Homa Mahmoodzadeh Reyhane AghiliThe present study was aimed to investigate the effects of titanium dioxide nanoparticles (nano-TiO2) on wheat (Triticumaestivum L.) plants cv. Parsi. The experimental treatments included seven concentrations of nano- TiO2 (10, 100, 1000, 1200, 1500 and 1700 ppm nano-TiO چکیده کاملThe present study was aimed to investigate the effects of titanium dioxide nanoparticles (nano-TiO2) on wheat (Triticumaestivum L.) plants cv. Parsi. The experimental treatments included seven concentrations of nano- TiO2 (10, 100, 1000, 1200, 1500 and 1700 ppm nano-TiO2 and control (without any TiO2). The results showed that among the wheat germination indices, germination rate and weighted germination index were affected by TiO2 nanoparticles treatments. The lowest and the highest germination rate (16.7 vs. 11.1n.day-1) were obtained in control and 1000 and 1200 ppm concentration of nano- TiO2 treatments, respectively. These values for weighted germination index were (2.4 vs. 2.08) in 2000 ppm and control treatments respectively. In addition, plumule and radicle length, seedling fresh weight and seedling vigor index were affected by nano- TiO2 concentrations, significantly. Plumule and radicle lengths at 1200 ppm concentration of nano-TiO2 were higher than untreated control. This study shows that using of TiO2nanoparticles in suitable concentration caused increasing of seed germination of wheat cv. Parsiin comparison to control plants, otherwise low concentrations had inhibitory effects on wheat germination characteristics. پرونده مقاله -
دسترسی آزاد مقاله
5 - Nano-TiO2 an Efficient, Clean and Eco-friendly Catalyst for Synthesis of Naphthoxazinone Derivatives as High Potent Antibacterial Agents
Khalil PourshamsianOxazines naturally occurs and synthetically exhibit wide-ranging biological activity. In this study, a highly practical and efficient of 1,2-dihydro-1-phenylnaphtho[1,2-e][1,3]oxazine-3-one derivatives was developed via a multi-component reaction of 2-naphthol, aldehyde چکیده کاملOxazines naturally occurs and synthetically exhibit wide-ranging biological activity. In this study, a highly practical and efficient of 1,2-dihydro-1-phenylnaphtho[1,2-e][1,3]oxazine-3-one derivatives was developed via a multi-component reaction of 2-naphthol, aldehydes and urea in the presence of nano-titanium oxide as solid, recyclable catalyst at one-pot and solvent-free conditions. These synthetic compounds 2a-e were evaluated as potential antibacterial agents. The structures of products were confirmed by spectral analysis FT-IR and 1H NMR. The antibacterial activity of the compounds was screened against Staphylococcus aureus and Escherichia coli. These results showed that these compounds exhibited significant to moderate activities against both Gram (+) and Gram (-) organisms. پرونده مقاله
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