Journal of Applied Chemical Research
Volume:6 Issue: 4, Autumn 2012

Nanocomposite of Ag/TiO2and nanocrystalline TiO2 were prepared by using TiCl4 as a precursor in a simple sol-gel process. The prepared photo-catalysts were characterized by X-ray diffraction (XRD), scanning electron micrographs (SEM), energy dispersive X-ray microanalysis (EDX), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS). A complete and effective photocatalytic degradation of a cationic aromatic dye, Methylene blue, in aqueous solutions has been carried out using nanocomposite of Ag/TiO2and nanocrystalline TiO2 under UV-C light irradiation. Experiments were conducted to compare the photocatalytic activities of nanocomposite Ag/TiO2 with nanocrystalline TiO2. The photoreactions were followed by monitoring the degradation of the dye as a function of irradiation time, in the presence of the nanophoto-catalysts, by the visible/ultraviolet absorption spectroscopy. It has been found that the presence of silver in TiO nanoparticles reduces the duration of complete photocatalytic degradation of Methylene blue by 20% due to the enhancement of electron-hole separation by the electron trapping of silver particles.

The ability of natural zeolite (Clinoptilolite) to remove copper from aqueous ecosystem was studied in real and laboratory conditions. Fresh water mussels (Anodonta Cygnea) of different sizes were Exposed to copper (150, 350, 450 μgl-1) for 10 days. Copper exposure induced DNA damage in the haemolymph cells of Anodonta of all sizes. In connection with real samples, the amount of damage and even much higher than the first (150 μgl-1) and second (450 μgl-1) treatments was observed. Presence of zeolite in the aquatic environment removed Cu2 and specially reduced DNA damage in all samples. In vitro results showed a significant reduction of copper metal. Decreasing of other heavy metals Concentration is also observed in vivo. Damage to DNA and to other biomolecules by copper, mean that the availability of Cu2 ions in vivo must be carefully controlled. analysis of variance and other tests were performed for determination of optimum quantities and exposure time of adsorbent in vivo and in vitro.

The 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/S2O8 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/S2O8 2- system at the same conditions.

Nanoparticles of nickel substituted cobalt ferrite (NixCo1-xFe2O4: 0£ X£ 1) have been synthesized by co-precipitation method. Triton x-100 and oleic acid as surfactants were used. Particles size as estimated by the full width half maximum (FWHM) of the strongest X-ray diffraction (XRD) peak were found 17 and 21nm. Their morphology structure have been determined by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis confirms the presence of Co, Ni, Fe and oxygen as well as the desired phases in the prepared nanoparticles. The results of SEM show that the surfactant played an important role in morphology of nanoparticles.

The inhibiting effects of some newly synthesized Schiff bases on the corrosion of Al-Pure in 1.0 M HCl have been studied by means of the chemical and electrochemical methods. The Schiff bases m-Chloroaniline-N-benzylidene (m-CANB), p-Chloroaniline–N-benzylidene (p-CANB), Benzylamine-N-(p-methoxy benzylidene) (BANPMB) and 2-Phenylethylamine-N-(p methoxy benzylidene) (2PANPMB) were synthesized from benzyldehyde or substituted benzyldehyde with the corresponding amines and characterized by IR studies. The corrosion inhibition properties of these compounds on Al-Pure in 1.0 M HCl were investigated by weight loss, galvanostatic polarization and electrochemical impedance techniques. The weight loss study showed that the inhibition efficiency increases with increase in the concentration of the inhibitor and was found to be inversely related to temperature. The values of activation energy (Ea), free energy of adsorption (ΔGads) and heat of adsorption (Qads) were calculated from the temperature data. The adsorption of these compounds on aluminium surface follows the Langmuir adsorption isotherm. The galvanostatic polarization data show that these compounds studied are mixed type inhibitors with predominant effect on the cathode. The mechanism of corrosion inhibition is also proposed.

The present work was directed toward the successful ability of electerocoagulation to remove color from synthetic and simulated textile effluent by aluminum/iron electrodes. Two representative reactive dyes were selected for the synthetic dye system, a black dye alone and mixed dye (black, blue, red, 1:1:1 vol/vol). Several important operating parameters such as electrode material, initial pH(3-9), current density(60-120 A/m2), operating time (6-40), initial dye concentration (100-120 mg/L) and solution conductivity (applied conductivity is better than literature) were studied in an attempt to reach higher color removal efficiency (%98). The chemical oxygen demand decreased by more than %87. The results of this work are comparable with those of recent studies. The electrical energy consumption in the above conditions was on order of 1.2-3.2 kWh/m3 of wastewater and the water recovery was 0.97m3 /m3 of wastewater, in this research “water recovery” was introduced and calculated in order to show the more economically feasible recycling of treated water. However the operating parameters used for the synthetic dye were less effective for treatment of simulated textile wastewater.