Abstract: The decolorization of Orange II was studied under visible light using bimetallic Cu–Ni/TiO2 prepared via precipitation method. Photocatalysts with different Cu:Ni mass compositions were prepared and the effect of calcination temperatures on the Orange II removal was investigated. The raw photocatalysts were activated by calcination at three different temperatures (180 xa0;°C, 200 xa0;°C and 300 xa0;°C) for 1 xa0;h duration. Photocatalysts were characterized using thermogravimetric analysis, Fourier-transformed infrared spectroscopy, powder X-ray diffraction and field-emission scanning electron microscopy, high resolution transmission electron microscopy, diffuse reflectance UV–Vis spectroscopy, temperature programed reduction studies and surface area analysis employing Brunauer–Emmet–Teller method. The photocatalytic degradation of Orange II was performed under the irradiation of visible light (500 xa0;W halogen lamp) at pH 6.8. The extent of Orange II degradation with initial concentration of 50 xa0;ppm was monitored using UV–Vis spectroscopy and at the end of the reaction, total organic carbon analysis (TOC) was conducted. Results from UV–Vis spectroscopy showed that high percentage of Orange II removal was achieved for Cu–Ni/TiO2 photocatalysts calcined at 180 xa0;°C and 200 xa0;°C compared to 300 xa0;°C. In addition, these photocatalysts also displayed lower TOC values as compared to the photocatalyst calcined at 300 xa0;°C. The best performing Cu–Ni/TiO2 photocatalyst has 9:1 Cu:Ni mass composition and calcined at 180 xa0;°C giving 100% Orange II removal with 16.1 xa0;ppm TOC value. Although the results from UV–Vis spectroscopy showed 100% Orange II removal, TOC analysis indicated the presence of organic compounds derived from the dye degradation process.
Abstract: he present study was conducted to determine the pesticide residues on selected summer vegetables. Five vegetables were grown with three replicates in a split plot randomized complete block design. Pesticides were sprayed on vegetables thrice at regular intervals each after 15 days. At maturity the pesticides residues were extracted from edible and leaf portions using anhydrous sodium sulfate and ethyl acetate while adsorption chromatography technique was used for cleanup. The extracts were subjected to high performance liquid chromatography (HPLC) for separation and analysis of the compounds. Significant differences (p<0.05) were found in the pesticides residues on edible portions whereas highly significant differences (p<0.001) were observed for the leafy portions. The residual level of cypermethrin was highest (16.2 mgkg-1) in edible portion of bitter gourd, while Lambdacyhalothrin and Mancozeb residues were detected high (4.50 mgkg-1, 6.26 mgkg-1) in edible portion of bitter gourd and Cucumber respectively. Cypermethrin residues were high (1.86 mgkg-1) in Okra leaves. Mancozeb and Lambdacyhalothrin residual level was high (1.23mgkg-1, and 0.0002 mgkg-1) in chili and tomato leaves. Cypermethrin residues were readily detected in edible and leaf portion of the selected vegetables.
Abstract: The effects of ultrasonic frequencies on both the mass transport process and diffusion layer were investigated during electrochemical treatment. The rates of mass transfer at a stainless steel cathode were measured for copper and lead in dilute acidified copper sulphate and lead nitrate solutions at different ultrasonic frequencies. Concentrations in bulk solution were determined by atomic absorption spectrophotometer. By increasing frequencies from 40 to 100 kHz, a high value for the mass transfer coefficient and an effective thinning of the diffusion layer were observed. Higher rates of mass transfer reduced energy consumption. Use of ultrasound with electrochemical processes can provide valuable contributions to remove metallic ions from industrial wastewater without using extra chemicals. The process has efficiently reduced the cost of energy consumption and deposition time.
Abstract: The decolorization of Orange II was studied under visible light using bimetallic Cu-Ni/TiO2 prepared via precipitation method. Cu:Ni mass composition of 9:1 was prepared and the effect of calcination temperature on the Orange II removal was investigated. The raw photocatalysts were activated by calcination at three different temperatures (180°C, 200°C and 300°C) for 1 hour duration. Photocatalysts were characterized using Thermogravimetric Analysis (TGA), Fourier-Transformed Infra red spectroscopy (FTIR), Powder X-Ray diffraction (XRD) and Field-Emission Scanning Electron Microscopy-Energy Dispersive X-ray (FESEM-EDX). The photocatalytic degradation of Orange II was conducted under the irradiation of visible light (500 W halogen lamp) at pH 6.8. The extent of degradation for Orange II with initial concentration of 50 ppm was monitored using UV-vis spectroscopy and TOC analysis was conducted at the end of the reaction. Results showed that complete Orange II removal was achieved for Cu:Ni/TiO2 photocatalysts calcined at 180°C, and 200°C Photocatalyst calcined at 180°C showed the best performance with 100the lowest TOC value of 16.1 ppm.
Abstract: Deposition of complex and heavy organic compounds, which exist in petroleum crude and heavy oil, can cause a number of severe problems. In present study wax deposition was studied at 80°C using cold finger device. Three crude oil samples were tested in original and demetalized composition for wax deposition. FTIR and GC-MS was used for chemical composition and structural analysis of the obtained wax. Significant difference was observed for wax deposition in original and demetalized crude oil samples. The chemical composition analysis of carbon-hydrogen stretching mode showed a strong absorption between 2850 cm-1, 2916 cm-1 and 2950 cm-1. GC-MS analysis confirmed the pattern of n alkanes with presence of other high molecular weight compounds in wax obtained from crude oil samples.
Abstract: The objective of the present work was to synthesize 10 wt % metal doped TiO2 (Degussa P-25) photocatalysts
using three methods: complex precipitation (CP), deposition precipitation (DP) and wet impregnation (WI) methods and to
evaluate their performance for a model azo dye, Orange II. The raw photocatalysts were activated by calcination at three
different temperatures (180°C, 200°C and 300°C) for 1 hour duration. Photocatalytic degradation for 50 ppm orange II was
studied at pH 6.8 under the irradiation of a UV light and visible light. The extent of dye degradation was determined
using UV-vis Spectrophotometery. On the basis of results it was observed that visible light has better effect for dye removal
compared to UV light and WI photocatalysts showed the best decolorization results with 100% Orange II removal for
photocatalysts calcined at 1800C and 2000C while 98.5% for 3000C calcination temperature. Selected photocatalysts were
characterized using Powder X-ray Diffraction (XRD), Field emission Scanning Electron Microscopy-Energy Dispersive Xray
(FESEM- EDX) and Diffuse Reflectance UV visible spectroscopy (DRUV vis).
