Vanadium is distributed widely and scarcely (150 ppm) on the earth. Its major applications are in steelmaking, dye-production and catalyst-fabrication industries. With the ever-increasing demand for this metal, secondary resource-exploitation of such waste materials as spent catalysts is recommended. Many reactions are involved in vanadium-extraction from these resources. Since roasting in comp...

Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and other synthetic polycarboxylic acids have been shown to possess substantial capacity as washing agents of heavy metal-polluted soils, but they are environmentally problematic. Therefore, a sample of natural soluble humic substances (HS) was tested as a possible substitute. The efficiency of HS to extract cadmium (Cd), copp...

This study compared the extractability of Cd, Cu, Ni, Pb, and Zn by 8 extraction protocols for 22 representative rural soils in Taiwan and correlated the extractable amounts of the metals with their uptake by Chinese cabbage for developing an empirical model to predict metal phytoavailability based on soil properties. Chemical agents in these protocols included dilute acids, neutral salts, and ...

introduction a large volume of sediments are dredged from water bodies such as ports, waterways and wetlands and deposited on land. sediments are typically polluted by contaminants such as heavy metals. metals in sediments are in soluble, carbonate bound, fe-mn oxide, sulfide/organic matter bound and residual fractions. the metal solubility and mobility are mainly controlled by organic matter c...

a simple and reproducible method for the rapid extraction and determination of trace amounts of copper(ii) ions using octadecyl-bonded silica membrane disks modified by 1-(2-pyridyl azo)2-naphtol(pan) and atomic absorption spectrometry was presented. the method was based on complex formation on the surface of the envi-18 disk tm disks followed by stripping of the retained species by minimum amo...

A new series of noncyclic ionophores containing two to four furan units (Ia to IIIb) i.e. 1,1-difurylethane (Ia), 2,5-bis(methylfurfuryl)furan (IIa) and 1,1’ ethyledenebis[5-(methylfurfuryl)furan] (IIIa), 2,2-difurylpropane (Ib), 2,5-bis (dimethylfurfuryl)furan(IIb), 2,2’-isopropylidenebis[5-(dimethylfurfuryl)furan] (IIIb) have been synthesized by the condensation of furan with acetaldehyde and...

A hydrmetallurgical study based on the extraction of Zn and Pb from a Nigerian sphalerite mineral leached with 4 M hydrochloric acid has been undertaken. Triphenylphosphite (TPP) has proved to be very effective for the extraction of zinc. With 2 M TPP and at ambient temperature of 25±2°C; 35.71% and 66.7% of Pb and Zn were extracted, respectively, into the organic phase within 60 min. The recov...

this paper presents a design of an uwb downconversion integrated cmos resistive ring mixer with linear voltage regulator (lvr), to supply required biasing voltages for the mixer section. the designed mixer circuit has been optimized for using in heart rate extraction system with microwave doppler radar at 2.4ghz frequency. this mixer needs 2 dc bias voltages equal to 0.5 and 1 volts for its bes...