Separation via Flotation, Spectrophotometric Speciation, and Determination of Vanadium(IV) in Wastes of Power Stations

Abstract

1-(2-Hydroxy-4-methoxybenzophenone)-4-phenylthiosemicarbazone (HMBPT) was investigated as a new reagent for the flotation of vanadium(IV). At pH ∼1.5, vanadium(IV) forms a 1:1 pale-violet complex with HMBPT in aqueous solution. An intense clear violet layer was formed after flotation, by adding an oleic acid (HOL) surfactant. The composition of the float was 1:1 [V(IV)]: [HMBPT]. A highly selective and sensitive spectrophotometric procedure was proposed for the determination of microamounts of V(IV) as its floated complex. The molar absorptivities of the V(IV)-HMBPT and V(IV)-HMBPT-HOL systems were 0.4 × 10 4 and 0.12 × 10 5 L mol -1 cm -1 at 560 nm, respectively. The formation constants of the species formed in the presence and absence of HOL were 4.6 × 10 7 and 8.7 × 10 5 L mol -1 , respectively. Beer's law was obeyed up to 1 × 10 -4 mol L -1 in the aqueous layer as well as in the oleic acid layer. The HMBPT-V(IV) complexes formed in the aqueous solution and scum layer were characterized by elemental analysis, infrared and UV spectrophotometric studies. The mode of chelation between V(IV) and HMBPT is proposed to be due to a reaction between the protonated bidentate HMBPT ligand and V(IV) through the S=C and N=C groups. Interferences from various foreign ions were avoided by adding excess HMBPT and/or Na2S2O3 as a masking agent. The proposed flotation 1 method was successfully applied to the analysis of V(IV) in synthetic mixtures, wastes of power stations, simulated samples and in real ores. The separation mechanism is discussed.

On-line separation/preconcentration of V(IV)/V(V) in environmental water samples with CTAB-modified alkyl silica microcolumn and their determination by inductively coupled plasma-optical emission spectrometry

“…The separation techniques for the vanadium speciation could be generally classified into chromatographic techniques [13][14][15] and non-chromatographic techniques [3,4,7,10,11,[16][17][18][19][20][21][22][23][24][25]. For a simple elemental speciation, especially for different oxidation states of a given element, non-chromatographic methods are more diffused than the chromatographic techniques.…”

Untitled

“…Industrial effluent from titanium and uranium processing plants as well as steel industries contain higher concentrations of vanadium 2,4 .…”

Synthesis, Characterization and Evaluation of Peanut Shells-Derived Activated Carbons for Removal of Methomyl from Aqueous Solutions

“…Some techniques include aerobic degradation [10], photo catalytic degradation [10,11]. Ultrasound combined with photo-Fenton treatment [12], electro dialysis membranes [13], filtration, ozonation [14], reactions with oxidants such as free radicals, disinfection, floatation [15], preconcentration [16] and adsorption [17]. Amongst these techniques, adsorption is considered as the most effective and widely used for control of taste and odor as well as removing synthetic organic compounds and wide range of pollutants from wastewater and water supplies [18,19].…”