Sequential Extraction of Vanadium in Different Soil Samples Using Conventional and Ultrasonic Devices

Abstract

Abstract A rapid ultrasound accelerated sequential extraction (USE) procedure was used to develop chemical partitioning of vanadium (V), proposed by the Community Bureau of Reference/European Union Measurement and Testing Programme (BCR). The effects of ultrasonic treatment on the extraction of V in different soil samples collected from the vicinity of a thermal power plant and agricultural areas of Sindh, Pakistan, were evaluated. In the conventional BCR-sequential extraction method, each extraction step takes 16 h. With the use of ultrasound energy, Steps 1–3 of the USE procedure (excluding the hydrogen peroxide digestion in Step 3, which was performed conventionally) could be completed in 45, 40, and 45 min, respectively. Analysis of the extracts was performed by electrothermal atomic absorption spectrometry. The total contents of V were obtained by digestion with two acid mixtures: H2O2–HF–HNO3–H2SO4 and HClO4–HF–HNO3–H2SO4. Validation was performed by the standard addition technique. Results obtained for each fraction by both methods were statistically compared; no significant differences were found (P < 0.05). The accuracy of the USE procedure was checked by comparing the sum of the V contents in the three fractions and residue with the total content of V. The results of this work provide information on the chemical composition, distribution, and potential mobility of the V in different soils.