Reviewing the current state of knowledge about sequential extraction applied for soil vanadium （V） fractionation, we identified an urgent requirement of an sequential extraction （SE） specified for V. Namely, almos...Reviewing the current state of knowledge about sequential extraction applied for soil vanadium （V） fractionation, we identified an urgent requirement of an sequential extraction （SE） specified for V. Namely, almost all previous SE extracted only 8.4%-48% of total V in soils （excluding residue）. Thus, we proposed an eight-step SE for V fractionation in soils according to the knowledge gained from literature and our own dissolution experiments with model minerals. After extracting the mobilisable and adsorbed V with de-ionised water and 5 mmol/L phosphate, I moVL pyrophosphate was applied to gather organic matter bound V which minimised the artefact dissolving AI and Fe （hydr）oxides occurred when using HNO3-H202 for extraction. Extraction with 0.4 mol/L NH2OH. HCI was highly selective toward manganese oxides. Fractionation of different crystalline A1 and Fe （hydr）oxides associated V with 1 mol/L HCI, 0.2 mol/L oxalate buffer and 4 mol/L HCI at 95℃especially improved the extractability of V incorporated with crystalline phase associated V. The suitability of our new SE scheme was confirmed by its higher selectivity against the target phases and higher extraction efficiencies （55%-77% of total V） with model minerals and 6 soils of different properties than previous SE.展开更多
基金Gunter Ilgen(University of Bayreuth,Germany)for the support with analysissupported by the China Scholarship Council(No.2011624130)the Swiss National Science Foundation(No.PZ00P2 142232)
文摘Reviewing the current state of knowledge about sequential extraction applied for soil vanadium （V） fractionation, we identified an urgent requirement of an sequential extraction （SE） specified for V. Namely, almost all previous SE extracted only 8.4%-48% of total V in soils （excluding residue）. Thus, we proposed an eight-step SE for V fractionation in soils according to the knowledge gained from literature and our own dissolution experiments with model minerals. After extracting the mobilisable and adsorbed V with de-ionised water and 5 mmol/L phosphate, I moVL pyrophosphate was applied to gather organic matter bound V which minimised the artefact dissolving AI and Fe （hydr）oxides occurred when using HNO3-H202 for extraction. Extraction with 0.4 mol/L NH2OH. HCI was highly selective toward manganese oxides. Fractionation of different crystalline A1 and Fe （hydr）oxides associated V with 1 mol/L HCI, 0.2 mol/L oxalate buffer and 4 mol/L HCI at 95℃especially improved the extractability of V incorporated with crystalline phase associated V. The suitability of our new SE scheme was confirmed by its higher selectivity against the target phases and higher extraction efficiencies （55%-77% of total V） with model minerals and 6 soils of different properties than previous SE.
