Rview of phytoremediation of soil contaminated by vanadium

Vanadium is a nontrivial multi-valent metallic element, which has been increasingly used in modern society. The widespread application of vanadium promotes the rapid and sound development of the economy and society, simultaneously brings out increasingly prominent environmental problems, e.g., soil vanadium pollution. Therefore, the remediation problem of vanadium-contaminated soil has been received growing attention. Phytoremediation has become a significant constituent in vanadium-contaminated soil remediation attributable to its veritable merits such as cleanness, esthetics, cost-effectiveness, convenience, and sustainability. Phytoremediation is mainly dependent on hyperaccumulator plants, even though the actuality that the vast majority of hyperaccumulator plants are characterized by low biomass yield and slow-growing. Consequently, the intensity in screening the undiscovered hyperaccumulators should be strengthened. Meanwhile, it is imperative to further explore the vanadium accumulation and translocation characteristics of some non-hyperaccumulative but tolerant plants with moderate biomass to remediate the soil contaminated with vanadium. Taken together, further comprehensive researches of tolerance mechanisms of remedial plants against vanadium are quite necessary to decontaminate soils contaminated by vanadium efficiently.

Uptake of Metals from Single and Multi-Component Systems by Spirulina Platensis Biomass

Spirulina platensis biomass is widely applied for different technological purposes. The process of lanthanum, chromium, uranium and vanadium accumulation and biosorption by Spirulina platensis biomass from single- and multi-component systems was studied. The influence of multi-component system on the spirulina biomass growth was less pronounced in comparison with the single-component ones. To trace the uptake of metals by spirulina biomass the neutron activation analysis was used. In the experiment on the accumulation the efficiency of studied metal uptake changes in the following order: La(V) > Cr(III) > U(VI) > V(V) (single-metal solutions) and Cr(III) > La(V) > V(V) > U(VI) (multi-metal system). The process of metals biosorption was studied during a two-hour experiment. The highest rate of metal adsorption for single-component systems was observed for lanthanum and chromium. While for the multi-component system the significant increase of vanadium and chromium content in biomass was observed. In biosorption experiments the rate of biosorption and the Kd value were calculated for each metal. Fourier transform infrared spectroscopy was used to identify functional groups responsible for metal binding. The results of the present work show that spirulina biomass can be implemented as a low-cost sorbent for metal removal from industrial wastewater.

Bioavailability of Vanadium in Alfalfa in V-Cd Contaminated Soil

A greenhouse experiment was performed to investigate the vanadium bioavailability of alfalfa grown in vanadium-cadmium contaminated soil. The results show bioavailable and total vanadium concentration in rhizosphere soil is higher than it in non-rhizosphere soil. With increasing vanadium addition, its speciation in soil is transformed to AC, RE, and OX fraction, especially to RE fraction. Alfalfa has high vanadium accumulation (up to 1221.86 mg/kg), and 70% of root samples belonged to strong absorption to vanadium. Both bioavailable and total vanadium in rhizosphere and non-rhizosphere soil have direct correlation with its content in alfalfa root. The increasing cadmium addition may inhibit vanadium absorption in alfalfa roots.

Advances in research on the accumulation, redox behavior, and function of vanadium in ascidians

The discovery of high levels of vanadium-containing compounds in ascidian blood cells goes back to 1911. Ascidians, which are also known as tunicates or sea squirts, belong to a subphylum of the Chordata, between the vertebrates and invertebrates. This discovery attracted the attention of an interdisciplinary group of chemists, physiologists, and biochemists, in part because of interest in the possible role of vanadium in oxygen transport as a prosthetic group in respiratory pigments, which was later shown not to be such a role, and in part because of the fact that high levels of vanadium were unknown in other organisms. The intracellular concentration of vanadium in some ascidian species can be as high as 350 mm, which is 107times that in seawater. Vanadium ions, which are thought to be present in the +5 oxidation state in seawater, are reduced to the +3 oxidation state via the +4 oxidation state and are stored in the vacuoles of vanadium-containing cells called vanadocytes, where high levels of protons and sulfate ions are also found. Recently, many proteins and genes that might be involved in the accumulation and reduction of vanadium have been isolated. In this review, we not only trace the history of vanadium research but also describe recent advances in our understanding of the field from several viewpoints: (i) vanadium-accumulating blood cells, (ii) the energetics of vanadium accumulation, (iii) the redox mechanism of vanadium, (iv) the possible role of sulfate, and (v) the physiological roles of vanadium.