Efficient and environment-friendly vanadium (V) extraction from vanadium shale leachate using tri-n-octylmethylammonium chloride

Removal of V(V) from a Mixed Solution Containing Vanadium and Chromium Using a Micropocrous Resin in a Column: Migration Regularity of the Mass Transfer Zone and Analysis of Dynamic Properties

In China, both vanadium(V) and chromium(VI) are present in wastewater resulting from vanadate precipitation (AVP wastewater) and from leaching vanadium-chromium reduction slag. Addressing environmental preservation and the comprehensive utilization of metal resources necessitates the extraction and separation of V(V) and Cr(VI) from these mixed solutions. However, their separation is complicated by very similar physicochemical properties. This study establishes a method for the dynamic selective adsorption of V(V) from such mixtures. It evaluates the impact of various operating conditions in columns on dynamic adsorption behavior. This study examines the migration patterns of the mass transfer zone (MTZ) and forecasts its effective adsorption capacity through multivariate polynomial regression and a neural network (NN) model. The NN model's outcomes are notably more precise. Its analysis reveals that C 0 is the most critical factor, with Q and H following in importance. Furthermore, the dynamic properties were analyzed using two established models, Thomas and Klinkenberg, revealing that both intraparticle and liquid film diffusion influence the rates of exchange adsorption, with intraparticle diffusion being the more significant factor. Using 3 wt % sodium hydroxide as the eluent to elute V(V)-loaded resin at a flow rate of 4 mL/min resulted in a chromium concentration of less than 3 mg/L in the V(V) eluate, indicating high vanadium-chromium separation efficiency in this method. These findings offer theoretical insights and economic analysis data that are crucial for optimizing column operation processes.

Vanadium recovery by electrodialysis using polymer inclusion membranes

Industrial applications and environmental awareness recently prompted vanadium recovery spell from secondary resources. In this work, a polymer inclusion membrane containing trioctylmethylammonium chloride as carrier was successfully employed in electrodialysis for vanadium recovery from acidic sulfate solutions. The permeability coefficient of V(V) increased from 0.29 µm·s^-1 (without electric field) to 4.10 µm·s^-1 (with the 20 mA·cm^-2 current density)_. The transport performance of VO₂SO₄^-, which was the predominant species containing V(V) in the acidic region (pH <3), was influenced by the aqueous pH value and sulfate concentration. Under an electric field, a low concentrated H₂SO₄ solution (0.2 M) effectively stripped V(V) from the membranes, avoiding the requirement of a highly concentrated H₂SO₄ without electric field. Under the optimum conditions, the permeability coefficient and flux reached 6.80 µm·s^-1 and 13.34 µmol·m^-2·s^-1, respectively. High selectivity was observed for the separation of V(V) and Mo(VI) from mixed solutions of Co (II), Ni (II), Mn (II), and Al (III). Additionally, the separation between Mo(VI) and V(V) was further improved by adjusting the acidity of the stripping solution. The V(V) selectivity for the resulting membrane was higher than that of commercial anion exchange membranes.

Study on Extraction Performance of Vanadium (V) from Aqueous Solution by Octyl-Imidazole Ionic Liquids Extractants

It is worth it to explore the extraction performance for vanadium by the imidazole ionic liquids. The extraction of vanadium (V) was studied using [Omim]Cl, [Omim]Br, and [Omim][BF4] as extractants. The effects of various diluents, equilibrium time, extraction temperature, and anion species were investigated. The structure-activity relationship of vanadium and ILs was discussed by calculating the lattice energy of ILs based on the Glasser theory and the volume of anions. The results show that n-pentanol is the optimum diluent. Under the extraction conditions of an equilibrium time of 60 s and extraction temperature of 25 °C, the extraction rates of V (V) by [Omim]Cl, [Omim]Br, and [Omim][BF4] reached 97.93%, 96.59%, and 87.01%, respectively. Furthermore, based on the Glasser theory, the lattice energy of ionic liquids decreased in the order [Omim]Cl > [Omim]Br > [Omim]BF4. The volume of the anions increased in the order Cl− < Br− < BF4− < HVO42−. The extraction rate of V (V) depended on the size of the anions and the strength of the interaction between the anion and imidazolium cation. The results of counterevidence experiments verified the larger the anion volume, the easier it is to combine with cation in the organic phase, and the lattice energy of extracted compound is lower. The statistical analysis showed that the effect of the equilibrium time and temperature were not significant in the model, and the anions species showed a significant effect on the extraction efficiency of V (V).

Efficient Separation and Recovery of Vanadium(V) from Hydrochloric Acid Solution Using N1923 as an Extractant

Hydrochloric acid leaching has been widely used in the recovery process of vanadium due to its efficient selectivity. It was necessary to further separate vanadium from hydrochloric acid leaching solution. Four extractants of P204, P507, Cyanex272, and N1923 were compared for extraction of vanadium from a simulated hydrochloric acid solution, and it is concluded that N1923 was an effective extractant suitable for the extraction and separation of V (V) in the medium. The single-stage extraction efficiency of vanadium reached more than 90% with a pH value of 2.0, extraction time of 5 min, and X _N1923 of 0.2 at 30 °C. The functional group characteristics of the extraction complex were analyzed by means of an extraction slope method, FT-IR, and ¹H NMR to judge the extraction mechanism of vanadium with N1923 as an extractant. The extraction of V (V) by using N1923 was in the coordination form of a molar ratio of 2:1, and the extraction process was an endothermic reaction. The N-H vibrational absorption peak in the -NH₂ group still appeared in the loaded N1923, in which the chemical shift of ¹H in the primary amine and secondary carbon still existed. This technology was a more efficient process for extraction of vanadium from hydrochloric acid solution.

Recovery of spent VOSO4 using an organic ligand for vanadium redox flow battery applications

To recover the spent vanadium compound, Rhodamine-B-based Schiff's base ligand (L₁) was synthesized via ultrasonication process and was evaluated with vanadyl sulfate (VOSO₄), which has shown considerable selectivity towards V(IV). The change of the solution color from colorless to pink is attributed to L₁ after the reaction with vanadium ion owing to the successful formation of the vanadium complex and the opening of the spirolactam ring in the L₁ structure. In FT-IR spectra, the vanadyl peaks are co-existed with the L₁ structure, which confirmed the complex formation of the L₁ with vanadium. Similarly, the binding energy of V(IV) was identified at 516.2 eV for V2p_3/2 in XPS spectra. The new strategy for VOSO₄ recovery was established through solvent extraction and acid leaching. After recovery process, the absence of vanadium peak in the XPS confirmed the complete removal of V(IV) from the complex. The recovered VOSO₄ solution used as an electrolyte in vanadium redox flow battery (VRFB) systems, where the unit cell performance is comparable with the conventional electrolyte solution. The advantage of study is reuse of VOSO₄ as a resource for energy storage applications.