Separation of vanadium and chromium by selective adsorption by titanium-based microspheres

The separation and recovery of V(V) and Cr(VI) from solution can achieve the dual purpose of resource utilization and environmental protection. In this work, amorphous titanium-based microspheres with a large specific surface area of 574.86 m2/g were prepared by the simple hydrolysis of titanium alcohol. This adsorbent exhibited excellent adsorption of V(V) and Cr(VI), with maximum capacities of 153.2 and 54.21 mg/g, respectively. Most importantly, in V(V)/Cr(VI) mixed solution, selective adsorption of V(V) can be achieved by competitive adsorption. The Dubinin-Radushkevich isotherm model and Elovich kinetic model yielded the best fit for experimental data, which indicated the adsorption of V(V) and Cr(VI) onto titanium-based microspheres is a combination of chemical adsorption and physical adsorption. Selective adsorption can be achieved when sufficient V(V) was present in the V(V)/Cr(VI) mixed solution (pH 3), which is due to H3V10O283− has the more negative values of Eads (-188.12 kJ/mol) and ΔG0 (−40.72 kJ/mol). The column experiment showed promise for application in the continuous removal and separation of V(V) and Cr(VI) from wastewater to obtain qualified pure V(V) and Cr(VI) products. Through the adsorption of different concentrations of V(V)-Cr(VI) solutions, real vanadium leaching solution and real vanadium precipitation wastewater, the purification of high-concentration solutions and the treatment of low-concentration solutions could be realized.