Simultaneous adsorption of V(V) in both anionic and cationic forms from acid leaching solution using iminodiacetic acid chelating resin

An efficient separation and extraction method for the recovery of V(V) in both anionic and cationic species from pressure acid leaching solution of vanadium shale was developed using the iminodiacetic acid chelating resin CH-90. The optimum process parameters were explored. The mechanism of V(V) adsorption and selective separation between V(V) and impurities were revealed by FTIR, XPS, SEM-EDS, and DFT theory. Experiments showed that under the conditions of pH=1.6, adsorption temperature of 40 degrees C, bed volume of 20 mL, and feed liquid flow rate of 2 BV/h, the resin had the best effect on V(V) with an adsorption rate of 91.3% and impurity ions adsorption rate less than 20%; The desorption rate of V(V) can reach 100% when 2 mol/L HCl as the desorption agent; 4 mol/L HCl could restore the performance of resin. The reaction between the resin and V(V) included the electrostatic interaction between H2V10O284- and -N, and the coordination reaction in which VO2+ chelated with N and O atoms. DFT calculation results showed that resin preferentially adsorbed H2V10O284- during the adsorption process. CH-90 resin contributed to simultaneously separating V(V) in the form of H2V10O284- and VO2+ from a complex sulfuric acid leaching system at low pH.

Automated summary

An efficient method for the separation and recovery of V(V) from the pressure acid leaching solution of vanadium shale was developed using the iminodiacetic acid chelating resin CH-90. By investigating the mechanism of V(V) adsorption and selective separation between V(V) and impurities, it was found that the resin preferentially adsorbed H2V10O284- during the adsorption process. The CH-90 resin contributed to simultaneously separating V(V) in the form of H2V10O284- and VO2+ from a complex sulfuric acid leaching system at low pH.