Synthesis of Di-(2-ethylhexyl) Phosphoric Acid (D2EHPA)-Tributyl Phosphate (TBP) Impregnated Resin and Application in Adsorption of Vanadium(IV)

Abstract

In order to improve the adsorption capability of solvent-impregnated resins (SIRs) for vanadium(IV) (V(IV)), the dual extractant (D2EHPA (Di-(2-ethylhexyl) phosphoric acid) and TBP (Tributyl phosphate)) impregnated resins (D-TIRs) were prepared by impregnating Amberlite TM XAD-16HP macroporous resins with the mixed extractant that is composed by different molar ratios of D2EHPA to TBP. The effects of the ratio of D2EHPA to TBP on the performance of D-TIRs were investigated. The results show that the impregnation ratio of the D-TIRs decreases gradually with the increasing proportion of TBP in the mixed extractant. The sole-TBP impregnated resins (TIRs) have no adsorption capability for V(IV), indicating that the adsorption of V(IV) is attributed to D2EHPA. The adsorption capacity of D-TIRs for V(IV) attained the maximum when the ratio of D2EHPA to TBP is 7:3 at pH 1.8, and it can be improved by increasing the extractants concentration during the impregnation process. Adsorption isotherm indicates that the addition of TBP can increase the adsorption capacity of D-TIRs for V(IV) from 24.65 to 29.75 mg/g after 16 h reaction. Adsorption kinetics verifies that the addition of TBP can largely accelerate the adsorption equilibrium of V(IV) onto the D-TIRs and V(IV). Electrospray ionization (ESI) mass spectra and Fourier transform infrared spectra (FT-IR) analysis indicates that the addition of TBP to D2EHPA can make some dimeric D2EHPA change to monomers by breaking the hydrogen bonds of D2EHPA-dimers, leading to the result that the pseudo-second order kinetic for the adsorption of V(IV) onto the D2EHPA impregnated resins (DIRs) converts to the pseudo-first order kinetic for that onto the D-TIRs. Also, D-TIRs have better separation capability of V(IV) from Fe(II) and Al(III) in the vanadium leaching solution than DIRs.

A High-Efficiency Approach for the Synthesis of N235-Impregnated Resins and the Application in Enhanced Adsorption and Separation of Vanadium(V)

“…Figure 1 shows that the impregnation ratio of the N-TIRs significantly decline with the decrease of the molar ratio of N235 to TBP, which may be attributed to the different affinity of N235 and TBP for the support resins. As is known to us, the weak polar N235 have relatively higher affinity for the non-polar matrix of the resins matrix (Phenyl ethylene-divinyl benzene) in comparison to polar TBP [17]. As the molar ratio of N235 to TBP decreases, the content of N235 decreases and thus the impregnation ratio of the N-TIRs decline with the decreasing molar ratio.…”

“…Figure 4 presents the FTIR spectra of the N-TIRs and NIRs. A literature shows that the characteristic vibration bands of P=O, 1281 cm −1 , would appear in the SIRs containing TBP [17]. It is obviously found that the characteristic adsorption peak of N235 (C-N bonds, 1099 cm −1 ) shifts to the lower wavenumber (1096 cm −1 ) and the intensity of the C-N bonds decreases (Figure 4a), and the P=O stretching bands also shifts to lower wavenumber 1263 cm −1 (Figure 4b), which may be attributed to that N235 is involved with TBP [23].…”

“…In addition, fewer stages could be used to achieve the required zinc recovery and its effective separation from solutions containing other metal ions by using TBP as a modifier [16]. Based on the fact that a positive synergic effect on the extraction of targeted metals can be achieved by introducing a secondary reagent, such as TBP, Zheng et al [17] introduced TBP into the DIRs and investigated the adsorption performance of the D2EHPA-TBP impregnated resins (D-TIRs) for V(IV). The results revealed that the D-TIRs have higher adsorption capacity for V(IV) at shorter adsorption equilibrium time and have better separation capability of V(IV) from Fe(II) and Al(III) when compared with DIRs.…”

Amphiphiles-metals interactions for applications in modern technologies: recent developments and future perspectives

“…The results show that the sole-TBP impregnated resins have no adsorption capability for V(IV), indicating that the adsorption of V(IV) is attributed to HDEHP. 75…”

Purification of cobalt solutions in several solvent extraction steps: Using MEXTRAL and D2EHPA as extractants

“…Many projects are planning to follow the SX path and are considering including up to three or four SX plants in series, with each of them using a different reagent. Ketoximes and aldoximes based extractants such as LIX 984N and MEXTRAL 984N are a judicious choice for removal of copper while D2EHPA is mainly used for the purification of cobalt sulphate solutions in order to remove iron, zinc and manganese (Roux et al, 2007;Kopper Chemical Industry, 2019a;Sato et al, 1985;Zhang et al, 2018).…”