Selective removal of tungstate anions from aqueous solutions by surface anion‐imprinted ceramic membranes

Abstract

BACKGROUND: It is significantly important to develop new technologies and materials for removal of tungstate anions (W(VI)) from aqueous solutions. An ion imprinted membrane not only possesses all virtues of a separation membrane, but also has tailor-made recognition sites. In this work, a novel surface anion-imprinted ceramic membrane (IIP-PEI/CM) was fabricated to remove W(VI) selectively from aqueous solutions. RESULTS: FT-IR, XPS, TGA, SEM, streaming potential, pore size distribution and water flux confirmed the successful fabrication of IIP-PEI/CM. With increasing pH, binding capacities (Q e ) of W(VI) onto IIP-PEI/CM and non-imprinted membrane (NIP-PEI/CM) rapidly decreased. At pH = 2.0, Q e values of IIP-PEI/CM and NIP-PEI/CM were 139.4 and 47.9 mg 100 g −1 , respectively. Binding equilibrium was achieved within 3 min, showing an ultra-fast kinetic process. Compared with NIP-PEI/CM, IIP-PEI/CM had higher selectivity for W(VI) in the presence of Mo(VI) and Cr(VI) ions, and its selectivity coefficients for W(VI)/Mo(VI) and W(VI)/Cr(VI) were 15.47 and 19.74, respectively. During dynamic filtration, IIP-PEI/CM was effective and selective for removal of W(VI), and it had a good reusability. Protonated amine groups within PEI participated the uptake of W(VI) by electrostatic interactions. CONCLUSION: IIP-PEI/CM showed ultrafast and selective binding of W(VI) anions, and has potential application for W(VI) removal/recovery from aqueous solutions.

Preparation and performance of UiO‐66‐(COOH)2‐based mixed matrix membranes for efficient separation of Sr2+ ions from aqueous solutions

“…The membrane flux ( J ) was calculated using Eqn (1), and the concentration of Sr 2+ ions was determined using the UV spectrophotometer at 618 nm. The rejection rate ( R ) of membrane was calculated using Eqn (4) 32 : where R represents the rejection rate of the membrane towards Sr 2+ ions and C f (mg L −1 ) and C p (mg L −1 ) are Sr 2+ concentrations in the feed and the permeate, respectively.…”

“…The membrane flux (J) was calculated using Eqn (1), and the concentration of Sr 2+ ions was determined using the UV spectrophotometer at 618 nm. The rejection rate (R) of membrane was calculated using Eqn (4) 32 :…”

Molecularly Imprinted Affinity Membrane: A Review

“…Another anion-selective MIAM was also synthesized on a ceramic support. 111 This later membrane is selective to tungstate ion with selectivities of 15.5 and 19.7 for W(VI)/Mo(VI) and W(VI)/Cr(VI), respectively. The membrane restricts tungstate ion permeation by binding the ion while allowing other ions and water to pass through.…”

“…Another anion-selective MIAM was also synthesized on a ceramic support. 111 This later membrane is selective to tungstate ion with selectivities of 15. the ion while allowing other ions and water to pass through. Polyethylenimine in the membrane contributes to tungstate ion adsorption by electrostatic interaction.…”

“…Similar to previously mentioned results, the imprinted cavities of Mo­(VI) increase MIAM selectivity for Mo­(VI). Another anion-selective MIAM was also synthesized on a ceramic support . This later membrane is selective to tungstate ion with selectivities of 15.5 and 19.7 for W­(VI)/Mo­(VI) and W­(VI)/Cr­(VI), respectively.…”