Recognition and separation of artemisinin by two-dimensional GO/MXene laminar imprinted composite membranes constructed based on self-supporting technology

Abstract

In order to solve the problem that some of the imprinted sites were embedded inside the membranes due to the blending method, resulting in low utilization of the imprinted sites, a two-dimensional click graphene oxide (GO)/MXene self-supported layered imprinted composite membranes (CGMMs) was devised and prepared for the adsorption and efficient discriminative separation of artemisinin. Firstly, MXene was modified by self-polymerization using dopamine (PDA), and PDA hybrid coating was constructed on the surface of MXene, which was effective in improving the oxidation brittleness and hydrophilicity of MXene. Given the structural and hydrophilic similarities between GO and MXene nanosheets, the produced CGMMs exhibit an outstanding hydrophilicity and a characteristic lamellar shape. Subsequently, spherical imprinted polymers based on MXene were successfully constructed on the surface and interlayer of stacked GO/MXene nanosheets. The performance of CGMMs was explored by isothermal adsorption, kinetic adsorption, selective adsorption tests and selective permeation tests. The equilibrium adsorption capacity of CGMMs reached 36.10 mg g−1 with satisfactory selective separation capacity (αArtemisinin/ Artesunate = 4.10 and αArtemisinin/ Dihydroartemisinin = 3.03) and excellent permeation selectivity (βArtesunate/ Artemisinin = 5.71 and βDihydroartemisinin/ Artemisinin = 4.40), which implied the successful construction of effective artemisinin-imprinted sites on CGMMs. An essential aspect of the excellent adsorption property and selectivity exhibited by the prepared CGMMs is that the cross-section of CGMMs is composed of MXene nanosheets and GO nanosheets superimposed on a laminar structure dotted with imprinted polymers, which extends the molecular transport channels and facilitates the construction of more molecular imprinting sites.