Imprinted membranes: a molecular modelling study

The removal of impurities with low molecular weight such as genotoxics from organic solvents is a challenge of considerable interest. The nanofiltration can definitely be a reliable solution. In addition, the solvent purification from a specific molecule by means of molecularly imprinted membranes (MIMs) can be a step forward compared to the traditional nanofiltration procedure. MIMs can be regarded as an intelligent improvement of the classical nanofiltration membranes. Progresses have been obtained in the field of the low molecular weight impurities removal from organic solvents using NF (OSN) and MIMs in relation to the material choice, used for the membrane preparation (material design), and in the optimization of the integrated separation processes (process design). However, from a theoretical point of view, up to date, there is not a wide literature concerning knowledge, at molecular level, on MIMs key properties. In this contribution, some sub-nano properties (binding energies) have been accurately calculated in order to begin to remedy this gap. In particular, the calculations presented here are useful to understand the cause determining the increase of affinity of a MIM to the 4,4'-methylendianiline (MDA) genotoxin, dissolved in an organic solvent (butanol). The MIM was prepared according to the dry-wet phase inversion method using a copolymer of acrylonitrile (AN) and acrylic acid (AA). The polyacrylonitrile (PAN) is thermally stable and resistance to bacterial attack and to most organic solvents [1,2]. In addition, the acrylic acid monomer is used in order to increase the interaction of the copolymer to the target molecule [3].