Evaluation of chiral separation by Pirkle-type chiral selector based mixed matrix membranes

Abstract

In the present approach, the chiral resolution capacity of mixed matrix membranes (MMMs) containing silicon-based mesoporous array (named MCM-41) and grafted with Pirkle-type chiral selector is presented. The mesoporous structure was prepared via the hydrothermal method and the polyethersulfone (PES)-based MMMs were obtained from the phase inversion method. The eco-friendly and sustainable synthesis of the mesoporous architecture from the use of silicon-rich waste proved to be efficient, since the MCM-41 structure exhibited interesting textural and structural features, such as high porosity, large pore volume, uniform pore diameter, and high surface area. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) measurements were useful to confirm the presence of MCM-41-Pirkle within the MMMs. The performance of the MMMs was evaluated through filtration tests with the analyte 2,2,2-trifluoro-1-(9-anthryl) ethanol (Pirkle’s alcohol). The concentration of both enantiomers throughout the filtration was monitored by liquid chromatography (LC) using L-phenylglycine column Regis® Technologies (25 cm, 4.6 mm d.i., 5 µm). The MCM-41-Pirkle incorporated within the PES matrix exhibited a good enantioselectivity (α = 1.28) and 45% of the (R)-Pirkle's alcohol was retained. According to our findings, this nano-architectured material can be considered a relevant alternative with great potential for chiral separations in polymeric membrane technology.