Purification of Pharmaceutical Solvents by Pervaporation through Hybrid Silica Membranes

Abstract

Solvents purification mainly used in pharmaceutical field such as acetone and methyl ethyl ketone (MEK) were performed through hybrid silica membranes and from binary and multi-components mixtures. Two hybrid silica membranes—zirconia doped bis(triethoxysilyl)methane and bis(triethoxysilyl)ethane (BTESE)—were studied. Flux, permeance, and separation factor were evaluated depending on temperature, composition, and number of organic compounds in the feed. Dehydration tests of acetone were operated at 30 and 45 °C following by acetone and MEK purification at 50 °C from multi-components hydro-organic mixtures where hydrophilic compounds (water, methanol) but also hydrophobic (dichloromethane (DCM) and/or toluene) were present. Results showed that the presence of Zr nanoparticles affected flux and improved selectivity in the case of dehydration. Experiments related to acetone and MEK purification, revealed a mass transfer alteration and a decrease of performance, from 99 to 97 wt% and from 98 to 95 wt% respectively, when the number of compounds in the initial feed grown up and more precisely, in the presence of DCM and toluene thus highlighting a possible coupling effect.

Progress on Silica Pervaporation Membranes in Solvent Dehydration and Solvent Recovery Processes

“…Their successful isolation from binary or multicomponent mixtures provides an invaluable route, bypassing the limitation and high costs associated with distillation and other conventional technologies in use. The study by La Rocca et al [ 97 ] deals with this problem using two variants of zirconium doped hybrid silica membranes. These variants defer in the precursor used, which are bis(triethoxysilyl)methane and bis(triethoxysilyl)ethane.…”

Spontaneous sieving of water from ethanol using angstrom-sized nanopores

“…Pore diameters of SWCNTs are usually calculated by subtracting the van der Waals diameter of carbon from the center-to-center distance between the diametrically opposite carbons in an SWCNT. Kinetic diameter of ethanol is between 0.43-0.45 nm, 18,19 whereas using the definition of the pore size of CNTs mentioned above, pore sizes are evaluated as 0.43 nm and 0.41 nm for (8,3) and (6,5)-SWCNTs. Based on these definitions of pore size, ethanol should not be able to fill these nanotubes.…”

Water/Ethanol and 13X Zeolite Pairs for Long-Term Thermal Energy Storage at Ambient Pressure

“…In fact, the amount of loaded sorbate depends on the affinity between its fluid molecules and the zeolite surface, and on the size of the fluid molecules with respect to that of the pores and cages in the zeolite framework. Ethanol and water are both polar liquids; yet, the kinetic diameter of water molecules is about 2.96 Å, while ethanol ones about 4.30 Å (La Rocca et al, 2019). Zeolite 13X has average pore size around 9 Å, which allows intrusion of both molecules; however, also because of their smaller size, water molecules can achieve larger adsorption on the zeolite structure.…”