(646f) Novel Metal Organic Brush Membranes (MOBs) for Organic Solvent Nanofiltration

2019 AICHE
Annual Meeting, Orlando, Florida (November 10^th -15^th,
2019)

Session: Separations: 02D12 Membrane-Based Organic Solvent Separations - Oral
Session

Chairs: Ryan Lively, Andrew Livingston and Guanghui
Zhu

Novel metal
organic brush membranes (MOBs) for organic solvent nanofiltration

Pranav Ramesh, Weiwei
Xu, Miao Yu and Georges Belfort

Howard P. Isermann
Department of Chemical and Biological Engineering and the Center of
Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute,
Troy, NY 12180-3590

Abstract

Polymer membranes suffer from selectivity limitations for liquid
applications that result from relatively wide pore size distributions and
polymer flexibilities. Although these membranes have been widely successful in
many industries and dominate membrane applications in general, their use has
been limited to large differences in solute size. The long-term objective of
this project is to narrow the pore size distribution and stiffen the polymer
structure by incorporating metal organic framework (MOF) entities and
cross-linking special designed brush membranes. Below, we report on preparing
the brushes and then incorporating the MOFs into the brushes and on their
characterization and filtration performance. 

Previously, we and others have reported on the use of Activators
Regenerated by Electron Transfer - Atom Transfer Radical Polymerization
(ARGET-ATRP) for grafting polymer brush membranes on a porous support.  In this
work, we focus on Single Electron Transfer–Living Radical Polymerization
(SET-LRP) due to the ‘green’ advantages of this method such as the ability to
carry out the reaction at room temperature and utilizing copper metal as
opposed to dissolving copper powder in solution. Several vinyl monomers were
evaluated based on carbon chain length, functional end-groups and polarity. 
More importantly, this work further investigates the role of incorporated MOFs
in the selective brush layer. Metal Organic Framework (MOF) were formed in-situ
within the brush upper layer. Characterization of MOB membranes as well as the
underlying brush membranes were carried out using a combination of ATR-FTIR and
EDX to understand the chemistry followed by SEM and AFM for morphological
information. The membranes were also tested for their ability to remove dyes
from organic solvents by filtration.

 The use of MOFs in membranes allows for greater structural rigidity as
well as to control pore size. MOFs may be altered to obtain a series of
membranes which may have the potential to replace energy chugging distillation
columns.  Due to their stability, tunability and ease of scaleup, we expect
MOBs to play a critical role in replacement of thermal systems for chemical and
petrochemical industries.