Development of Membrane Based Operations for Emerging Separations Challenges
Ranil Wickramasinghe
Ralph Martin Department of Chemical Engineering
University of Arkansas
Abstract
Membrane based separations are attractive for a number of reasons such as easy scale up,
lower operating cost and the potential for significant process intensification. For applications
in bioseparations linear scale up is important given the regulatory approvals needed for amanufacturing process. For water treatment applications such as reverse osmosis, lower
operating costs compared to evaporative processes are a major advantage. Catalytic membranesprovide the possibility of combining reaction and separation into one unit operation which leads
to significant process intensification. This could enable the economic conversion of waste
biomass to bio-based chemical intermediates. In this presentation the potential for membranes
in each of these areas will be discussed.
Biopharmaceutical manufacturing processes make use of cell lines to produce
therapeutics such as monoclonal antibodies, fusion proteins etc. Today, biopharmaceuticalmanufacturing processes are typically run in batch mode. There is however a great deal ofinterest in developing continuous biomanufacturing processes in order to minimize batch tobatch variation. Membrane based bioseparations are run in batch mode. Development ofcontinuous membrane based bioseparations is essential. Here virus filtration will be highlighted.
Virus filtration is routinely used for validation of virus clearance in the manufacture ofbiopharmaceutical products. Validation of virus clearance is required by regulatory agencies.
Development of virus filtration operations that are compatible with continuous
biomanufacturing operations will be essential. Our results indicate that development ofmembranes that are compatible with constant flux operation as opposed current practice which
is based on constant pressure operation will be required.
Sustainable waste management practices will be essential in order promote a circulareconomy. The use of electrocoagulation as a feed pretreatment operation prior to membranedistillation will be described. Today highly impaired hydraulic fracturing flow back water istypically reinjected into a geologically isolated formation in the Earth’s crust. However, treating
this highly impaired water for beneficial uses will promote a circular economy. The advantagesof an integrated electrocoagulation, microfiltration and membrane distillation process for
maximizing water recovery from hydraulic fracturing produced water will be described.
The overall agricultural industry contributes more than 25% to world greenhouse gas
emissions. Agricultural residues represent an abundant source of fuels and chemicalintermediates. Here lignocellulosic biomass hydrolysis and dehydration has been conductedusing a synthetic polymeric solid acid catalyst consisting of dual polymer chains grafted fromthe surface of a ceramic membrane. These novel, patented, polymeric solid acid catalysts aresuperior to cellulases enzymes as they can be operated at a higher temperature and at a muchhigher hydrolysis rates. These catalysts are stable and maintain high catalytic activity overrepeated runs. Moreover, they can be easily regenerated and are environmentally friendly.
These polymeric solid acid catalysts can be used not only for hydrolysis but also dehydrationof cellulose leading to the production of 5-hydroxymethylfurfural (HMF) or levulinic acid. By
using a catalytic membrane, reaction and separation can be combined into a single unit
operation leading to an intensified process.