Project Summary
Our project aims to recover solvents from waste streams with low concentrations of solvents, such
as chlorinated and aromatic solvents, DNAPL, MTBE, tetrahydro furan, and others. These waste
streams are typically produced by Superfund sites, and our primary objective is to recover the
solvents from them. These wastes are currently treated as hazardous waste for disposal, which
is an expensive and wasteful approach. Our proposal offers a sustainable solution by
concentrating dilute (1 to 10%) solvent waste to 60 or 70%, which can be sent to a distillation
column or purified through membrane separations such as pervaporation and nanofiltration to
generate pure solvents (95-99%). These recycled solvents can be resold in the market or
repurposed for other applications. To achieve our goals, we propose the development of
Microwave Induced Membrane Distillation (MIMD) with Carbon Nanotube Immobilized Membrane
(CNIM) or MIMD-CNIM. Here, a hydrophobic porous membrane with immobilized carbon
nanotubes separates a hot feed waste stream and a cold permeate. The membrane prevents the
aqueous solution from entering the pores, while the solvent vapor passes through and is
condensed on the permeate side of the membrane. The major advantage of CNIM is its ability to
selectively transport solvents by increasing the partitioning on the nanotube surface. The waste
stream is heated using a microwave heater, which enhances recovery via non-thermal effects
such as localized superheating, breakdown of hydrogen-bonded structures in aqueous
environments, and the creation of nanobubbles. We propose three specific aims, which include
1) membrane development; 2) testing of MIMD for different solvent streams and 3) testing with
real-world wastes. By developing this technology, we hope to provide a sustainable solution for
recovering solvents from aqueous solvent wastes, which can reduce the amount of hazardous
waste generated by Superfund sites and other industries. Moreover, this approach can contribute
to the circular economy by promoting the recycling and reuse of solvents.
