Membrane Distillation Apparatus and Methods

Abstract

Membranes for membrane distillation include at least one hollow fiber porous hydrophobic membrane, the at least one membrane including carbon nanotubes incorporated into the pore structure of the membrane. Membrane distillation systems may include a heat exchanger operably connected to a hollow fiber membrane module with one or more membranes including carbon nanotubes. Methods of solvent removal, sample preconcentration and desalination employing hollow fiber porous hydrophobic membranes with carbon nanotubes are disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)[0001]This application claims the benefit of U.S. Provisional Patent Application No. 61 / 323,860 filed Apr. 13, 2010, the entirety of which is incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to membrane distillation and in particular to carbon nanotube enhanced membrane distillation apparatus and methods.BACKGROUND[0003]There has been significant interest in using membranes separation for both industrial scale processes and the preparation of analytical samples. In part, this is due to the fact that membranes facilitate extraction and separation without allowing the mixing of two phases. Membrane distillation (MD) is a low temperature (60-90° C.) distillation process that has been used in diverse applications ranging from water desalination to concentration of fruit juice and sucrose. Conventional distillation relies strictly on thermal vaporization, whereas in MD the water vapors are selectively tran...

AI Technical Summary

Benefits of technology

The present invention is about improving membrane distillation by adding carbon nanotubes (CNTs) to the structure of a membrane. This enhances membrane distillation by improving the separation of trace quantities of pharmaceuticals and other compounds from water. The CNTs increase the surface area of the membrane, act as molecular transporters and sorbents, and allow for quick desorption. The membrane with CNTs also has higher solvent reduction and vapor transport capacity. This invention can be applied to a wide range of membranes and forms of membrane distillation.

Problems solved by technology

In part, this is due to the fact that membranes facilitate extraction and separation without allowing the mixing of two phases.

However, the hot solution has a high vapor pressure and MD relies on the net flux of water vapor from the warm side of the membrane to the cool side.

Analytical applications of membrane extraction have relied on the selective permeation of the analyte, and this is a challenge because selective membranes for diverse analytes are not always available.

To date, however, CNTs have not been employed in connection with membrane distillation techniques.

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