A membrane filtering device includes a substrate, a support membrane supported by the substrate, and a separation membrane supported by the support membrane. The separation membrane includes material that is substantially embedded into pores of the underlying support membrane. Optionally, the support membrane includes particles that are also substantially embedded into pores of the substrate.
U.S. GOVERNMENT RIGHTS
 This invention was made with Government support under contract no. DE-FG02-05ER84315 awarded by the Department of Energy and grant no. 2003-33610-13085 awarded by the Department of Agriculture. The Government has certain rights in this invention.