This project aims to demonstrate molecular sieve zeolite membranes for effective ion removal from water by reverse osmosis (RO) processes and to investigate the underlying mechanisms of ion rejection and the effects of the membrane microstructure and material chemistry.

Effective management of coalbed gas and oilfield produced brines and radioactive low-level wastewater (LLW) is of critical importance to the nation’s environmental safety. However, current technologies, such as polymeric RO membranes, multiple-effect evaporation, and ion exchange, are either technically or economically unsuitable for treating these particular systems. Zeolite membranes, due to their ceramic nature and unique size exclusion ability, will be capable of efficiently separating the high-concentration produced water and the LLW and withstand high temperature, corrosive environment, and dissolved organic solvents. Ion and water transport in the polycrystalline MFI zeolite membranes (aperture size 0.55nm) will be studied by steady-state RO and transient ion diffusion with zero water permeation. The experimental data will be used to establish a phenomenological mass transfer model for the new RO process and to guide the improvement of membrane and optimization of operation parameters. Success of this research will enable a new membrane approach for effective management of high concentration wastewater.

Team: Tina Nenoff, Junhang Dong (NM Tech)

Funding: SURP/OIT, SURP (Sandia), NMTech, FY04