Alternative Technologies
Desalination by In-Situ Crystallization
Sandia has developed low cost inorganic ion exchange materials that can desalt brackish water using an in-situ precipitation approach. This technology uses inexpensive raw materials to form anion and cation materials for in-situ deionization of oil-field produced waters.
For anion exchange, we have focused on hydrotalcite (HTC), a low-cost layered hydroxide similar to clay in structure. For cation removal, we have developed an amorphous silica material (permutite) that has enhanced cation (in particular Na+) selectivity. In the case of produced waters with high concentrations of Ca2+, a lime softening step is included.
Capacitive Deionization
Sandia is testing the use of capacitive deionization technology from
Biosource Inc. The patented charge barrier electrode technology has been used to deionize produced water from a coal-bed methane well.
