EDBM cross-flow stack

In bipolar membranes H2O is splitted into caustic (OH-) and acid (H+), by electricity. This acid or caustic can be reused in production processes. The EDBM cross flow stack is typically used for:

  1. NH4+ removal from strippers liquids, convert into highly concentrated pure NH3 solution.
  2. CO2-removal from flue gas or direct air capture, convert into bottled pure CO2-gas
  3. Lithium recovery from brines as Lithium Hydroxide.
EDBM cross-flow stack​

NH4 removal from NH4 strippers

Ammonium (NH4+) rich streams, such as digestate are generally treated in ammonium strippers, where NH4+ is stripped from the digestate by increasing pH and temperature, into NH3 in gas form. This NH3 is then washed in a scrubber with H2SO4, to remove the NH3 as (NH4)2SO4.

REDstacks EDBM cross flow stacks can be used to convert the NH4 to NH3 and regenerate the H2SO4 so that a chemistry free process can be operated. The liquid NH3 in general has a higher value than the liquid (NH4)2SO4.

CO2 removal from solvents

REDstack EDBM stacks are used in Direct Air Capture (DAC) technologies to extract the CO2 from alkaline solvents.

In the alkaline solvents CO2 is dissolved as CO32-, which with acid produced in the bipolar membranes of the EDBM stack, is released as CO2 and H2O. The CO2 can be harvested as pure gas. The alkaline solution can be reused in the process.

The EDBM stacks of REDstack have no carry over of liquids between compartments. This makes a 100% reuse of the alkaline solution possible, which is essential in DAC applications.