Kinetics and adsorption isotherm of ammonia uptake by cation exchange resins and treatment of mixed aqueous lactate–ammonia by Mg–Al layered double oxide and the resins

The proliferation of pluripotent stem cells in mass cell culture is hindered by the release of cell metabolites such as lactate and ammonia. In this work, a porous strong-acid cation exchange resin (PK216LH) and Mg–Al layered doubled oxide (LDO) were used to take up NH₄⁺ and lactate, respectively. Initially, PK216LH could take up NH₄⁺ from an aqueous solution. The uptake of NH₄⁺ by PK216LH followed pseudo-second-order kinetics and corresponded to the Langmuir adsorption isotherm, with an apparent activation energy of 28.2 kJ/mol and a maximum adsorption amount of 1.38 mmol/g. The simultaneous use of Mg–Al LDO and PK216LH could not sufficiently take up lactate and NH₄⁺. In contrast, the individual use of Mg–Al LDO and PK216LH in two stages enabled efficient removal of lactate and NH₄⁺.