Proton-based solid acids for ammonia absorption in ammonia water

Abstract Ammonia absorption behavior of insoluble proton-based solid acids such as proton-exchanged montmorillonite, proton-exchanged zeolites α-zirconium phosphate and acid impregnated activated carbon in the water solution, was studied by ammonia and pH meters. The ammonia absorption capacity of α-zirconium phosphate was 10.2 wt%, which was highest among those acids. The ammonia absorption capacities corresponded to the proton exchange capacities, indicating that NH3 reacts with H+ to form NH4+ in the solid acids. The nitrogen concentration in the solution (NH3, NH4+) about 2500 ppm decreased with time, approaching about 50 ppm by addition of α-zirconium phosphate which is also useful to suppress the water pollution. Simulated leaked ammonia gas about 1000 ppm was removed by addition of aqueous dispersion of α-zirconium phosphate.