Interactions of ammonia with the surface of microporous carbon impregnated with transition metal chlorides

The BPL carbon samples impregnated with chlorides of copper, nickel, and zinc were used as ammonia adsorbents in dynamic conditions with various amounts of water present in the systems. The initial and exhausted samples were characterized using adsorption of nitrogen, XRF, XRD, FTIR, SEM, and thermal analysis. The results indicate that metal chlorides are active centers for ammonia adsorption via formation of complexes. Water enhances the amount of ammonia adsorbed, promoting its dissolving into the film of water adsorbed in micropores and formation of NH4+ ions. Even though the pore system of activated carbon provides spaces for dispersion of metals, it still contributes significantly to the amount of ammonia adsorbed (about 80%) via dispersive forces. The most efficient adsorbent for ammonia removal is the carbon impregnated with copper. In this material the efficiency is governed by the amount of copper introduced to the carbon and its dispersion on the surface.