Deodorization performance of charcoal particles loaded with orthophosphoric acid against ammonia and trimethylamine Original Research Article

A deodorant was prepared by drying charcoal particles after dipping in aqueous H3PO4 solutions. The deodorization performances of the samples against NH3 and (CH3)3N odor gases were examined by a detection test tube method and compared with those of a conventional coconut shell-derived active carbon loaded with H3PO4 in the same manner. The charcoal particles with H3PO4 exhibited higher performances than those of the other against both the odor gases. Ammonia gas was caught on the sample surface through reaction with the loaded H3PO4 to form NH4H2PO4 and further (NH4)2HPO4 but the deodorization mechanism for (CH3)3N could not be decided. The high performances of the charcoal particles loaded with H3PO4 were due to its characteristic porous structure consisting of large pores, i.e., such pores were suited for loading a large amount of H3PO4 and were not apt to be blocked by the loaded H3PO4. Also large pores were not blocked by expansion of H3PO4 on the pore surface through the deodorization reactions. The active carbon being composed of a large number of micropores did not exhibit these advantages.