Pourable solid filter material, particularly for the removal of unpleasant odors from the air, and a process for its manufacture

A pourable solid filter material for th removal of foreign gases, particularly unpleasant odors, from air consisting of granular mass comprised of granules having a substantially spherical shape and a diameter of about 0.5 to 8.0 mm characterized in that said granules have:

• a. a skeleton core of a substance which stores moisture selected from a class consisting of:
• swellable clay, expanded clay, tuff, pumice, brick dust, rigid plastic foam, silica gel and Kieselguhr, and
• b. a coating on said core comprising a mixture of:
• i. a water soluble binder selected from a class consisting of:
• cellulose derivatives, polyvinyl alcohol, collagen, alginates, pectins and starch, and
• ii. at least one chemosorptive substance which reacts chemically with said foreign gas selected from the class consisting of:
• acidic chemosorptive substances and basic chemosorptives substances, wherein said acidic chemosorptive substances are selected from a class consisting of:
• organic monocarboxylic acids, organic polycarboxylic acids, amidosulphonic acid, p-toluenesulphonic acid, boric acid, sodium hydrogen sulphate, potassium hydrogen sulphate, ammonium hydrogen sulphate and phthalic anhydride, and wherein said basic chemosorptive substances are selected from a class consisting of:
• sodium carbonate, potassium carbonate, calcium oxide, calcium hydroxide, barium oxide, barium hydroxide, sodium metasilicate, lithium carbonate, sodium hydroxide, potassium hydroxide, cement, and waterglass,
• said selected chemosorptive substance being present in a proportion greater than said substance which stores moisture;
• said granular mass is comprised of granules having a coating which includes at least one of said selected acidic chemosorptive substances and further including granules having a coating which includes at least one of said selected basic chemosorptive substances.