Noxious gas purificant and its preparation and purification method thereof

A preparation method for a noxious gas purificant for the removal of nitrogen oxides from a gas stream at a temperature ranging from 150 to 550° C., the preparation method comprising:

• (1) mixing material U, material V and water in a mixing reactor,
• wherein said material U is one compound selected from ferrous sulfate heptahydrate, cobalt sulfate heptahydrate, manganese sulfate tetrahydrate and copper sulfate pentahydrate, and said material V is a combination of sodium hydroxide and calcium oxide, at a mole ratio of about 1:1:3 (material U:sodium hydroxide:calcium oxide);
• or
• wherein said material U is one compound selected from ferrous carbonate, manganese carbonate and basic copper carbonate, and said material V is a combination of potassium hydroxide and calcium carbonate, at a mole ratio of about 1:2:2:6 (material U:potassium hydroxide:calcium carbonate:water);
• or
• wherein said material U is one of solutions (50% water) of ferrous chloride, ferric chloride, cobalt chloride, manganese chloride and copper chloride, and said material V is a combination of sodium hydroxide and calcium carbonate, at a mole ratio of 1:2:2 (material U:sodium hydroxide:calcium carbonate);
• or
• wherein said material U is a combination of ferrous sulfate heptahydrate, cobalt sulfate heptahydrate, manganese sulfate tetrahydrate, copper sulfate pentahydrate, and said material V is potassium hydroxide, at a mole ratio of 1:1:1:1:8 (ferrous sulfate heptahydrate:cobalt sulfate heptahydrate:manganese sulfate tetrahydrate:copper sulfate pentahydrate:potassium hydroxide);
• and
• (2) molding a reaction product of step (1) to a shape of honeycombs, plates, granules, or loading on a general-purpose catalyst carrier;
• (3) drying the reaction product at a temperature above 40° C.;
• (4) activating the reaction product at a temperature above 150° C. after step (3);
• and
• wherein the composition of the purificant comprises at least one component of sulfate, chloride, and carbonate, and at least one component of Na, K, Li, Ca, Ba, and Mg.