| 摘要 |
PURPOSE: A removal method for nitrate nitrogen and nitrite nitrogen of river system using zinc powder and zinc foam is provided, which can denitrify nitrate nitrogen and nitrite nitrogen in river system more economically and effectively than the conventional method using aluminum, iron, tin, nickel and copper. The powder or foam of zinc can be reused by acid(2.5 % HCl) washing for 3-5 hours. CONSTITUTION: The method comprises as follows: (i) mix zinc powder of 1-53 micrometer in diameter with an additive such as ethyl alcohol and a binder selected from the group consisting of gum, wax, methyl cellulose, poly vinyl alcohol, hydroxy ethyl cellulose, polyvinyl butyral and polyethylene glycol; (ii) impregnate the mixture in a slurry state into sponge made of polyurethane; (iii) remove excess sludge in the sponge; (iv) dry at 60-120 deg.C; (v) burn the sponge at 200-250 deg.C for 2-4 hours; (vi) sinter the zinc powder at 400-420 deg.C for 10-15hours; and (vi) anneal the zinc powder to prepare foam.
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