Elimination of Organic Pollutants using Supported Catalysts with Hydrogen Peroxide

Picric acid (2, 4, 6, tri-nitro-phenol), which is a hardly-oxidized aromatic compound, was studied as a water pollutant. Different supported catalysts were tested in the presence of hydrogen peroxide as a method for elimination of the organic pollutant from waste water. Among some transition metal ions, Cobalt (II) nitrate immobilized in silica gel was selected for detailed study. The effect of pH, initial concentration of hydrogen peroxide, amount of catalyst, and temperature were studied to find the optimum conditions for the wet oxidation of this organic pollutant. Experimental kinetic study was conducted using visible spectrophotometric techniques and chemical oxygen demand (COD). Supported catalysts demonstrated experimentally some reusability. The present data show that the rate of oxidation is a first order with respect to pollutant concentration, hydrogen peroxide concentration and the amount of catalyst used. The dependence of the reaction rate on the nature of the immobilized transition metal, temperature, and pH of reaction media has also been discussed.