Catalytic wet air oxidation of p-nitrophenol (PNP) aqueous solution using multi-component heterogeneous catalysts

This study investigated the decomposition of high strength p-nitrophenol (P NP) of 2,000 mg/l (3,400 mg of COD/1,250 mg of TOC) by catalytic wet air ox idation. Multi-component heterogeneous catalysts were used as catalysts for this purpose. The study results using a batch reactor showed that catalyst "D" (Mn-Ce-Zr 22.4 g plus CuSO4 1.0 g; Mn-Ce-Zr-Cu [CuSO4]) was more Effec tive (56 similar to 74%) than catalyst "A" (Mn-Ce-Zr 22.4 g) under the give n conditions (O-2 partial pressure of 1.0 MPa; temperature of 170 similar t o 190 degreesC; 30 min of reaction time). The best result was obtained when 2 g of Mn-Ce-Zr-Cu [CuSO4] was used per 1L of PNP aqueous solution. COD an d TOC removal efficiencies were 18% and 23% without catalysts during 20 min of reaction at 190 degreesC. They were improved to 79% and 71% with 2 g/L of Mn-Ce-Zr-Cu [CuSO4] under the same conditions. The ratio of BOD5/COD was measured to evaluate biodegradability. It was 0.05 without catalyst and in creased to 0.33 with 2 g/L of Mn-Ce-Zr-Cu [CuSO4] for 20 min of reaction.