Abstract:

The effects of the removal of Acid Green 16 (100 mg AG-16/dm³, COD=111 mg O₂/dm³) from aqueous solutions by the UV/H₂O₂ process in UV reactors: low pressure lamp (LP, 15W) and medium pressure lamps (MP, 150W) are presented. The best results of AG-16 removal were obtained for H₂O₂ 250 mg/dm³ (99.85%, AG-16=0.15 mg/dm³) and 200 mg/dm³ (99.80%, AG-16=0.20 mg/dm³) for LP and MP lamps, respectively, with the same parameters, i.e. 30 min reaction time and pH 6. Under these conditions, the AG-16 solution was completely discolored and the COD removal efficiency was 57.3% (LP lamp) and 63,4% (MP lamp). However, at optimum conditions of decolorisation, no decrease in the toxicity of solutions (Microtox test) was observed. For the MP lamp, the toxicity of solutions remained at the same level as in the initial solutions (Toxicity Unit, TU=3), whereas in the case of the LP lamp, the TU value after the process increased to 6. In conclusion, the AOPs for toxic pollutants should also be optimised from the point of view of toxicity.