Peroxone process for RO-16 and RB-19 dye solutions treatment

To obtain a better treatment efficiency for dye or textile wastewater, a semi-batch and a continuous peroxone process using a new gas-inducing reactor were investigated in this study. In the semi-batch peroxone process, the results show that the peroxone process does not improve the color value (ADMI) removal rate, regardless of the pH value. However, the chemical oxygen demand (COD) removal rate could be enhanced in this peroxone process at higher pH value, but the extent of improvement is only slight. The optimal molar ratio of hydrogen peroxide to ozone (H2O2/O3) is 1.0, and at this condition, the mass ratio of removed COD to consumed ozone (deltaCOD/deltaO3) is twice as high as that in the ozone alone process. In the continuous peroxone process, the hydrogen peroxide addition also does not improve the ADMI removal. However, the COD removal is improved more significantly in the continuous peroxone process. The optimal H2O2/O3 molar ratio for the continuous peroxone process varies with the input liquid flow rate (QL). For liquid flow rate of 0.5 L/min, the optimal H2O2/O3 molar ratio is 3.0 and the COD removal percentage (R(COD)) reaches 50.0 to approximately 55.8%, providing about 15 min oxidation time, for the two kinds of dye solutions that were investigated in this study. The optimal residual hydrogen peroxide concentration in the working solution ([H2O2]res.) is about 1.7 x 10(-2) mol/L, providing an input rate of ozone at 8.8 x 10(-2) mol/h.