Optimized O₃/Fe(II) Using Response Surface Methodology for Organic Phosphorus Removal in Tetrakis(hydroxymethyl)phosphonium Sulfate Wastewater

Tetrakis(hydroxymethyl)phosphonium sulfate (THPS) wastewater is a kind of industrial wastewater which is difficult to biodegrade. In this work, O3/Fe(II) was used to remove organic phosphorus from THPS wastewater. The operating conditions in this process were optimized using the Box-Behnken response surface method based on single-factor experimentation. A response model of the organic phosphorus removal rate considering the initial pH, reaction time, ozone concentration, and Fe(II) dosage was established. The results showed that the ozone concentration and initial pH had a significant effect on the removal rate of organic phosphorus, and the model fit well (R2 = 0.98). The maximum removal rate of organic phosphorus predicted by this model was 86.04%, while the deviation between the predicted and experimental values was 0.91%. We concluded that the quadratic model was an effective tool for optimizing the removal of organic phosphorus in the THPS wastewater by O3/Fe(II).