Fenton Oxidation Catalyzed By OR-SON And Its Application In Advanced Treatment Of Industrial Wastewater

In this paper, the catalytic mechanism and the removal ability of biorefractory organics in industrial wastewater were studied by using a novel Fenton catalyst OR-SON. Four aspects of this research were discussed: the catalytic and adsorption properties of OR-SON; The influence factors and the treatment effect of Fenton reaction catalyzed by OR-SON; The reasons for OR-SON deactivation when it was reused; The treatment effects of Fenton reaction catalyzed by OR-SON when pilot scale tests were carried out in a wastewater treatment plant in the Tianjin industrial park.The catalytic effect and catalytic mechanism of OR-SON in acidic and neutral conditions were examined. The results showed that when pH was 3, Fenton had better catalytic ability when OR-SON was added, the utilization ratio of H₂O₂ in Fenton reaction was increased by OR-SON, so the removal of phenol was more quickly and more thoroughly. When the pH was 7, the removal of phenol was depended on the adsorption of OR-SON, the removal rate was 14.8%. The adsorption of OR-SON made the utilization ratio of H₂O₂ in Fenton reaction decreased 30%.The influence factors of the Fenton reaction catalyzed by OR-SON were the initial pH, H₂O₂ dosage, Fe2+ dosage and OR-SON dosage. It was concluded that the order of influence on COD removal: OR-SON dosage>Fe2+ dosage>H₂O₂ dosage>initial pH. The optimum reaction condition was pH=4, H₂O₂=27.75mg/L, Fe2+=50mg/L, OR-SON=40mg/L. When the OR-SON was added, the COD removal rate of Fenton reaction was increased and the dosage of H₂O₂ and Fe2+ was reduced. The concentration of aromatic compounds was decreased obviously by 3DEEM when the raw water was treated by Fenton reaction analyzed by OR-SON.OR-SON can be reused, and its catalytic effect was declined along with its reuse time. The OR-SON was deactivated when it was reuse for six times. Through SEM?XRD?nitrogen adsorption-desorption analysis, it was discovered that the OR-SON surface was covered and the pores inside were blocked by several instrumental analysis, which meaned the surface and intenal catalytic sites of OR-SON were covered, so the catalytic of OR-SON was lost.The secondary effluent from wastewater treatment plant in the Tianjin industrial park was treated by OR-SON Fenton oxidation device in pilot scale. The results showed that at pH was 7, the wasterwater was treated by dosing-reaction-flocculation –precipitation, the COD, SS, TP of effluent could achieved the one-class A standard?GB18918-2002?. The method of utilizing the OR-SON settling sluge was adopted, so the OR-SON dosage and chemical cost was reduced.The treatment effect of Fenton reaction catalyzed by OR-SON was better, and this technique had broadened the pH range, achieved the reuse of catalyst, and the dosage expense and sulge production were low, so it was suitable for wastewater treatment plants to upgrade.