Catalytic Wet Co-oxidation Of Endocrine Disrupting Chemical-bisphenol A

Bisphenol A(BPA) belongs to bisphenol compounds and has estrogenic activity, which is considered to be an endocrine disruptor that may affect human and animal health. BPA is the precursor of many industrial productions, such as polycarbonate plastic, epoxy, phenolic and so on and widely used in industries. In recent years, BPA are widely used as the raw material in production. And increasingly BPA-containing waste water is discharged, causing a potential threat to the environment. Owing to the toxicity and biodegradation of BPA, there are many difficulties to deal with these waste water by conventional methods. Besides, the traditional processing methods are hardly to meet the need of pollutantion removal.Wet Air oxidation technology(WAO) is an important organic wastewater treatment, and there are many good prospects in water treatment. It could be proved that Wet Air oxidation technology can handle toxic refractory material. But this technology needs very rigour reaction conditions, which only could be used at 125 ~ 320 ℃ high temperature and 0.5 ~ 20 MPa high oxygen pressure. For improving the wet oxidation defects, such as lowering the reaction conditions, to run under mild conditions, it has already become the focus and hotspot in the research field.An efficient catalytic wet co-oxidation(CWCO) system was developed for the treatment of BPA. The CWCO system was conducted with Na NO2 as catalyst and 2,4,6-trichlorophenol(TCP) as co-oxidizing substance, and the results showed that the addition of TCP could significantly promote the degradation of BPA in the presence of Na NO2: when the mixture of BPA and TCP reacted at 170℃ and 0.5MPa oxygen pressure for 6 h, the COD removal reached to 71.2%, while the COD removal was only 24.7% after single BPA reacted at the same experimental conditions. On this basis, the effects of temperature, time, oxygen pressure, TCP concentration and Na NO2 concentration on the CWCO of BPA were investigated in detail, and the experimental conditions were optimized. Under the optimized conditions, BPA and TCP removal reached 100% and 96.4%, respectively, meanwhile the biodegradability index of the mixture after the CWCO process was significantly improved with the ratio of BOD5/COD increasing from 0.08 of the raw mixture to 0.95. In addition, the main degradation products determined by GC-MS were some small organic acids, including acetic acid, 2-methylglutaric acid, succinic acid, 3-methyladipic acid, propanetricarboxylic acid and 1-propenyl-1,2,3-tricarboxylic acid. Moreover, iso-propyl alcohol as radical scavenger was used to study the radical mechanism for the CWCO of BPA, and the result demonstrated hydroxyl radicals had been involved in the reaction process.