Efficient Treatment of Antibiotic Cefalexin Sludge by Wet Oxidation: an Experimental and Theoretical Study

Abstract

In the present study, wet oxidation of antibiotic cefalexin sludge from pharmaceutical wastewater treatment was investigated. The experiments were carried out in a stainless-steel batch autoclave reactor. The results show that the maximum removal rate of volatile suspended solids (VSS) can reach 91.3% at 260 °C within 60 min with an initial oxygen pressure of 1.0 MPa. Simultaneously, the chemical oxygen demand (COD) removal rate of 64.1% was reached. The antibiotic cefalexin was totally eliminated under wet oxidation conditions. DFT calculation was performed to illustrate the initial reaction pathway. The energy diagram proposed initial thermal hydrolysis pathway of cefalexin. These results indicated that wet oxidation provided a promising treatment method for the antibiotic cefalexin sludge, which can be used for the efficient removal of cefalexin.