FeO nanoparticles loading on cow dung based activated carbon as an efficient catalyst for catalytic microbubble ozonation of biologically pretreated coal gasification wastewater.

Cow dung based activated carbon was successfully modified by FeO nanoparticles as the novel catalyst (FeO nanoparticles@CDAC) to improve the microbubble ozonation treating biologically pretreated coal gasification wastewater (BPCGW). When the pH, ozone dosage, ozone bubble diameter and catalyst dosage of the ozonation were 7, 0.4 L/min, 5 μm and 3 g/L, the chemical oxygen demand (COD) removal efficiency reached 74% and the ratio of biochemical oxygen demand in five days/COD (BOD/COD) increased from 0.04 to 0.52, which were attributed to the electron transfer of Fe and Fe in FeO and enhanced hydroxyl radicals generation by the reaction of iron ions and ozone. Meanwhile, benzene derivatives, naphthalene and aromatic proteins were significantly removed while multiple chain hydrocarbons and their derivatives composed the main residual organic matters. The catalytic activity was slightly decreased even the catalyst has been reused for five times. Therefore, catalytic microbubble ozonation using FeO nanoparticles@CDAC represented excellent performance treating BPCGW and it is a promising process for wastewater advanced treatment.