Cyclic utilization of livestock wastes into nitrogen-doped porous biochar for efficient treatment of real livestock wastewater and its bio-toxicological assessment via zebrafish (Danio rerio) model

Cyclic utilization of livestock wastes, which are deemed as the most common solid pollutants in livestock farms, into metal-free biochar for wastewater treatment may offer a sustainable approach to achieve the conversion of waste into treasure. Herein, we have first reported the nitrogen-doped porous biochars (NPBs), derived from goat manure, as a metal-free carbon nanomaterial in the efficient treatment of wastewater via peroxymonosulfate (PMS) activation. Multifarious characterizations remarked that goat manure had been converted into NPBs, which were composed of biochar and SiO 2 , at 700 ​°C calcination. NPB-2/PMS system exhibited the highest catalytic performance in bisphenol A (BPA) degradation, with 90.6 ​% degradation efficiency and 73.4 ​% removal efficiency of TOC. Electrochemical analysis suggested that the doping of N atoms onto biochars exhibited a much lower resistivity than that of non-nitrogen-doped catalyst and improved the electron transfer between BPA and PMS, promoting BPA degradation via non-free radical pathway. Then, NPB-2/PMS system was further successfully applied for the treatment of real wastewater. Indeed, the intensity of the characteristic peaks (red colour) was greatly reduced by 72.6 ​%, 85.1 ​% and 84.3 ​% for real goat manure wastewater, real sheep manure wastewater and real pig manure wastewater, respectively, confirming its highly potential practical application. Finally, zebrafish ( Danio rerio ) model confirmed that the bio-toxicity of BPA to zebrafish was significantly decreased after treatment of NPB-2/PMS system.