Oleophilic pitch derived porous carbon loading with microbials for selective absorption and efficient degradation of petroleum pollutions

Highly efficient elimination of oils or petroleum pollutions in water is of great importance for both human health and society sustainability. In this work, we report the fabrication of oleophilic porous carbon loading with microbials (OPC-M), which was prepared through a carbonization of pitch followed by a multi-step doping of the microbials into the as-prepared carbon, for selective absorption and efficient degradation of petroleum pollutions. Thanks to its abundantly porous structure and oleophilic wettability, the petroleum pollutions in wastewater (using n-hexadecane as model compound) can be selectively absorbed inside the OPC-M and then could be biodegraded by the loaded microbials. Compared with that of free microbials and porous carbon loading with microbials (PC-M) which has a degradation rate of 64.10%, and 89.3%, respectively, the OPC-M possesses a higher degradation performance of 96.75%. Also, their degradation half-lives are measured to be 72.96 h, 29.53 h and 15.34 h, respectively. The degradation kinetics of both PC-M and OPC-M fit well with the first-order kinetic equation. The degradation mechanism for n-hexadecane were explored by GC–MS and the results show that n-hexadecane can be degraded by enzymes in microbials into n-hexadecyl alcohol, n-hexadecaldehyde, n-hexadecanoic acid, and finally converted into water and carbon dioxide. This combination of selective absorption and biodegradable OPC-M may open up an effective green way for the purification of oily wastewater.