Graphene oxide composite membrane accelerates organic pollutant degradation by Shewanella bacteria

Abstract

Degradation of various organic pollutants by bacteria has been proved to be an economical and environmentally friendly method. The key challenge in making these technologies widely available is their low degradation efficiency. Here, we report a composite membrane composed of graphene oxide and polyvinyl alcohol (GO-PVA) which can markedly enhance the efficiency and rate of Shewanella bacteria to degrade Congo red (CR). The degradation efficiency of Shewanella bacteria alone on CR solution was about 42% at 72 h. After the addition of the GO-PVA membrane, the degradation efficiency reached 91% at the degradation time at 36 h. The degradation efficiency of CR was increased by two times and the degradation rate was increased by four times in the presence of GO-PVA membrane and Shewanella bacteria compared to Shewanella bacteria alone. This indicates that the CR could be rapidly and completely degraded by increasing the input amounts of GO-PVA membrane in the process of Shewanella algae degradation of CR. Moreover, the GO-PVA membrane showed good recyclability and reusability. The biocatalysts performance of the GO-PVA membrane did not decrease after 10 cycles. Furthermore, the role of the GO-PVA membrane in the degradation process and the degradation products of CR were discussed. HIGHLIGHTS The efficiency of Shewanella bacteria to degrade CR is about 42% at 72 h.; The GO-PVA can significantly improve the degradation rate and efficiency of CR.; The degradation rate was increased by four times and the efficiency was increased by about two times.; The GO in the GO-PVA plays as a redox mediator in the degradation of CR.; The GO-PVA shows good recyclability and reusability.;

Keywords

• congo red degradation
• efficiency enhance
• graphene oxide
• recyclability
• shewanella bacteria