Preparation of bionanomaterial based on green reduced graphene immobilized Ochrobactrum sp. FJ1: Optimization, characterization and its application

Biodegradation using free cells is limited to low cell density, biological activity, and subsequent cell collection and regeneration are difficult. Meanwhile the limitations of using graphene-based nanomaterials for the removing emerging contaminants are adsorption and required further regeneration. To address these problems, reduced graphene oxide (rGO) synthesized by green tea extract as the carrier served to immobilize Ochrobactrum sp. FJ1 to form a functional bionanomaterial (FJ1@rGO). Its function was to degrade 17beta-estradiol (E2). To obtain a highly functional bionanomaterial, response surface methodology (RSM) with central composite design (CCD) was deployed to evaluate the synthesis conditions, which guided the ability of FJ1@rGO to remove pollutants. Results show that inoculation amount and immobilization time greatly affect removal efficiency, and the efficiency in removing E2 utilizing the optimized FJ1@rGO reached 93.7 % within 10 days. This proved to be significantly higher than prior to optimization. To provide evidence for functional FJ1@rGO, a series of advanced characterization results confirmed that FJ1 was successfully immobilized on rGO. It appears that FJ1@rGO has: firstly, excellent removal effect on E1, BPA, and triclosan; and secondly, excellent recycling properties.

Automated summary

Green tea extract was used to synthesize reduced graphene oxide (rGO) as a carrier to immobilize Ochrobactrum sp. FJ1, forming a functional bionanomaterial (FJ1@rGO) for the degradation of 17beta-estradiol (E2). Response surface methodology (CCD) was used to optimize the synthesis conditions, and the optimized FJ1@rGO showed a significantly higher removal efficiency of 93.7% for E2 within 10 days. Advanced characterization confirmed the successful immobilization of FJ1 on rGO, and FJ1@rGO exhibited excellent removal effects on E1, BPA, and triclosan, as well as excellent recycling properties.