Biocomposite based on graphene oxide immobilized Pseudomonas psychrotolerans for the recovery of Y(III) in acid mine drainage.

ABSTRACT

Rare earth elements (REEs) recovery is a critical issue concerning both resource recovery and wastewater utilization. In this study, a new bio-composite was fabricated using graphene oxide immobilized Pseudomonas psychrotolerans (PP@GO), which was isolated from the soil of REEs mine. Results showed that 99.6% Y(III) was removed in 48 h and various characterization confirmed that S-S, -NH2, HPO42-, -OH and -COOH from extracellular polymeric substances (EPS) secreted by microorganisms formed complexation with Y(III). As well, the Y(III) adsorption best followed Freundlich isotherm and non-linear pseudo-second-order kinetic model having R2 of 0.985 and 0.996, respectively, demonstrating that the adsorption was governed by multilayered chemisorption. Additionally, the effectiveness of PP@GO was not limited to Y(III), where 27.9% of this substance was removed in acid mine drainage (AMD), also exhibited great adsorption for other REEs, such as Er (45.0%) and Ho (43.8%). Furthermore, the adsorption efficiency of Y(III) remained high (70.0%) after a 5th cycle, emphasizing the consistent stability of PP@GO. Finally, REEs adsorbed could be greatly desorbed by KNO3, like Sm (80.1%) and La (80.0%), which revealed that PP@GO has great potential to recover REEs in AMD. Overall, this study offers a promising strategy for the green and sustainable REEs recovery and wastewater treatment.