Effects of carboxyl single-walled carbon nanotubes on synthetic wastewater nutrient removal by an algal-bacterial consortium: Regulation and interaction

In this study, the morphology, ultrastructure, nutrient removal, metabolite levels, and interaction of an algal-bacterial consortium exposed to different concentrations of carboxylic single-walled carbon nanotubes (C-SWCNT) were investigated. At a C-SWCNT concentration of 0.05 mg . L-1, the removal rates of TN, NH3-N, PO43--P, and COD were 94.7%, 94.8%, 86.4% and 84.3%, respectively. When cells were exposed to 50 mg . L-1 C-SWCNT, its intracellular levels in individual algae and the algal-bacterial consortium were 23.6 mu g . g(-1 )and 12.1 mu g . g(-1), respectively. C-SWCNT (0.05 mg . L-1) promoted the metabolism of fatty adds, amino acids, small molecules, and acid in the algal-bacterial consortium. The main response to the interaction of C-SWCNT and the consortium was the change in extracellular carbohydrate levels. C-SWCNT also increased chlorophyll a and glycine levels. These findings reveal new insights into our understanding of the biological responses and interactions between C-SWCNT and algal-bacterial consortium. (C) 2019 Elsevier B.V. All rights reserved.