Enhanced removal of nitrate, copper, and bisphenol A from immobilized bioreactors by exogenous acyl homoserine lactones-6 (AHLs-6) and iron-cobalt modified biochar.

Currently, treating industrial wastewater with complex components and difficult-to-degrade pollutants has become a focal point for research. In this study, sodium alginate (SA), polyvinyl alcohol (PVA), and shell powder (SP) were used as a carrier backbone to embed ferric cobalt-modified biochar (FCBC), exogenous acyl homoserine lactone-6 (AHLs-6), and the salt-tolerant strain Stutzerimonas sp. ZW5, resulting in the preparation of immobilized microbial carriers. Experimental results demonstrated that, under optimal operating conditions, the bioreactor achieved removal efficiencies of 97.11 % for nitrate (NO3--N), 81.20 % for calcium (Ca2+), 93.22 % for chemical oxygen demand (COD), 91.05 % for phosphorus (PO43--P), 98.57 % for copper (Cu2+), and 96.16 % for bisphenol A (BPA). The rough surface and numerous functional groups of the reactor packing effectively adsorbed BPA and Cu2+, thereby reducing the inhibitory effects of these pollutants on microbial metabolic activity. In addition, FCBC provides mass transfer channels and active sites to enhance electron transfer. The introduction of exogenous AHLs-6 markedly increased the abundance of functional microbial communities and the activity of key enzymes by regulating microbial metabolism, thus improving the removal efficiency of complex pollutants. This research offers new perspectives on treating complex industrial wastewater.