Layered double hydroxide modified biochar combined with sodium alginate: A powerful biomaterial for enhancing bioreactor performance to remove nitrate

A novel layered double hydroxide (LDH)-orange peel (OP) biochar/sodium alginate (SA) (LBSA) synthetic material was prepared as an immobilized carrier for Acinetobacter sp. FYF8 to improve the removal of nitrogen and phosphorus in the bioreactor. Results demonstrated that under optimum conditions, the nitrate and phosphate removal efficiency reached 95.32 and 86.11%, respectively. The response surface methodology was used to illustrate the adsorption properties of the material and obtained optimal conditions for the removal of nitrate. The adsorption kinetics and isotherm were well fitted with the pseudo-second-order and Langmuir isotherm model, respectively, indicating that the adsorption process was mainly controlled by chemical adsorption and was favorable. Moreover, the morphology and composition of LBSA immobilized bacteria were analyzed and the mechanism of removing nitrate and phosphate was the synergistic effect of biological metabolism and adsorption. Community structure analysis and microbial distribution showed that FYF8 might was the dominant strain in bioreactors.

Automated summary

A novel synthetic material LBSA was prepared as an immobilized carrier for Acinetobacter sp. FYF8 to enhance the removal efficiency of nitrogen and phosphorus in the bioreactor. The study showed that under optimal conditions, the removal efficiencies of nitrate and phosphate reached 95.32% and 86.11% respectively, with the adsorption process mainly controlled by chemical adsorption and the synergistic effect of biological metabolism and adsorption for nitrate removal.