A Novel Approach to Brewery Effluent Treatment: Adsorption, Electrochemical Oxidation, and in Situ Regeneration for Efficient Nitrogenous Pollutants Removal

Abstract Nitrogenous pollutants from wastewater pose a serious environmental concern and have to be managed by an efficient treatment technique. In this context, the main objective of this study was to remove nitrogenous pollutants (NH 4 + , NO 3 − , and NO 2 − ) from real brewery effluent using an adsorption (AD) process and to regenerate the saturated adsorbent through a direct anodic oxidation (DAO) process. The regeneration aimed at enabling the reuse of the adsorbent for additional applications. The experiments were conducted on brewery effluent sampled in N’Djamena (Chad). Adsorption tests were performed in batch mode by mixing a volume of effluent with a specific amount of activated carbon (AC) prepared from the core shell of Balanites Aegyptiaca . Based on the characterization results, the activated carbon exhibited an amorphous graphitic structure with the main functional groups (O–H, C-O, C = O), and a micro- and mesoporous structure showing a specific surface area of 153 m 2 g −1 . DAO was employed to enhance adsorption efficiency and to regenerate the active sites of the AC that had been previously saturated with pollutants. The maximum adsorption capacities for NH 4 + , NO 3 − , and NO 2 − ions were 40.16, 34.13, and 28.82 mg/g, respectively. The adsorption kinetics followed a pseudo-second-order model. Thermodynamic analysis revealed that the adsorption is endothermic with low enthalpy values (ΔH° = 3.40—9.02 kJ/mol), confirming that the adsorption mechanism is predominantly governed by physisorption involving Van der Waals forces and electrostatic interactions. The regeneration efficiency of saturated activated carbon via the DAO process was 84.29%, 88.57%, and 40.83% for NH 4 + , NO 2 − , and NO 3 − ions, respectively. Based on these findings, coupling AD and DAO processes is a viable method for treating effluents containing nitrogenous pollutants and effectively regenerates AC.