Magnesium doped biochar for simultaneous adsorption of phosphate and nitrogen ions from aqueous solution

Authors: BISWAS, B - Auburn University; AMMAR, M - Lehigh University; ADHIKARI, S - Auburn University; BALTRUSAITIS, J - Lehigh University; JAHROMI, H - Auburn University; Torbert, Henry - Allen; LINHOSS, J - Auburn University; LAMBA, J - Auburn University

Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2024
Publication Date: 5/8/2024
Citation: Biswas, B., Ammar, M., Adhikari, S., Baltrusaitis, J., Jahromi, H., Torbert III, H.A., Linhoss, J., Lamba, J. 2024. Magnesium doped biochar for simultaneous adsorption of phosphate and nitrogen ions from aqueous solution. Chemosphere. 358:142130. https://doi.org/10.1016/j.chemosphere.2024.142130.
DOI: https://doi.org/10.1016/j.chemosphere.2024.142130

Interpretive Summary: Phosphorus (P) and Nitrogen (N) represent fundamental plant nutrients that play a crucial role in maintaining environmental equilibrium, however, excessive levels in water contribute to eutrophication, causing significant degradation of aquatic ecosystems. Although adsorption presents a promising solution for addressing this issue, the ongoing challenge lies in identifying suitable adsorbent materials that are readily available, cost-effective, and highly efficient. In this study, magnesium (Mg), iron (Fe), and Mg-Fe doped biochars (BC) were synthesized and evaluated for for P and N absorption from wastewater. The thermodynamic experiments showed that the adsorptions of P and N were feasible and naturally spontaneous. Multiple characterizations and comparative analysis demonstrated that engineering surface functional groups of adsorbents can be crucial for the development of suitable wastewater treatment technology for removing nutrients.

Technical Abstract: Phosphorus (P) and Nitrogen (N) represent fundamental plant nutrients that play a crucial role in maintaining environmental equilibrium. Excessive levels of P and N in water contribute to eutrophication, causing significant degradation of aquatic ecosystems. Although adsorption presents a promising solution for addressing this issue, the ongoing challenge lies in identifying suitable adsorbent materials that are readily available, cost-effective, and highly efficient. In this study, magnesium (Mg), iron (Fe), and Mg-Fe doped biochars (BC) were synthesized. The metal-doped biochars were evaluated for individual phosphorus (P) and nitrogen (N) and the mixture of P and N from the solution and wastewater. Mg-BC exhibited excellent performance for P and N adsorption from an aqueous solution with a large adsorption capacity of 64.65 mg/g and 62.50 mg/g from individual P and N solutions, and 30.3 mg/g and 27.67 mg/g from P and N from the mixture solution, respectively. In addition, Mg-BC efficiently removed P and N from real-life wastewater. From the real wastewater, P and N removal efficiencies reached 88.30% and 59.36%, respectively. Kinetics analysis shows that pseudo-second-order was fitted to describe the adsorption process of P and N for all solutions. The adsorptions of P and N onto the biochar were found to follow the monolayer-Langmuir isotherm for N ions and the multilayer-Freundlich isotherm for P. The thermodynamic experiments showed that the adsorptions of ammonia and phosphate were feasible and naturally spontaneous. Multiple characterizations and comparative analysis demonstrated that engineering surface functional groups of adsorbents can be crucial for the development of suitable wastewater treatment technology for removing nutrients.