Nutrients in domestic wastewater, particularly nitrogen in the form of ammonium (NH4+), have the potential to meet up to 30% of the global demand for nitrogen fertilizers. Electrochemical techniques enable the selective extraction of ammonia through electrochemical production of hydroxide that converts ammonium into gaseous ammonia for its recovery from wastewater. However, the production of a final product suitable for commercial application is often energy-intensive and cost-inefficient, thereby limiting its practical and economic viability. The goal of this proposed project is to employ biochar-based adsorbents to capture ammonia recovered from wastewater via an electrochemically mediated process for the production of an affordable and applicable biochar-alginate composite as a slow-release fertilizer. This project will explore the use of an electrolysis cell divided by a low-cost membrane to create pH gradients for both CO2 removal and NH3 recovery. The recovered NH3 will be adsorbed onto biochar, providing carbon sequestration and slow-release nutrient delivery. The proposed work includes the design and characterization of biochar tailored for ammonia adsorption and its incorporation into the alginate composite. The fabricated biochar-alginate can enhance water retention, reduce nutrient leaching, and prevent biochar runoff, enhancing the viability of using ammonia recovered from wastewater to promote a circular economy.
