Geopolymer-Based Adsorbents for Pollutant Removal: a Tunable Platform Ranging from CO2 Capture to Nitrogen/Phosphorus Removal and Recovery from Wastewater

This study investigates the development and performance of geopolymer-based materials developed as solid sorbents for tunable applications, ranging from CO2 capture to nitrogen and phosphorus removal and recovery from wastewater. Innovative material fabrication routes are used including Cold Sintering Process (CSP). The novel geopolymer-zeolite composites exhibited CO2 adsorption capacities of up to 3 mmol/g at 1 bar, with CO2/N2 selectivity ranging from 50 to 300 at 0.1 bar, highlighting their potential for the separation of gas mixtures. For water treatment, composites showed maximum adsorption capacities of 32 mgN/g and 29 mgP/g for nitrogen and phosphorus pollutants, respectively. The findings demonstrate the tunability of these materials for different environmental applications, offering sustainable and efficient alternatives to conventional separation processes.