Abstract
Our previous work discussed synthesizing and characterizing a macroporous anionic polyacrylamide monolith as a new adsorbent. This monolith showed the potential removal of heavy metals and organic dye molecules in aqueous solutions. In this work, we continue our work and study the effectiveness of the synthesized monoliths in removing uranyl ions (UO22+) from aqueous solutions. Our investigation conclusively determined the impact of pH, contact time, monolith dosage, initial metal concentration and temperature on removing uranyl ions. Several isotherm models, including the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models, were employed to analyze the adsorption data; the Freundlich and Langmuir models were the most suitable for describing the equilibrium data. According to the Langmuir model, the monolith has an adsorption capacity of 111 mg/g of uranyl ions at 25 °C. The pseudo-second-order kinetic model was suitable for describing the uranyl ion adsorption onto the synthesized monolith with an R2 coefficient ³ 0.999. The thermodynamic studies showed that uranyl ions adsorb onto the monolith spontaneously and endothermically.