Oxidized biochar obtained from rice straw as adsorbent to remove uranium (VI) from aqueous solutions

In this study, rice straw derived biochar (RSBC) was used as a precursor for obtaining oxidized biochar (RSBCOx), for which the capability for adsorbing/removing uranium (VI) from aqueous solutions was investigated. The U(VI) removal efficacy of RSBC-Ox was tested for different values of pH, ionic strength, initial concentration of U (VI) and temperature. RSBC-Ox reached 242.65 mg g(-1) as the most effective score regarding uptake. Experimental adsorption data fitted well to a pseudo-second-order kinetic model (reaching a value at equilibrium of q(e) = 148.9 mg g(-1), R-2 = 0.99), and to the Langmuir isotherm (achieving a maximum score of q(max) = 242.65 mg g(-1) complexation, and entropy-driven with a relatively increased randomness in the solid-solution interface. This research could be of aid for reusing rice straw as an effective and low-cost adsorbent for U(VI) removal in various environmental conditions, simultaneously promoting resource utilization and sustainable management of the materials, aiding to protect the environment and human health. , R-2 = 0.99). Thermodynamics revealed that adsorption was endothermic, and indicated inner-sphere complexation, and entropy-driven with a relatively increased randomness in the solid-solution interface. This research could be of aid for reusing rice straw as an effective and low-cost adsorbent for U(VI) removal in various environmental conditions, simultaneously promoting resource utilization and sustainable management of the materials, aiding to protect the environment and human health.

Automated summary

This study investigated the use of rice straw derived biochar as a precursor for oxidized biochar to adsorb/ remove uranium (VI) from aqueous solutions. The RSBC-Ox showed high removal efficacy with a maximal adsorption capacity of 242.65 mg g(-1), fitting well to kinetic and isotherm models. The research highlights the potential of reusing rice straw as an effective and low-cost adsorbent for U(VI) removal, promoting resource utilization and sustainable materials management.