Orange waste Biochar-Magnesium Silicate (OBMS) composite for enhanced removal of U(VI) ions from aqueous solutions

Abstract

The removal of toxic radioactive pollutants from water sources for further disposal and treatment is a critical issue. Development of an effective adsorbent with high adsorption capacity and stability for the adsorption of hexavalent uranium, U(VI) ions is interesting research task. In this study, orange waste biochar‑magnesium silicate (OBMS) composite was prepared by simple hydrothermal method and utilized for U(VI) ions adsorption removal from aqueous solution. The successfully synthesized OBMS composite consists of graphitic carbon biochar and interconnected magnesium silicate nanosheets exhibiting 73.9 m2/g surface area with H3 type hysterias loop suggests mesoporous texture having stacked and agglomerated magnesium silicate layers covered by biochar. The prepared composite was used to study the influence of pH, U(VI) ion concentration, mass of adsorbent, presence of other cations and determination of thermodynamic functions. It was observed that OBMS composite showed high adsorption capacity (Langmuir adsorption capacity of 352.6 mg/g at 298 K, pH 4) irrespective of presence of other cations. A series of batch experiments and characterization results revealed that the superior adsorption performance of the composite is due to interaction between U(VI) ions and functional groups presented on the OBMS composite surface. The observed results suggesting the interaction between U(VI) ions OBMS surface functional groups such as CC, COH, CO, MgOSi and Mg(OH)2 is playing a key role in removal of U(VI) ions from aqueous solution. This low-cost and easily synthesized absorbent has a great potential for use in the remediation of radioactive U (VI) ions in aquatic environments.