Bisphosphonate functionalized biogenic nanostructured silicon carbide for uranium and scandium recovery

The extraction and recovery of metals from wastewater produced as a result of anthropogenic activities such as ore processing and mining, address not only environmental concerns but also offer economic benefits by reducing reliance on primary ores. Adsorption is a commonly used approach for extraction and decontamination of effluent containing low concentrations of metals, but most adsorbents degrade quickly and are inadequate in the selective removal of metals. The study focuses on the preparation and utilization of biogenic nanostructured silicon carbide (nSiC) functionalized with bisphosphonates (BP-nSiC) for recovering U and Sc effectively from metal-containing streams. The high-temperature self-propagating magnesiothermic reduction was selected to produce nanostructured silicon carbide (nSiC) from agricultural residue, i.e., barley husk. The nSiC was then conjugated with bisphosphonates, which act as a metal chelator to extract U and Sc from tailing effluent and leached ore solutions, respectively. The BP-nSiC exhibited the adsorption capacity of 58.76 μmol/g and 48.07 μmol/g for U and Sc, respectively, at pH 1. The BP-nSiC reusability potential was tested in a flow-through setup showing good stability to withstand at least 20 consecutive cycles without a significant drop in adsorption capacity, highlighting its potential for repeated use in metal recovery applications. The BP-nSiC was capable of recovering U and Sc, indicating that the adsorbent could be used to recover metals effectively.