Functionalized nanoporous silicon for extraction of Sc from a leach solution

Recovery of Phosphorus and Metals from the Ash of Sewage Sludge, Municipal Solid Waste, or Wood Biomass: A Review and Proposals for Further Use

“…Common examples are inorganic acids such as sulfuric acid (H 2 SO 4 ) [2,4,[22][23][24][25][37][38][39], nitric acid (HNO 3 ) [4,23,25,37,39], and hydrochloric acid (HCl) [4,15,40,41]; organic acids and chelating agents such as citric acid (CA) [25,[37][38][39], oxalic acid (OA) [4,22,25,[37][38][39], lactic acid (LA) [37], ethylenediaminetetraacetic acid (EDTA) [25,38,39], and ethylenediamine tetra (methylene phosphonic acid) (EDTMP) [25,38,39]; and bases such as NaOH [4]. Novel chelating agents for ashes could also be bisphosphonates [42].…”

“…The use of Cyanex, a highly stable P-based chelating extractant, is effective for the extraction of heavy metals (Zn, Pb, and Cd) from leachates after wet extraction [27,44]. However, the selective separation of REEs requires very specific kinds of chelating agents, where bisphosphonates could be a promising option [42]. They contain a carbon center with two phosphonate groups (PO(OH) 2 ) and two other substituents (e.g., a hydroxyl group and a carbon chain with a primary amine group) [45].…”

“…They contain a carbon center with two phosphonate groups (PO(OH) 2 ) and two other substituents (e.g., a hydroxyl group and a carbon chain with a primary amine group) [45]. Bisphosphonates have been immobilized on nanoporous silicon and then applied to selectively recover Sc from a highly complex ore sample leaching solution [42]; a similar approach could be applied to ashes. The desorption of Sc from bisphosphonates can be conducted by using acids such as H 3 PO 4 and H 2 SO 4 [42].…”

“…Bisphosphonates have been immobilized on nanoporous silicon and then applied to selectively recover Sc from a highly complex ore sample leaching solution [42]; a similar approach could be applied to ashes. The desorption of Sc from bisphosphonates can be conducted by using acids such as H 3 PO 4 and H 2 SO 4 [42]. Bisphosphonates can also be used for a relatively selective recovery of other REEs, but information remains scarce [46].…”