Gadolinium Complex for the Catch and Release of Phosphate from Water

Abstract

The ability of complexes of hard and labile metal ions with one or more open coordination sites to capture phosphates with high affinity and selectivity directly in water at neutral pH and release them under acidic conditions is evaluated with Gadolinium- 2,2',2''-(((nitrilotris(ethane-2,1-diyl))tris(azanediyl))tris(carbonyl))tris(4-oxo-4H-pyran-3-olate) (Gd-TREN-MAM). This model lanthanide complex has two open coordination sites that, at neutral pH, are filled with water molecules. In water at neutral pH, Gd-TREN-MAM binds phosphate with high affinity (K = 1.3 × 10) via the formation of a ternary complex in which one phosphate replaces both inner-sphere water molecules. The formation of this complex is highly pH-dependent; the phosphate is completely released from Gd-TREN-MAM below pH 2. Because the Gd ion remains complexed by its ligand, even under strong acidic conditions, Gd-TREN-MAM can be used at least 10 times in a pH-based recycling scheme that enables the catch and release of one phosphate per cycle. Gd-TREN-MAM is highly selective for phosphate over other anions of environmental concerns, including HCO, HCO, CHCO, SO, NO, NO, BrO, AsO, F, Cl, and Br and, to a lesser extent, ClO. The development of such receptors that bind phosphate reversibly in a pH-dependent manner opens the possibility to design catch-and-release systems for the purification of surface waters.

Solid and Aqueous Speciation of Yttrium in Passive Remediation Systems of Acid Mine Drainage

“…The results yielded an average Y-O distance of 2.37 ± 0.02 Å for the Y-sol sample and 2.38 ± 0.01 Å for YSO4-sol ( Table 1). The intense peak in the FT function at 2.38 Å for the two aqueous references represents the first solvation shell, and its asymmetry reveals a distribution of Y-O interatomic distances, as reported previously by Lindqvist et al 24 The coordination numbers (CN) were 7.6 ± 1.9 and 7.9 ± 0.9 for Y-sol and YSO4-sol, respectively, which are close to the expected value of 8 for 23,24,28 Likewise aqueous REE carbonate and phosphate complexes, [31][32][33] aqueous Y-SO4 ion-pairs form inner-sphere complexes. This result contrasts with other ligands such as chloride, which hardly forms inner sphere complexes at similar concentrations to those used in this study.…”

Environmental sustainability of phosphorus recycling from wastewater, manure and solid wastes

“…agricultural fertilizers, feed and food additives, laundry detergents and other industrial applications (Belboom et al, 2015;Mottet et al, 2017;Noya et al, 2017;Van Hoof et al, 2017). The final step corresponds to the dissipation and the recycling of phosphorus (Chen & Graedel, 2016;Fowdar et al, 2017;Harris et al, 2017;Hobbs et al, 2017;Leon & Kohyama, 2017;Maguire & Fulweiler, 2017;Ortiz-Reyes & Anex, 2018). In recycling, other materials such as nitrite associated with phosphorus can be recovered in parallel.…”

“…The loss of phosphorus occurs due to various phenomena; e.g. soil loss, leaching, runoff and erosion (Fowdar et al, 2017;Harris et al, 2017;Ortiz-Reyes and Anex, 2018). Another source of phosphorus in the marine system is the effluents containing detergents, industrial wastewater and animal production waste (Chen and Graedel, 2016;Hobbs et al, 2017;Maguire and Fulweiler, 2017).…”

Tinospora cordifolia derived biomass functionalized ZnO particles for effective removal of lead(ii), iron(iii), phosphate and arsenic(iii) from water

“…One main example is Microcystis algae, which produces microcystin that is lethal to both human as well as aquatic life. 18 For removal of the above mentioned metal ions and anions, different techniques used are reverse osmosis, ion exchange, solvent extraction, electrochemical methods etc. [19][20][21][22] ZnO is a biocompatible material and because of its unique physical and chemical properties, it has been used for multifunctional purposes.…”