Fig. 3
From: Origin of the unusually strong and selective binding of vanadium by polyamidoximes in seawater
Potentiometric and calorimetric titrations along with V(V) speciation diagrams under seawater conditions. a Potentiometric titration for the complexation of vanadium with H3IDO at 25 °C and I = 0.5 M (NaCl); observed (diamonds) and calculated (−) pH (left axis) with corresponding speciation (right axis); titration conditions: V o = 20.2 mL, [V] = 1.01 mM, [H3IDO] = 10.3 mM, [H] = 0.0129 M, titrant: 0.100 M HCl. b Calorimetric titration thermogram showing heat flow rate after each injection. c Cumulative observed (diamonds) and calculated (−) heats (left axis) with corresponding speciation (right axis) per injection; titration conditions: V o = 0.750 mL, [V] = 1.0 mM, [H3IDO] = 4.16 mM, [H] = 3.32 mM; titrant: 0.020 M HCl; 5 μL per injection. d Speciation of vanadium under seawater conditions with H3IDO and e HAO ligands; [V] = 3.6 × 10−8 M, [H3IDO] = 0.5 M, [HAO] = 0.5 M. Structures of prevalent species at the seawater pH are visualized for clarity
