Print version Updated: 8 April 2020 Lecture #41 Precipitation and - PowerPoint PPT Presentation

Print version Updated: 8 April 2020 Lecture #41 Precipitation and Dissolution: Solubility of Mixed Solids (Stumm & Morgan, Chapt.7) Benjamin; Chapter 8.7-8.15 David Reckhow CEE 680 #41 1

0 ZnOH + Zn +2 -1 Zn Total H + Zn(OH) 2 -2 -3 Zn(OH) 2 (aq) -4 From Lecture #36 Zn 2 (OH) +3 -5 Morgan’s fig. 6.8c, pg.273 -6 -2 Log C Zn(OH) 4  Compare to Stumm & -7 -2 Zn 2 (OH) 6 -8 -9 OH - - Zn(OH) 3  Zn solubility -10 -11 -12 -13 -14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH David Reckhow CEE 680 #40 2

0 H + -1 Al Total -2 -3 - Al(OH) 4 Al Total -4 -5  Gibbsite -6 Al(OH) 3  0.0001 M Log C -7 total + Al(OH) 2 -8 phosphate AlOH +2 -9  Aluminum Al(OH) 3 hydroxide in -10 black AlOH +2 -11  Aluminum phosphate in red + Al(OH) 2 OH - Al +3 -12 - Al +3 Al(OH) 4 -13 Similar to HW prob. -14 9.1, except that is for 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 amorphous Al(OH) 3 pH David Reckhow CEE 680 #41 3

0 H + -1 AlPO 4 Al(OH) 3 (gibbsite) Al Total -2 -3 - Al(OH) 4 Al Total -4  Gibbsite -5  0.0001 M -6 Al(OH) 3 Log C total -7 + Al(OH) 2 phosphate -8 AlOH +2  Aluminum -9 hydroxide in Al(OH) 3 black -10  Aluminum AlOH +2 -11 phosphate in + red Al(OH) 2 OH - Al +3 -12 - Al +3 Al(OH) 4 -13 -14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH David Reckhow CEE 680 #41 4

0 H + Al Total -1 Al Total -2 -3 - Al(OH) 4 Al(OH) 3 -4 -5  Amorphous -6 Log C Al(OH) 3 + -7 Al(OH) 2 + Al(OH) 2  0.0001 M -8 AlOH +2 total -9 phosphate Al(OH) 3 -10  Aluminum AlOH +2 hydroxide in -11 Al +3 black OH - -12  Aluminum phosphate in red - Al +3 Al(OH) 4 -13 -14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH David Reckhow CEE 680 #41 5

0 H + Al(OH) 3 (am) Al Total -1 Al Total AlPO 4 -2 -3 - Al(OH) 4 Al(OH) 3 -4  Amorphous -5 Al(OH) 3 -6 Log C  0.0001 M + -7 Al(OH) 2 + Al(OH) 2 total -8 AlOH +2 phosphate -9  Aluminum Al(OH) 3 hydroxide in -10 black AlOH +2 -11 Al +3  Aluminum phosphate in red OH - -12 - Al +3 Al(OH) 4 -13 -14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH David Reckhow CEE 680 #41 6

0 Fe Total -1 Fe(OH) 2 FeCO 3 -2 H + -3 -4 Fe(OH) + -5 -6 Log C -7 OH - -8 Fe +2 -9 - Fe(OH) 3 -10 -11 -12 C T = 10 -3 -13 -14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH David Reckhow CEE 680 #41 7

 Fig 8.7 in Benjamin David Reckhow CEE 680 #41 8

 To next lecture David Reckhow CEE 680 #41 9

Practice  Prepare solubility diagrams separately for:  Zn(OH) 2  ZnCO 3  Combine  Others?  Mn, Pb, Cd David Reckhow CEE 680 #40 10