## 3 Results
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & \multicolumn{3}{c}{pEG1M} \\ \hline
**pH** & **\%Pb(II) abs (log D) * & **\%Cd(II) abs (log D)** & **\%Cu(II) abs (log D)** & **\%Zn(II) abs (log D)** \\ \hline
1.41 & 95.5\% (2.77) & 83.1\% (2.15) & 82.7\% (2.14) & 62.2\% (1.68) \\
1.00 & 80.9 (2.07) & 54.7 (1.54) & 53.6 (1.51) & 23.6 (0.949) \\
0.699 & 47.7 (1.40) & 36.6 (1.22) & 24.6 (0.976) & 10.8 (0.549) \\
0.398 & 19.5 (0.841) & 11.8 (0.587) & 8.15 (0.398) & 0.990 (-0.545) \\
0.00 & 11.7 (0.567) & 8.95 (0.448) & 4.60 (0.145) & - \\ \hline \hline \multicolumn{5}{c}{**pGlyM**} \\ \hline
**pH** & **\%Pb(II) abs (log D)** & **\%Cd(II) abs (log D)** & **\%Cu(II) abs (log D)** & **\%Zn(II) abs (log D)** \\ \hline
1.41 & 96.5 (2.91) & 93.2 (2.60) & 88.5 (2.35) & 80.7 (2.08) \\
1.00 & 86.1 (2.25) & 75.4 (1.96) & 68.0 (1.79) & 51.8 (1.49) \\
0.699 & 52.9 (1.53) & 43.4 (1.35) & 32.1 (1.15) & 17.3 (0.775) \\
0.398 & 21.2 (0.893) & 17.2 (0.786) & 14.4 (0.683) & 9.27 (0.483) \\
0.00 & 12.7 (0.638) & 8.14 (0.418) & 7.56 (0.389) & - \\ \hline \hline \multicolumn{5}{c}{**pPentaM**} \\ \hline
**pH** & **\%Pb(II) abs (log D)** & **\%Cd(II) abs (log D)** & **\%Cu(II) abs(log D)** & **\%Zn(II) abs (log D)** \\ \hline
1.56 & 99.6 (3.84) & 98.4 (3.26) & 98.1 (3.17) & 93.5 (2.63) \\
1.00 & 95.4 (2.79) & 87.4 (2.30) & 83.0 (2.16) & 69.8 (1.82) \\
0.699 & 84.4 (2.21) & 62.3 (1  
The monoprotic ligands have greater affinities than diprotic phosphonic acid (Table 3); e.g., whereas DPA sorbs 52%, 25%, and 8% Lu(III) from 1, 2, and 5 M HNO\({}_{3}\), pGlyM sorbs 92%, 74%, and 49% Lu(III) from the same solutions. Though fully functionalized polystyrene-bound phosphoric acid could not be prepared, the differences in affinity between phosphoric and phosphonic acids are not significant: the phosphoric acid ligand bound to poly(glycidyl methacrylate) has a low affinity for La(III) from a 1 M HNO\({}_{3}\) solution and complexes 50% La(III) at pH 0.33 [17] while polystyrene-bound phosphonic acid has the same low La(III) affinity from 1 M HNO\({}_{3}\) and complexes 50% of the La(III) at pH 0.63 [18]. Both have the same affinities for trivalent ions: Fe(III) >> Lu(III) > Al(III) > Gd(III) > La(III) > Cr(III). The DPA affinities for divalent and trivalent ions are summarized in Figure 4. Over a range of solution acidities, DPA shows an order of Fe(III) > Lu(III) > Al(III) > La(III) > Pb(II) > Cd(II), Cu(II) > Zn(II); the monoprotic phosphates have nearly the same sequence: Fe(III) > Lu(III) > La (III) > Al(III) > Pb(II) > Cd(II), Cu(II) > Zn(II). There is a very high Fe(III) affinity which is less dependent on solution acidity, though at 5 M HNO\({}_{3}\), more Fe(III) is sorbed by pPentaM (95%) than DPA (86%). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**pH** & **\%Pb(II) abs (log D)** & **\%Cd(II) abs (log D)** & **\%Cu(II) abs (log D)** & **\%Zn abs (II) (log D)** \\ \hline
1.64 & 94.3 (2.84) & 86.8 (2.44) & 83.4 (2.35) & 78.6 (2.17) \\
1.00 & 60.1 (1.77) & 34.5 (1.35) & 28.2 (1.25) & 21.4 (1.09) \\
0.699 & 26.6 (1.16) & 9.58 (0.642) & 11.5 (0.74) & 12.8 (0.508) \\
0.398 & 10.4 (0.595) & 5.05 (0.355) & 2.48 (0.0658) & 5.71 (0.412) \\
0.00 & 7.71 (0.535) & - & 1.79 (\(-\)0.116) & - \\ \hline
**pH** & **\%Fe(III) abs (log D)** & **\%Al(III) abs (log D)** & **\%La(III) abs (log D)** & **\%Lu abs (III) (log D)** \\ \hline
1.00 & 99.6 (3.99) & 98.8 (3.55) & 98.1 (3.34) & 99.8 (4.34) \\
0.523 & - & 91.2 (2.64) & 68.3 (1.95) & 95.2 (2.95) \\
0.222 & 98.6 (3.49) & 62.0 (1.86) & 23.5 (1.12) & 80.7 (2.27) \\
0.00 & 97.2 (3.19) & 33.8 (1.36) & 11.1 (0.724) & 52.2 (1.68) \\ \(-\)0.301 & 91.5 (2.67) & 1.05 (0.271) & 0.74 (\(-\)0.48) & 24.5 (1.17) \\ \(-\)0.699 & 86.1 (2.41) & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Metal ion affinities of the diprotic phosphonic acid (DPA). Figure 3: Divalent and trivalent metal ion affinities for pPentaM. The higher affinities of the monoprotic phosphates over the phosphonic acid are illustrated in Figure 5, with Pb(II) and Lu(III) as representative examples.