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Guar gum grafted poly (acrylonitrile) templated silica xerogel: Nanoengineered material for lead ion removal

Table. S1 Lead binding by the template silica xerogel (H80–H900) with respect to s-GG-g-PAN and nontemplated silica xerogel (S900) using adsorbent dose 50 mg, Pb2+ 500 mgL-1, temperature (30 ◦C), at 120 rpm, pH 5, 2 h, in 50 mL solution.

S. No. / Sample / Adsorption Pb2+
(mgL-1)
1. / s-GG-g-PAN / Dissolves
2. / template silica xerogel (H80) / 442
3. / template silica xerogel (H250) / 460
4. / template silica xerogel (H500) / 473
5. / template silica xerogel (H900) / 480
6. / S900 / 190

Table. S2 Data of crystalline peaks in H900 sample along with 2θ(degree) and d spacing.

Peak No. / 2θ(degree) / d(ang.)
1 / 20.6577 / 4.29611
2 / 21.8035 / 4.07286
3 / 23.3809 / 3.80153
4 / 27.4926 / 3.24161
5 / 28.3593 / 3.14448
6 / 30.1513 / 2.96154
7 / 36.1316 / 2.48391
8 / 37.7626 / 2.38028
9 / 39.0797 / 2.30304
10 / 54.1561 / 1.69217
11 / 56.8218 / 1.61895
12 / 60.3588 / 1.53226
13 / 66.4403 / 1.40599
14 / 72.3651 / 1.30477
15 / 80.8784 / 1.18753

Table.S3 Change of pH after adsorption. [Initial pH (pH0); Equilibrium pH after adsorption (pHe)].

Ion / C0 (mgL-1) / pH0 / pHe
Pb2+ / 500 / 1.00 / 1.01
2.00 / 2.02
3.00 / 3.05
4.00 / 4.09
5.00 / 5.11
6.00 / 5.10
7.00 / 5.62

Table.S4 Constant of kinetic models for Pb2+ adsorption on template silica xerogel (H900)

Pb2+ in ppm / Lagergren
R2 kL (min-1) / Pseudo second order
R2 k’(gmg-1min-1) / Second order
R2 k2 (gmg-1min-1)
500
700
900 / 0.962 1.543 x 10-2
0.824 1.496 x 10-2
0.906 1.335 x 10-2 / 0.999 2.85 x 10-4
0.999 1.25 x 10-4
0.999  1.25 x 10-4 / 0.962 3.8 x 10-4
0.952 1.7 x 10-4
0.964 1.43 x 10-4

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