Figure 1: Loading Curve for Sulfonate SAMMS
Figure 2: The Kinetic Curve for Sulfonate SAMMS
Steward’s SAMMS can provide excellent solutions for removing scale formers in industrial process streams such as the bleaching process of the pulp and paper industry.
Sulfonate-SAMMS has comparable specificity as conventional ion exchange resins with faster kinetics, higher capacity and no swelling or shrinking in service.
Kinetics – Sulfonate SAMMS
The loading capacity of Sulfonate-SAMMS in a 55 ppb Ca process stream is quite high compared to ion exchange resins. Figure 1 shows the loading curve for a test of SAMMS on calcium in a pulp and paper process stream.
The kinetics of adsorption by Sulfonate-SAMMS is extremely fast and comparable to mercury adsorption by Thiol-SAMMS. Most adsorption is complete within 1 minute. Figure 2 shows the kinetics of calcium adsorption in the same process stream described in Figure 1. As shown in Table 1, the adsorption coefficient, Kd varied from about 800 to 3860 ml/g over a range of solution-to-solid ratios of 100 to 10,000.
Table 1. The Distribution Coefficients for Sulfonate SAMMS (process stream of Figure 1)
| Solution-to-Solid Ratio, ml/g | Eq Conc., mg/L | Loading, mg/g | Kd, ml/g |
|---|---|---|---|
| 100 | 1.45 | 5.4 | 3719 |
| 500 | 15.7 | 20.0 | 1429.5 |
| 1000 | 30.1 | 30.9 | 1188 |
| 5000 | 48.3 | 33.5 | 694.5 |
| 10000 | 51.3 | 42.0 | 827 |
Other Adsorbents for Scale-Formers
The carboxylate-SAMMS is also attractive for binding scale-formers and EDA-SAMMS and can be selected depending on the pH of the solutions.
Adsorbents for Mn (Mn2+, and Mn7+) and pH accommodation
The carboxylate-SAMMS very effectively binds Mn in the pH range of 2-11 with a preferred range of 5-11. The carboxylate-SAMMS outperforms ion change resins. In more acidic solutions (pH~2) the Sulfonate-SAMMS works moderately well.
The binding strength of Sulfonate- and Carboxylate SAMMS has not been fully evaluated. These adsorbents can be replenished by recovering the adsorbed metals. Recycling ten times did not influence kinetics or capacity.
Selectivity
Sulfonate-SAMMMS and Carboxylate-SAMMS show good selectivity as the Kd values in Table 1 suggest. These SAMMS products are highly selective for calcium, magnesium, manganese and iron.
Cation and Anion Interference
Many adsorbents are sensitive to co-occurrence of certain cations and anions. Sulfonate- and Carboxylate SAMMS exhibits strong adsorption behavior towards these scale-forming metals over a wide range of pH (2-12) with limited sensitivity to the presence of anions or cations. Figure 1 shows a typical background environment where good adsorption is obtained.
Good capacity and fast kinetics of the SAMMS adsorption for Ca and Mg is observed in the presence of cations and anions: Cl, ClO3, C2O4, CHO2, F, NO2, NO3, PO4, SO3, SO4 , Al, B, Ba, Cd, Cr, Cu, Ca, Cu, K, Mg, Mn, Mo, Na, Pb, Si, Sr, and Zn.
Material Properties:
- Bulk Density – The bulk density for THSL is approximately 0.3 g/cc.