Thiol-SAMMS for liquid applications (THSL) provides an excellent solution for lead remediation of aqueous waste streams. Evaluation in organic solutions is not complete.
Thiol-SAMMS can treat lead contaminated liquid streams with kinetics and capacity specific to that type of waste stream. This datasheet illustrates performance on spent aqueous leachate liquor from a mining operation.
Kinetics
The kinetics of lead adsorption by Thiol-SAMMS is extremely fast and comparable to mercury adsorption. Most adsorption is complete within 1 minute (>99.9% reduction). Figure 1 shows the reaction times for a test of SAMMS adsorption of lead on an effluent stream containing ~769 ppb (g/L) in an alkaline (pH 9.5) aqueous solution.
Figure 1: Lead Adsorption Kinetics
Figure 2: Capacity for Lead Dependence on Solution/adsorbent Ratio.
pH Accommodation
Thiol-SAMMS exhibits strong adsorption behavior towards lead over a wide range of pH (2-12) with limited sensitivity to the presence of anions or cations. This data set was obtained at pH 9.5.
Figure 2 shows the effect of adsorbent loading on capacity at the background 1 ppm concentration.
(The stability of this adsorbent in alkaline conditions will be the same as THSL which showed no sign of dissolution in a stirred solution of NaOH (50% NaOH by weight) after 1 week. The non-functionalized support immediately dissolved. Longer term stability has not been verified.)
The distribution co-efficient, Kd, The Kd (ml/g) varied between 50,000 and 4x109 Additional characterization is required to fully determine the range of use for Pb. Cation and Anion Interference
Good capacity and fast kinetics of the SAMMS lead adsorption is observed in the presence of cations and anions: PO43-, SO42- , CN-, Ca2+, Cu2+, K+, Na+, Si4+, Zn2+ ; and also in the presence of other anions bound by Thiol-SAMMS (Ag+, Cd2+, Pd2+, Hg2+, Ni2+)
Material Properties:
- Bulk Density – The bulk density for THSL is approximately 0.3 g/cc.