H. Biester et al., Effectiveness of mossy tin filters to remove mercury from aqueous solutionby Hg(0) reduction and Hg(0) amalgamation, WATER RES, 34(7), 2000, pp. 2031-2036
Reduction of bivalent mercury (Hg(II)) by mossy tin combined with Hg(0) air
stripping has been recently proposed as a method to remove Hg from groundw
ater. We investigated the effectiveness of mossy tin to remove Hg(II) from
aqueous solution at different flow rates and determined the retention of Hg
through the formation of HgSn amalgams Results show that mossy tin layers
of only 2 cm thickness can reduce 100% of 800 mu g Hg(II) l(-1) at a how ra
te of about 1 Volume of drainable porosity min(-1) (Vol min(-1)), and even
100% of 5000 mu g 1(-1) at 0.125 Vol min(-1), 89% and 97% of the Hg(0) were
retained in the filter through amalgamation. No Hg was remobilized from th
e loaded tin filters by chloride (10-50 mg Cl- I-1) or dissolved organic ca
rbon DOC (0.5-6 mg DOC l(-1)). The capacity of mossy tin to adsorb Hg was f
ound to be at least 5-6% of the weight of the filter. The study shows that
mossy tin has a high capacity to remove Hg effectively from aqueous solutio
n. Disadvantages arise from the release of tin from the filters exceeding l
egal limits of 20 mu g 1(-1) in most cases but occurred as mostly insoluble
tin particles or Sn hydroxide. (C) 2000 Elsevier Science Ltd. All rights r
eserved.