Coupling effect of Fe 3+ (aq) and biological, nano-sized FeS-coated limestone on the removal of redox-sensitive contaminants (As, Sb and Cr): Implications for in situ passive treatment of acid mine drainage

Abstract

Nano-sized FeS particles have been shown to improve the adsorption performance in permeable reactive barrier (PRB) technologies that are used to treat acid mine drainage. To investigate the coupling effect of Fe 3+ and biological nano-sized FeS on removal of redox-sensitive contaminants and the permeability of a limestone system, Fe-reducing bacteria (FRB) and sulfate-reducing bacteria (SRB) were used to form nano-sized FeS coatings on limestone grains. For initial acidic solutions containing 0.5 mg/L As(V), Cr(VI) and Sb(V), retardation factors increase from 26, 5 and 7, respectively, in a limestone-only (pristine) system to >>367, 89 and 9, respectively, in an FeScoated limestone system, and to 345, 367 and 308, respectively, in an FeS-Fe 3+ (aq) system. The permeability coefficient of the FeS-coated limestone system is better than that of the pristine limestone system, but declines to two-thirds of the pristine limestone system in the presence of Fe 3+ (aq), possibly due to the formation of secondary ferric hydroxides. XPS analysis suggests that the FeS particles are effective at reducing As(V), Sb(V) and Cr(VI) and removing them from solution. These results demonstrate that FeS particles improve retention of redox-sensitive contaminants with and without Fe 3+ (aq). These new findings give new insights on the coupling effect of redox systems used in PRBs.

A systematic mapping study on the development of permeable reactive barrier for acid mine drainage treatment

“…The potential of the combination of reactive media has been realized due to its promising performance in terms of removal of sulfates and reduction of toxic metals. For example, the result showed that the permeability coefficient of an iron-based limestone system is better than that of the pristine limestone system [55]. It also improves the retention of redox contaminants.…”

Optically Important Transparent Syndiotactic Polystyrene/FeS Composites Grown by Low Sol-gel Route

“…Iron-based nanoparticles like iron oxide (Fe 2 O 3 ), Iron Sulphide (FeS) are a new class of emerging materials. Such Materials show their significant application in superconductor, photocatalyst electric cell and also for removal of environmental pollutants due to its excellent optical-electrical properties [1][2][3][4][5] . The bandgap of such materials varies with tensile and compression strain in the crystals [6][7][8] .…”