Use of caustic magnesia to remove cadmium, nickel, and cobalt from water in passive treatment systems: column experiments

Journal Article · Sun Oct 15 00:00:00 EDT 2006 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es061092g· OSTI ID:20823815

Roetting, Tobias Stefan; Cama, Jordi; Ayora, Carlos; Cortina, Jose-Luis; Pablo, Joan De ^[1]

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1. Institute of Earth Sciences Jaume Almera, CSIC, Barcelona (Spain)

In the present study caustic magnesia obtained from calcination of magnesium carbonate was tested in column experiments as an alternative material for passive remediation systems to remove divalent metals. Caustic magnesia reacts with water to form magnesium hydroxide, which dissolves increasing the pH to values higher than 8.5. At these pH values, cadmium is precipitated as otavite and to a minor amount as a hydroxide. Cobalt and nickel are precipitated as hydroxides which form isostructural solids with brucite. Thus, metal concentrations as high as 75 mg/L in the inflowing water are depleted to values below 10 {mu}g/L. Magnesia dissolution is sufficiently fast to treat flows as high as 0.5 m{sup 3}/m{sup 2} per day. For reactive grain size of 2-4 mm, the column efficiency ends due to coating of the grains by precipitates, especially when iron and aluminum are present in the solution. 23 refs., 7 figs., 1 tab.

• OSTI ID: 20823815
• Journal Information: Environmental Science and Technology, Vol. 40, Issue 20; Other Information: [e-mail]; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ACID MINE DRAINAGE
WATER POLLUTION CONTROL
CADMIUM
NICKEL
COBALT
MAGNESIUM OXIDES
REMEDIAL ACTION
WATER TREATMENT
WATER TREATMENT PLANTS
BENCH-SCALE EXPERIMENTS
PRECIPITATION
DEMETALLIZATION
PH VALUE
CADMIUM CARBONATES
CADMIUM HYDROXIDES
COBALT HYDROXIDES
HYDROXIDES
GROUND WATER