Page 250 - Materials Chemistry, Second Edition

Technologies for Treatment of Heavy Metal–Contaminated Groundwater 231

Definite outcomes from the remediation process (treatment of
heavy metal contaminated groundwater)

Complete or substantial destruction/degradation of the pollutants

Extraction of pollutants for further treatment or disposal

Stabilization of pollutants in forms less mobile or toxic

Seperation of non-contaminated materials and their recycling
from polluted materials that require further treatment

Containment of the polluted material to restrict exposure of the
wider environment

FIGURE 11.4 Definite outcomes from the remediation process (treatment of heavy
metal–contaminated groundwater).

Cementation
Electro chemical
Electro winning
treatment

Treatment methodologies
Adsorption Ion exchange
(Removal of heavy metals)

Chemical Coagulation
precipitation
Membrane filtration

FIGURE 11.5 Treatment methodologies for the removal of heavy metals.

of heavy metals, such as hydroxide, sulfide, carbonate, and phosphate. This pro-
cedure relies on the creation of insoluble metal precipitation by reacting dispersed
metals in the system with a precipitant (Veeken et al., 2003). To change the dispersed
metals into a strong molecular form, a precipitation reagent is added to the blend. A
coalescence response, activated by the reagent, causes the dispersed metals to form
strong particles. Filtration can then be used to remove the particles from the blend
(Ku and Jung, 2001; Fu and Wang, 2011). In hydroxide precipitation, a commonly
used compound precipitation process, calcium or sodium hydroxide is used as the
reagent to produce strong metal hydroxides. Nonetheless, it can be hard to make
hydroxides from dispersed metal particles in wastewater on the grounds that numer-
ous wastewater arrangements contain blended metals.