5.4 Decontaminating Heavy Metals – The Conventional Strategies

71

oxygen species (ROS), which could ultimately lead to cell damage or death or by

replacing metals in pigment molecules or the activators of other metallo-proteins

such as enzymes disrupting their function.

5.4

Decontaminating Heavy Metals – The Conventional

Strategies

The conventional decontamination strategies could be in situ and ex situ in nature,

but none of these proven to optimize the sustainable environmental decontam-

ination of heavy metals. The heterogeneous and multidimensional nature of

environment makes most remediation efforts economically demanding. Traditional

decontamination strategies of heavy metal remediation have a wide range of

strategies (Table 5.2).

Table 5.2

Various conventional metal decontamination strategies.

Method

Key features

Advantages

Disadvantages

References

Heat treatment

Substrate heated,

heavy metals exposed

to very high

temperature, making

them evaporate and

later recovered by

condensation

●Shorter

treatment time

●Complete

removal of

metals (e.g. Cd

and Cu)

●Need of very

high

temperature

leading to more

leaching of the

metals

[15]

Electroremediation

Based on the principle

of electrokinesis,

involving application

of low electric current

to contaminated

substrate for

recovering the

pollutants

●Shorter time

interval

●Lower

extraction of

heavy metals

from soil

[16]

Vitrification

Bringing

contaminated soil to a

very high temperature

until they melts and

vitrified

●Volume

reduction of

natural soils

●Cost effective

●The treatment

soil is limited to

a maximum of

7–10% organics

by weight

[17]

Precipitation

Traditional chemical

precipitation method

for effective

elimination of heavy

metals

●Simple,

cost-effective,

and non-toxic

procedure

●Requirement of

an array of

chemicals

●Secondary waste

generation

[18]

Chemical leaching

This process involves

dissolving heavy

metal ions into the

leaching liquid

followed by extraction

●This is the

method of

choice when the

concentration of

heavy metals is

significant

●Requirement of

large amount of

acid to maintain

the pH for

solubilization,

followed by its

neutralization

[19]