3
the downside of its full commercialization. This has however prompted researchers
to explore agricultural residues (biowastes) for its synthesis. The use of these biowastes as adsorbents has several advantages which include high efficiency, low cost,
and regeneration ability as well as possibility for metal recovery (Dai et al. 2018;
Mashhadi et al. 2016).
Potential removal of heavy metal ions by synthesized carbonaceous biowastes
hinge on several factors which subsequently influence its adsorbing characteristics.
Considerations based on the methods of preparation, forms of modification, treatment, and adsorption process conditions (pH, temperature, and initial concentration) are vital in understanding the mechanism of the adsorption process.
This present overview therefore provides an in-depth review on the synthesis,
mechanism, and modification types of activated carbon. In addition, the essential
characteristics of activated carbon, both physical and chemical properties, are well
covered. Isotherms, kinetics, and thermodynamics of several works were appraised
to draw a conclusion based on some selected adsorption variables.
1.2 Types of Activated Carbon
Depending on the industrial applications, methods of preparation, forms or shapes,
as well as their sizes, activated carbon exists mainly in three categories, namely, (1)
extruded or pelletized activated carbon, (2) granular activated carbon, and (3) powdered activated carbon (Çeçen 2000). Figure 1.1 shows the three categories of activated carbon.
1.2.1 Powdered Activated Carbon
Powdered activated carbon has a distinctive average size of 15–25 μm. Fine particles of pulverized carbon are the major constituents of powdered activated carbon,
95–100% of which will not be retained in a designated mesh sieve of 80 (0.177 mm)
and below according to ASTM D5158-98. Powdered activated carbon is composed
of high carbon content organic materials such as wood, lignite, and coal.
Fig. 1.1 Major classes of activated carbon – (a) extruded or pelletized activated carbon, (b) granular activated carbon, (c) powdered activated carbon (Wikipedia)
1 Synthesis of Activated Carbons for Heavy Metals Removal
the downside of its full commercialization. This has however prompted researchers
to explore agricultural residues (biowastes) for its synthesis. The use of these biowastes as adsorbents has several advantages which include high efficiency, low cost,
and regeneration ability as well as possibility for metal recovery (Dai et al. 2018;
Mashhadi et al. 2016).
Potential removal of heavy metal ions by synthesized carbonaceous biowastes
hinge on several factors which subsequently influence its adsorbing characteristics.
Considerations based on the methods of preparation, forms of modification, treatment, and adsorption process conditions (pH, temperature, and initial concentration) are vital in understanding the mechanism of the adsorption process.
This present overview therefore provides an in-depth review on the synthesis,
mechanism, and modification types of activated carbon. In addition, the essential
characteristics of activated carbon, both physical and chemical properties, are well
covered. Isotherms, kinetics, and thermodynamics of several works were appraised
to draw a conclusion based on some selected adsorption variables.
1.2 Types of Activated Carbon
Depending on the industrial applications, methods of preparation, forms or shapes,
as well as their sizes, activated carbon exists mainly in three categories, namely, (1)
extruded or pelletized activated carbon, (2) granular activated carbon, and (3) powdered activated carbon (Çeçen 2000). Figure 1.1 shows the three categories of activated carbon.
1.2.1 Powdered Activated Carbon
Powdered activated carbon has a distinctive average size of 15–25 μm. Fine particles of pulverized carbon are the major constituents of powdered activated carbon,
95–100% of which will not be retained in a designated mesh sieve of 80 (0.177 mm)
and below according to ASTM D5158-98. Powdered activated carbon is composed
of high carbon content organic materials such as wood, lignite, and coal.
Fig. 1.1 Major classes of activated carbon – (a) extruded or pelletized activated carbon, (b) granular activated carbon, (c) powdered activated carbon (Wikipedia)
1 Synthesis of Activated Carbons for Heavy Metals Removal