ADSORPTION
Activated CarbonWhat is Adsorption?• Organic molecules bond to the internal
pores of activated carbon
Some Definitions
• Adsorption• Absorption• Sorption• Adsorbent• Adsorbate
Applications• Drinking water treatment
• Groundwater remediation
• Industrial wastewater treatment
• Polishing of treated municipal waste
• In a variety of gas-phase applications
Activated CarbonThe Three Types/Forms of AC
Powdered Granular Pelleted / Extruded
Activated CarbonWater Treatment Methods for GAC & PAC
Activated carbon is prepared in two steps
• Carbonization step
• Activation step:– Macropores: >25nm– Mesopores: >1 nm and <25nm– Micropores: <1nm
Activation Types
• Steam activation
• Chemical activation
15
-0,04-0,035-0,03
-0,025-0,02
-0,015-0,01
-0,0050
3 4 5 6 7 8 9pH
Sur
face
Cha
rge,
mm
ol/m
g
Raw Water Ozonated Water
Biologically Treated Water Ozonated - Biologically Treated Water
Charge on NOM
-0,4
-0,3
-0,2
-0,1
0
0,1
0,2
0,3
0 2 4 6 8 10 12
pH
Sur
face
Cha
rge,
meg
/g
Row Supra CAgran Norit 1240 HD 4000
pHPZC
pHPZC
Norit 1240
8.90
Row Supra
8.95
HD 4000 6.50CAgran 4.20
The point of zero charge (pHPZC) pH at which the GAC surface charge =0pH> pHPZC (-) chargepH< pHPZC (+) charge