Photocatalytic Processes for the Removal of Dye - Green Chemistry for Dyes Removal from Wastewater - page 165

and Hameed [86], where the crushed date pits were initially carbonized at
700 C and then the resultant char was soaked in potassium hydroxide and
activated in a microwave oven at a power of 600 W for an irradiation time
of 8 min. The obtained activated carbon demonstrated a well-developed
porous structure with BET surface area of 856 m 2 .g -1 and total pore volume
of 0.47 cm 3 .g -1 . As shown in Figure 5.13, the SEM images of the char and
the activated carbon clearly illustrate the creation of pores after the activa-
tion process. The adsorption capacity of the activated carbon for methy-
lene blue was determined as 296.5 mg.g -1 under the operating conditions of
pH 6 and adsorbent dose 1 g.L -1 . The strong dependence of the adsorption
capacity to the pH level was ascribed to the protonation of the dye mole-
cule in the acidic medium and presence of excess H + ions which can
( a )
( b )
Figure 5.13 SEM micrographs of (a) date stone char and (b) date stone activated
carbon [86].