1 (Sharma and Upadhyay 2009; Rahman et al. 2012). Similarly, activated carbon
prepared from apricot stones by carbonization and activation with a mixture of
phosphoric acid and nitric acid displayed efficient adsorption (99.5%) of methyl
orange (8) and 1 (Djilani et al. 2015).
Activated carbon prepared from the epicarp of Ricinus communis also effectively
removed 2 at pH 7 following Langmuir adsorption isotherm model and pseudosecond-order kinetics (Santhi et al. 2010). The activated carbon based on sludge and
prepared by pulp wastewater was subjected to fixed-bed adsorption column to
remove 1 and Reactive Red 24 (11). The results showed weaker desorption for
1 as compared to 11 because of the stability onto the sorbent, but overall analysis
proved sludge-based activated carbon to be much better than commercial activated
carbon (Li et al. 2011c). The activated carbon prepared from the cotton stalk with
microwave radiations proved as good adsorbent for removal of 1 in another study,
and adsorption data followed the Langmuir adsorption isotherm. Optimum pH range
for absorption was from 9.0 to 10.0, and adsorption efficiency as determined from
Langmuir adsorption isotherm was 315.04 mg g
À1 (Deng et al. 2009).
Activated carbon has also been applied to remove 19, 1, and many anionic and
cationic dyes in wastewater treatment (Rodríguez et al. 2009). Different other
sludge-based activated carbons are also reported for dye removal from aqueous
media (Li et al. 2011a). Silver nanoparticle-loaded activated carbon also depicted
significant adsorption affinity (98%) toward Direct Yellow 12 under optimized
conditions. Adsorption data followed Langmuir adsorption isotherm model and
provided q max value of 454 mg g
À1 . The thermodynamics studies disclosed the
process as endothermic, while kinetics studies revealed pseudo-second-order kinetics (Ghaedi et al. 2012).
Another study employed activated carbon extracted from pineapple waste biomass to adsorb 1, and adsorption data was analyzed based on the goodness-of-fit to
Langmuir adsorption isotherm with q max of 288 mg g
À1 . The study supported the
potential of pineapple waste biomass as efficient and cheap raw material to produce
activated carbon for dye removal (Mahamad et al. 2015). Likewise, activated carbon
prepared from orange peels is reported to have good efficacy for Direct Blue
86 removal from simulated wastewater. Adsorption data based on Langmuir adsorption isotherm with pseudo-second-order kinetics showed 92% removal of Direct
Blue 86 (100 mg/L) on 25
C, pH 2 for 6 g L
À1 adsorbent dose (El Nemr et al. 2009).
Using fly ash as an adsorbent, the maximum absorption for Reactive Red
23, Reactive Blue 171, Acid Black 1, and Acid Blue 193 (16) was noted as 2, 1.8,
11, and 10 mg g
À1 , respectively, in basic medium with Langmuir adsorption
isotherm. Moreover, adsorption kinetics followed pseudo-second-order, and thermodynamics analysis showed the spontaneous and endothermic nature (Sun et al.
2010). Another study revealed that the fly ash or fly ash-based adsorbent might be
easily applied for the photocatalytic degradation or removal of 1 along with other
heavy metals from the aqueous solutions, and the results were quite optimistic (Visa
et al. 2011).
Using fly ash and photo-Fenton system, the possibility of simultaneous removal
of hazardous dyes like 8 increases, and fly ash composition assists the adsorption
608
R. S. Ashraf et al.
prepared from apricot stones by carbonization and activation with a mixture of
phosphoric acid and nitric acid displayed efficient adsorption (99.5%) of methyl
orange (8) and 1 (Djilani et al. 2015).
Activated carbon prepared from the epicarp of Ricinus communis also effectively
removed 2 at pH 7 following Langmuir adsorption isotherm model and pseudosecond-order kinetics (Santhi et al. 2010). The activated carbon based on sludge and
prepared by pulp wastewater was subjected to fixed-bed adsorption column to
remove 1 and Reactive Red 24 (11). The results showed weaker desorption for
1 as compared to 11 because of the stability onto the sorbent, but overall analysis
proved sludge-based activated carbon to be much better than commercial activated
carbon (Li et al. 2011c). The activated carbon prepared from the cotton stalk with
microwave radiations proved as good adsorbent for removal of 1 in another study,
and adsorption data followed the Langmuir adsorption isotherm. Optimum pH range
for absorption was from 9.0 to 10.0, and adsorption efficiency as determined from
Langmuir adsorption isotherm was 315.04 mg g
À1 (Deng et al. 2009).
Activated carbon has also been applied to remove 19, 1, and many anionic and
cationic dyes in wastewater treatment (Rodríguez et al. 2009). Different other
sludge-based activated carbons are also reported for dye removal from aqueous
media (Li et al. 2011a). Silver nanoparticle-loaded activated carbon also depicted
significant adsorption affinity (98%) toward Direct Yellow 12 under optimized
conditions. Adsorption data followed Langmuir adsorption isotherm model and
provided q max value of 454 mg g
À1 . The thermodynamics studies disclosed the
process as endothermic, while kinetics studies revealed pseudo-second-order kinetics (Ghaedi et al. 2012).
Another study employed activated carbon extracted from pineapple waste biomass to adsorb 1, and adsorption data was analyzed based on the goodness-of-fit to
Langmuir adsorption isotherm with q max of 288 mg g
À1 . The study supported the
potential of pineapple waste biomass as efficient and cheap raw material to produce
activated carbon for dye removal (Mahamad et al. 2015). Likewise, activated carbon
prepared from orange peels is reported to have good efficacy for Direct Blue
86 removal from simulated wastewater. Adsorption data based on Langmuir adsorption isotherm with pseudo-second-order kinetics showed 92% removal of Direct
Blue 86 (100 mg/L) on 25
C, pH 2 for 6 g L
À1 adsorbent dose (El Nemr et al. 2009).
Using fly ash as an adsorbent, the maximum absorption for Reactive Red
23, Reactive Blue 171, Acid Black 1, and Acid Blue 193 (16) was noted as 2, 1.8,
11, and 10 mg g
À1 , respectively, in basic medium with Langmuir adsorption
isotherm. Moreover, adsorption kinetics followed pseudo-second-order, and thermodynamics analysis showed the spontaneous and endothermic nature (Sun et al.
2010). Another study revealed that the fly ash or fly ash-based adsorbent might be
easily applied for the photocatalytic degradation or removal of 1 along with other
heavy metals from the aqueous solutions, and the results were quite optimistic (Visa
et al. 2011).
Using fly ash and photo-Fenton system, the possibility of simultaneous removal
of hazardous dyes like 8 increases, and fly ash composition assists the adsorption
608
R. S. Ashraf et al.