Preparation And Characterization Of Activated Carbons From Rattan And Bamboo Waste For Color And Cod Removal
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Date
2010-10
Authors
Abdulrahman Ahmad, Abdulbari
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Abstract
The focus of this work was to study the feasibility of producing mesoporous
activated carbons from agriculture waste by-products low cost and available in
Malaysia, namely rattan and bamboo waste. The adsorption perfonnance of the rattan
activated carbon (RAC) and bamboo activated carbon (BMAC) were evaluated for the
removal of dyes C.I. Disperse Orang30 (D030), C.I. Reactive Black 5 (RB5) and C.I.
Vat Blue 4 (VB4)) from synthetic wastewater and chemical oxygen demand (COD) and
color reduction of a real cotton textile mill effluent. The activated carbons RAC and
BMAC were prepared by chemical activation method using phosphoric acid (H3P04) as
a chemical agent. Statistical design of an experiment (DOE) was used to obtain the
optimum operating conditions. Central Composite Design (CCD) was applied to
optimize three preparation variables activation temperature 400-600 °C, activation time
1-3 and (wt %) (H3P04 : precursor) impregnation ratios (IR) 3:1- 6:1 for the carbons
yield and adsorption perfonnances. The optimum conditions for RAC and BMAC were
obtained by using temperature of 501 - 556 °C activation times of 1.79 - 2.33 h and a
chemical impregnation ratio of 4.70:1, 5.23:1, respectively. The optimized activated
carbons were characterized by BET surface area analysis, SEM, FTIR, TGA, and EA.
The activated carbons characteristic prepared under the optimum conditions were BET
surface areas (1 037.18, 988.24 m2/g), total pore volume (0.66, 0.69 cm3 /g) and the
average pore diameters (2.56, 2.82 nm), for RAC and BMAC, respectively. The
activated carbons prepared were in the mesopores region according to the IUP A C. The
SEM images revealed large and well-developed pores on the surface structure of the
activated carbons. The FTIR analysis revealed the presence of various functional groups
on the activated carbons surface. The effect of various experimental parameters for
synthetic and industrial wastewater in a batch system such as temperature (30 -50 °C),
pH (2-12), initial dyes concentration (50-500 mg/L), and contact time, were investigated.
Adsorption isothenns, kinetics and thermodynamics of synthetic wastewater on
activated carbons were detennined from batch tests. The equilibrium data for both
activated carbons were best represented by Langmuir isotherm model, which fits the
data very well at different temperatures studied. The adsorption kinetics was found to
follow the pseudo-second-order kinetic model. All the systems show favourable
adsorption of the synthetic and industrial wastewater. In fixed bed column experiments,
the effects of an inlet effluent concentration, feed flow rate and activated carbon bed
height on the breakthrough curves were determined. The highest bed capacities of RAC
on industrial wastewater and BMAC on synthetic wastewater were obtained at 80 mm
bed height and 10 mL/min flow rate. The adsorption data were fitted to three-wellestablished
fixed bed adsorption models namely, Adam-Bohart, Thomas and Y oonNelson
models. The results showed that Thomas and Yoon-Nelson were the best models
with high coefficients of correlation and lower percentage errors ( s%) at different
conditions. The regeneration efficiencies of the spent activated carbons were studied
with acetic acid solvent. The results indicate that RAC and BMAC were suitable
adsorbents for treatment of synthetic and industrial wastewater.
Description
Keywords
the feasibility of producing mesoporous activated carbons , from agriculture waste by-products low cost.