ADSORPTION OF SIMULATED AND REAL EFFLUENTS ONTO ACTIVATED CARBON SURFACES
ADSORPTION OF SIMULATED AND REAL EFFLUENTS ONTO ACTIVATED CARBON SURFACES
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Date
2012-11
Authors
OCHOLI, ODIKE JOTHAM
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Abstract
Adsorption studies of simulated and real effluents was carried out with an aim to
better understand adsorption processes in multi-component dye and heavy metal
mixtures. Three (3) different Activated Carbon (AC) matrices were used as
adsorbent: Unmodified activated carbon (UMAC), chemically modified activated
carbon (CMAC) and physically modified activated carbon (PMAC). Simulated
effluent systems were developed from various aqueous combinations of
methylene blue (MB), methyl orange (MO), indigo carmine (IG), Pb(NO3)2 and
Cd(NO3)2.4H2O. A total of twenty two (22) different simulated effluent systems
were developed which were interacted with the AC matrices and three (3) textile
effluents samples (TXT 1, TXT 2 and TXT 3) were also collected from a textile
industry in Kaduna and used for this study. Adsorption results from single dye
rate experiments revealed that the adsorption process was particle-diffusion
controlled with chemisorption as the predominant adsorption type. For single dye
effluent systems, adsorption results showed that the AC matrices had good
performance especially at low concentrations of adsorbates. The order of
adsorption for the different dyes was MO > MB > IG, while the efficiency of the
matrices was PMAC > UMAC > CMAC. For binary dye effluent systems,
adsorption of combinations of MB and MO (MBMO) and MO and IG (MOIG) in
aqueous and aqueous Pb(NO3)2 and Cd(NO3)2.4H2O mixtures onto the AC
matrices was observed. Results revealed that for MBMO system, the
component that was preferentially adsorbed was dependent on the heavy metal
environment and the AC sample involved. Generally, the adsorption range was
89 – 98%. For the MOIG system, the result showed similar adsorption trends
irrespective of the heavy metal environment. MO was preferentially adsorbed
than IG while the performance of the matrices was PMAC > UMAC > CMAC.
The adsorption range was 54 – 82 %. For MBMOIG in aqueous Pb(NO3)2 and
Cd(NO3)2.4H2O mixture, the components were preferentially adsorbed as
follows: MO > MB > IG with an adsorption range of 73 – 97%, while the
performance of the matrices was PMAC > UMAC > CMAC. With the real textile
effluents, the AC matrices adsorbed components of TXT 2 and TXT 3
appreciably with average adsorption ranges of 72 – 82% and 19 – 68%
respectively, while the adsorption range for TXT 1 was wide between 2 – 70%
(close to 80% of the results were below 31%). The performance of the matrices
was PMAC > UMAC > CMAC, just like most of the simulated effluent cases.
Generally, adsorption involving multi-component adsorbate systems is dynamic
and is influenced by numerous factors, like pH of AC surface, pH of adsorbate
solution, size, shape and orientation of adsorbate species, concentration of
adsorbate species and contact time between adsorbate and adsorbent. The
resulting adsorption trend for any component is usually an inter-play of all these
factors.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF
POSTGRADUATE STUDIES, AHMADU BELLO
UNIVERSITY,ZARIA IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE AWARD OF THE DEGREE OF
DOCTOR OF PHILOSOPY IN ANALYTICAL CHEMISTRY
DEPARTMENT OF CHEMISTRY
AHMADU BELLO UNIVERSITY
ZARIA
NOVEMBER 2012
Keywords
ADSORPTION,, SIMULATED,, REAL,, EFFLUENTS,, ACTIVATED,, CARBON,, SURFACES.