Studies on the Potential Application of Bio-Waste for Heavy Metals Removal from Aqueous Solution
Date
2014-10
Authors
Journal Title
Journal ISSN
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Publisher
Department of Chemistry
Abstract
An efficient and effective biosorbents were investigated by using waste tealeaves. It was
prepared by amination with three different aminating reagents to introduce amino groups
onto the surface of biosorbent. The biosorbent was animated by using ethylenediamine,
dimethylamine and hydrazine monohydrate. They are called CATL-1, CATL-2 and
CATL-3, respectively. The prepared biosorbents were characterized with elemental
analysis, analysis of cellulose, hemicelluloses and lignin, SEM images, FTIR spectra,
XRD analysis, TG/DTA analysis and zeta potential analysis.
These aminated biosorbents were used for sequestration of heavy metals like lead,
copper, cadmium and zinc. Their metal uptake performance were also elucidated by using batch experiments. The adsorption capacities of biosorbents were studied as the function of solution pH, initial concentration of metal ions and contact time of adsorption. The effect of pH on adsorption were studied by varying the solution pH from 1-7. The results indicated that the uptake performance of biosorbents significantly change with pH of solution and optimum pH for adsorption was also determined. The initial concentration of metal ions varying from 25-800 mg/L were used to calculate the optimum loading
capacity of biosorbents. The optimum time for adsorption were determined by contacting
the adsorbent with metal solution at different interval of time.
The experimental data were found to be well fitted with langmuir isotherm model. From
the isotherm plots the maximum adsorption capacities for lead was found to be highest
for all of the three adsorbents while the values were lowest for zinc. Among the three
biosorbents, CATL-3 is found to be having highest adsorption capacity for all metal ions
used in this study. In CATL-3, the maximum adsorption capacity for Pb (II), Cu (II), Cd
(II) and Zn (II) are found to be 120.8, 90.4,114.3 and 79.76 mg/g, respectively. The
optimum contact time for metal ions are found to be between 120 - 150 min for all the
biosorbents. The kinetic data were well fitted with pseudo - second order model.
Hence the biosorbents prepared from waste tealeaves can be potentially applied for
treatment of waste water contaminated with toxic heavy metals.
Description
Keywords
Adsorption, Biosorbents,, Heavy metals, Langmuir isotherm