Adsorptive Separation of Heavy Metals onto Xanthated Apple Waste From Aqueous Solution
Date
2006
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Chemistry
Abstract
Biosorption is potentially an attractive technology for the treatment of
wastewater retaining heavy metals in aqueous solution. This study
investigated the feasibility of chemically modified apple waste as a novel type
of biosorbent for lead, cadmium, zinc and Iron removal from aqueous
medium. Xanthated apple waste as a biosorbent was prepared by simple
chemical reaction with carbon disulphide
under alkaline condition. The
maximum exchangeable cations of the H
V
+
-form xanthated apple waste (XAWgel)
were
as
high
as
2.52
mol/kg.
The
effect
of
pH,
sorption
kinetics,
effect
of
competitive
ion and isotherm were studied by batch method. The significant
effect of pH was in the range of 3 to 6. Time dependency experiments for the
metal ions uptake showed the biosorption rate was fast initially for 2h,
followed by slow attainment of equilibrium. Sorption isotherm test showed
that equilibrium sorption data were better represented by Langmuir model
than the Freundlich model, and the maximum adsorption capacity of Pb(II),
Cd(II), Zn(II) and Fe(III) were found to be 250, 192.30, 123.45 and 62.89
mg/g respectively. The pseudo first-order, pseudo second-order, and secondorder
models were used to analyze the kinetic data. The good correlation
coefficient was obtained for pseudo second-order kinetic model. XAW-gel
was found to be more efficient than the conventionally used adsorbent
activated carbon and other most of the biosorbent. Based on the result, a
judicious choice of modification strategy for raw apple waste precursors can
produce adsorbent with active xanthated surface functional groups and
appears to be a promising biosorbent for removal of heavy metals from
aqueous water.
Description
Keywords
cadmium, sorption kinetics