| Summary: | Study on the biosorption of [AuCl4] - using Bacillus subtilis biomass has been carried out in a batch system with variation of pH, biomass concentration, contact time and initial concentration of [AuCl4]. Zero order, first order, second
order, pseudo-first order and pseudo-second order model kinetics were used to
determine the biosorption kinetics. Langmuir and Freundlich adsorption isotherm
model were used to determine the biosorption capacity and energy of biosorption.
The interaction mechanism of [AuCl4] - was studied by sequensial desorption with
aquabides, HCl 0.1 M and Na2EDTA 0.1 M. In the binary system [AuCl4] - [FeCl4], effect of interference ions on the biosorption process were examined using [FeCl4]. The concentration of [AuCl4] was analyzed using atomic absorption pectrophotometer (AAS).
The results showed that the optimum pH was 3 and biomass concentration
was 500 mg/L. The biosorption occurred fast in the first 45 min and was relatively
constant there after. The process reached the equilibrium at the initial concentration of 50 mg/L. The biosorption process could be described by pseudosecond order kinetic model with rate constant 6,37�10 -2 g mg -1 .menit -1, respectively. The biosorption capacity were 8.82 mg/g followed by Langmuir isotherm and energy of biosorption were 29.49 kJ/mol, respectively. The maximum desorption was obtained using HCl 0.1 M. In the binary system [AuCl4] - -[FeCl4], it was observed that [FeCl4]
-
might interfere the biosorption of
[AuCl4]
-
on the biomass.
|
|---|