BCEJ 54-2011-124

Recovery of gold(III) from an aqueous solution onto a durio zibethinus husk

The recovery of gold(III) ions from an aqueous solution onto a durio zibethinus husk (DZH) was examined
after varying pH, contact time, adsorbent dosage, initial Au(III) concentration, and temperature. The functional
groups ofDZHwere analyzed by FTIR and Au(III) recovery ontoDZHwasverified byFESEM–EDXand
XRD analysis. Adsorption equilibrium isotherms and kinetics of the DZH were studied using Freundlich
and Langmuir models, as well as pseudo first-order, second-order kinetic and intraparticle diffusion equations.
The experimental data obtained withDZHfitted best to the Langmuir isotherm model and exhibited
a maximum adsorption capacity (qmax) of 1724mol g−1. The data followed the pseudo second-order
equation. The activation energy of the adsorption (Ea) was estimated to be 38.5 kJ mol−1. Thermodynamic
parameters, such as changes in enthalpy, entropy and Gibbs free energy, showed that the adsorption is
exothermic, spontaneous at low temperature, and is a chemisorption process. These results indicate
that DZH adsorbs efficiently and could be used as a low-cost alternative for the adsorption of Au(III) in
wastewater treatment.