Abstract:
Activated bamboo carbon (ABC) was chemically synthesized using phosphoric activation method,
and the resulting material was used to remove Rhodamine B from aqueous solutions. The surface
characteristics of the ABC were studied, and the conditions for the maximum removal of dye were
established. The capacity of Rhodamine B removal from ABC was 100% for a system with 0.02 g of
ABC and initial Rhodamine B concentration of 50 mg L–1 at 300 K. The best-fit adsorption isotherm was
Langmuir model with maximum adsorption capacity of 111.11 mg g–1 at 300 K. The L4-type adsorption
suggests that at low Rhodamine B concentrations, adsorption occurs in a flat orientation and
becomes end-on orientation at higher concentrations. Thermodynamic data reveal that the adsorption
process is endothermic with increasing entropy and moderately large negative free energy values indicate
the feasibility of the adsorption process. Pseudo-second-order kinetic model fitted well to both
adsorption and desorption processes suggesting the rate-limiting step involves chemical interactions.
Furthermore, intraparticle diffusion model indicates the simultaneous occurrence of three diffusion
steps caused by external mass transfer to the bulk solution, intraparticle diffusion and desorption of
the adsorbed dye molecules.
