Abstract:
The presence of chromium (VI) in water is extremely harmful because it can cause illnesses,
disorder and diseases to human. In this study, the performance of low- cost natural sorbents was
evaluated for the removal of Cr(VI) from aqueous solutions. Batch adsorption experiments were
performed in order to examine the removal process under different parameters which are
contact time, pH and initial concentration. The Cr(VI) ion uptake was pH dependent and
reached maximum at pH 2 and 3 for both Tella residue and pea (Pisum. sativum) seed shell,
respectively. The adsorbents were characterized using FTIR and XRD. In order to describe the
relationship between the concentration of Cr(VI) ions in the solution and the amount of Cr(VI)
ions adsorbed to both adsorbents, Langmuir and Freundlich isotherm models were used for the
equilibrium tests. The results of the studies showed that with lower initial concentration, lower
solution pH, and at optimum contact time, the removal efficiency of Cr(VI) was found to
increase. The Freundlich isothermal equation model describes a stronger adsorption mechanism
than the Langmuir isotherm regression coefficient. Pseudo-first-order and pseudo-second-order
models were used to evaluate biosorption kinetics and it was found that the pseudo-second-order
model mechanism is the best-described Cr(VI) biosorption for powdered Tella residue and Pea
(Pisum sativum) seed shell. Therefore, the batch studies showed that Tella residue and Pea
(Pisum sativum) are favorable adsorbent for removal of Cr(VI) from aqueous solution.
