Background: In this work, Cr (VI) adsorption on nano-ZrO2๏TiO2 impregnated orange
wood sawdust (Zr๏Ti/OWS) and nano-ZrO2๏TiO2 impregnated peach stone shell (Zr๏Ti/PSS) was
investigated by applying different adsorption parameters such as Cr (VI) concentrations, contact
time, adsorbent dose, and pH for all adsorbents.
Methods: The adsorbents were characterized by SEM and FT-IR. The equilibrium status was
achieved after 120 min of contact time and optimum pH value around 2 were determined for Cr (VI)
adsorption. Adsorption data in the equilibrium is well-assembled by the Langmuir model during the
Results: Langmuir isotherm model showed a maximum adsorption value of OWS: 21.65 mg/g and
Zr๏Ti/OWS: 27.25 mg/g. The same isotherm displayed a maximum adsorption value of PSS: 17.64
mg/g, and Zr๏Ti/PSS: 31.15 mg/g. Pseudo-second-order kinetic models (R2=0.99) were found to be
the best models for describing the Cr (VI) adsorption reactions.
Conclusion: Thermodynamic parameters such as changes in ΔG°, ΔH°, and ΔS° have been estimated,
and the process was found to be spontaneous.