Double-layer modelling and physicochemical parameters interpretation for chromium adsorption on ZnMnOAC nanocomposite

Abstract

An efficient ZnMnO nanocomposite-based activated carbon (AC) was synthesized using the co-precipitation technique and was characterized by XRD, FTIR, FE-SEM and EDAX spectroscopic methods. The as-synthesized nanocomposite-based activated carbon was applied for the adsorption of toxic chromium using batch experiments. To enhance the removal efficiency, the effect of parameteric alterations such as adsorbent dose; pH; shaking time etc. have been studied. The kinetic model for adsorption of chromium onto the ZnMnOAC follows the pseudo-second-order reaction. According to the evidence obtained from isotherm work, the Langmuir model is acceptable and adequate as compared to that of other models under-study with a Q_max of 250 mg/g. The negative value of thermodynamic parameters indicates that the adsorption process is both spontaneous and stable. Among the three statistical models used for the adsorption process, double-layer was best fitted with n < 0.5 (0.369-0.339) values, representing a parallel orientation of adsorbate onto the surface of adsorbent (ZnMnOAC).

Keywords:

• ZnMnOAC
• FE-SEM
• pseudo-second-order
• statistical model
• double-layer
• thermodynamic parameters

Acknowledgements

Taif University Researchers Supporting Project number (TURSP-2020/04), Taif University, Taif, Saudi Arabia.

Disclosure statement

No potential conflict of interest was reported by the authors.