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

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).

Automated summary

An efficient activated carbon based on ZnMnO nanocomposite was synthesized and characterized. This material showed good adsorption performance for toxic chromium. The effects of parameter variations on adsorption efficiency were studied, and the pseudo-second-order reaction was found to be the most suitable kinetic model. The Langmuir model was found to be more appropriate for describing the adsorption process compared to other models. The negative values of thermodynamic parameters indicated that the adsorption process was spontaneous and stable. Among the statistical models used, the double-layer model was the best fit for the adsorption process.