Kinetic, isotherm, and thermodynamic studies on Cr(VI) adsorption using cellulose acetate/graphene oxide composite nanofibers

In the present study, cellulose acetate/graphene oxide (CA/GO) composite nanofibers were prepared via the electrospinning method to remove Cr(VI) ions from aqueous solution via adsorption process in a batch mode. The impact of adsorption parameters, including contact time, pH, Cr(VI) concentration, and temperature was investigated to obtain the optimum conditions for the uptake of maximum Cr(VI) ions from water within a short time. The kinetic data of Cr(VI) adsorption were well fitted by pseudo-first-order and pseudo-second-order kinetic models, whereas Redlich-Peterson, Langmuir and Freundlich, isotherm models were used to describe the equilibrium data of Cr(VI) adsorption by the CA/GO nanofibers. The effect of temperature on the adsorption capacity of Cr(VI) ions using the nanofibers indicated that the higher temperatures were favorable for higher adsorption of Cr(VI) ions using the nanofibers. The thermodynamic parameters results indicated the spontaneous and endothermic of Cr(VI) sorption nature using the CA/GO nanofibrous adsorbent. The maximum monolayer adsorption capacity of nanofibers toward Cr(VI) ions sorption was 422.3 mgg(-1) which was comparable with other adsorbents. The reusability of composite nanofibers was carried out for five adsorption-desorption cycles. The obtained results exhibited the high capability of CA/GO nanofibrous adsorbents for Cr(VI) ions sorption from actual wastewater.

Automated summary

In this study, cellulose acetate/graphene oxide (CA/GO) composite nanofibers were prepared and used for the removal of Cr(VI) ions from water. The impact of adsorption parameters, such as contact time, pH, and temperature, on the adsorption efficiency was investigated. The results showed that higher temperature favored the adsorption of Cr(VI) ions. The adsorption process was described by various kinetic and isotherm models. The composite nanofibers exhibited high adsorption capacity and reusability.