Notice of RetractionCr(III) Removal with Fly Ash Modified by Hydrochloric Acid

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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In this paper, fly ash modified by hydrochloric acid was used as adsorbent to remove Cr(III) in aqueous solution. Adsorption isotherms and kinetics models were analyzed, the thermodynamic constants were calculated on the basis of data achieved. Optimal operation conditions were attained through groups of orthogonal experiments, and the effect was compared to that of active carbon. The results showed that modified fly ash was effective on Cr(III) removal. The adsorption process fit Langmuir and Freundlich isotherm equations, with correlation coefficients R² 0.9988 and 0.9590 respectively, the maximum adsorption capacity was 16.5017 mg/g in theory. Pseudo-second order kinetics model was better to reveal the dynamic adsorption characteristics than pseudo-first-order kinetics model did, the adsorption process could proceed spontaneously. Concentrations of Cr(III) was the most important factor for Cr(III) removal shown in orthogonal experiments, the highest efficiency was 72.04%. With acceptable adsorption capacity and lower cost, the adsorption system with modified fly ash was of more advantages in practical application.