Cr VI reductive transformation process by humic acid extracted from bog peat: Effect of variables and multi-response modeling.

Autor: Alidokht L; Department of Soil Science, Faculty of Agriculture, University of Tabriz, 51666-16471, Tabriz, Iran; Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, 51666-16471, Tabriz, Iran., Oustan S; Department of Soil Science, Faculty of Agriculture, University of Tabriz, 51666-16471, Tabriz, Iran., Khataee A; Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, 51666-16471, Tabriz, Iran; Department of Environmental Engineering, Gebze Technical University, 41400, Gebze, Turkey; Institute of Research and Development, Duy Tan University, Da Nang 550000, Viet Nam. Electronic address: a_khataee@tabrizu.ac.ir.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2021 Jan; Vol. 263, pp. 128221. Date of Electronic Publication: 2020 Sep 03.
DOI: 10.1016/j.chemosphere.2020.128221
Abstrakt: The present paper reports the efficiency of bog peat-derived humic acid (HA) in the reductive removal of hexavalent chromium (Cr VI ) from aqueous solution as affected by solution pH, the dose of Fe III and reaction time (numeric variables) and light irradiation (categorical variable). A three-level Box-Behnken design (BBD) applied to design experimental matrix, model the effects and interactions of variables on four determined responses (residual concentration of dissolved Cr VI , dissolved Cr III , dissolved Fe II and total Cr VI ) and optimize the experimental conditions for highest Cr VI removal efficiency (Cr VI RE). Reaction mechanisms are also well discussed. Regression models were developed and analyzed by the ANOVA test and models determination coefficient R 2 . Obtained models were significant (F values > 13) and an excellent relationship between experimental and predicted responses (R 2 : 98.1-99.6%) was observed. The optimum conditions were established corresponding to the residual concentration of dissolved Cr VI as an index for Cr VI removal efficiency (RE). In the dark system, the highest Cr VI RE (98.1%) was obtained under the following conditions: pH = 1, reaction time = 7 d and Fe III dosage = 0.110 mM. In the light-irradiated system, the optimal Cr VI RE of 98.3% was observed in pH = 1, reaction time = 5 d and Fe III dosage = 0.075 mM. Almost all reduced Cr III remained in the solution even at high pH value. No adsorption or precipitation of Cr III on the HA surface at pH 5 was confirmed by surface analyses of HA using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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