Transient reactive transport model for physico-chemical transformation by electrochemical reactive barriers

• Published in: Journal of hazardous materials Vol. 358; pp. 171 - 177
• Main Authors: Hojabri, Shirin, Rajic, Ljiljana, Alshawabkeh, Akram N.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.09.2018
• Subjects: Electrochemical remediation; Groundwater remediation; pH modeling; Physico-chemical modeling; Physico-chemical modeling; Groundwater remediation; Electrochemical remediation; pH modeling
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2018.06.051

•Theoretical one-dimensional model is developed for electrochemical transformation.•Chemical reaction model is combined with the transport and transformation.•Adopted a two-step iterative finite difference method to solve for the species.•Verification is provided for pH profiles.•Close correlation to experimental data; batch: R2 = 0.99; flow-through: R2 = 0.78. A comprehensive model that integrates coupled effects of chemical, physical, and electrochemical processes, is necessary for design, analysis, and implementation of the electro-remediation of groundwater under flow conditions. A coupled system of equations to solve for transport and multiple reactions in an electrochemical reactor is numerically intensive due to highly stiff nature of reaction model formulation. In this study, the focus is to develop an efficient model for reactions associated with the transport and physico-chemical transformation in an electrochemical reactor. The model incorporates effects of transport mechanisms as well as chemical and electrochemical reactions. Model verification is provided for pH profiles under different electrolyte compositions in two sets of reactors; a batch and a flow-through reactor. The model is able to predict the concentration of species during the electrochemical remediation process with a close correlation to experimental data (R2 = 0.99 for batch and R2 = 0.78 for flow-through reactor.) Imposing polarity reversal to the system will cause fluctuation of pH, however, the trend stays the same as if no polarity were applied. Ultimately, volumetric charge flow is introduced as a unique parameter characterizing the electroremediation reactor for operating purposes.