Modeling of electrodialytic and dialytic removal of Cr, Cu and As from CCA-treated wood chips

Ribeiro, Alexandra B.; Rodríguez‐Maroto, José Miguel; Mateus, Eduardo P.; Velizarova, Emiliya; Ottosen, Lisbeth M.

doi:10.1016/j.chemosphere.2006.07.014

Cited by 27 publications

(18 citation statements)

References 22 publications

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“…To do this, it is assumed that the cations are incoming in the cell from the (j -1)th cell, and simultaneously anions are moving out to that volume element crossing this one. Now, assuming perfect mixing in the cell and using the transport number, a typical electrochemical parameter, which represents the fraction of the current intensity (or the charge) carried by a particular ion [11,17,18]: where k i is molar conductivity of ith ion (ohm -1 mol -1 cm 2 ) and z i its charge number. S(x) is a function key,…”

Section: Electromigration Transport Of Ionsmentioning

confidence: 99%

“…1, based on a concept developed at the Technical University of Denmark [4] and described in detail elsewhere [5,11]. The ED cell is divided into three compartments, consisting of two electrode compartments (I and III) and a central one (II) of L = 10 cm (stirred batch) or 3.8 cm (column), internal diameter = 8 cm.…”

Section: Laboratory Cellmentioning

confidence: 99%

“…In our previous studies, a comparison between ED and DI processes was carried out for the remediation of CCA treated wood [11,13]. The present work extends those ones, adding the following new features: (i) the use of different assisting agents; (ii) the comparison between a stationary cell and a stirring cell, which is closer to pure electrodialysis/dialysis; (iii) the development of a onedimensional model for simulating the ED and DI treatment of a fly ash containing Cd, Cu and Pb, incorporating information obtained by chemical characterization, X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), as well as by previous equilibrium simulation using Visual Minteq at zero time.…”

Section: Introductionmentioning

confidence: 99%

“…In a dialytic (DI) process, ion-exchange membranes are used in order to regulate the ion transfer from a polluted matrix suspension into a contiguous compartment, where a lower salt concentrated solution is placed [10,11]. The driving force in dialysis is a concentration gradient, where concentration differences between two subsequent solutions dictate the migration of ions, flowing from a high to a low concentration medium [12].…”

Section: Introductionmentioning

confidence: 99%

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Experimental and modeling of the electrodialytic and dialytic treatment of a fly ash containing Cd, Cu and Pb

et al. 2010

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A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a fly ash containing cadmium, copper and lead. Two experimental systems have been used, a column of ash and a stirred ash suspension. The movement of Cd, Cu and Pb has been modeled taking into account the diffusion transport resulting from the concentration gradients of their compounds through the membranes and boundary layers and the electromigration of their ionic, simple and complex species during the operation. The model also includes the electromigration of the non-contaminant most important principal ionic species in the system, H ? and OH -, proceeding of the electrolysis at the electrodes, Ca 2? , CO 3 = , SO 4 = , etc. proceeding from the ash and Na ? and NO 3 -, or citrate and ammonium ions incorporated as electrolyte solutions and/or as agent solution during the ash treatment. The simulation also takes into account that OH -generated on the cathode, during the electrodialytic remediation, is periodically neutralized by the addition of nitric acid in the cathode compartment. The anion and cation-exchange membranes are simply represented as ionic filters that preclude the transport of the cations and anions, respectively, with the exception of H ? which is retarded but pass through the anion-exchange membrane.

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Section: Electromigration Transport Of Ionsmentioning

confidence: 99%

Section: Laboratory Cellmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental and modeling of the electrodialytic and dialytic treatment of a fly ash containing Cd, Cu and Pb

et al. 2010

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“…The reduction and oxidation of water at the electrodes are the primary reactions occurring in the EDR system [12]. The half reactions are: (1) cathode reaction 2H 2 O+2e - H 2 ↑ + 2OH -, and (2) anode reaction 2H 2 O  O 2 ↑ +4H + +4e -.…”

Section: Introductionmentioning

confidence: 99%

Electrodialytic remediation of fly ash from co-combustion of wood and straw

Chen

Jensen

Ottosen

et al. 2015

Electrochimica Acta

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The heavy metal content in fly ash from biomass combustion, such as straw, wood and sludge, often needs reducing before the ash can be used as fertilizer for agricultural land or as a component in the production of construction materials. In this study, fly ash from a boiler fueled with wood chips and straw was treated either by electrodialytic remediation (EDR) directly or by a combination of EDR and pre-wash with distilled water to investigate the possibilities of reducing the heavy metal content and reusing nutrients as fertilizer and bulk material in construction materials. Different experimental set-ups were tested for EDR treatment primarily of Cd and Pb as well as of Cu and Zn.Elemental contents such as K, P and Ni were compared in ash samples before and after treatment.The results showed that pre-washing caused an increase in total concentrations of most heavy metals because the highly soluble fraction, mainly KCl and K 2 SO 4 , was removed. After EDR treatment, the Cd concentration was reduced to below 2 mg kg -1 in all ash samples with high and stable average removal of above 95%, no matter how high the initial concentration was. The amount of Pb removed varied from 12% to 67%. Even though Pb was extracted from the ash samples, its concentrations in the treated ash samples were elevated due to the ash dissolution, except in the case of pre-washed ash treated in a two-compartment EDR cell, where the mass of Pb removed was the highest with a final concentration of about 100 mg kg -1 . The two-compartment EDR cell probably performed better due to a fast acidification process. In addition, this process was less energy-consuming. However, the fast acidification did in turn affect the leaching property of the treated ash, such as As and Ni, exceeding the limiting concentrations. The EDR/pre-wash-EDR treated ash mainly contained quartz, and the X-ray diffraction (XRD) peaks of K salts had disappeared. This shows that the potassium fertilizer potential was lost in the treated ashes, but the quartz mineral is beneficial in construction materials, such as ceramics. The K fertilizer could be recovered from the water after pre-washing and also from the catholyte through chemical operations, including a separation step.

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