Original scientific paper
https://doi.org/https://doi.org/10.5599/jese.3240
Synergistic heterogeneous electro-Fenton process using iron-loaded bentonite for binary dyes degradation from wastewater
Hind H. Thwaini
; Department of Chemical Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq
*
Zahraa M. Hameed
; Department of Chemical Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq
Rasha H. Salman
; Department of Chemical Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq
* Corresponding author.
Abstract
This study examines the impact of operational parameters on the performance of a heterogeneous electro-Fenton process for removing a binary mixture of malachite green (MG) and methylene blue (MB) using iron-loaded bentonite clay (Fe-Bent.) particles as a heterogeneous catalyst. The effects of current density (j), Fe-Bent.* dosage (Bent. quantity variable) and Fe*-Bent. dosage (iron concentration variable), were investigated. Brunauer-Emmett-Teller analysis, X-ray diffraction, X-ray fluorescence and scanning electron microscopy were used to extensively evaluate the synthesized catalyst, confirming the effective incorporation and uniform distribution of iron within the bentonite clay. The results showed that increase of j enhanced dye removal efficiency to over 95 % for MG and 90 % for MB at 20 mA cm-². Furthermore, increasing the dose of Fe-Bent.* from 1 to 3 g improved the overall removal efficiency, although this was accompanied by a decrease in adsorption capacity and a deviation from ideal kinetic behaviour at higher loadings. Fe*-Bent. dosage with a variable iron concentration from (0.1 to 0.2 mM) exhibited the highest removal efficiency, while increasing to 0.3 mM resulted in decreased process performance. The comparison results showed that the electro-Fenton process alone achieved limited removal, whereas bentonite adsorption alone provided high but incomplete removal. In contrast, the heterogeneous electro-Fenton process achieved the highest efficiency (98.06 % for MG and 91.14 % for MB, with COD values of 84.53 % for MG and 79.82 % for MB), with the lowest iron leaching (<0.1 ppm), well below regulatory limits. These results demonstrate the clear advantage of the heterogeneous electro-Fenton process for efficient and environmentally friendly removal of mixed dye pollutants.
Keywords
Natural clay; iron incorporation; heterogenous catalyst; mixed dyes: electrochemical removal; wastewater treatment
Hrčak ID:
351974
URI
Publication date:
21.5.2026.
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