Using iron-loaded sepiolite obtained by adsorption as a catalyst in the electro-Fenton oxidation of Reactive Black 5

Abstract

This study explores the possibility of using iron-loaded sepiolite, obtained by recovering iron from polluted water, as a catalyst in the electro-Fenton oxidation of organic pollutants in textile effluents. The removal of iron ions from aqueous solution by adsorption on sepiolite was studied in batch tests at iron concentrations between 100 and 1,000 ppm. Electro-Fenton experiments were carried out in an electrochemical cell with a working volume of 0.15 L, an air flow of 1 L/min, and 3 g of iron-loaded sepiolite. An electric field was applied using a boron-doped diamond anode and a graphite sheet cathode connected to a direct current power supply with a constant potential drop. Reactive Black 5 (100 mg/L) was selected as the model dye. The adsorption isotherms proved the ability of the used adsorbent. The removal of the iron ion by adsorption on sepiolite was in the range of 80-100 % for the studied concentration range. The Langmuir and Freundlich isotherms were found to be applicable in terms of the relatively high regression values. Iron-loaded sepiolite could be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process. Successive batch processes were performed at optimal working conditions (5 V and pH 2). The results indicate the suitability of the proposed combined process, adsorption to iron remediation followed by the application of the obtained iron-loaded sepiolite to the electro-Fenton technique, to oxidize polluted effluents.

Electrochemical removal of Reactive Black 5 azo dye using non-commercial boron-doped diamond film anodes

“…RB5 has been chosen as a model organic pollutant by a number of researchers, and details are available concerning degradation of the dye by electro-assisted Fenton and Fentonlike oxidation [4,[22][23][24][25], photo-electrochemical [26,27] and electro-coagulation [28] processes, electrochemical reduction [29][30][31][32], and electrochemical oxidation with Ti/SnO2-SbPt [3], Pt [33], graphite [34] and Pt/Ti [35] electrodes. However, very few studies have focused on the application of BDD as electrodic material for the removal of RB5.…”

“…However, very few studies have focused on the application of BDD as electrodic material for the removal of RB5. For example, Iglesias et al [22] investigated the removal of RB5 by the electro-Fenton process using a BDD anode and graphite sheet cathode and reported that 97.2% of color was removed after 90 min of electrolysis at 5 V applied potential. Additionally, electro-oxidation of RB5…”

Enhanced selective metal adsorption on optimised agroforestry waste mixtures

“…A suitable low-cost adsorbent requires a porous structure, mechanical and chemical stability and affinity for the target pollutants (Cobas et al, 2014). Recent the utilisation of non-conventional adsorbents; natural clays (Iglesias et al, 2013;Padilla-Ortega et al, 2013), various industrial and agricultural materials such as hazelnut straws, peanut shell, banana peel, orange peel, walnut shell, rice husk and sawdust (Nguyen et al, 2013;Alothman et al, 2013;Ma et al, 2014;Park et al, 2008;Krishnani et al, 2008;Abdolali et al, 2014a) and forestry materials such as fern or oak leaves (Prasad and Freitas, 2000;Barriada et al, 2009) have been tested. These agroforestry materials have been mainly applied to the removal of a single or a couple of metals, while little attention has been paid to the simultaneous adsorption of multiple metals (Krishnani et al, 2008;Abdolali et al, 2014b;Hossain et al, 2014a).…”

Electrochemical degradation of RB-5 dye by anodic oxidation, electro-Fenton and by combining anodic oxidation–electro-Fenton in a filter-press flow cell

“…EF processes have been used to degrade RB-5 using anode and cathode graphite electrodes of 84.16 cm 2 area [28]. Glassy carbon electrodes also have been used [29] as well as graphite (area 15 cm 2 ) and Fe alginate gel beads and iron-loaded sepiolite [30,31]. Bocos et al used two graphite sheets electrodes of 15 cm 2 area and an iron supported in polyacrylamide hydrogel [32].…”