Carbon nanotube modified glassy carbon electrode for electrochemical oxidation of alkylphenol ethoxylate

Abstract

Electrochemical oxidation of an emerging pollutant, 2-(4-methylphenoxy)ethanol (MPET), from water has been studied by cyclic voltammetry (CV). Multiwall carbon nanotubes glassy carbon electrodes (MWCNT-GCE) were used as working electrode due to their extraordinary properties. The oxidation process is irreversible, since no reduction peaks were observed in the reverse scan. The electrocatalytic effect of MWCNT was confirmed as the oxidation peak intensity increases in comparison to bare-GCE. The effect of functional groups on MWCNT was also studied by MWCNT functionalized with NH (MWCNT-NH) and COOH (MWCNT-COOH) groups. The oxidation peak current decreases in the following order: MWCNT > MWCNT-NH > MWCNT-COOH. Taking into account the normalized peak current, MWCNT-NH exhibits the best results due to its strong interaction with MPET. Under optimal conditions (pH = 5.0 and volume of MWCNT = 10 μL), degradation was studied for MWCNT-GCE and MWCNT-NH-GCE. A complete MPET removal was observed using MWCNT-GCE after four CV cycles, for a volume/area (V/A) ratio equal to 19. In the case of MWCNT-NH-GCE, the maximum MPET removal was close to 90% for V/A = 37, higher than that obtained for MWCNT-GCE at the same conditions (≈80%). In both cases, no organic by-products were detected.

Removal of nonylphenol ethoxylate from laundry wastewater using modified and functionalized activated carbon

“…Particle interaction may also desorb some sorbate that is only loosely and reversibly bound to the carbon surface. 67 The COD removal and adsorption capacity show the same trend as NPEO [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . By comparison to NPEO 3-17 removal, and as shown in Fig.…”

“…Conventional technologies are poorly efficient in eliminating these refractory and nonbiodegradable substances. 7 Therefore, employing a developed technology such as advanced oxidation processes (AOPs) or hybrid processes can overcome this problem and reach treated water with reuse quality. 9 One of the proposed technologies for the removal of APEOs is adsorption.…”

“…It is, however, technically and economically impossible to substitute them with alternative chemicals in some industrial applications. 7 In the USA, the Environmental Protection Agency (EPA) has issued a recommendation stating that the NP concentrations should not exceed 6.6 and 1.7 μg L −1 in freshwater and saltwater, respectively. In addition, these emerging compounds exert endocrine disruption effects on marine organisms since they mimic natural hormones by interacting with estrogen receptors.…”