Electrochemical treatment of bisphenol-A using response surface methodology

Abstract

The decomposition of bisphenol-A (BPA) in synthetic solution and in municipal effluent was investigated using an electro-oxidation process. Electrolysis was conducted using a cylindrical electrolytic cell containing two circular anodes (expanded metal) and two circular cathodes (stainless steel) alternated in the electrode pack. Different anode materials (Ti/SnO 2 , Ti/IrO 2 and Ti/PbO 2 ) were tested, and Ti/PbO 2 was found to be the most effective electrode for BPA degradation. An experimental design methodology (2 3 Box-Behnken design) was applied to determine the optimal experimental conditions in terms of cost effectiveness. The BPA concentration (C 0 = 1.0 mg l -1 ) could be optimally diminished by up to 90% by applying a current intensity of 2.0 A for a 100-min reaction period in the presence of 250 mg Na 2 SO 4 l -1 (used as a supporting electrolyte). Then, the optimal conditions were applied on a municipal wastewater effluent (sampled after secondary treatment) artificially contaminated with 1 mg BPA l -1 without the addition of a supporting electrolyte. The treatment was more effective with the municipal effluent due to the presence of a high concentration of chloride ions that could easily be transformed into active chlorine. BPA could be oxidized by both direct anodic electrochemical oxidation (by means of OHÁ) and indirect electrochemical oxidation via mediators, such as hypochlorous acid generated by chloride oxidation. Both actions (direct and indirect effects) lead to the formation of powerful oxidizing agents capable of rapidly oxidizing BPA.

Optimization of sono-electrochemical oxidation of ibuprofen in wastewater

“…For instance, pharmaceutical 33 IBU was removed from water using an electrochemical oxidation 34 process by means of carbon nanotubes electrodes [10]. After 35 116 min of electrooxidation, a relatively high degradation rate of 36 78% and a high mineralization rate of 60.84% were recorded at a 37 potential of +1.25 V versus Ag/AgCl in the presence of 10 mg L À1 of 38 IBU. Ambuludi et al [3] have also studied IBU (C 0 = 0.2 mM) 39 oxidation using an electrochemical advanced oxidation process in 40 the presence of boron-doped diamond (BDD) anode electrode.…”

“…By comparison, LC/MS/MS technique which combines simulta-510 neously a powerful physical separation technique and a powerful 511 technique of analysis and mass detection has a very high sensitivity 512and selectivity towards several pharmaceutical compounds[36].Secondly, this discrepancy may be attributed to the initial 514 characteristic of MWE. Indeed, this type of municipal effluent can 515 contain chloride ions, which facilitated the passage of electrical 516 current intensity[37]. Besides, these ions can favor hypochlorous 517 acid (HClO) production and can improve IBU oxidation.…”

Heavy metal removal from simulated wastewater using electrochemical technology: optimization of copper electrodeposition in a membraneless fluidized bed electrode

“…(7)-(9) were plotted to facilitate the understanding of the role of the variable effects on the response studied and to help on defining the optimal experimental conditions given the parameters in study. This tool has been used by many authors to study electrochemical processes for metal electrodeposition (Poroch-Seritan et al 2011) and organic degradation (Zaviska et al 2012). The influence of the supporting electrolyte concentration was not considered in this analysis because it was already discussed, but its effect on the response surface plots can be verified in Figs.…”

Interface behavior of PbO2on pure lead and stainless steel as anode for dye degradation

“…Additionally, the limiting current can be estimated from the value of COD for AO of a real wastewater, as indicated by Panizza and Cerisola [7,13].…”

“…Anodic oxidation (AO) is attracting more and more attention as efficient methods to remove toxic organic compounds from wastewater [6] and textile effluents [7]. AO is based on the electrogeneration of hydroxyl radicals as environmentally friendly oxidants.…”