Low Pd loadings onto Printex L6: Synthesis, characterization and performance towards H2O2 generation for electrochemical water treatment technologies. (November 2020)

• Record Type: Journal Article
• Authors: Fortunato, Guilherme V.; Kronka, Matheus S.; dos Santos, Alexsandro J.; Ledendecker, Marc; Lanza, Marcos R.V.
• Is Part Of: Chemosphere. Volume 259(2020)
• Publication Date: 2020-11
• Subjects: H2O2 electrogeneration -- Palladium -- Wastewater treatment -- Electrochemical advanced oxidation processes -- Methyl paraben; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127523
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In order to enhance hydrogen peroxide (H2 O2 ) electrogeneration, a catalyst based on less than 1 wt% of Pd nanoparticles dispersed onto commercially available Printex L6 carbon black (PCL6) is proposed and synthetized. The material was characterized by physico-chemical and electroanalytical methods, demonstrating high activity with a 320 mV lower onset potential compared to pristine PCL6 and high stability after 5000 potential cycles. Its performance places it among the most efficient bi- and monometallic electrocatalysts for H2 O2 production. When testing the accumulation of H2 O2, a 1.69-fold molar increase was observed for Pd1% /PCL6 compared to PCL6. Different electrochemical advanced oxidation processes based on H2 O2 generation have been performed to oxidize and remove pollutants as exemplarily shown on methyl paraben in Na2 SO4 solution as model pollutant. A boron-doped diamond electrode was used as anode while Pd1% /PCL6 was tested in a rotating ring disk electrode (RRDE) and gas diffusion setup. Pollutant degradation followed a pseudo-first-order reaction kinetic in the following order: anodic oxidation along with H2 O2 generation (AO-H2 O2 ) < AO-H2 O2 /UVC < electro-Fenton (EF) < photoelectro-Fenton (PEF). The best mineralization performance was found for PEF due to the photodecarboxylation of Fe (III) complexes with UVC light, while the process with lowest energy consumption per order was EF with 0.488 kWh m −3 order −1 . At the end of the work a route for pollutant mineralization was suggested. Graphical abstract: Image 1 Highlights: H2 O2 generation using less than 1 wt% of Pd nanoparticles on Printex L6 carbon black. Treatment of 0.50 mM methyl paraben by EAOPs based H2 O2 generation. 100% of pollutant removal by EF and PEF processes. Main by-products detected: 3 aromatic compounds and 1 short-chain carboxylic acid.