Hydrogen Peroxide Interference in Chemical Oxygen Demand Assessments of Plasma Treated Waters

Abstract

Plasma-driven advanced oxidation represents a potential technology to safely re-use waters polluted with recalcitrant contaminants by mineralizing organics via reactions with hydroxyl radicals, thus relieving freshwater stress. The process results in some residual hydrogen peroxide, which can interfere with the standard method for assessing contaminant removal. In this work, methylene blue is used as a model contaminant to present a case in which this interference can impact the measured chemical oxygen demand of samples. Next, the magnitude of this interference is investigated by dosing de-ionized water with hydrogen peroxide via dielectric barrier discharge plasma jet and by solution. The chemical oxygen demand increases with increasing concentration of residual hydrogen peroxide. The interference factor should be considered when assessing the effectiveness of plasma to treat various wastewaters.

Use of mine waste for H2O2-assisted heterogeneous Fenton-like degradation of tetracycline by natural pyrite nanoparticles: Catalyst characterization, degradation mechanism, operational parameters and cytotoxicity assessment

“…As COD is one of the most widely used indicators of the extent of organic compounds removal in various synthetic and real wastewater samples (Groele and Foster, 2019), the COD concentration of the TTC solution before and after treatment was also measured. It is known that significant levels of some inorganic species including manganese, ferrrous iron and sulfide cause inaccuracies in the COD analysis (Lee et al, 2011).…”

Effect of Water Parameters on Decolourization Efficiency of Organic Dyes by Dielectric Barrier Discharge Plasma

“…This effect can be related to the reaction of dye materials or their decomposition products which react directly with H 2 O 2 or with the OH radicals produced by plasma. Plasma occurring in air close to water surface, generates many direct and indirect reactions in water, especially by the impact of electrons, producing hydroxyl radicals (OH) at the plasma-water interface [Liu et al 2016, Groele et al 2019] which contributes to the main process of H 2 O 2 formation in the solution. However, the reaction scheme is rather complicated owing to secondary hydroxyl radicals produced by the action of plasma generated ozone and UV.…”

Using auxiliary electrochemical working electrodes as probe during contact glow discharge electrolysis: A proof of concept study

“…[45][46][47][48][49][50] A key aspect is the detection of H 2 O 2 , which is usually determined after the electrolysis by means of titration. 30,[51][52][53] This approach does, however, not provide any information on the spatial distribution or temporal evolution of the H 2 O 2 formed during aCGDE. Other methods are able to circumvent this issue to some extend.…”