Evidence of singlet oxygen and hydroxyl radical formation in aqueous goethite suspension using spin-trapping electron paramagnetic resonance (EPR)

Oxidative stress inhibition and oxidant activity by fibrous clays

“…The reaction mixture of clay, DMPO and H 2 O 2 showed a quartet signal with intensity 1:2:2:1 and hyperfine coupling constants a N = 1.50 mT and a H = 1.50 mT and g = 2.0056, characteristic of the DMPO-OH adduct [31]. Signal intensity values were determined from the peak-height of the second peak in the presence and absence of clay in dispersion (not shown).…”

Microwave–ultrasound assisted synthesis of β-FeOOH and its catalytic property in a photo-Fenton-like process

“…Goethite is the most studied oxyhydroxides because goethite is the most stable phase having the lowest Gibbs energy [9]. Recently, the use of goethite (a-FeOOH) with hydrogen peroxide was found to effectively degrade organic compounds [10][11][12][13][14][15]. Moreover, the degradation capability of goethite/H 2 O 2 can be greatly improved by the combination of UV irradiation [16][17][18].…”

Insight on the fundamentals of advanced oxidation processes. Role and review of the determination methods of reactive oxygen species

“…DMPO is, perhaps, the spin trap and one of the probes most used for the quantitative determination of the •OH generated in different AOPs. Although some works focus on monitoring the DMPO‐OH formation (reaction ) for example in photocatalysis, sonolysis and Fenton systems, in general, most of them analyze and compare the signals recorded during the EPR technique without quantifying the generated product when electrocatalysis, Fenton and photocatalysis are applied. There are also examples in which the main objective is the calculation of kinetic constants of benzenes and halobenzenes by means of a competitive kinetic method with DMPO, the scavenging percentage of different phenolic compounds and the evaluation of different ROS generated in a photoelectrocatalytic system in aqueous and methanol media .…”