Degradation of 4-aminoantipyrine by electro-oxidation with a boron-doped diamond anode: Optimization by central composite design, oxidation products and toxicity

Abstract

Electro-oxidation with electrogenerated HO (EO-HO) was applied to treat acidic aqueous solutions of 4-aminoantipyrine (4-AA), a persistent drug metabolite of dipyrone, in sulfate medium. Trials were made using a boron-doped diamond anode in the presence of HO electrogenerated on site. A 2 central composite design (CCD) was employed to evaluate the effect of four independent variables, namely current density (j), pH, 4-AA concentration and electrolysis time, on the percentages of degradation and mineralization, as well as on mineralization current efficiency (MCE). Predicted responses agreed with observed values, showing linear trendlines with good R and R values. The degradation was optimum at j=77.5mAcm, pH3.5 and 62.5mgL 4-AA, leading to 63% and 99% removal after 3 and 7min, respectively. For those solutions, the largest mineralization was found at j=77.5mAcm, attaining 45% abatement at 175min. Low MCE values were obtained in all electrolyses. An initial route for 4-AA degradation is proposed based on one dimer and eleven aromatic and aliphatic intermediates detected in the treated solutions at pH3.5 by LC-MS. The initial 62.5mgL solution at pH3.5 presented acute toxicity on Artemia salina larvae, with LC=13.6mgL, being substantially reduced after 3 and 7min of EO-HO at j=77.5mAcm due to the formation of less toxic derivatives.

Environmentally Safe Photodynamic Control of Aedes aegypti Using Sunlight-Activated Synthetic Curcumin: Photodegradation, Aquatic Ecotoxicity, and Field Trial

“…The solutions, prepared in the proportion of 5 mL of sample to 5 mL of methanol (CL-MS grade, Panreac), were injected (1 µL) in a liquid chromatograph/mass spectrometer (UFLC Shimadzu LC-20AD—IES Detector-Q-QTOF microTOFIII (Bruker Daltonics)) equipped with a Phenomenex onyx monolithic C-18 column (100 × 3.0 mm). The operating parameters were set up following the method reported by Da Silva et al, 2018, and Da Rosa et al, 2019 [ 65 , 66 ]. The system operated in positive electrospray ionization mode with a spray voltage of 0.8–1.2 V and a capillary voltage of 3500 V (200 °C).…”

Quality-by-design model in optimization of PEG-PLGA nano micelles for targeted cancer therapy

“…PEGabsPLGA drug delivery system was optimized by the response surface methodology. According to preliminary studies and literature review [20][21][22], PLGA amount, PEG amount and PLGA molecular weight were selected as three important factors. Three factors were studied at 5 different levels (-α, -1, 0, +1, +α) using a CCD.…”

The Analgesic Metamizol (Dipyrone). Part 2: Adsorption, Oxidative and Reductive Degradation

“…Some work has been done to either electrochemically generate H 2 O 2 [5,6] or to degrade metamizol using supported electrodes [7,8,9,10]. Reis et al [7] used anodes comprising boron-doped diamond films supported on titanium in a flow-by reactor.…”

“…This chemical system was then irradiated at 525 nm, and about 80% of metamizol was removed through the formation of O 2 · as a result of the interaction between O 2 with the electrons of the conduction band of ZnO/Ag. Da Silva et al [10] treated 4-MAA in acidic solution with electrogenerated H 2 O 2 at boron-doped diamond. The authors optimized current density, pH and the concentration of 4-MAA.…”