Rapid mineralization rate of acetylsalicylic acid in a tubular photochemical reactor: The role of the optimized excess of H2O2

Cunha-Filho, Fernando J.; Mota-Lima, Andressa; Ratkievicius, Luciana Avelino; Silva, Danielle J.; Silva, Douglas N.; Chiavone‐Filho, Osvaldo; Nascimento, Cláudio Augusto Oller do

doi:10.1016/j.jwpe.2019.100856

“…On average, the photo-Fenton reached an efficiency of ~15 %, a mark that is substantially inefficient in comparison to the approximately 33% of efficiency obtained with the tubular reactor for the oxidation of Acetyl Salicylic Acid [19]. Attribute the inefficiency to differences on the micropollutant molecular structure is insufficient to formulate a complete justification.…”

Section: Fenton Oxidationsmentioning

confidence: 93%

Stoichiometric Excess of H2O2 as Strategy of Oxidant Dosing for Intensifying Both Degradation and Mineralization of the Hydrochlorothiazide via UVCH2O2, Dark-Fenton, and Photo-Fenton

Cunha-Filho¹,

Mota-Lima²,

Nascimento³

et al. 2020

Preprint

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<div>Hydrochlorothiazide (HCT) is a pharmaceutical micropollutant highly toxic to the environment, being strictly mandatory to oxidize it completely toward CO2. In this context, how could the HCT oxidation via advanced oxidative processes benefit from the accelerated oxidation rates promoted by the mineralization stoichiometric excess of H2O2 ? Overall, this work elucidates the role of stoichiometric H2O2 concentration on promoting fast degradation/mineralization rates across Advanced Oxidative Processes (AOP). Employing 0.68 excess of H2O2, it was found absolute (100%) HCT degradation within 60 minutes and 95% within 30 min for UVC-H2O2 oxidation; however, the mineralization of HCT suffered limited optimization even at high H2O2 excess, being at the best performance 26.76% HCT mineralized via UVC photo-Fenton within 60 min at initial 2.00 H2O2 excess. Very presumably, the evaporation of H2O2 was the underlying reason for a low mineralization performance. Together with a detailed mathematical methodology, the time-synchronized evolution of both the residual H2O2 concentration and the TOC depletion were employed to infer the quantity of radical ∙OH that effectively was consumed by the micropollutant mineralization. The global mean efficiency of radicals •OH consumption by the HCT mineralization laid around 15% for UVC Fenton considering H2O2 excess of 2.00. Under these conditions, the residual H2O2 concentration depletes significantly within 30 minutes of UVC photo-Fenton oxidation, which indicates that either the solution heating or stirring is very likely to promote a substantial loss of H2O2 by evaporation in the beaker-assembled reactor<br></div>

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“…column. The two liters of synthetic pollutant solution was treated in the tubular reactor described previously (Cunha-Filho et al, 2019) . For the vanadate method, (Nogueira et al, 2005) it was used a UV-Visible Spectrophotometer (Varian-Cary) and cell of quartz.…”

Section: Analytical Proceduresmentioning

confidence: 99%

“…formed from H2O2 react rapidly and indiscriminately with several scavengers present in the aqueous matrix, being the organic pollutant just one among them. In practical terms, however, the H2O2 dose has been added in overdose of [𝐻 2 𝑂 2 ] 𝑆𝑇 for some recent work (Cunha-Filho et al, 2020;Cunha-Filho et al, 2019) , yet without attaining full degree of mineralization, thus needing to optimize the H2O2 overdose for reaching an absolute performance. The better way to expresses such overdose is by the initial excess of the H2O2 concentration (Cunha-Filho et al, 2019) and hydroperoxide ion (HO2 -) that readily consume the radicals •OH.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Efficiency of the H2O2 consumption by the mineralization of hydrochlorothiazide via photo-Fenton UVA: a time dependent analysis

Mota-Lima

¹

,

Cunha-Filho²,

Chiavone‐Filho³

et al. 2022

Braz. J. Chem. Eng.

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In the photo-chemical conversion of hydrogen peroxide (H2O2) into radical ⦁OH, the impact of radiation dose (the quantum yield) on the oxidation kinetics has been properly reported, whereas the H2O2 dose is mostly treated as an attempt-and-error variable. This present work formally analyses the oxidant dose in terms of the efficiency of ⦁OH consumption by the micropollutant mineralization, which ultimately enables a generalist strategy for more cost-effective dosimetry of the oxidant. The experimental timedependent measure of two reagents (pollutant and oxidant) and one product (CO2) enables assessment to the micro-kinetics from the perspective of the chemical dynamic. The analysis was demonstrated for photo-Fenton (FP) oxidation of hydrochlorothiazide (HCT) using a tubular photo-reactor and UVA radiation. The average value of ~ 38% was on top of the best efficiencies in association with some of the fastest rates of mineralization. Such efficiencies are demonstrated to depend on the stochiometric concentration of the oxidant. Here, the variable stoichiometric H2O2 excess for mineralization is proposed as a universal metric to quantify the (under-) over-dose of H2O2. Overall, H2O2 excess between 2 and 5 leads to H2O2 consumption efficiencies above 30% together with a fast rate of CO2 formation (mineralization), whereas any value below 1 invariably leads to a sluggish oxidation rate, leading even to the full depletion of the oxidant. Aside from proposing a selection criterion for the most cost-effective H2O2dose and providing some examples, this work carefully analyzes the commitment of the H2O2 excess with respect to the energy costs (EEO).

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“…Several details were already described in previous work. [19] In summary, metavanadate of ammonium is added into the sample, the metavanadate anion then reacts with the residual peroxide forming a red-orange color peroxovanadium cation (𝑉𝑂 2 +3 ), which in turn could be detected and quantified by 450 nm absorption. Spectroscopic determinations were performed using a UV-Visible Spectrophotometer (Varian-Cary) and 1 cm cells of quartz.…”

Section: Chemical Analysismentioning

confidence: 99%

“…Exceptionally distinct from this general role, recent findings showed the synchrony between absolute degradation and mineralization via photo-Fenton for a model micropollutant, the Acetyl Salicylic Acid, when manipulating the initial concentration of 𝐻 2 𝑂 2 [19]. Also, it indicated that the initial concentration of 𝐻 2 𝑂 2 calibrates the quantity of  𝑂𝐻 that effectively engages with the micropollutant oxidation, which was found to be around 33% for the photo-Fenton [19].…”

Section: Introductionmentioning

confidence: 99%

Stoichiometric Excess of H2O2 as Strategy of Oxidant Dosing for Intensifying Both Degradation and Mineralization of the Hydrochlorothiazide via UVCH2O2, Dark-Fenton, and Photo-Fenton

Cunha-Filho¹,

Mota-Lima²,

Nascimento³

et al. 2020

Preprint

Self Cite

0

View full text Add to dashboard Cite

<div>Hydrochlorothiazide (HCT) is a pharmaceutical micropollutant highly toxic to the environment, being strictly mandatory to oxidize it completely toward CO2. In this context, how could the HCT oxidation via advanced oxidative processes benefit from the accelerated oxidation rates promoted by the mineralization stoichiometric excess of H2O2 ? Overall, this work elucidates the role of stoichiometric H2O2 concentration on promoting fast degradation/mineralization rates across Advanced Oxidative Processes (AOP). Employing 0.68 excess of H2O2, it was found absolute (100%) HCT degradation within 60 minutes and 95% within 30 min for UVC-H2O2 oxidation; however, the mineralization of HCT suffered limited optimization even at high H2O2 excess, being at the best performance 26.76% HCT mineralized via UVC photo-Fenton within 60 min at initial 2.00 H2O2 excess. Very presumably, the evaporation of H2O2 was the underlying reason for a low mineralization performance. Together with a detailed mathematical methodology, the time-synchronized evolution of both the residual H2O2 concentration and the TOC depletion were employed to infer the quantity of radical ∙OH that effectively was consumed by the micropollutant mineralization. The global mean efficiency of radicals •OH consumption by the HCT mineralization laid around 15% for UVC Fenton considering H2O2 excess of 2.00. Under these conditions, the residual H2O2 concentration depletes significantly within 30 minutes of UVC photo-Fenton oxidation, which indicates that either the solution heating or stirring is very likely to promote a substantial loss of H2O2 by evaporation in the beaker-assembled reactor<br></div>

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Rapid mineralization rate of acetylsalicylic acid in a tubular photochemical reactor: The role of the optimized excess of H2O2

Cited by 9 publications

References 44 publications

Stoichiometric Excess of H2O2 as Strategy of Oxidant Dosing for Intensifying Both Degradation and Mineralization of the Hydrochlorothiazide via UVCH2O2, Dark-Fenton, and Photo-Fenton

Stoichiometric Excess of H2O2 as Strategy of Oxidant Dosing for Intensifying Both Degradation and Mineralization of the Hydrochlorothiazide via UVCH2O2, Dark-Fenton, and Photo-Fenton

Efficiency of the H2O2 consumption by the mineralization of hydrochlorothiazide via photo-Fenton UVA: a time dependent analysis

Stoichiometric Excess of H2O2 as Strategy of Oxidant Dosing for Intensifying Both Degradation and Mineralization of the Hydrochlorothiazide via UVCH2O2, Dark-Fenton, and Photo-Fenton

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