Degradation of diclofenac and carbamazepine by the copper(II)-catalyzed dark and photo-assisted Fenton-like systems

BACKGROUND The Fenton‐based processes have been extensively studied for the treatment of pollutants contained in olive mill wastewater (OMW). These processes have some limitations, such as the need for acidic pH control, the generation of a sludge, and the separation of soluble iron species. Mined pyrite (FeS2) and chalcopyrite (CuFeS2) avoid the problem associated with sludge formation and the acidic pH adjustment. The catalytic activity of pyrite and chalcopyrite was investigated for the Fenton and LED (light emitting diode) photo‐Fenton‐like oxidation of tyrosol (TY) and in the treatment of aqueous mixtures containing phenolic compounds. RESULTS The highest mineralization of TY (85%) and lowest Fe leaching (0.89 mg L‐1) was obtained by using chalcopyrite and the LED photo‐Fenton‐like process (0.50 mmol L‐1 of TY initial concentration and 19.0 mmol L‐1 of H2O2 stoichiometric dosage). Complete degradation of the phenolic pollutants and mineralization of 98% was also achieved. CONCLUSION Mined chalcopyrite can be an appropriate photo‐Fenton‐like catalyst in the degradation of phenolic compounds found in OMW because it can provide a high TOC removal, proper acidic pH conditions, low leaching of iron species and spontaneous formation of a small amount of H2O2. However, the catalyst stability must be improved to minimize the leaching of metals. © 2017 Society of Chemical Industry

{SO}_{4}^{2 -},

H + and Cu 2+ (the later only in the case of chalcopyrite):

2 {FeS}_{2} + 7 O_{2} + 2 H_{2} O \to 2 {Fe}^{2 +} + 4 {SO}_{4}^{2 -} + 4 H^{+}

{CuFeS}_{2} + 4 O_{2} \to {Cu}^{2 +} + {Fe}^{2 +} + 2 {SO}_{4}^{2 -}

…”

Section: Resultsmentioning

confidence: 99%

Mined pyrite and chalcopyrite as catalysts for spontaneous acidic pH adjustment in Fenton and LED photo‐Fenton‐like processes

Ltaïef

Pastrana‐Martínez

Ammar

et al. 2017

“…16,18 Moreover, Cu 2+ promoted direct generation of •OH, acting as a Fenton-like reaction catalyst. 29,30 Its reactions with H 2 O 2 , O 3 , and UV are summarized in Fig. 4(d).…”

Section: Effects Of Water Matrix On Aniline Degradation Effects Of Camentioning

confidence: 99%

Treatment of aniline contaminated water by a self‐designed dielectric barrier discharge reactor coupling with micro‐bubbles: optimization of the system and effects of water matrix

Liu

Shen

Sun

et al. 2018

BACKGROUND A self‐designed dielectric barrier discharge reactor coupling with micro‐bubbles (DBD/MB) system is proposed as a promising method to remove aniline in waste water. The optimum geometric dimensions of the reactor and the operating parameters of the DBD/MB system as well as the influence of the water matrix (including cations, anions, and coexisting organics) were investigated. The functional mechanisms of the DBD/MB system were explored. RESULTS By setting the double‐dielectric barrier discharge reactor (DDBD) with electrode gap as 5 mm, discharge voltage as 50 kV, and air intake flow of the MB generator as 40 mL min−1, the aniline removal efficiency reached 82% within an hour. The removal efficiency could be promoted by the presence of metal ions (Cu2+, Fe2+ and Mn2+), while it was also found that with the presence of certain anions (CO32−, Cl−, NO3− and SO42−), the degradation process was inhibited by more than 40%. The coexisting organics did not influence aniline removal. Active species (•OH, H2O2 and O3) generated in the DDBD/MB treatment and micro‐bubbles played important roles in the aniline degradation process. CONCLUSIONS This study provides fundamental information for the application of a DDBD/MB system to effectively remove aniline from water. © 2018 Society of Chemical Industry

“…•-. 14,41,49 In acidic media, the latter can be further converted into the hydroperoxyl radical (HO 2 • ) (Eqn (10)). Although all these radical species can then take part in ATZ alkyl chain oxidation, 11 • OH radicals present the highest redox potential and the highest reactivity against organic compounds, 50,51 therefore playing a more important role in ATZ oxidation.…”

Section: Degradation Intermediatesmentioning

confidence: 99%

Non‐traditional atrazine degradation induced by zero‐valent‐copper: process optimization by the Doehlert experimental design, intermediates detection and toxicity assessment

Hollanda

Graça

Andrade

et al. 2018

BACKGROUND Over recent years, several studies exploring new technologies capable of degrading persistent organochlorine compounds have been published. Special attention has been dedicated to atrazine (ATZ), due to its ecotoxicological relevance together with its frequent detection in the environment. Degradation of organochlorines via zero‐valent metals has gained great importance given its practicality and versatility, zero‐valent‐iron (ZVI) being the most applied metal for this purpose. Alternatively, zero‐valent‐copper (ZVCu) was proved to exhibit higher reactivity against chlorinated aromatics, therefore deserving further investigation. RESULTS The optimum degradation conditions for ATZ removal with ZVCu were explored through a Doehlert experimental design. The same conditions were tested for the traditional ZVI, which confirmed that ZVCu was more reactive. The analysis of the degradation products suggests that both reductive and oxidative pathways coexist in the studied process. CONCLUSIONS ZVCu was effective in ATZ degradation, both by reductive and oxidation pathways, within a wide range of pH values, although faster in acidic media. The resulting solution from the experiment that promoted the fastest degradation is less toxic than ATZ against microalgae Chlorella vulgaris, which is a positive output regarding the application of this process as a pre‐treatment step of ATZ‐contaminated water matrices. © 2018 Society of Chemical Industry