Degradation Of Phenacetin Research Articles

Amorphous zirconium phosphate as a recycled material anchored cobalt for catalytic degradation of phenacetin via peroxymonosulfate activation

Herein, zirconium phosphate as a recycled material was used for the first time to support cobalt (Co-ZrP) serving as a catalyst for activating peroxymonosulfate (PMS) to remove phenacetin (PNT). It was found that PNT (5 mg L−1) was completely eliminated in the Co-ZrP (0.2 g L−1)/PMS (2 mM) system in an initial pH range of 5 to 7 within 10 min. The pseudo-first-order rate constant of PNT degradation by PMS combined with Co-ZrP was 0.625 min−1, far faster than those with ZrP (0.0065 min−1) and with Co3O4 (0.104 min−1). The introduction of HA and HCO3− significantly inhibited PNT removal, while the addition of H2PO4− accelerated PNT elimination in the Co-ZrP/PMS system. Nevertheless, PNT could still be completely removed by Co-ZrP-activated PMS in actual water. Recycling experiments indicated that the degradation efficiency of PNT could reach 98 % after four cycles and calcining Co-ZrP could completely restore its catalytic activity. In addition, effective decomposition of chloramphenicol, bisphenol A, sulfamethazine and rhodamine B was also achieved by Co-ZrP-activated PMS within 15 min. Hence, the combination of Co-ZrP and PMS had great potential in removing organic pollutants from water environment. EPR analysis and quenching tests suggested that the rapid degradation of PNT was mainly ascribed to the generation of •OH and SO4•− in the Co-ZrP/PMS system. Based on HPLC-HRMS analysis, the main degradation products were determined and the possible degradation pathways were further proposed.

Co3O4 anchored on biochar derived from chitosan (Co3O4@BCC) as a catalyst to efficiently activate peroxymonosulfate (PMS) for degradation of phenacetin

Chitosan, as a bio-friendly and abundant biochar precursor, was employed to prepare cobalt-based catalyst (Co3O4@BCC) by calcination for activating peroxymonosulfate (PMS) to degrade phenacetin (PNT). Various characterization technologies and experimental designs were performed to investigate the physicochemical properties and catalytic performance of Co3O4@BCC. Approximately 99.0% of phenacetin (10 mg/L) was degraded in the system of Co3O4@BCC (0.05 g/L)/PMS (1.0 mM) within 15 min and the rate constant was 6 times higher than that in the system of Co3O4 (0.05 g/L)/PMS (1.0 mM). The results demonstrated that BCC as a carrier not only dispersed Co3O4 nanoparticles and improved the stability of catalyst, but also provided abundant electron-rich groups to facilitate the activation of PMS and the production of reactive oxygen species (ROS). Co3O4@BCC composite also exhibited good universality and reusability. More than 90% of BPA, SIZ and CAP was degraded by Co3O4@BCC activated PMS within 15 min at pH 7. The degradation rate of PNT was recovered from 90% to 98.0% via the regeneration of the used catalyst after the third run (calcination at 400 °C for 5 min). SO4•−, •OH and 1O2 were identified to be responsible for PNT degradation. Furthermore, the activation mechanism of PMS and the possible pathways of PNT degradation were reasonably speculated according to the results of electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), quenching experiments and HPLC-TOF-MS2. This study explored the application of chitosan as a recycled material and provides a feasible strategy for designing and fabricating environmentally friendly and efficient catalysts for PMS activation to degrade organic pollutants.

Acid-washed zero-valent aluminum as a highly efficient persulfate activator for degradation of phenacetin.

Phenacetin (PNT) is one of the most frequently detected nonsteroidal anti-inflammatory drugs in the water ecosystems, which poses a potential risk to environmental aquatic organisms. Acid-washed zero-valent aluminum (ZVAl) as a highly efficient activator for persulfate (PS) process was investigated to degrade PNT from the aqueous solution. The results indicated that acid-washed pretreatment for ZVAl could efficiently increase the degradation efficiency of PNT in the PS treatment. The degradation efficiency of PNT (50 μM) was up to 90% in 4 hours with the addition of 0.2 g/L acid-washed ZVAl and 8 mM PS at pH 6.8 and 25 °C. The PNT degradation followed pseudo-first order kinetics in the present system. High activator dosage, PS concentration, and reaction temperature could enhance the PNT degradation. The presence of inorganic anions (i.e., NO3-, HCO3-) and humic acid (HA) showed inhibitory effects on the PNT degradation. The reuse results illustrated the acid-washed ZVAl material would have continuous and efficient activation performance for PS to degrade thePNT. Radical scavenger experiments and electron paramagnetic resonance indicated that both SO4•- and •OH were major reactive species during the PNT degradation. The possible degradation pathways of PNT mainly included the break of C-N and C-O bonds and further oxidation.

CrPO4 as a recycled material supported Co3O4 as an efficient peroxymonosulfate catalyst for phenacetin elimination from aqueous solution

In this study, CrPO4-supported Co3O4 (CrPO4@Co3O4) as an efficient peroxymonosulfate (PMS) catalyst was obtained for the first time and used to eliminate phenacetin (PNT) from aqueous solution efficiently. CrPO4@Co3O4 composite exhibited a superb catalytic performance, and over 98% PNT was degraded by PMS (0.5 mM) within 15 min, which is much more efficient than in the systems of CrPO4/PMS and Co3O4/PMS. The excellent catalytic performance of CrPO4@Co3O4 was attributed to its higher BET surface area. On the other hand, the presence of PO43- in the catalyst might improve the conversion of Co(III) to Co(II). The latter served as the main active site for the PMS activation. CrPO4@Co3O4 also possessed superior stability and reusability, and the removal rates of PNT remained over 91% through 4 cycle tests. Solution pH significantly impacted the PNT decomposition, and the optimal catalytic degradation of PNT was achieved in an initial range of 5 to 7. Humic acid, HCO3−, and Cl− inhibited PNT degradation. Radical scavenging experiments and EPR technology revealed that SO4•− free radicals were the main reactive oxygen species (ROS) responsible for PNT degradation. While O2•− mainly acted as the intermediate to form SO4•− and 1O2. To assess the practical application of the CrPO4@Co3O4/PMS system, the PNT degradation was investigated in real lake water. Based on HPLC-TOF-MS2 analysis, 14 intermediates were identified, and the degradation pathways were further inferred. Therefore, this study provides a feasible strategy for the valuable use of CrPO4 as recycled material and a practical solution for the efficient degradation of organic contaminants.

Kinetics degradation of phenacetin by solar activated persulfate system

Kinetic degradation of phenacetin (PNT) by solar activated persulfate (PS) system was evaluated in study. The decomposition of PNT well fitted with a pseudo-first order kinetic pattern, and the exceptional removal performance towards PNT (100%) was obtained in the presence of solar irradiation (1.14 × 10-4 E· m−2· s−1) and 0.3 mM PS at pH 7.0 in 10 min. The consume ratios of persulfate were calculated to be 2.3~16.7%. The steady-state concentrations of hydroxyl radicals ([HO*]ss) and sulfate radicals ([SO4-·]ss) were calculated to be (2.41~2.59) × 10-13 M and (3.75~4.06) × 10-12 M by probes of nitrobenzene (NB) and benzoic acid (BA), respectively. The contribution of HO* and SO4-· accounts for 27.4% and 11.0% in degradation of PNT. The formation of typical trihalomethanes (THMs) after pre-oxidation of solar/PS was evaluated. The concentration of total THMs decreased from 16 μg·L-1 to 15.4 μg·L-1 through pre-oxidation, with cytotoxicity decreased from 1.38 × 10-5 to 1.27 × 10-5. The calculated electrical energy per order (EE/O) in solar/PS were in range of 0.069~0.106 kWh/m/order.

Factors affecting UV/persulfate treatment of phenacetin and its disinfection byproduct formation potential

The pollution of aquatic bodies in the natural environment by pharmaceuticals has become a matter of increasing concern. In this study, we investigated the effects of the various influencing factors on the degradation of phenacetin (PNT) and its disinfection byproduct formation potentials (DBPFPs) by UV/persulfate (UV/PS) treatment. We first examined the effects of factors such as the PS concentration, pH, HCO3–, NO3–, NO2–, and natural organic matter (NOM) on the PNT degradation kinetics. The PNT degradation rate exhibited a positive correlation with the PS concentration. The PNT degradation rate was also pH-dependent, and it was highest under mild-alkalinity conditions. The presence of NO3–, NO2–, and NOM all inhibited PNT degradation, whereas HCO3– slightly accelerated PNT degradation. We next adopted LC/MS/MS to identify the degradation products of PNT, and the possible degradation pathways were proposed accordingly. The effects of UV/PS pretreatment on the DBPs from chlorination exhibit a close relationship with the abovementioned factors influencing the PNT degradation performance. Upon prolonging the pretreatment time and increasing the PS concentration, it was observed that trichloromethane (TCM) formation continuously decreased, while dichloroacetonitrile (DCAN) and trichloronitromethane (TCNM) exhibited patterns of increase and subsequent decrease in concentration. Mild alkalinity enhanced TCM formation and largely restrained DCAN and TCNM formation. Additionally, the presence of NOM enhanced TCM formation, while HCO3– hardly affected DBP formation. Meanwhile, NO2– profoundly affected the formation of TCNM. Therefore, these factors influencing PNT degradation by UV/PS should be carefully considered when integrating such technology as an alternative pretreatment for PNT-polluted water before disinfection.

Theoretical investigation on the contribution of HO[rad], SO4[rad]- and CO3[rad]- radicals to the degradation of phenacetin in water: Mechanisms, kinetics, and toxicity evaluation

Indirect oxidation induced by reactive free radicals, such as hydroxyl radical (HO), sulfate radical (SO4-) and carbonate radical (CO3-), plays an important or even crucial role in the degradation of micropollutants. Thus, the coadjutant degradation of phenacetin (PNT) by HO, SO4- and CO3-, as well as the synergistic effect of O2 on HO and HO2 were studied through mechanism, kinetics and toxicity evaluation. The results showed that the degradation of PNT was mainly caused by radical adduct formation (RAF) reaction (69% for Г, the same as below) and H atom transfer (HAT) reaction (31%) of HO. For the two inorganic anionic radicals, SO4- initiated PNT degradation by sequential radical addition-elimination (SRAE; 55%), HAT (28%) and single electron transfer (SET; 17%) reactions, while only by HAT reaction for CO3-. The total initial reaction rate constants of PNT by three radicals were in the order: SO4- > HO > CO3-. The kinetics of PNT degradation simulated by Kintecus program showed that UV/persulfate could degrade target compound more effectively than UV/H2O2 in ultrapure water. In the subsequent reaction of PNT with O2, HO and HO2, the formation of mono/di/tri-hydroxyl substitutions and unsaturated aldehydes/ketones/alcohols were confirmed. The results of toxicity assessment showed that the acute and chronic toxicity of most products to fish increased and to daphnia decreased, and acute toxicity to green algae decreased while chronic toxicity increased.

Anti-inflammatory drugs degradation during LED-UV365 photolysis of free chlorine: roles of reactive oxidative species and formation of disinfection by-products

Light-emitting diode (LED) is environmentally friendly with longer life compared with traditionally mercury lamps. This study investigated the non-steroidal anti-inflammatory drugs (NSAIDs)- phenacetin (PNT) and acetaminophen (ACT)- removal during LED-UV (365 nm) photolysis of free available chlorine (FAC). Degradation of PNT and ACT during LED-UV365/FAC treatment at pH 5.5-8.5 followed the pseudo-first order kinetics. The presence of hydroxyl radicals (·OH), reactive chlorine species (RCS), and ozone (O3, transformed from O (3P)) were screened by using scavengers of ethanol (EtOH), tert-Butanol (TBA), and 3-buten-2ol, and 4-hydroxy-2,2,6,6-tetramethylpiperidine (TEMP), and quantified by competition kinetics with probing compounds of nitrobenzene (NB), benzoate acid (BA), 1,4-dimethoxybenzene (DMOB). Higher pH would lead to decrease of ·OH contribution and an increase of FAC contribution to PNT and ACT degradation. It has been determined that the contribution of O3 to degradation of PNT and ACT was less than 5% for all pHs, and O3(P) reacts toward EtOH with second-order constant of 1.52 × 109 M−1s−1. LED-UV365/FAC system reduced the formation of five typical CX3-R type disinfection by-products (DBPs) as well as the cytotoxicity and genotoxicity of water samples at pH 5.5 and 8.5, compared with FAC alone. The decrease of DBPs formation resulted from fast FAC decomposition upon LED-UV365 irradiation. A feasible reaction pathway of DBPs formation in the LED-UV365/FAC system was examined with density functional theory (DFT). For FAC decay during LED-UV365/FAC with effluent from wastewater, the residual FAC in 15 min was 0.8 mg/L (lower than limit of 0.2 mg/L) once initial FAC was 2.0 mg/L. The results indicate that more tests on the balance of target pollutant removal efficiency, residual FAC and cost should be explored in LED-UV365/FAC system for application.

Activation of peroxymonosulfate with CuCo2O4@kaolin for the efficient degradation of phenacetin

CuCo2O4@kaolin was successfully synthesized by a sol-gel method and used as a heterogeneous catalyst to activate peroxymonosulfate (PMS) for the degradation of phenacetin (PNT). The results demonstrated that 10 mg/L PNT was completely decomposed by 1 mM PMS activated with 0.1 g/L CuCo2O4@kaolin within 15 min at initial pH 7. CuCo2O4@kaolin exhibited the best excellent catalytic performance among the tested catalysts, and the pseudo-first-order rate constants of PNT degradation were CuCo2O4@kaolin (0.40 min−1)>CuCo2O4 (0.22 min−1)>Co3O4@kaolin (0.10 min−1)>CuO@kaolin (0.08 min−1)>kaolin (0.02 min−1). CuCo2O4@kaolin also possessed superior stability, and the degradation efficiency of PNT declined from 100% in the first round to 80% in the fourth round. Nevertheless, a simple calcinating treatment (20 min) after the third round could restore its catalytic activity substantially and 95% removal of PNT was realized, 15% higher compared to without treatment. OH, SO4−, and 1O2 were the reactive oxygen species driving the PNT degradation. Based on the results mentioned above, characterizations of CuCo2O4@kaolin, and intermediates of PNT degradation, the possible pathways and underlying mechanisms of the PNT degradation in the CuCo2O4@kaolin/PMS system were deduced. CuCo2O4@kaolin/PMS had a universal degradation potential toward various organic pollutants, and the degradation efficiencies of sulfisoxazole, p-nitrophenol, chloramphenicol, and 2,4,6-Trichlorophenol reached 95–100% within 5–45 min. Thus, this work provides a novel and efficient PMS activator through an eco-friendly synthetic route, and it may be put into practice to degrade organic matter in wastewater.

Fabrication of a novel high photocatalytic Ag/Ag3PO4/P25 (TiO2) heterojunction catalyst for reducing electron-hole pair recombination and improving photo-corrosion

Noble metal Ag nanoparticles were deposited on Ag3PO4/P25 heterojunction structure by ultraviolet (UV) light induction to construct Ag/Ag3PO4/P25 double heterojunction catalyst for efficient decomposition of phenacetin (PNT). X-Ray Diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Raman and photoluminescence (PL) spectroscopy analyses were employed to evaluate the microstructure, chemical structure and photocatalytic activity of synthesized catalyst materials. PL spectroscopy analyses revealed that a considerable enhancement in photochemistry activity of Ag3PO4/P25 due to the deposition of Ag. The effects of Ag3PO4 mass ratios, operating conditions on PNT degradation and catalyst stability were also investigated. Results showed that Ag/10% Ag3PO4/P25 under the operating conditions of catalysts concentration of 0.5 g L−1 and pH of 9.0 with UV light irradiation displayed a better photocatalysis degradation performance. When the concentration of PNT was 20 mg L−1, the removal rate of PNT and TOC obtained from Ag/Ag3PO4/P25 system were up to 97 % and 83%, respectively. The removal rate of PNT drops from 97% to 85% between the first and last cycles after 60-min conversion. Ag/Ag3PO4/P25 with a high catalytic reaction efficiency was ascribed to the deposition of Ag. Ag is an electron acceptor and Ag3PO4 have excellent electron conductivity in a heterostructure, the novel Ag/Ag3PO4/P25 composite catalyst could reduce the recombination rate of electron-hole pairs and prolong the lifetime of photogenerated electrons.

Degradation of phenacetin by the UV/chlorine advanced oxidation process: Kinetics, pathways, and toxicity evaluation

The degradation of phenacetin (PNT) by the combination of low-pressure mercury lamp and chlorine (UV/chlorine), an advanced oxidation process (AOP) of recent interest, was systematically investigated in terms of degradation kinetics, effects of chlorine dosage and water parameters, oxidation products as well as toxicity evaluation. The degradation of PNT followed pseudo first-order kinetics. The first-order rate constant (kobs) in the UV/chlorine AOP was 4.3, 8.4, and 11.1 times that of dark chlorination, UV/H2O2, and UV/PS, respectively, with the same molar dosage of oxidant at pH 7.2. Radical quenching tests suggested that chlorination, OH and reactive chlorine species were responsible for the UV/chlorine oxidation of PNT with contributions of 26.33%, 14.6% and 59.07%, at pH 7.2. As chlorine dosage gradually increased from 100 to 500 μM, the corresponding kobs monotonically increased from 0.0229 to 0.216 min−1. kobs was not apparently affected by the pH and coexisting chloride, but decreased by 56.5% and 75.4% in the presence of 10 mM HCO3− and 10 mg/L NOM. Slight decreases (around 15%) of kobs occurred in the raw water and tap water tests, while little effect was observed in filtered water samples compared with ultrapure water tests. Six typical disinfection byproducts including trichloromethane (TCM), chloral hydrate, dichloropropanone, trichloropropanone, trichloronitromethane, and dichloroacetonitrile were detected. The TCM yields increased to 159.95 μg/L within 20 min reaction of UV/chlorine, comprising 13.3% of the degraded PNT (per mole of carbon). The acute toxicity to luminescent bacterium Q67 by UV/chlorine was lower than chlorination under similar reaction conditions.

Electro-catalytic oxidation of phenacetin with a three-dimensional reactor: Degradation pathway and removal mechanism

Phenacetin is a common analgesic, anti-arthritic and anti-rheumatic drug. This study dealt with the degradation of phenacetin in alkaline media using a three-dimensional reactor with particle electrodes. Particular attention was paid to the degradation pathway and the reaction mechanism in the system. Liquid chromatography coupled with time-of-flight mass spectrometry was used to identify the intermediates. The phenacetin was observed to be firstly cut off the branch chains main by direct oxidation, and then the intermediates further degraded to ring opening products by hydroxyl radical resulting from indirect oxidation and finally mineralized to CO2, H2O. A possible removal mechanism was proposed that direct and indirect oxidation together did effect on the pollutants with oxygen.

Heterogeneous catalytic ozonation of phenacetin in water using magnetic spinel ferrite as catalyst: Comparison of surface property and efficiency

In this study, a systematic investigation on the degradation of phenacetin (PNT) by magnetic spinel ferrite (including MnFe2O4 and NiFe2O4) via catalytic ozonation was carried out. The structural and surface property of the catalyst, the performance and mineralization during PNT degradation, and •OH/H2O2 identification were studied. The precursors of the catalyst, i.e. MnFe2(OH)8 and NiFe2(OH)8, showed certain magnetic properties and a superior catalytic activity for ozonation enhancement than spinel ferrites. Spinel ferrites containing manganese initiate an ozone mass transfer into the solution, where the critical intermediate (H2O2) is generated. The manganese ferrite spinel triggers H2O2 decomposition in the presence of ozone and generates •OH for the mineralization of PNT and its intermediates. Spinel ferrites involved nickel catalyzed ozone decomposition and generate H2O2 and •OH. All catalysts showed a weak heavy metal leaching, which suggests that the heterogeneous reaction dominates the catalytic reaction and the resultant effluent is safe for the aqueous environment. The magnetic variation of catalysts involving nickel is insignificant, suggesting that the catalyst can be reused many times. The fate of the intermediates on spinel oxides surface influenced for the catalytic ozonation process differently.

Ozonation of phenacetin in associated with a magnetic catalyst CuFe2O4: The reaction and transformation

Abstract The application of CuFe2O4 (CFO), a magnetic spinel, in catalytic ozonation for the degradation of phenacetin (PNT) has been investigated. The performance and the mineralization of PNT in CFO catalytic ozonation (CFOO) were compared with the sole ozonation (SOP), respectively. In SOP, the molecular ozone was reacted with PNT fast, but it was less effective for PNT’s mineralization. The presence of CFO improved the mineralization significantly. Based on the observed kinetics analysis and effect of radical scavenger, the contribution of molecular ozone or hydroxyl radical for PNT degradation was identified and quantified. Influence of reaction conditions (e.g. [ozone], [catalyst], and solution pH) on the performance of CFOO was evaluated; a predictive empirical model was developed for CFOO. Especially, the degradation pathways of PNT contributed by molecular ozone or hydroxyl radical oxidation have been studied in detail with 23 intermediates identified.

New aspects on the question of phenacetin nephrotoxicity

Experiments on the metabolism of phenacetin in the rat are reported. Estimations of phenacetin, total acetyl-p-aminophenol,p-phenetidine and 2-hydroxyphenetidine-sulfate in the urine excreted after ingestion of phenacetin reveal an unusual dose-dependence of the metabolic pattern. The degradation of phenacetin through deacetylation to phenetidine is greatly enhanced by raising the dose. The results are briefly discussed in view of their possible significance in the development of analgesic nephropathy in man. As a working hypothesis for further experiments it is assumed, that phenetidine is the main toxic agent in nephropathy due to phenacetin abusus.