scholarly journals Ozone-Based Advanced Oxidation Processes for Primidone Removal in Water using Simulated Solar Radiation and TiO2 or WO3 as Photocatalyst

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1728 ◽  
Author(s):  
Manuel A. Figueredo ◽  
Eva M. Rodríguez ◽  
Manuel Checa ◽  
Fernando J. Beltran
Keyword(s):  
Transformation Products ◽  
Degradation Pathway ◽  
Secondary Effluent ◽  
Ultrapure Water ◽  
Visible Radiation ◽  
Beneficial Effects ◽  
Photocatalytic Ozonation ◽  
Toc Removal ◽  
Water Matrix ◽  
Environmentally Safe

In this work, primidone, a high persistent pharmacological drug typically found in urban wastewaters, was degraded by different ozone combined AOPs using TiO2 P25 and commercial WO3 as photocatalyst. The comparison of processes, kinetics, nature of transformation products, and ecotoxicity of treated water samples, as well as the influence of the water matrix (ultrapure water or a secondary effluent), is presented and discussed. In presence of ozone, primidone is rapidly eliminated, with hydroxyl radicals being the main species involved. TiO2 was the most active catalyst regardless of the water matrix and the type of solar (global or visible) radiation applied. The synergy between ozone and photocatalysis (photocatalytic ozonation) for TOC removal was more evident at low O3 doses. In spite of having a lower band gap than TiO2 P25, WO3 did not bring any beneficial effects compared to TiO2 P25 regarding PRM and TOC removal. Based on the transformation products identified during ozonation and photocatalytic ozonation of primidone (hydroxyprimidone, phenyl-ethyl-malonamide, and 5-ethyldihydropirimidine-4,6(1H,5H)-dione), a degradation pathway is proposed. The application of the different processes resulted in an environmentally safe effluent for Daphnia magna.

scholarly journals Degradation of norfloxacin in aqueous solution with UV/peroxydisulfate

2019 ◽  
Vol 79 (12) ◽  
pp. 2387-2394 ◽  
Author(s):  
Honghai Xue ◽  
Siyu Gao ◽  
Na Zheng ◽  
Ming Li ◽  
Xue Wen ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Removal Rate ◽  
Inorganic Ions ◽  
Transformation Products ◽  
Neutral Condition ◽  
Advanced Treatment ◽  
Ultrapure Water ◽  
Toc Removal ◽  
Laboratory Results ◽  
Removal Technology

Abstract The frequent detection of antibiotics in water bodies gives rise to concerns about their removal technology. In this study, the degradation kinetics and mechanisms of norfloxacin (NOR), a typical fluoroquinolone pharmaceutical, by the UV/peroxydisulfate (PDS) was investigated. NOR could be degraded effectively using this process, and the degradation rate increased with the increasing dosage of PDS but decreased with the increasing concentration of NOR. In real water, the degradation of NOR was slower than that in ultrapure water, which indicated that laboratory results cannot be directly used to predict the natural fate of antibiotics. Further experiments suggested that the degradation of NOR was the most fast under neutral condition, the existence of HA or FA inhibited the degradation of NOR, and the presence of inorganic ions (NO3−, Cl−, CO32− and HCO3−) had no significant effect on degradation of NOR. Total organic carbon (TOC) removal rate (40%) indicated NOR was not completely mineralized, and six transformation products were identified, and possible degradation pathways of NOR had been proposed. It can be prospected that UV/PDS technology could be used for advanced treatment of wastewater containing fluoroquinolones.

scholarly journals Degradation pathway of triazole fungicides and synchronous removal of transformation products via photo-electrocatalytic oxidation tandem MoS2 adsorption

2021 ◽  
Author(s):  
Junwen Wang ◽  
Xiaoxin Chen ◽  
Xiaoli Sun ◽  
Miao Liu ◽  
Xingqiang Wu ◽  
...  
Keyword(s):  
Electrocatalytic Oxidation ◽  
Aquatic Toxicity ◽  
Water Environment ◽  
Transformation Products ◽  
Degradation Pathway ◽  
Stir Bar Sorptive Extraction ◽  
Secondary Effluent ◽  
Triazole Fungicides ◽  
Irradiation Intensity ◽  
Tandem Process

AbstractA simple and effective tandem process of photo-electrocatalytic oxidation (PECO)-MoS2 adsorption was developed for the synchronous removal of triazole fungicides (TFs) and toxicological transformation products (TPs). In order to accurately identify trace TPs and evaluate degradation pathway during water treatment, a sensitive analytical method was developed on the basis of the stir bar sorptive extraction (SBSE) pretreatment tandem LC-MS/MS technique. Firstly, the typical TFs (PRO, TET, and DIN, C0 = 1.0 mg/L) in actual water samples were treated under the optimal process (bias voltage 1.8 V, pH 4, irradiation intensity 50 mW/cm2, 0.05 g MoS2/100 mL, 350 rpm, adsorption of 5 min). The result indicated that the residues of PRO, TET, and DIN in secondary effluent were 0.0973, 0.0617, and 0.0012 mg/L, respectively, with the removal rates of 90.3%, 93.8%, and 99.9%, respectively, undergoing 30-min photo-electrocatalysis and 5-min adsorption. The alkaline medium was favorable for the adsorption of MoS2 to TFs. The assessment results of potential cancer risk indicated that the residues of TFs in secondary effluent were safe for drinking water consumption. Besides, the major TPs were identified via the SBSE-HRLC-MS/MS technique, and one possible transformation pathway of TFs was proposed. TFs mainly underwent dehydrochlorination, cyclization, hydroxylation, etc. to produce a series of nitrogenous heterocyclic compounds that possess higher polarity than parents, hinting that TPs might pose potential aquatic toxicity. However, TPs can be removed synchronously by this tandem technique. The current study can provide a theoretical basis for the harmless treatment of TFs in the water environment.

scholarly journals Comparison of radical-driven technologies applied for paraben mixture degradation: mechanism, biodegradability, toxicity and cost assessment

2019 ◽  
Vol 26 (36) ◽  
pp. 37174-37192 ◽  
Author(s):  
Marta Gmurek ◽  
João F. Gomes ◽  
Rui C. Martins ◽  
Rosa M. Quinta-Ferreira
Keyword(s):  
Photocatalytic Oxidation ◽  
Degradation Mechanism ◽  
Transformation Products ◽  
Degradation Pathway ◽  
Toxicity Assessment ◽  
Degradation Efficiency ◽  
Lepidium Sativum ◽  
Cost Assessment ◽  
Aqueous Environment ◽  
Photocatalytic Ozonation

AbstractParabens (esters of p-hydroxybenzoic acid) are xenobiosis belonging to endocrine disruptors and commonly used as a preservative in cosmetics, food, pharmaceutical, and personal care products. Their wide use is leading to their appearance in water and wastewater in the range from ng/L to mg/L. In fact, the toxicity of benzylparaben is comparable to bisphenol A. Therefore, it is important to find not only effective but also ecofriendly methods for their removal from aqueous environment since the traditional wastewater treatment approaches are ineffective. Herein, for the first time, such extended comparison of several radical-driven technologies for paraben mixture degradation is presented. The detailed evaluation included (1) comparison of ozone and hydroxyl peroxide processes; (2) comparison of catalytic and photocatalytic processes (including photocatalytic ozonation); (3) characterisation of catalysts using SEM, XRD, DRS, XPS techniques and BET isotherm; (4) mineralisation, biodegradability and toxicity assessment; and (5) cost assessment. O3, H2O2/Fe2+, H2O2/UVC, O3/H2O2, O3/UVA, O3/H2O2/UVA, UVA/catalyst, O3/catalyst and O3/UVA/catalyst were selected from advanced oxidation processes to degrade parabens as well as to decrease its toxicity towards Aliivibrio fischeri, Corbicula fluminea and Lepidium sativum. Research was focused on the photocatalytic process involving visible light (UVA and natural sunlight) and TiO2 catalysts modified by different metals (Ag, Pt, Pd, Au). Photocatalytic oxidation showed the lowest efficiency, while in combining ozone with catalysis and photocatalysis process, degradation efficiency and toxicity removal were improved. Photocatalytic ozonation slightly improved degradation efficiency but appreciably decreased transferred ozone dose (TOD). Results indicate that the degradation pathway is different, or different transformation products (TPs) could be formed, despite that the hydroxyl radicals are the main oxidant.

scholarly journals UV and (V)UV irradiation of sitagliptin in ultrapure water and WWTP effluent: Kinetics, transformation products and degradation pathway

Chemosphere ◽  
2021 ◽  
pp. 132393
Author(s):  
Dániel Krakkó ◽  
Ádám Illés ◽  
Attila Domján ◽  
Attila Demeter ◽  
Sándor Dóbé ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Transformation Products ◽  
Degradation Pathway ◽  
Ultrapure Water ◽  
Wwtp Effluent

scholarly journals Removal of crotamiton and its degradation intermediates from secondary effluent using TiO2–zeolite composites

2017 ◽  
Vol 77 (3) ◽  
pp. 788-799 ◽  
Author(s):  
Qun Xiang ◽  
Shuji Fukahori ◽  
Youhei Nomura ◽  
Taku Fujiwara
Keyword(s):  
Biological Treatment ◽  
Photocatalytic Decomposition ◽  
Secondary Effluent ◽  
Ultrapure Water ◽  
Water Matrix ◽  
Treatment Processes ◽  
Adsorption Capacities ◽  
High Silica ◽  
Adsorption Rates ◽  
Degradation Intermediates

Abstract Crotamiton, a scabicide and antipruritic agent persistent during biological treatment processes, is frequently detected in secondary effluent. In this study, titanium dioxide (TiO2) and high-silica zeolite (HSZ-385) composites were synthesized and applied for the treatment of crotamiton in secondary effluent. Crotamiton was rapidly adsorbed by HSZ-385, and the adsorption performance of crotamiton in the secondary effluent was quite close to that in the test using ultrapure water. Even though the TiO2–zeolite composites showed lower adsorption rates than that of HSZ-385, similar crotamiton adsorption capacities were revealed using both test materials. The photocatalytic decomposition of crotamiton was significantly inhibited by the water matrix at low initial concentrations. The TiO2–zeolite composites rapidly adsorbed crotamiton from secondary effluent, and then the crotamiton was gradually decomposed under ultraviolet irradiation. Importantly, when using TiO2–zeolite composites, coexisting material in the secondary effluent did not markedly inhibit crotamiton removal at low initial crotamiton concentration. The behaviors of the main intermediates during treatment demonstrated that the main degradation intermediates of crotamiton were also captured by the composites.

scholarly journals Oxidation of Citalopram with Sodium Hypochlorite and Chlorine Dioxide: Influencing Factors and NDMA Formation Kinetics

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3065
Author(s):  
Juan Lv ◽  
Yan Wang ◽  
Na Li
Keyword(s):  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Wastewater Treatment Plants ◽  
Ph Value ◽  
High Reactivity ◽  
Secondary Effluent ◽  
Water Matrix ◽  
Formation Kinetics ◽  
Operational Variables ◽  
Two Stages

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.

Evaluation of water matrix effects, experimental parameters, and the degradation pathway during the TiO2photocatalytical treatment of the antibiotic dicloxacillin

2014 ◽  
Vol 50 (1) ◽  
pp. 40-48 ◽  
Author(s):  
Paola Villegas-Guzman ◽  
Javier Silva-Agredo ◽  
Duván González-Gómez ◽  
Ana L. Giraldo-Aguirre ◽  
Oscar Flórez-Acosta ◽  
...  
Keyword(s):  
Matrix Effects ◽  
Degradation Pathway ◽  
Water Matrix ◽  
Experimental Parameters

scholarly journals Degradation of Bisphenol-A: A Contaminant of Emerging Concern Using Catalytic Ozonation By Activated Carbon Impregnated Nanocomposite-Bimetallic Catalyst

2021 ◽  
Author(s):  
Hariprasad Pokkiladathu ◽  
Salman Farissi ◽  
Anbazhagi Sakkarai ◽  
Muthukumar Muthuchamy
Keyword(s):  
Activated Carbon ◽  
Bisphenol A ◽  
Bimetallic Catalyst ◽  
Degradation Pathway ◽  
Catalytic Ozonation ◽  
Toc Removal ◽  
Treated Sample ◽  
Aromatic Degradation ◽  
Exponential Population Growth ◽  
Pollution Events

Abstract Rampant water pollution events and rising water demand caused by exponential population growth and depleting freshwater resources speak of an impending water crisis. The inability of conventional wastewater treatment systems to remove Contaminants of Emerging Concern (CEC) such as Bisphenol-A (BPA) beckons for new and efficient technologies to remove them from wastewater and water sources. Advanced oxidation processes such as ozonation are primarily known for their capability to oxidize and degrade organic entities in water but optimum mineralization levels were hard to achieve. In this study, we synthesized an activated carbon impregnated nanocomposite-bimetallic catalyst (AC/CeO2/ZnO) and used it along with ozonation to remove BPA from water. The catalyst was characterized using BET, XRD, FESEM, Raman spectra, and DLS studies. Catalytic ozonation achieved TOC removal 25% higher than non-catalytic ozonation process. The degradation pathway of BPA was proposed using LC-MS/LC-Q-TOF studies that found six main aromatic degradation byproducts. Catalytic ozonation and non-catalytic ozonation followed similar degradation pathways. The formation of persistent aliphatic acidic byproducts in the treated sample made TOC removal above 61% difficult.

scholarly journals Solar Light Photoactive Floating Polyaniline/TiO2 Composites for Water Remediation

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3071
Author(s):  
Ermelinda Falletta ◽  
Anna Bruni ◽  
Marta Sartirana ◽  
Daria C. Boffito ◽  
Giuseppina Cerrato ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Transformation Products ◽  
Water Remediation ◽  
Solar Light ◽  
Reaction Conditions ◽  
Doping Agent ◽  
Water Matrix ◽  
Physico Chemical ◽  
Materials Behavior

In the present study, the development of innovative polyurethane-polyaniline/TiO2 modified floating materials applied in the sorption and photodegradation of rhodamine B from water matrix under solar light irradiation is reported. All the materials were fabricated with inexpensive and easy approaches and were properly characterized. The effect of the kind of polyaniline (PANI) dopant on the materials’ behavior was investigated, as well as the role of the conducting polymer in the pollutant abatement on the basis of its physico-chemical characteristics. Rhodamine B is removed by adsorption and/or photodegradation processes depending on the type of doping agent used for PANI protonation. The best materials were subjected to recycle tests in order to demonstrate their stability under the reaction conditions. The main transformation products formed during the photodegradation process were identified by ultraperformance liquid chromatography-mass spectrometry (UPLC/MS). The results demonstrated that photoactive floating PANI/TiO2 composites are useful alternatives to common powder photocatalysts for the degradation of cationic dyes.

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