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 Solar Photocatalytic Degradation of Sulfamethoxazole by TiO2 Modified with Noble Metals

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 500 ◽  
Author(s):  
Ewa Borowska ◽  
João F. Gomes ◽  
Rui C. Martins ◽  
Rosa M. Quinta-Ferreira ◽  
Harald Horn ◽  
...  
Keyword(s):  
Rate Constants ◽  
Noble Metals ◽  
Photocatalytic Oxidation ◽  
Geographic Location ◽  
Transformation Products ◽  
Similar Rate ◽  
Lepidium Sativum ◽  
Water Matrix ◽  
Amine Groups ◽  
Xrd Techniques

Application of solar photocatalysis for water treatment is intensively studied. In this work, we investigated TiO2 modified with platinum (Pt/TiO2) and palladium (Pd/TiO2) using sulfamethoxazole (SMX) as the model contaminant. We considered the following parameters: (i) level of TiO2 modification with Pt/Pd, (ii) initial concentration of photocatalysts, (iii) geographic location where processes were conducted, and (iv) natural water matrix. The catalysts characterized by SEM, EDX, DRS, and XRD techniques showed successful deposition of Pd and Pt atoms on TiO2 surface that enabled light absorption in the visible (Vis) range, and therefore caused efficient SMX removal in all tested conditions. A comparison of the rate constants of SMX degradation in various conditions revealed that modification with Pd gave better results than modification with Pt, which was explained by the better optical properties of Pd/TiO2. The removal of SMX was higher with Pd/TiO2 than with Pt/TiO2, independent of the modification level. In the experiments with the same modification level, similar rate constants were achieved when four times the lower concentration of Pd/TiO2 was used as compared with Pt/TiO2. Formation of four SMX transformation products was confirmed, in which both amine groups are involved in photocatalytic oxidation. No toxic effect of post-reaction solutions towards Lepidium sativum was observed.

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 Effective electrocatalytic elimination of chloramphenicol: Mechanism, degradation pathway, and toxicity assessment

2021 ◽  
Author(s):  
Haiyang Liu ◽  
Yihan Lv ◽  
Ya-nan Zhang ◽  
Yushu Zhang ◽  
Jiao Qu ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Advanced Oxidation Process ◽  
Parent Compound ◽  
Degradation Process ◽  
Quantitative Structure Activity Relationship ◽  
Degradation Pathway ◽  
Toxicity Assessment ◽  
Degradation Efficiency ◽  
Electrocatalytic Degradation ◽  
High Efficient

Abstract The residual antibiotics in different environmental media pose a serious threat to human health and the ecosystem. The high-efficient elimination of antibiotics is one of the foremost works. In this study, chloramphenicol (CAP) was eliminated efficiently by electrocatalytic advanced oxidation process with carbon nanotubes/agarose/indium tin oxide (CNTs/AG/ITO) electrode. The influences of different experimental parameters on the degradation efficiency were systematically studied. Under the optimal conditions (4 V potential, 10 wt% CNTs dosage, and pH = 10), the maximum degradation efficiency of CAP (20 mg L− 1) achieved 88% within 180 min. Besides, the electrocatalytic degradation pathway and mechanism for CAP were also investigated, •O2− played a major role in the process of electrocatalytic degradation. Based on the QSAR (quantitative structure-activity relationship) model, the toxicities of CAP and identified intermediates were analyzed. Compared with the parent compound, the maximal chronic toxicity of intermediate ((E)-3-(4-nitrophenyl)prop-1-ene-1,3-diol) for daphnid increased 197-fold. Besides, the hybrid toxicity of the degradation system was further confirmed via disk agar biocidal tests with Escherichia coli ATCC25922, which changed slightly during the degradation process. Based on the above results, it is worth noting that the degradation pathway and toxicity assessment should be paid more attention to the treatment of antibiotic wastewater.

Efficient degradation of refractory contaminants with silver ferrite for persulfate activation

2019 ◽  
Vol 12 (06) ◽  
pp. 1950083
Author(s):  
Cong Li ◽  
Wei Yang ◽  
Sheng Guo ◽  
Zhixiong Yang ◽  
Hussain Fida ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Degradation Mechanism ◽  
Catalytic Performance ◽  
Degradation Pathway ◽  
Degradation Efficiency ◽  
Radical Scavenger ◽  
Solution Ph ◽  
Practical Applications ◽  
Co Precipitation ◽  
Adsorption Desorption

The advanced oxidation processes (AOPs) based on sulfate radicals have triggered tremendous research efforts in environmental remediation field. In this study, we proposed a facile silver ferrite ([Formula: see text] nanocatalyst via a simple co-precipitation at room temperature. The as-prepared AgFeO2 was characterized by XRD, SEM, TEM, XPS, FTIR and N2 adsorption–desorption techniques and was used for persulfate (PDS) activation for the first time. The result showed that AgFeO2 as a PDS activator exhibited superior degradation efficiency of Rhodamine B (RhB) as compared to bare Ag2O, FeOOH and CuFeO2. Moreover, the AgFeO2 catalyst also demonstrated high degradation efficiency for 4-nitrophenol and Methyl Orange in the presence of PDS. The catalytic performance of AgFeO2 was further evaluated in terms of various parameters, including solution pH, PDS concentration and catalyst dosage. The degradation pathway was proposed based on Liquid Chromatography Mass Spectrometer (LC-MS) result and the degradation mechanism was elucidated through radical scavenger experiments. These findings will extend the scope of novel catalysts for PDS activation and promote the use of AgFeO2 in more practical applications.

Biodegradation of Fipronil: Transformation Products, Microbial Characterisation and Toxicity Assessment

2021 ◽  
Vol 232 (3) ◽  
Author(s):  
Rafaela Tomazini ◽  
Flavia T. Saia ◽  
Bas van der Zaan ◽  
Guilherme M. Grosseli ◽  
Pedro S. Fadini ◽  
...  
Keyword(s):  
Transformation Products ◽  
Toxicity Assessment

scholarly journals Toxicity assessment of pickling liquors containing TiF₃, HF and HCl before and after neutralization using a phytotesting method

2017 ◽  
Vol 6 (2) ◽  
pp. 24-27
Author(s):  
Nikolay Alekseevich Bykovsky ◽  
Timur Zulfukarovich Zabirov ◽  
Inna Vyacheslavovna Ovsyannikova ◽  
Lyudmila Nikolaevna Puchkova ◽  
Nadezhda Nikolaevna Fanakova
Keyword(s):  
Dilution Rate ◽  
Average Length ◽  
Ground Surface ◽  
Dry Weight ◽  
Sewage Water ◽  
Toxicity Assessment ◽  
Rate Equations ◽  
Lepidium Sativum ◽  
Before And After ◽  
Acute Toxic Effect

The paper evaluates the toxicity of spent acid pickling liquor (SAPL) formed in the production of titanium products during its etching with a mixture of hydrofluoric and hydrochloric acids. The SAPL contained TiF₃, HF and HCl in the amounts of 21,9 g/l, 1,7 g/l and 6,2 g/l, respectively. To determine the toxicity of SAPL, a phytotesting method was used. As a phytoecological indicator, cress of Zabava variety was used. The experiment was carried out according to the procedure for determining the toxicity of drinking, ground, surface and sewage water; the toxicity of chemical solutions by measuring the germination index, average length and average dry weight of seed germs of cress (Lepidium sativum). The toxicity of the SAPL was determined before and after neutralizing with alkali. It has been shown that SAPL has an acute toxic effect both before and after its neutralization by alkali. To determine a safe dilution rate, the influence of SAPL dilution on seed germination, average length and average dry weight of the seedlings was studied. It was found that the seedlings average length-dilution rate equations most reliably describe the experimental findings. The safe dilution rate calculated from these relations is 669,2 for non-neutralized SAPL and 382,5 for alkaline neutralized SAPL.

Uniform flower-like BiOBr/BiOI prepared by a new method: visible-light photocatalytic degradation, influencing factors and degradation mechanism

2019 ◽  
Vol 43 (37) ◽  
pp. 14829-14840 ◽  
Author(s):  
Jianhui Li ◽  
Quan Zhou ◽  
Fan Yang ◽  
Lijie Wu ◽  
Wenying Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Influencing Factors ◽  
Solvothermal Method ◽  
Degradation Mechanism ◽  
Degradation Efficiency ◽  
New Method ◽  
Molar Ratios ◽  
One Step ◽  
Visible Light Photocatalytic

BiOBr/BiOI photocatalyst with different molar ratios was synthesized via a simple one-step solvothermal method. The uniform flower-like BiOBr/BiOI (3 : 1) owns high photocatalytic degradation efficiency, excellent recyclability and stability.

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