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.

scholarly journals Degradation of fluorescent dye-Solvent Green 7 (HPTS) in wastewater by advanced oxidation process

2020 ◽  
Vol 82 (11) ◽  
pp. 2525-2535
Author(s):  
Shaokang Cai ◽  
Shurong Zhang ◽  
Canzhu Gao ◽  
Zhongfa Cheng
Keyword(s):  
Advanced Oxidation Process ◽  
Advanced Oxidation ◽  
Strong Acid ◽  
Degradation Process ◽  
Chloride Ions ◽  
Fluorescent Dye ◽  
Degradation Efficiency ◽  
Oxidant Concentration ◽  
Fluorescence Characteristics ◽  
Polycyclic Aromatic

Abstract Solvent Green 7 (HPTS) is a widely used fluorescent dye. As a kind of polycyclic aromatic hydrocarbon (PAHs) derivative, HPTS would cause pollution when it is discharged into the environment. This study adopted advanced oxidation processes (UV/H2O2) to degrade the HPTS in aqueous solution and investigated the effects of various factors on the degradation. The results showed that: the initial concentration and the fluorescence characteristics of HPTS reduced the degradation efficiency. When the oxidant concentration of H2O2 was 3 mg/L, the degradation efficiency and cost of HPTS (20 mg/L) were the most appropriate; when there were various inorganic anions in the solution, the degradations were not affected, but when the solution was strong acid and there existed a lot of chloride ions, the degradation of HPTS was inhibited. The degradation pathways indicated HPTS degraded into naphthalene derivatives, benzene derivatives through oxidation and decarboxylation reactions, finally into water and carbon dioxide. Further research for substances similar to HPTS structure will make progress in understanding the degradation process of PAHs.

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 Secondary Effects of Hypochlorite Treatment on the Emerging Pollutant Candesartan: The Formation of Degradation Byproducts and Their Toxicological Profiles

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3422
Author(s):  
Giovanni Luongo ◽  
Lorenzo Saviano ◽  
Giovanni Libralato ◽  
Marco Guida ◽  
Antonietta Siciliano ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Parent Compound ◽  
Antihypertensive Agents ◽  
Parent Drug ◽  
Degradation Pathway ◽  
Hplc Method ◽  
Chlorination Process ◽  
Emerging Pollutant ◽  
Ecotoxicity Tests ◽  
First Time

In recent years, many studies have reported the frequent detection of antihypertensive agents such as sartans (olmesartan, valsartan, irbesartan and candesartan) in the influents and effluents of wastewater treatment plants (WWTPs) and in the superficial waters of rivers and lakes in both Europe and North America. In this paper, the degradation pathway for candesartan (CAN) was investigated by simulating the chlorination process that is normally used to reduce microbial contamination in a WWTP. Twelve isolated degradation byproducts (DPs), four of which were isolated for the first time, were separated on a C-18 column by employing a gradient HPLC method, and their structures were identified by combining nuclear magnetic resonance and mass spectrometry and comparing the results with commercial standards. On the basis of these results, a mechanism of formation starting from the parent drug is proposed. The ecotoxicity of CAN and its DPs was studied by conducting a battery of ecotoxicity tests; bioassays were performed using Aliivibrio fischeri (bacterium), Daphnia magna (planktonic crustacean) and Raphidocelis subcapitata (alga). The ecotoxicity results shed new light on the increased toxicity of DPs compared with the parent compound.

scholarly journals Application of Catalytic Wet Peroxide Oxidation for Industrial and Urban Wastewater Treatment: A Review

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 673 ◽  
Author(s):  
Juan Rueda Márquez ◽  
Irina Levchuk ◽  
Mika Sillanpää
Keyword(s):  
Wastewater Treatment ◽  
Advanced Oxidation Process ◽  
Fixed Bed ◽  
Toxicity Assessment ◽  
Batch Reactors ◽  
Peroxide Oxidation ◽  
Urban Wastewater ◽  
Wet Peroxide Oxidation ◽  
Catalytic Wet Peroxide Oxidation ◽  
Urban Wastewater Treatment

Catalytic wet peroxide oxidation (CWPO) is emerging as an advanced oxidation process (AOP) of significant promise, which is mainly due to its efficiency for the decomposition of recalcitrant organic compounds in industrial and urban wastewaters and relatively low operating costs. In current study, we have systemised and critically discussed the feasibility of CWPO for industrial and urban wastewater treatment. More specifically, types of catalysts the effect of pH, temperature, and hydrogen peroxide concentrations on the efficiency of CWPO were taken into consideration. The operating and maintenance costs of CWPO applied to wastewater treatment and toxicity assessment were also discussed. Knowledge gaps were identified and summarised. The main conclusions of this work are: (i) catalyst leaching and deactivation is one of the main problematic issues; (ii) majority of studies were performed in semi-batch and batch reactors, while continuous fixed bed reactors were not extensively studied for treatment of real wastewaters; (iii) toxicity of wastewaters treated by CWPO is of key importance for possible application, however it was not studied thoroughly; and, (iv) CWPO can be regarded as economically viable for wastewater treatment, especially when conducted at ambient temperature and natural pH of wastewater.

scholarly journals The Role of Chaperone-Mediated Autophagy in Hepatitis C Virus-Induced Pathogenesis

2021 ◽  
Vol 11 ◽  
Author(s):  
Chieko Matsui ◽  
Putu Yuliandari ◽  
Lin Deng ◽  
Takayuki Abe ◽  
Ikuo Shoji
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Hepatocyte Nuclear Factor ◽  
Selective Degradation ◽  
Substrate Protein ◽  
Hepatocyte Nuclear Factor 1Α ◽  
Chaperone Mediated Autophagy

Lysosome incorporate and degrade proteins in a process known as autophagy. There are three types of autophagy; macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Although autophagy is considered a nonselective degradation process, CMA is known as a selective degradation pathway. All proteins internalized in the lysosome via CMA contain a pentapeptide KFERQ-motif, also known as a CMA-targeting motif, which is necessary for selectivity. CMA directly delivers a substrate protein into the lysosome lumen using the cytosolic chaperone HSC70 and the lysosomal receptor LAMP-2A for degradation. Hepatitis C virus (HCV) NS5A protein interacts with hepatocyte-nuclear factor 1α (HNF-1α) together with HSC70 and promotes the lysosomal degradation of HNF-1α via CMA, resulting in HCV-induced pathogenesis. HCV NS5A promotes recruitment of HSC70 to the substrate protein HNF-1α. HCV NS5A plays a crucial role in HCV-induced CMA. Further investigations of HCV NS5A-interacting proteins containing CMA-targeting motifs may help to elucidate HCV-induced pathogenesis.

scholarly journals Steroid Degradation in Comamonas testosteroni TA441: Identification of the Entire β-Oxidation Cycle of the Cleaved B Ring

2019 ◽  
Vol 85 (20) ◽  
Author(s):  
Masae Horinouchi ◽  
Hiroyuki Koshino ◽  
Michal Malon ◽  
Hiroshi Hirota ◽  
Toshiaki Hayashi
Keyword(s):  
Gene Clusters ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Comamonas Testosteroni ◽  
Content Type ◽  
Coa Transferase ◽  
Degrading Bacteria ◽  
Globally Distributed

ABSTRACT Comamonas testosteroni TA441 degrades steroids via aromatization of the A ring, followed by degradation of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid, mainly by β-oxidation. In this study, we revealed that 7β,9α-dihydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostanoic acid-coenzyme A (CoA) ester is dehydrogenated by (3S)-3-hydroxylacyl CoA-dehydrogenase, encoded by scdE (ORF27), and then the resultant 9α-hydroxy-7,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid-CoA ester is converted by 3-ketoacyl-CoA transferase, encoded by scdF (ORF23). With these results, the whole cycle of β-oxidation on the side chain at C-8 of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid is clarified; 9-hydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid-CoA ester is dehydrogenated at C-6 by ScdC1C2, followed by hydration by ScdD. 7β,9α-Dihydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostanoic acid-CoA ester then is dehydrogenated by ScdE to be converted to 9α-hydroxy-17-oxo-1,2,3,4,5,6,10,19-octanorandrostan-7-oic acid-CoA ester and acetyl-CoA by ScdF. ScdF is an ortholog of FadA6 in Mycobacterium tuberculosis H37Rv, which was reported as a 3-ketoacyl-CoA transferase involved in C ring cleavage. We also obtained results suggesting that ScdF is also involved in C ring cleavage, but further investigation is required for confirmation. ORF25 and ORF26, located between scdF and scdE, encode enzymes belonging to the amidase superfamily. Disrupting either ORF25 or ORF26 did not affect steroid degradation. Among the bacteria having gene clusters similar to those of tesB to tesR, some have both ORF25- and ORF26-like proteins or only an ORF26-like protein, but others do not have either ORF25- or ORF26-like proteins. ORF25 and ORF26 are not crucial for steroid degradation, yet they might provide clues to elucidate the evolution of bacterial steroid degradation clusters. IMPORTANCE Studies on bacterial steroid degradation were initiated more than 50 years ago primarily to obtain materials for steroid drugs. Steroid-degrading bacteria are globally distributed, and the role of bacterial steroid degradation in the environment as well as in relation to human health is attracting attention. The overall aerobic degradation of the four basic steroidal rings has been proposed; however, there is still much to be revealed to understand the complete degradation pathway. This study aims to uncover the whole steroid degradation process in Comamonas testosteroni TA441 as a model of steroid-degrading bacteria. C. testosteroni is one of the most studied representative steroid-degrading bacteria and is suitable for exploring the degradation pathway, because the involvement of degradation-related genes can be determined by gene disruption. Here, we elucidated the entire β-oxidation cycle of the cleaved B ring. This cycle is essential for the following C and D ring cleavage.

scholarly journals Magnetically recyclable Ag/TiO2 co-decorated magnetic silica composite for photodegradation of dibutyl phthalate with fluorescent lamps

2020 ◽  
Vol 81 (4) ◽  
pp. 790-800
Author(s):  
Zhiqiang Ding ◽  
Yue Liu ◽  
Yong Fu ◽  
Feng Chen ◽  
Zhangpei Chen ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Dibutyl Phthalate ◽  
Degradation Process ◽  
Environmental Safety ◽  
Degradation Efficiency ◽  
Precipitation Method ◽  
Solution Ph ◽  
Fluorescent Lamps ◽  
Butyl Phthalate ◽  
Co Precipitation

Abstract In recent years, industrial contaminants and especially organic pollutions have been threatening both environmental safety and human health. Particularly, dibutyl phthalate (DBP) has been considered as one of the major hazardous contaminants due to its widespread production and ecological toxicities. Consequently, reliable methods toward the efficient and environmentally benign degradation of DBP in wastewater would be very desirable. To this end, a novel magnetically separable porous TiO2/Ag composite photocatalyst with magnetic Fe3O4 particles as the core was developed and successfully introduced to the photocatalytic degradation of DBP under visible irradiation with a fluorescent lamp. The presented work describes the grafting of Ag co-doped TiO2 composite on the silica-modified porous Fe3O4 magnetic particles with a simple and inexpensive chemical co-precipitation method. Through the investigation of the influencing factors including photocatalyst dosage, initial concentration of DBP, solution pH, and H2O2 content, we found that the degradation efficiency could reach 74%. The photodegradation recovery experiment showed that the degradation efficiency of this photocatalyst remained almost the same after five times of reuse. In addition, a plausible degradation process was also proposed involving the attack of active hydroxyl radicals generated from this photocatalysis system and production of the corresponding intermediates of butyl phthalate, diethyl phthalate, dipropyl phthalate, methyl benzoate, and benzoic acid.

Risk Assessment of Cosmetic Preservatives Using QSAR

2020 ◽  
Vol 5 (1) ◽  
pp. 44-62
Author(s):  
Monika Bhardwaj ◽  
Neeraj Masand ◽  
Jagannath Sahoo ◽  
Vaishali M. Patil
Keyword(s):  
Microbial Contamination ◽  
Antimicrobial Agents ◽  
Quantitative Structure Activity Relationship ◽  
Toxicity Assessment ◽  
Cosmetic Products ◽  
Toxicity Prediction ◽  
Safety And Efficacy ◽  
Regulatory Aspects ◽  
Structure Activity ◽  
Consumer Safety

Cosmetic manufacturers need to demonstrate the safety and efficacy of the products against microbial contamination to assure consumer safety and to improve shelf-life. The preservation strategies include chemical, physical, or physiological strategies. The most common is the use of antimicrobial agents. The toxicity assessment of preservatives used in cosmetic products is essential. It can be done by computational methods such as quantitative structure-activity relationship (QSAR) using several software such as ADME-Tox, TOPKAT, Dragon, T.E.S.T., and ECOSAR. The present manuscript elaborates a detailed view on cosmetic preservatives, regulatory aspects and application of computational strategies for toxicity prediction.

scholarly journals Optimization of ibuprofen degradation in water using high frequency ultrasound-assisted biological reactor

2020 ◽  
Vol 81 (10) ◽  
pp. 2250-2259
Author(s):  
Arwa Abdelhay ◽  
Aya Allafi ◽  
Abeer Albsoul
Keyword(s):  
Power Density ◽  
Advanced Oxidation Process ◽  
Oxygen Demand ◽  
Pharmaceutical Product ◽  
Degradation Efficiency ◽  
Operating Parameters ◽  
Sonication Time ◽  
High Frequency Ultrasound ◽  
Working Volume ◽  
Ultrasound Assisted

Abstract Ultrasound (US) is being considered as a promising emerging advanced oxidation process to degrade persistent organic-pollutants. This paper investigated the effect of several operating parameters on the degradation of a recalcitrant pharmaceutical product, namely ibuprofen (IBP), using an ultrasound-assisted biological reactor. The tested operating parameters are the power density (960, 480) W/L, US frequency (1,142, 860, 578) kHz, working volume (500, 250) mL, initial IBP concentration (30, 60) mg/L, and pH (8.2, 4). It was observed that the IBP degradation was directly influenced by the power density, and the highest degradation efficiency (99%) was obtained at 960 w/L. However, the degradation of IBP at sonication time of 120 min was found to increase from 39% to 96% while decreasing the US frequency from 1,142 to 578 kHz. The working volume had no clear effect on the IBP degradation. The optimal pH was found to be 4, which resulted in 99.5% IBP degradation efficiency after 120 min of sonication time. The degradation of IBP followed the first order kinetics. Finally, the sonically-treated water was fed to a subsequent aerobic biological reactor. The results revealed that the remaining chemical oxygen demand (COD) after sonication was lowered in the biological reactor by a percentage of 47%.

scholarly journals Degradation of the antibiotic ornidazole in aqueous solution by using nanoscale zero-valent iron particles: kinetics, mechanism, and degradation pathway

RSC Advances ◽  
2018 ◽  
Vol 8 (61) ◽  
pp. 35062-35072 ◽  
Author(s):  
Yanchang Zhang ◽  
Lin Zhao ◽  
Yongkui Yang ◽  
Peizhe Sun
Keyword(s):  
Aqueous Solution ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Zero Valent Iron ◽  
Main Mechanism ◽  
Iron Particles ◽  
Nanoscale Zero Valent Iron ◽  
Nitro Reduction

The whole possible process of ONZ removal by nZVI. The reduction on the surface of nZVI was the main mechanism. A potential pathway including dechlorination, nitro reduction, N-denitration, and cleavage was proposed for the degradation process.

Sign in / Sign up

Export Citation Format

Share Document