scholarly journals Efficient and economical degradation of minocycline by natural bornite-activated hydrogen peroxide and persulfate: kinetics and mechanisms

2021 ◽  
Author(s):  
Taikang Yuan ◽  
Xu-dong Wang ◽  
Xiaochen Zhao ◽  
Tingting Liu ◽  
Hongmin Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Free Radical ◽  
Raw Materials ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Degradation Mechanism ◽  
Cost Effective ◽  
Degradation Pathway ◽  
Sulfide Mineral ◽  
Resonance Spectroscopy ◽  
Copper Extraction

Abstract Natural bornite (NBo), a sulfide mineral of copper and iron, is one of the main mineral raw materials for copper extraction. In this study, NBo-activated hydrogen peroxide (H2O2) and persulfate processes (PS) for the degradation of minocycline (MNC) in aqueous solution were systemically investigated and compared. The MNC removal rates with the NBo/PS and NBo/H2O2 processes were 86.40% and 87.50%, respectively. The mineralization rate of NBo/PS (33.96%) was higher than that of NBo/H2O2 (29.94%) after reaction for 180 min. The effects of oxidant and activator dosage, pH, common inorganic anions (i.e., Cl−, NO3−, and HCO3−), and water composition on MNC degradation were systematically evaluated. In addition, the degradation of MNC in natural water matrix and toxicity evaluation were also studied to better evaluate the feasibility of practical application of those two processes. The results of free radical quenching experiments and electron paramagnetic resonance spectroscopy (EPR) showed that HO· was the main activated species in the NBo/H2O2 system, while SO4·− and HO· were the main activated species in the NBo/PS system. The degradation of MNC in the NBo/PS system was achieved through electron transfer, while the degradation of MNC in the NBo/H2O2 system was mainly achieved through free radical addition. The degradation pathway mainly included deamidation reactions, C-C bond breakage and hydroxylation. Reusability of NBo showed that NBo was considerably stable in activating PS and H2O2 for degradation of MNC, which was cost-effective activator. This work provides a new perspective on the degradation mechanism of pollutants by Fe-Cu bimetallic sulfide activation of PS and H2O2.

Antioxidant Activity of Selected Thyme (Thymus L.) Species and Study of the Equivalence of Different Measuring Methodologies

2015 ◽  
Vol 98 (4) ◽  
pp. 876-882 ◽  
Author(s):  
Marta Orłowska ◽  
Teresa Kowalska ◽  
Mieczysław Sajewicz ◽  
Katarzyna Pytlakowska ◽  
Mariola Bartoszek ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Free Radical ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Radical Scavenging ◽  
Cost Effective ◽  
Resonance Spectroscopy ◽  
Dpph Radical ◽  
Dot Blot ◽  
Phenolic Fraction ◽  
Measuring Techniques

Abstract This study presents the results of comparative evaluation of the antioxidant activity of the phenolic fraction exhaustively extracted with aqueous methanol from 18 different thyme (Thymus L.) specimens and species. This evaluation is made with use of the same free radical source (DPPH• radical), three different free radical scavenging models (gallic acid, ascorbic acid, and Trolox), and three different measuring techniques (the dot blot test, UV-Vis spectrophotometry, and electron paramagnetic resonance spectroscopy, EPR). A comparison of the equivalence of these three different measuring techniques (performed with use of hierarchical clustering with Euclidean distance as a similarity measure and Ward's linkage) is particularly important in view of the fact that different laboratories use different antioxidant activity measuring techniques, which makes any interlaboratory comparison hardly possible. The results obtained confirm a semiquantitative equivalence among the three compared methodologies, and a proposal is made of a simple and cost-effective dot blot test that uses the DPPH• radical and provides differentiation of antioxidant activity of herbal matter comparable with the results of the UV-Vis spectrophotometry and EPR.

Synthesis, Characterization and Application of Multi-Generations Hyperbranched Polyurethane Based on Isophorone Diisocyanate

2012 ◽  
Vol 554-556 ◽  
pp. 126-129 ◽  
Author(s):  
Shun Yin ◽  
Ning Sun ◽  
Chun Yun Feng ◽  
Zhi Mou Wu ◽  
Zhao Hua Xu ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raw Materials ◽  
Degradation Mechanism ◽  
Resonance Spectroscopy ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Isophorone Diisocyanate ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Hyperbranched Polyurethane

A series of different generation hyperbranched polyurethane(HBPU) was synthesized based on the raw materials of isophorone diisocyanate(IPDI) and diethanolamine(DEOA). Their structure, thermal degradation mechanism and glass transition temperature(Tg) were characterized by fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance spectroscopy(NMR), thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC). The results showed that: the yield of each generation HBPU was up to 90%, different generation HBPU had almost the same initial degradation temperature(about at 200°C) and they all had two decomposition platforms; with the increase of generation, Tg increased from 107.2°C to 132.1°C. The gloss and hardness of the HBPU coatings were significantly improved.

The Process of Phenol Hydroxylation in the Water Solution and over the Ti-MWW Catalyst

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Agnieszka Wróblewska
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Raw Materials ◽  
Water Solution ◽  
Uniform Design ◽  
Mathematical Optimization ◽  
Cost Effective ◽  
Molar Ratio ◽  
Phenol Hydroxylation ◽  
Technological Parameters

Abstract This work presents the studies on the optimization of the process of phenol hydroxylation over the Ti-MWW catalyst. The medium of the reaction was only water introduced into the rector with the 30 wt% hydrogen peroxide (oxidizing agent) and formed during the reaction from the hydrogen peroxide. For the mathematical optimization the rotatable-uniform design was used. The main investigated technological parameters were: the temperature, the molar ratio of phenol/hydrogen peroxide, the catalyst content and the reaction time. The course of the main functions describing the process were presented in the form of layer drawings. The analysis of the layer drawings allowed to establish the most beneficial parameters for this process. Studies have shown that in water solution it is best to conduct phenol hydroxylation process at: the temperature of 93-100oC, phenol/hydrogen peroxide molar ratio 0.9-1, catalyst concentration 3-3.5 wt% and during the reaction time of 55-60 minutes. Under these conditions, it is possible to achieve phenol conversion of 85 mol%, selectivity of transformation to organic compounds in relation to phenol consumed 50 mol% and the yield of hydroquinone about 19 mol%. The phenol hydroxylation method, presented in this article, is a preferred alternative to conventional solutions, as it is more environmentally and cost-effective, taking into account consumption of raw materials and energy.

scholarly journals Green Waste-Derived Substances Immobilized on SBA-15 Silica: Surface Properties, Adsorbing and Photosensitizing Activities towards Organic and Inorganic Substrates

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 162 ◽  
Author(s):  
Maria Tummino ◽  
Maria Testa ◽  
Mery Malandrino ◽  
Roberta Gamberini ◽  
Alessandra Bianco Prevot ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance Spectroscopy ◽  
Pure Water ◽  
Inorganic Ions ◽  
Nitrogen Adsorption ◽  
Cost Effective ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Simulated Solar Light ◽  
Good Potential ◽  
Electron Paramagnetic

Urban wastes are a potential source of environment contamination, especially when they are not properly disposed. Nowadays, researchers are finding innovative solutions for recycling and reusing wastes in order to favour a sustainable development from the viewpoint of circular economy. In this context, the lignin-like fraction of biomass derived from Green Compost is a cost-effective source of soluble Bio-Based Substances (BBS-GC), namely complex macromolecules/supramolecular aggregates characterized by adsorbing and photosensitizing properties. In this work BBS-GC were immobilized on a silica support (SBA-15) and the chemico-physical properties of the resulting hybrid material (BBS-SBA) were analysed by zeta-potential measurements, nitrogen adsorption at 77K and micro-calorimetric techniques. Successively, the BBS-SBA photosensitizing and adsorption abilities were tested. Adsorption in the dark of Rhodamine B and Orange II on BBS-SBA and their degradation upon irradiation under simulated solar light were shown, together with the formation of hydroxyl radicals detected by Electron Paramagnetic Resonance spectroscopy. Furthermore, the adsorption of six inorganic ions (Al, Ni, Mn, As, Hg, Cr) on BBS-SBA was studied in pure water at two different pH values and in a landfill leachate, showing the good potential of this kind of materials in the removal of wastewater contaminants.

Evaluation of oxidative stability of vegetable oils enriched with herb extracts by EPR spectroscopy

2015 ◽  
Vol 69 (7) ◽  
Author(s):  
Mariola Kozłowska ◽  
Katarzyna Zawada
Keyword(s):  
Free Radical ◽  
Lipid Oxidation ◽  
Vegetable Oils ◽  
Epr Spectroscopy ◽  
Unsaturated Fatty Acids ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Radical Scavenging ◽  
Spin Trapping ◽  
Resonance Spectroscopy ◽  
Herb Extracts

AbstractVegetable oils are important constituents of a healthy diet. Still, unsaturated fatty acids present in vegetable oils are susceptible to oxidation, which leads to undesirable changes in sensory, chemical and nutritional properties of oils. To prevent this problem, antioxidants are applied with herbs and spices being one of the most important sources of natural antioxidants. Electron paramagnetic resonance spectroscopy (EPR) can be used to detect free radicals, which are the short-lived intermediates of lipid oxidation, and to monitor changes in oxidation susceptibility. In this study, the ESR spin trapping technique was used as a potential method for the evaluation of the resistance to free radical formation in rapeseed and sunflower oils enriched with herb extracts. The antioxidant effect of herb extracts on vegetable oils was also investigated by measuring their ability to scavenge DPPH free radical using EPR spectroscopy. The herb extracts generally improved the radical scavenging properties of sunflower and rapeseed oils but their influence on the onset of rapid lipid oxidation as measured by spin-trapping EPR depended on the type of oil and on the extract concentration.

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