Enhanced simultaneous absorption of NOx and SO2 in oxidation-reduction-absorption process with a compounded system based on Na2SO3.

Oxidation of sulfite and competitive absorption existed in Na2SO3 solution for simultaneous removal of NOx and SO2, inhibited the long-term high-efficiency when used for practical applications. A matching strategy was developed to solve these problems. Antioxidants combination was used to retard the oxidation of antioxidant and enhance inhibition of S(IV) (tetravalent sulfur) oxidation. Hydroquinone (HQ) and sodium thiosulfate (ST) showed a positive synergistic effect on inhibition of S(IV) oxidation. When SO2 concentration was 500 and 2000 ppmV, the addition of 0.1 wt.% HQ and 1 wt.% ST decreased the percentage of S(IV) oxidized by oxygen by over 30% and 40%, respectively. Alkali (Na2CO3) alleviated the competitive absorption between NOx and SO2. Moreover, Na2CO3 exhibited an enhancement effect on the absorption of NOx and SO2 when coupled with anti-oxidants. While the increase of oxygen pressure accelerated the oxidation of S(IV), the anti-oxidants can retard the oxidation. The measurement of pH suggested the removal efficiency of NOx highly depended on SO32⁻ concentration rather than pH. The further investigation of the mechanism suggested the match effect was related to the interaction between ST and the intermediate product of HQ. The match strategy holds a potential for application of SO32⁻ to denitration.

Evaluating the oxidation inhibition of sulfide in urban sewers using a novel quantitative method.

Sulfide inhibition is a critical task for the secure operation of sewer systems, and oxidation is usually utilised to achieve this purpose. However, the effects and mechanism of oxidation during the transformation of sulfur-associated pollutants in gas-liquid-solid phases of sewers have not been extensively evaluated. In this study, a method for quantifying sulfur-associated pollutant exchange pathways in gas-liquid-solid phases of sewers was established. The results showed that although the concentration of sulfide decreased under different oxidation conditions, the consumption of sulfate in sewers clearly increased. The transformation strength of elemental sulfur was high (18.65 mg/L, 35.52% of sulfate from the influent) and the accumulation of sulfate in sediment was obvious (3.49 mg/L, 6.65% of sulfate from the influent). Higher concentrations of sulfate in the influent promoted the generation of sulfide in sediment (8.98 mg/L, 17.10%). Thus, the oxidation process led to the generation of more absolute sulfide. In addition, promoting the metabolism of sulfate-reducing bacteria enhanced the loss of organic carbon in sewers, which might weaken the efficacy of nitrogen and phosphorus removal in wastewater treatment plants. Based on the evaluation of the exchange pathways of sulfur-associated pollutants in sewers, further studies into sulfide inhibition in sewers should consider the above issues to enhance the safe management of urban sewers.

Buffer effect of MgO on Na2SO3 to stabilize S(IV) for the enhancement in simultaneous absorption of NOx and SO2 from non-ferrous smelting gas.

Oxidation-reduction-absorption based on sulfite is a promising process for simultaneous removal of NOx and SO2. However, excessive oxidation of sulfite and competitive absorption between NOx and SO2 limit its application. A matching strategy between antioxidants and alkaline agents has been proposed to solve these problems and enhance the absorption process. The comparison results of inhibitors showed that hydroquinone exhibited long-term high-efficiency inhibition of S(IV) (SO32-/HSO3-) oxidation. The comparison of alkaline agents showed that the Na2SO3 solution with heterogeneous mixture of MgO and hydroquinone exhibited better absorption performance than that with other combinations. The absorption amounts of NOx in 0.15 mol/L Na2SO3 50 mL solution added 0.1% hydroquinone (HQ) with 0.09 mol/L MgO were 2.24 mmol, which improved 5 times than that without additives. In addition, studies on the influence of pH showed that the pH of MgO mixture could be stabilized at 9-10 for a long time, while the pH of Na2CO3 mixture decreased faster. Further studies suggested that the hydration of MgO resulted in the solution with MgO keeping high pH. This is also the main reason why the combination of MgO and hydroquinone is superior to the combination of Na2CO3 and hydroquinone in desulfurization and denitration performance.

Remarkable promotion in particle dispersion and electron transfer capacity of sulfidated nano zerovalent iron by coating alginate polymer.

Alginate has been widely employed to increase the performance of nanoscale zerovalent iron (nZVI)-based materials for site remediation. Yet, the effects of alginate on reactivity of sulfidated nZVI (an efficient reductant material) towards contaminants have been understood poorly. In this study, we have developed a one-step synthesis of alginate-coated sulfidated nZVI (S-nZVI@alginate) under air atmosphere and evaluated the reactivity of S-nZVI@alginate towards tetrabromobisphenol A (TBBPA) debromination. Surface analysis shows that S-nZVI has been successfully coated by alginate through the interaction of OH and COO- groups of alginate with Fe species. The coating of alginate increases particle stability and dispersion under various conditions and facilitates FeS precipitation on the particle surface. Reactivity experiments show that the coating of alginate significantly enhances TBBPA debromination by S-nZVI. The optimized alginate to Fe weight ratio of S-nZVI@alginate is 0.06, with ~3-fold greater TBBPA debromination rate than S-nZVI. S-nZVI@alginate can completely debrominate TBBPA into bisphenol A via a four-sequential step debromination pathway while S-nZVI not. Its superior reactivity may be attributed to that the formation of alginate-Fe complex can lower the redox potential of Fe species to accelerate electron transfer on the particle surface. The TBBPA debromination rate by S-nZVI@alginate is initially enhanced followed by a decrease with an increase in TBBPA concentration, while it can increase 3.3-, 8.9- and 5.6-fold by increasing S-nZVI@alginate dosage, decreasing pH and adding co-contaminant Cd2+, respectively. S-nZVI@alginate has greater performance in aging and reusability tests than S-nZVI, and achieves rapid TBBPA removal from wastewater, which may be due to the role of alginate on inhibiting surface oxidation of Fe and S species. Taken together, these results suggest that S-nZVI@alginate provides better reactivity, longevity and reusability than S-nZVI, having the great potential for application into site remediation.

Influence of enzyme concentrations in enzymatic bioprocessing of red rice bran: A detailed study on nutraceutical compositions, antioxidant and human LDL oxidation inhibition properties.

Enzymes and their concentrations are crucial factors in improving the release of nutraceuticals bounded to rice bran's cell wall matrix. This study aims to investigate the optimal concentrations of Viscozyme and Fiberzyme at 3-30 beta-glucanase units/2 g in improving the release of phenolics, tocopherols, tocotrienols, and γ-oryzanol fractions and enhancing the bioactivities of red rice bran. At specific concentrations, Fiberzyme increased ferulic (301%) and caffeic acid (691%) in soluble phenolics, p-coumaric acid (98%), and catechin (161%) in bound phenolics as well as γ-oryzanol fractions(32%-134%) and increased ferric reducing power (90%), DPPH (41%), and hydroxyl (25%) radical scavenging activities. Viscozyme enhanced δ,γ,α-tocopherols (11%-164%) and tocotrienols (39%-271%) and scavenging activities against nitric oxide (144%), superoxide anion (120%), and inhibition of human LDL oxidation (40%). Cycloartenyl ferulate, ferulic acid, soluble phenolics, campesteryl ferulate, 24-methylenecycloartanyl ferulate, and α-tocotrienol showed a significant positive correlation with bioactivities. Thus, optimization of enzymatic processing will help process the red rice bran into a nutraceutical rich ingredient having higher biological activity.

Preparation of gelatin films incorporated with tea polyphenol nanoparticles for enhancing controlled-release antioxidant properties.

Gelatin films incorporated with chitosan nanoparticles in various free/encapsulated tea polyphenol (TP) ratios were prepared in order to investigate the influence of different ratios on the physicochemical and antioxidant properties of films. The TP-containing nanoparticles were prepared by cross-linking chitosan hydrochloride (CSH) with sulfobutyl ether-ß-cyclodextrin sodium (SBE-ß-CD) at three different encapsulation efficiencies (EE; ∼50%, ∼80%, and ∼100%) of TP. The stability of TP-loaded nanoparticles was maintained during the film drying process from the analysis of free TP content in the redissolved film solutions. Composite films showed no significant difference in visual aspects, while the light transmittance (250-550 nm) was decreased with incorporation of TP. Nanoparticles appeared to be homogeneously dispersed within the film matrix by microstructure analysis (SEM and AFM). TP-loaded films had ferric reducing and DPPH radical scavenging power that corresponded to the EEs. Sunflower oil packaged in bags made of gelatin films embedded with nanoparticles of 80% EE showed the best oxidation inhibitory effect, followed by 100% EE, 50% EE, and free TP, over 6 weeks of storage. However, when the gelatin film was placed over the headspace and was not in contact with the oil, the free TP showed the best effect. The results indicate that sustained release of TP in the contacting surface can ensure the protective effects, which vary with free/encapsulated mass ratios, thus improving antioxidant activities instead of increasing the dosage.

Herbal extracts differentially inhibit oxidative effects caused by the biotransformation of nifurtimox, nitrofurantoin and acetaminophen on rat liver microsomes / Extractos herbales inhiben diferencialmente los efectos oxidativos causados por la biotransformación de nifurtimox, nitrofurantoína y acetaminofeno en microsomas hepáticos de rata]

Inflammation is a cellular defensive mechanism associated to oxidative stress. The administration of nitrofurantoin, nifurtimox and acetaminophen generates oxidative stress by their biotransformation through CYP450 system. The main adverse effect described for the first two drugs is gastrointestinal inflammation and that of the last, hepatitis. Therefore, standardised dry extracts from Rosmarinus officinalis, Buddleja globosa Hope, Cynara scolymus L., Echinacea purpurea and Hedera helix were tested to evaluate their capacity to decrease drug-induced oxidative stress. For that, rat liver microsomes were incubated with drugs in the presence of NADPH (specific CYP450 system cofactor) to test oxidative damage on microsomal lipids, thiols, and GST activity. All drugs tested induced oxidation of microsomal lipids and thiols, and inhibition of GST activity. Herbal extracts prevented these phenomena in different extension. These results show that antioxidant phytodrugs previously evaluated could alleviate drugs adverse effects associated to oxidative stress.

Inflamación es un mecanismo de defensa el cual está asociado a estrés oxidativo. La administración de nitrofurantoína, nifurtimox y paracetamol genera estrés oxidativo al metabolizarse a través del sistema CYP450. El principal efecto adverso de los dos primeros fármacos es inflamación gastrointestinal y del tercero, hepatitis. Por lo tanto, utilizamos diversos extractos herbales para disminuir el estrés oxidativo inducido por estos fármacos. Para esto se incubaron microsomas hepáticos de rata con dichos fármacos en presencia de NADPH (cofactor específico del sistema CYP450) y se evaluó el daño oxidativo generado sobre los lípidos, los tioles y la actividad GST microsómica. Todos los fármacos indujeron oxidación de los lípidos y los tioles microsómicos e inhibieron la actividad GST. Los extractos herbales previnieron estos fenómenos oxidativos en diferente extensión. Estos resultados indican que fitofármacos antioxidantes previamente evaluados, podrían aliviar los efectos adversos asociados a estrés oxidativo de los fármacos.

Antioxidant properties of the carotenoid extracts of three Deinococcus­Thermus phylum bacteria, Meiothermus sp. strains RP and TP and Thermus sp. strain YY from Paniphala hot spring, India

BACKGROUND:The purpose of the study was to extract carotenoids from thermophilic bacteria which show efficient antioxidant and protein oxidation inhibition properties, characterize and identify those isolates, extract the carotenoids in different solvents, quantify the carotenoids and perform concentration-dependent and solvent-dependent quantitative assays validated and analysed by appropriate statistical tests. METHODS: Three pigment-forming thermophilic strains were isolated from water sample of Paniphala hot spring, India, and tentatively identified by 16S ribosomal DNA (rDNA) homology. Different concentrations of the carotenoid extracts (100, 80, 40 and 20µg) in three solvents, methanol, DMSO and water, were used to determine the antioxidant activity through five methods: the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, the ABTS (2,2-azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid)) assay, the hydrogen peroxide assay, TOC (total antioxidant capacity) assay and inhibition of protein oxidation assay. Statistical analysis of mean, standard deviation, ANOVA and Pearson correlationcoefficient was performed in Microsoft Excel statistical package.Results:The isolates were tentatively identified as Meiothermussp. strain RP, Meiothermussp. strain TP and Thermusstrain YY.Meiothermussp. formed red coloured pigment, where as Thermussp. formed yellow coloured pigment. Allof the extracts showed positive results in DPPH assay, ABTS assay and hydrogen peroxide radical scavenging assaywith best results obtained when the extracts were dissolved in water. Total antioxidant capacity assay was also highin all the extracts. Protein oxidation inhibition activity was only seen in extracts of strain YY. One-way ANOVA(analysis of variance) clearly showed that choice of solvent influenced the antioxidant capacity of all of the extracts. CONCLUSIONS: Newer and efficient antioxidative compounds are constantly being searched for, and the carotenoid extracts of RP, TP and YY have been shown to catalyze various types of antioxidative reactions, including proteinoxidation inhibition by YY. Thus, all these extracts have huge potential to be industrially and pharmaceutically useful.