| 1. |
- Ji, Yuanhui, et al.
(författare)
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Thermodynamic analysis on the mineralization of trace organic contaminants with oxidants in advanced oxidation processes
- 2009
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 48:23, s. 10728-10733
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing demand for the efficient treatment of organic polluted wastewaters by advanced oxidation processes (AOPs) which calls for the determination of the mineralization order of ease for the organic contaminants with oxidants. The mineralization abilities of organic contaminants in AOPs are investigated in this work. Photocatalytic experiments for three representative organic contaminants are carried out, and their corresponding reaction rates are determined experimentally. Meanwhile, molar Gibbs free energy changes Delta(r)G(m)degrees for the reactions of 31 organic contaminants (10 chlorinated hydrocarbons, four brominated hydrocarbons, I I aromatic hydrocarbons and their derivatives, three chloroacetic acid, and three chloroacetyl chloride) with oxidants of (OH)-O-center dot, H2O2, O-center dot(-), O-3, and O-2 are calculated, and the mineralization order of ease is determined theoretically on the basis of Delta(r)G(m)degrees. The agreement of the theoretical and experimental mineralization abilities for most of the organic contaminants investigated implies the reliability of the determination of the mineralization ability from the magnitude of Delta(r)G(m)degrees for the mineralization of trace organic contaminants. Results also show that for most of the organic contaminants studied, the mineralization abilities are (OH)-O-center dot > H2O2 > O-center dot(-) > O-3 > O-2, and the mineralization ability of the organic contaminants depends on not only the oxidants but also the structure and properties of the organic contaminants themselves, and the degradation reaction products.
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| 2. |
- Ji, Yuanhui, et al.
(författare)
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Thermodynamic study on the reactivity of trace organic contaminant with the hydroxyl radicals in waters by advanced oxidation processes
- 2009
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Ingår i: Fluid Phase Equilibria. - : Elsevier BV. - 0378-3812 .- 1879-0224. ; 277:1, s. 15-19
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Tidskriftsartikel (refereegranskat)abstract
- This paper is to investigate the degradation abilities of various chlorinated aliphatics, benzene and its derivatives in order to treat organic polluted wastewaters efficiently by advanced oxidation processes (AOPs). A thermodynamic method is proposed to calculate the standard molar Gibbs energy of formation for aqueous organic species. Using the method proposed, the standard molar Gibbs energies of formation for 31 aqueous organic species are obtained. Moreover, the molar Gibbs energy change of reaction Δr Gm0 for the organic species with hydroxyl radicals is calculated from the standard molar Gibbs energy of formation for aqueous organic species to determine the degradation order of ease for the organic species. New photocatalytic experiments are carried out for the model verification. The calculation results of the model agree with the available and new experimental results. This work shows that the thermodynamics of the degradation reaction for the organic pollutants in AOPs can find the corresponding relationships with the degradation reaction rate by experimental measurements. The work in this paper represents a success of thermodynamics for the application in environmental area.
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| 3. |
- Mason, R Preston, et al.
(författare)
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Loss of arterial and renal nitric oxide bioavailability in hypertensive rats with diabetes : effect of beta-blockers
- 2009
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Ingår i: American Journal of Hypertension. - : Oxford University Press (OUP). - 0895-7061 .- 1941-7225. ; 22:11, s. 1160-1166
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Endothelial cell (EC) dysfunction contributes to hypertension and mechanisms of atherosclerosis. Agents that improve EC function may provide vascular protection, especially in patients with multiple risk factors. In this study, we examined the effects of beta(1)-selective antagonists, nebivolol and metoprolol, on vascular and renal EC function in spontaneously hypertensive (SH) rats with diabetes. METHODS: Male SH rats were treated with streptozotocin (STZ) to induce type 2 diabetes, followed by treatment with nebivolol or metoprolol at 2 mg/kg/day (vs. vehicle). After 4 weeks, aortic and glomerular ECs were isolated, stimulated with calcium ionophore (CaI), and assayed for nitric oxide (NO), and peroxynitrite (ONOO(-)) release using amperometric approaches. RESULTS: Glucose and mean blood pressure (BP) levels were significantly elevated in diabetic SH rats. In aortic ECs isolated from diabetic SH rats, NO production decreased by 20% whereas ONOO(-) increased by 16%, an effect linked to NAD(P)H oxidase and endothelial NO synthase (eNOS) uncoupling. Nebivolol treatment reduced glucose and BP levels and restored aortic EC function in diabetic SH rats, as indicated by a 30% increase and 23% decrease in NO and ONOO(-) levels, respectively. The NO/ONOO(-) ratio increased by more than twofold with nebivolol treatment in aortic and glomerular ECs. Despite similar reductions in glucose and mean BP levels, metoprolol had a smaller effect on the NO/ONOO(-) ratio in glomerular ECs but no effect in aortic ECs. CONCLUSIONS: Vascular and renal NO was significantly reduced in diabetic hypertensive rats and correlated with metabolic changes. Nebivolol reversed these effects in a manner consistent with enhanced endothelial function.
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