ABSTRACT
A novel and efficient photo-Fenton catalyst of Fe(III)-5-sulfosalicylic acid (ssal) supported on Al(2)O(3) was prepared and characterized by FT-IR and TEM-EDX technique. A detailed investigation of photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol (DNBP) using this catalyst and H(2)O(2) under solar light irradiation was carried out. The effects of reaction parameters on photodegradation performance were investigated by examining H(2)O(2) dosage, catalyst loading, solution pH, initial DNBP concentration and temperature. The optimal conditions were an initial DNBP concentration of 40 mg L(-1) at pH 2.5 and temperature 30 degrees C with catalyst loading of 1.0 g L(-1) and H(2)O(2) concentration of 5 mmol L(-1) under solar light irradiation for 100 min. Almost complete degradation of DNBP was observed with [Fe(III)-ssal]-Al(2)O(3)/H(2)O(2) process under the optimal conditions. The degradation of DNBP by photo-Fenton-type process can be divided into the initiation phase and the fast phase. The kinetics of Fenton oxidation is complex and the degradation of DNBP in the two phases both can be described by a pseudo-first-order kinetic model. No obvious decline in efficiency of the [Fe(III)-ssal]-Al(2)O(3) catalyst was observed after 5 repeated cycles indicating this catalyst is stable and reusable. A possible reaction mechanism was proposed on the basis of all the information obtained under various experimental conditions.
Subject(s)
2,4-Dinitrophenol/analogs & derivatives , Pesticides/chemistry , Photolysis , Salicylates/chemistry , 2,4-Dinitrophenol/chemistry , 2,4-Dinitrophenol/radiation effects , Aluminum Oxide , Benzenesulfonates , Catalysis , Ferric Compounds , Hydrogen Peroxide/chemistry , Iron , Kinetics , Oxidation-Reduction , Pesticides/radiation effects , SunlightABSTRACT
In the present article, the high signal-to-noise ratio surface enhanced Raman spectrum of rat serum was analyzed. To be high efficient substrate of SERS, the novel silver colloid was synthesized by microwave method. The characteristic peaks of the rat Raman spectrum were assigned. The mechanism of "hot spot" which was formed by aggregated silver particles was explained by electromagnetic fields enhancements theory, i. e. the excitation of plasmons in the metallic nanoparticles created greatly enhanced local electromagnetic fields, contributing to the major component of the SERS effect. The field distribution at novel silver aggregates exhibits a dramatic enhancement. These strongly localized fields provide an important mechanism for surface enhanced Raman scattering. The surface enhanced Raman spectrum of low quality of component in rat serum was acquired so that the change of body could be known in time. A new method for acquiring abundant information of macro-biomolecule by spectrum means was brought out. It is hopeful to be a novel technique to diagnose diseases in the early stage with serum.
Subject(s)
Serum/chemistry , Silver/chemistry , Spectrum Analysis, Raman/methods , Animals , Colloids/chemistry , Microscopy, Electron, Transmission , RatsABSTRACT
Three-dimensional time-dependent quantum wave packet calculation for the O((1)D)+HBr reaction has been carried out using an accurate ab initio global potential energy surface [K. A. Peterson, J. Chem. Phys. 113, 4598 (2000)]. The calculations show that the initial state-selected reaction probabilities are dominated by resonance structures, and the lifetime of the resonance is generally in the subpicosecond time scale. The energy dependence of the reaction cross section is computed, which manifests still resonance structures, and is a decreasing function of the translational energy. The thermal rate constants are also computed, which are nearly independent on the temperature. The calculation results are discussed and compared to similar reaction with deep well.
