Influence of the buffer gas on the multiphoton absorption and dissociation in different mixtures was investigated. Simple method based on the empirical and theoretical vibrational energy distribution is applied for high fluence regime. Collisional effects of buffer gas (Ar) are introduced to enhance the absorption and relaxation of irradiated molecules (SF_6 and C_2H_4). Functional dependences of mean number of absorbed photons per molecule (ீ nு_{total}) on the molecular excitation level are presented, enabling us to confirm or predict the level of excitation, number of molecules directly involved in the absorption process and dissociated during the laser pulse.
Generalized coupled two-level model is applied in different gas mixtures and investigated for high fluence regime. Functional dependences of mean number of absorbed photons per molecule 〈 nு_{total} on buffer-gas pressure (p_{buff}) are presented, used to confirm or predict some possible physical and chemical processes, like enhanced absorption and/or dissociation. Limitations of proposed models are analyzed depending on both gas pressure and laser fluence. Results are compared with other previously obtained by the same experimental technique, but for different absorbing molecule.
The scope of this study was the removal of heavy metal ions, ammonium and organic substances by ion exchange from municipal wastewaters. Clinoptilolite, bentonite, and palygorskite are especially interesting in the group of inorganic sorbents because of their specific physico-chemical properties. Specific surface areas and pore distributions were determined for the above sorbents. Sorption kinetics of Zn(II), Cu(II), Ni(II), Pb(II) and ammonium ions in synthetic solutions and wastewaters were investigated on the above sorbents. Ion sorption process was carried out with a static method at various phase contact times. The atomic adsorption spectroscopy method was used for measurements of heavy metal contents. The adsorption process was found to be pH and concentration dependent. The removal mechanism of metal ions was by adsorption and ion exchange processes. The FT-IR photoacoustic spectroscopy method was used to study mechanism of Zn(II), Cu(II), Ni(II), Pb(II) and ammonium ions sorption on the clinoptilolite, bentonite and palygorskite. The spectra of FT-IR/PAS before and after sorption of Zn(II), Cu(II), Ni(II), Pb(II) and ammonium ions were investigated.
Clays and zeolites are some of the most important industrial minerals. They have practical applications in geology, agriculture, construction, engineering, process industries, and environment. This article is about one of them: radioactive waste disposal. We are investigating characteristics of bentonite clay and clinoptilolite in case of Cs(I), Th(IV), U(VI) sorption.
The possibility of removal of copper(II) complexes with ethylenediaminetetraacetic acid (EDTA) from waters and wastewaters by the chelating ion exchangers Lewatit TP 214, Lewatit TP 260 and Diaion CR-20 as well as the mechanism of their sorption onto them were investigated. In order to describe the sorption process of Cu(II) ions in the presence of EDTA, the FT-IR/PA spectra of the abovementioned chelating ion exchangers were recorded.
Chromium is a major pollutant for the environment, usually as a result of some industrial pollution. Chromium is used in various industries such as metallurgical (steel, ferrous and nonferrous alloys), refractories (chrome and chrome-magnesite), and chemical (pigments, electroplating, tanning). For this reason, significant amounts of chromium pass into the environment and cause adverse ecological effects. In the present paper the investigations of solvent impregnated resin preparation was conducted. Photoacoustic and diffuse reflectance spectra were recorded for the prepared solvent impregnated resin. Photoacoustic spectra in the infrared area allow distinguishing the differences between the sorbent applied before and after the impregnation process. Impregnation of resin is a result of physical sorption of Aliquat 336 on macroporous Amberlite XAD 16.
The paper makes an attempt to create a polymer sorbent competitive for the commercial Lewatit OC-1026. Therefore the commercial Amberlite XAD-7 was impregnated with the D2EHPA acid. After preparation of both exchangers, their sorption properties towards In(III) and Ga(III) ions were studied [1]. It proved that for pH = 2.17 Amberlite XAD-7 impregnated with D2EHPA acid is characterized by larger sorption capacities than those of commercial Lewatit OC-1026 towards both Ga(III) and In(III) ions. Lewatit OC-1026 as well as the prepared impregnant (XAD-7 + D2EHPA) were examined by means of Raman spectroscopic, FT-IR photoacoustic spectroscopy and FT-IR methods.
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