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Libor Pátý 《Die Naturwissenschaften》1959,46(13):422-423
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Minoo Tasbihi Kamila Kočí Ivana Troppová Miroslava Edelmannová Martin Reli Libor Čapek Reinhard Schomäcker 《Environmental science and pollution research international》2018,25(35):34903-34911
The photocatalytic reduction of CO2 with H2O was investigated using Cu/TiO2 photocatalysts in aqueous solution. For this purpose, Cu/TiO2 photocatalysts (with 0.2, 0.9, 2, 4, and 6 wt.% of Cu) have been synthesized via sol-gel method. The photocatalysts were extensively characterized by means of inductively coupled plasma optical emission spectrometry (ICP-OES), N2 physisorption (BET), XRD, UV-vis DRS, FT-IR, Raman spectroscopy, TEM-EDX, and photoelectrochemical measurements. The as-prepared photocatalysts contain anatase as a major crystalline phase with a crystallite size around 13 nm. By increasing the amount of Cu, specific surface area and band gap energy decreased in addition to the formation of large agglomeration of CuO. Results revealed that the photocatalytic reduction of CO2 decreased in the presence of Cu/TiO2 in comparison to pure TiO2, which might be associated to the formation of CuO phase acting as a recombination center of generated electron-hole pair. Decreasing of photoactivity can also be connected with a very low position of conduction band of photocatalysts with high Cu content, which makes H2 production necessary for CO2 reduction more difficult. 相似文献
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Microbial degradation of two diastereoisomeric forms 2 and 3 of a selected juvenoid (insect juvenile hormone bioanalog), ethyl N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate was studied and the degradation products analyzed. Degradation experiments were performed using simple modeling under laboratory conditions. A Candida sp. strain T1, isolated from soil, was chosen as a biodegradation species. Radiolabeling of the studied compounds 2 and 3 was used in combination with radio-HPLC and MS analysis to increase the limits of detection, monitoring and isolation of trace quantities of the products of degradation and/or transformation. Resulting from the microbial processes using 2 or 3 as source compounds, three identical products (4-6) of their biodegradation were produced. Compound 2 also afforded two additional products (7, 8). Radio-HPLC analysis and separation, and subsequent MS analysis of the degradation mixtures resulted in identification of the degradation products. The degree and the rate of biodegradation of 2 and 3 were analyzed after 1, 3 and 7 days from the beginning of the experiment. 相似文献
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Limitations for heavy metal release during thermo-chemical treatment of sewage sludge ash 总被引:1,自引:0,他引:1
Nowak B Perutka L Aschenbrenner P Kraus P Rechberger H Winter F 《Waste management (New York, N.Y.)》2011,31(6):1285-1291
Phosphate recycling from sewage sludge can be achieved by heavy metal removal from sewage sludge ash (SSA) producing a fertilizer product: mixing SSA with chloride and treating this mixture (eventually after granulation) in a rotary kiln at 1000 ± 100 °C leads to the formation of volatile heavy metal compounds that evaporate and to P-phases with high bio-availability. Due to economical and ecological reasons, it is necessary to reduce the energy consumption of this technology. Generally, fluidized bed reactors are characterized by high heat and mass transfer and thus promise the saving of energy. Therefore, a rotary reactor and a fluidized bed reactor (both laboratory-scale and operated in batch mode) are used for the treatment of granulates containing SSA and CaCl2. Treatment temperature, residence time and - in case of the fluidized bed reactor - superficial velocity are varied between 800 and 900 °C, 10 and 30 min and 3.4 and 4.6 m s−1. Cd and Pb can be removed well (>95 %) in all experiments. Cu removal ranges from 25% to 84%, for Zn 75-90% are realized. The amount of heavy metals removed increases with increasing temperature and residence time which is most pronounced for Cu.In the pellet, three major reactions occur: formation of HCl and Cl2 from CaCl2; diffusion and reaction of these gases with heavy metal compounds; side reactions from heavy metal compounds with matrix material. Although, heat and mass transfer are higher in the fluidized bed reactor, Pb and Zn removal is slightly better in the rotary reactor. This is due the accelerated migration of formed HCl and Cl2 out of the pellets into the reactor atmosphere. Cu is apparently limited by the diffusion of its chloride thus the removal is higher in the fluidized bed unit. 相似文献
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Chrastný V Vaněk A Teper L Cabala J Procházka J Pechar L Drahota P Penížek V Komárek M Novák M 《Environmental monitoring and assessment》2012,184(4):2517-2536
The soils adjacent to an area of historical mining, ore processing and smelting activities reflects the historical background
and a mixing of recent contamination sources. The main anthropogenic sources of metals can be connected with historical and
recent mine wastes, direct atmospheric deposition from mining and smelting processes and dust particles originating from open
tailings ponds. Contaminated agriculture and forest soil samples with mining and smelting related pollutants were collected
at different distances from the source of emission in the Pb–Zn–Ag mining area near Olkusz, Upper Silesia to (a) compare the
chemical speciation of metals in agriculture and forest soils situated at the same distance from the point source of pollution
(paired sampling design), (b) to evaluate the relationship between the distance from the polluter and the retention of the
metals in the soil, (c) to describe mineralogy transformation of anthropogenic soil particles in the soils, and (d) to assess
the effect of deposited fly ash vs. dumped mining/smelting waste on the mobility and bioavailability of metals in the soil.
Forest soils are much more affected with smelting processes than agriculture soils. However, agriculture soils suffer from
the downward metal migration more than the forest soils. The maximum concentrations of Pb, Zn, and Cd were detected in a forest
soil profile near the smelter and reached about 25 g kg − 1, 20 g kg − 1 and 200 mg kg − 1 for Pb, Zn and Cd, respectively. The metal pollutants from smelting processes are less stable under slightly alkaline soil
pH then acidic due to the metal carbonates precipitation. Metal mobility ranges in the studied forest soils are as follows:
Pb > Zn ≈ Cd for relatively circum-neutral soil pH (near the smelter), Cd > Zn > Pb for acidic soils (further from the smelter).
Under relatively comparable pH conditions, the main soil properties influencing metal migration are total organic carbon and
cation exchange capacity. The mobilization of Pb, Zn and Cd in soils depends on the persistence of the metal-containing particles
in the atmosphere; the longer the time, the more abundant the stable forms. The dumped mining/smelting waste is less risk
of easily mobilizable metal forms, however, downward metal migration especially due to the periodical leaching of the waste
was observed. 相似文献
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Kamila Kočí Ivana Troppová Miroslava Edelmannová Jakub Starostka Lenka Matějová Jaroslav Lang Martin Reli Helena Drobná Anna Rokicińska Piotr Kuśtrowski Libor Čapek 《Environmental science and pollution research international》2018,25(35):34818-34825
Lanthanum-modified TiO2 photocatalysts (0.2–1.5 wt% La) were investigated in the methanol decomposition in an aqueous solution. The photocatalysts were prepared by the common sol-gel method followed by calcination. The structural (X-ray diffraction, Raman, X-ray photoelectron spectroscopy), textural (N2 physisorption), and optical properties (diffuse reflectance spectroscopy, photoelectrochemical measurements) of all synthetized nanomaterials were correlated with photocatalytic activity. Both pure TiO2 and La-doped TiO2 photocatalysts proved higher yields of hydrogen in comparison to photolysis. The photocatalyst with optimal amount of lanthanum (0.2 wt% La) showed almost two times higher amount of hydrogen produced at the same time as in the presence of pure TiO2. The photocatalytic activity increased with both increasing photocurrent response and decreasing amount of lattice and surface O species. It has been shown that both direct and indirect mechanisms of methanol photocatalytic oxidation participate in the production of hydrogen. Both direct and indirect mechanisms take part in the formation of hydrogen. 相似文献