Degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) in soils by Fe3O4 nanoparticles combined with soil indigenous microbes was investigated, and the effects of Fe3O4 nanoparticles on soil microbial populations and enzyme activities were also studied. 相似文献
In the present work, we explored the kinetics of dichlorvos (2,2-dichlorvinyl dimethyl phosphate, DDVP) decay through UV-A
light-induced TiO2 photocatalysis at pH 4 and 9, and the formation of degradation intermediates and final products under specific experimental
conditions. Experimental observations and theoretical considerations allowed us to suggest the degradation mechanism of DDVP
by the UV/TiO2 process in aqueous solution. 相似文献
Photocatalytic oxidation using UV irradiation of TiO2 has been studied extensively and has many potential industrial applications, including the degradation of recalcitrant contaminants
in water and wastewater treatment. A limiting factor in the oxidation process is the recombination of conduction band electrons
(e−cb) with electron holes (hvb+) on the irradiated TiO2 surface; thus, in aqueous conditions, the presence of an effective electron scavenger will be beneficial to the efficiency
of the oxidation process. Ferrate (FeO42−) has received much recent attention as a water treatment chemical since it behaves simultaneously as an oxidant and coagulant.
The combination of ferrate [Fe(VI)] with UV/TiO2 photocatalysis offers an oxidation synergism arising from the Fe(VI) scavenging of e−cb and the corresponding beneficial formation of Fe(V) from the Fe(VI) reduction. This paper reviews recent studies concerning
the photocatalytic oxidation of problematic pollutants with and without ferrate. 相似文献
The kinetics of the transformation of ammonia and acid gases into components of PM2.5 has been examined. The interactions of existing aerosols and meteorology with the transformation mechanism have also been
investigated. The specific objective was to discern the kinetics for the gas-to-particle conversion processes where the reactions
of NH3 with H2SO4, HNO3, and HCl take place to form (NH4)2SO4, NH4NO3, and NH4Cl, respectively, in PM2.5. 相似文献
It is predicted that demand for electricity in Islamic Republic of Iran will continue to increase dramatically in the future
due to the rapid pace of economic development leading to construction of new power plants. At the present time, most of electricity
is generated by burning fossil fuels which result in emission of great deal of pollutants and greenhouse gases (GHG) such
as SO2, NOx, and CO2. The power industry is the largest contributor to these emissions. Due to minimal emission of GHG by renewable and nuclear
power plants, they are most suitable replacements for the fossil-fueled power plants. However, the nuclear power plants are
more suitable than renewable power plants in providing baseload electricity. The Bushehr Nuclear Power Plant, the only nuclear
power plant of Iran, is expected to start operation in 2010. This paper attempts to interpret the role of Bushehr nuclear
power plant (BNPP) in CO2 emission trend of power plant sector in Iran. 相似文献
The impact of shipping emissions on urban agglomerations close to major ports and vessel routes is probably one of the lesser
understood aspects of anthropogenic air pollution. Little research has been done providing a satisfactory comprehension of
the relationship between primary pollutant emissions, secondary aerosols formation and resulting air quality. 相似文献
Urban ambient air pollution exposures continue to be a global public health concern. Although air quality targets are often
exceeded in Lisbon, the largest city in Portugal, there is currently no study that has assessed the quantitative impact of
these pollutants on daily mortality. 相似文献
The impact of air pollution on school children’s health is currently one of the key foci of international and national agencies.
Of particular concern are ultrafine particles which are emitted in large quantities, contain large concentrations of toxins
and are deposited deeply in the respiratory tract. 相似文献
The purpose of this work was to study the efficiency of different treatments, based on the combination of O3, H2O2, and TiO2, on fresh surface water samples fortified with wild strains of Escherichia coli. Moreover, an exhaustive assessment of the influence of the different agents involved in the treatment has been carried out by kinetic modeling of E. coli inactivation results. The treatments studied were (i) ozonation (O3), (ii) the peroxone system (O3/0.04 mM H2O2), (iii) catalytic ozonation (O3/1 g/L TiO2), and (iv) a combined treatment of O3/1 g/L TiO2/0.04 mM H2O2. It was observed that the peroxone system achieved the highest levels of inactivation of E. coli, around 6.80 log after 10 min of contact time. Catalytic ozonation also obtained high levels of inactivation in a short period of time, reaching 6.22 log in 10 min. Both treatments, the peroxone system (O3/H2O2) and catalytic ozonation (O3/TiO2), produced a higher inactivation rate of E. coli than ozonation (4.97 log after 10 min). While the combination of ozone with hydrogen peroxide or titanium dioxide thus produces an increase in the inactivation yield of E. coli regarding ozonation, the O3/TiO2/H2O2 combination did not enhance the inactivation results. The fitting of experimental values to the corresponding equations through non-linear regression techniques was carried out with Microsoft® Excel GInaFiT software. The inactivation results of E. coli did not respond to linear functions, and it was necessary to use mathematical models able to describe certain deviations in the bacterial inactivation processes. In this case, the inactivation results fit with mathematical models based on the hypothesis that the bacteria population is divided into two different subgroups with different degrees of resistance to treatments, for instance biphasic and biphasic with shoulder models.
In this paper, a novel method in the estimation and prediction of PM10 is introduced using wavelet transform-based artificial neural networks (WT-ANN). 相似文献
Denitrification is an important biochemical process in global nitrogen cycle, with a potent greenhouse gas product N2O. Wastewater irrigation can result in the changes of soil properties and microbial communities of agricultural soils. The
purpose of this study was to examine how the soil denitrification genes responded to different irrigation regimes. 相似文献
The degradation of a common textile dye, Reactive-brilliant red X-3B, by several advanced oxidation technologies was studied in an air-saturated aqueous solution. The dye was resistant to the UV illumination (wavelength λ 320 nm), but was decolorized when one of Fe3+, H2O2 and TiO2 components was present. The decolorization rate was observed to be quite different for each system, and the relative order evaluated under comparable conditions followed the order of Fe2+–H2O2–UV Fe2+–H2O2 > Fe3+–H2O2–UV > Fe3+–H2O2 > Fe3+–TiO2–UV > TiO2–UV > Fe3+–UV > TiO2–visible light (λ 450 nm) > H2O2–UV > Fe2+–UV. The mechanism for each process is discussed, and linked together for understanding the observed differences in reactivity. 相似文献
Increases in dissolved organic carbon (DOC) concentrations have been reported in surface waters worldwide in the last 10 to
20 years. The causes behind these increases have been attributed to many factors, including climate change and decreasing
depositions of atmospheric sulphate (
\textSO42 - {\text{SO}}_4^{{{2} - }} ). Trends in DOC concentrations and their potential causal factors were examined in a network of 30 lakes lying in undisturbed
temperate and boreal catchments in the province of Quebec, Canada. 相似文献
The increasing use of nanoparticles (NPs) worldwide has raised some concerns about their impact on the environment. The aim of the study was to assess the toxicity of metal oxide nanoparticles, singly or combined, in a freshwater fish (Carassius auratus). The fish were exposed for 7, 14, and 21 days to different concentrations of NPs (10 μg Al2O3.L?1, 10 μg ZnO.L?1, 10 μg Al2O3.L?1 plus 10 μg ZnO.L?1, 100 μg Al2O3.L?1, 100 μg ZnO.L?1, and 100 μg Al2O3.L?1 plus 100 μg ZnO.L?1). At the end of each exposure period, antioxidant enzyme activity (catalase, glutathione-S-transferase, and superoxide dismutase), lipid peroxidation, and histopathology were assessed in the gills and livers of C. auratus. The results show an increase in catalase (CAT) and superoxide dismutase (SOD) activity in the gills and livers of fish, especially after 14 days of exposure to single and combined NPs, followed by a reduction at 21 days. An increase in glutathione S-transferase (GST) was observed in gills after 7 days for all tested NP concentrations (single and combined); while in livers, a significant increase was determined after 14 days of exposure to 100 μg.L?1 of both single ZnO and Al2O3 NPs. Lipid peroxidation (LPO) significantly increased in gills after 7 days of exposure to 100 μg.L?1 Al2O3 NPs (single or combined). In livers, LPO increased significantly after 7 days of exposure to all tested concentrations of both single ZnO and Al2O3 (except for 10 μg Al2O3.L?1), and after 14 days of exposure to ZnO (10 and 100 μg.L?1) and Al2O3 (100 μg.L?1). The results from histological observations suggest that exposure to metal oxide NPs affected both livers and gills, presenting alterations such as gill hyperplasia and liver degeneration. However, the most pronounced effects were found in gills. In general, this study shows that the tested NPs, single or combined, are capable of causing sub-lethal effects on C. auratus, but when combined, NPs seem to be slightly more toxic than when added alone. 相似文献
Cuttings and seedlings of Jatropha curcas L. were exposed to different regimes of lead (Pb) stress as Pb(NO3)2 at 0 (CK), 0.5, 1, 2, 3, and 4 mM kg−1 soil. 相似文献
Photochemical smog, characterized by high concentrations of O3 and fine particles, is of great concern in the urban areas, in particular megacities and city clusters like the Pearl River
Delta. 相似文献
Open-top chambers were used to study the impact of simultaneous exposure to atmospheric SO2 pollution and heavy metal contamination in soils on the metal contents and productivity of soybean plant. 相似文献
This study assessed the potential exposure risks for workers in the workplace exposed to airborne titanium dioxide nanoparticles
(TiO2-NPs) and carbon black nanoparticles (CB-NPs). The risk management control strategies were also developed for the NP engineering
workplace. 相似文献
Precipitation samples collected from 1995 to 2000 at meteorological station in the eastern outskirts of Herceg Novi (Montenegro)
were analysed on Na+, K+, Mg2+, Ca2+, Cl–, SO42–, NO3– and NH4+. Four-day backward trajectory simulations were conducted during the precipitation period to investigate the regional transport
of main ions and their deposition in the region of the southeastern Adriatic Sea. The air mass trajectories were classified
into six trajectory categories by the origin and direction of their approach to Herceg Novi. 相似文献