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991.
992.
Simultaneous removal of chromium and arsenate from contaminated
groundwater by ferrous sulfate: Batch uptake behavior 总被引:1,自引:0,他引:1
Chromium and/or arsenate removal by Fe(II) as a function of pH, Fe(II) dosage and initial Cr(VI)/As(V) ratio were examined in
batch tests. The presence of arsenate reduced the removal e ciency of chromium by Fe(II), while the presence of chromate significantly
increased the removal e ciency of arsenate by Fe(II) at pH 6–8. In the absence of arsenate, chromium removal by Fe(II) increased to
a maximum with increasing pH from 4 to 7 and then decreased with a further increase in pH. The increment in Fe(II) dosage resulted
in an improvement in chromium removal and the improvement was more remarkable under alkaline conditions than that under acidic
conditions. Chromium removal by Fe(II) was reduced to a larger extent under neutral and alkaline conditions than that under acidic
conditions due to the presence of 10 mol/L arsenate. The presence of 20 mol/L arsenate slightly improved chromium removal by
Fe(II) at pH 3.9–5.8, but had detrimental e ects at pH 6.7–9.8. Arsenate removal was improved significantly at pH 4–9 due to the
presence of 10 mol/L chromate at Fe(II) dosages of 20–60 mol/L. Elevating the chromate concentration from 10 to 20 mol/L
resulted in a further improvement in arsenate removal at pH 4.0–4.6 when Fe(II) was dosed at 30–60 mol/L. 相似文献
993.
Polycyclic aromatic hydrocarbons (PAHs) investigation in different matrices has been reported largely, whereas reports on snow samples were limited. Snow, as the main matrix in the polar region, has an important study meaning. PAHs in snow samples were analyzed to investigate the distribution and contamination status of them in the Antarctic, as well as to provide some references for global migration of PAHs. Snow samples collected in Fildes Peninsula were enriched and separated by solid-phase membrane disks and eluted by methylene dichloride, then quantified by gas chromatography/mass spectrometry. All types of PAHs were detected except for Benzo(a)pyrene. Principal component analysis method was applied to characterize them. Three factors (Naphthalene, Fluorene and Phenanthrene) accounted for 60.57%, 21.61% and 9.80%, respectively. The results showed that the major PAHs sources maybe the atmospheric transportation, and the combustion of fuel in Fildes Peninsula. The comparison of concentration and types of PAHs between accumulated snow and fresh snow showed that the main compound concentrations in accumulated snow samples were higher than those in fresh ones. The risk assessment indicated that the amount of PAHs in the snow samples would not lead to ecological risk. 相似文献
994.
A kinetic model for the Ti(IV)-catalyzed H2O2/O3 process was established, and the experimental results demonstrated that the model could well describe this ozone-based oxidative system mathematically and chemically. 相似文献
995.
996.
997.
伴随着城市化的快速推进,非点源污染已成为城市污染的又一重大污染源,对其进行研究有着重要意义。文章从城市非点源污染的研究方法、研究手段、目前国内外城市非点源的研究进展、城市非点源污染管理和控制措施等方面进行了综述,最后提出了存在的问题和研究展望。 相似文献
998.
摘要:文章选取了乌鲁木齐市环境与经济相关的18个指标,建立了环境与经济协调发展指标体系。并运用协调发展评价模型对乌鲁木齐2006~2009年的环境与经济协调发展关系进行了初步研究。结果表明:乌鲁木齐市这几年的环境与经济协调’关系优良。 相似文献
999.
锡林郭勒草原荒漠化气候因素分析 总被引:1,自引:0,他引:1
利用1961-2006年锡林郭勒草原年、季、月降水量、平均气温、沙尘暴日数等气象资料,针对锡林郭勒草原荒漠化的现状进行分析。在气候变暖背景下,研究锡林郭勒草原干旱发生的规律及其成因,分析其带给锡林郭勒草原荒漠化的影响,得到以下结论:1.锡林郭勒草原沙化、荒漠化严重,沙化面积位居内蒙古自治区第一,荒漠化面积位居内蒙古自治区第二。2.锡林郭勒草原春夏季降水趋势存在准25a气候振动,年代际变化特征比较突出。干旱发生的频率较高。3.气候变暖给锡林郭勒草原干旱带来较大的影响。4.沙尘暴频发与干旱相互影响,同时对锡林郭勒草原草场生态资源产生一定的影响。5.生态环境恶化,导致大面积土地资源和生物资源丧失。恶化的生态环境已经影响到了锡林郭勒草原社会经济的发展。 相似文献
1000.