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991.
在硫酸系统中,通过水平衡分析计算烟气带入净化工序的SO2体积分数和含水量,确定净化工序的能力,控制干燥塔进口烟气温度,使干吸工序生产出合格产品;通过计算,烟气带入净化工序的水量小于产品带出的水量,制酸净化污水经过污水处理工序处理后返回到净化工序重复使用,实现净化污水零排放,消除对环境的污染. 相似文献
992.
993.
生活污水水质对处理工艺的选择、设计参数的选取以及稳定运行十分重要。运用SPSS软件,对四川某中小城镇污水处理厂为期一年的进水指标(水量、COD、氨氮、总磷、pH、SS)进行方差和相关性分析。方差分析结果显示进水量、氨氮和SS在月份和季节之间存在显著性差异,而总磷和pH仅在月份之间存在显著差异,COD在季度和月份之间无显著性差异;指标相关性分析表明,进水量和氨氮之间呈负相关,氨氮和总磷、COD和总磷之间呈正相关,且相关性显著。在此分析的基础上对污水处理厂设计、工艺选择及运行管理提出了一些建议。 相似文献
994.
Chih Ming M Ya Wen Lee Gui Bing Hong Te Li Su Je Lueng Shie Chang Tang Chang 《环境科学学报(英文版)》2011,23(4):687-692
TiO2 nanoparticles, doped with di erent Pt contents, were prepared by a modified photodeposition method using Degussa P-25 TiO2,
H2PtCl6 6H2O and methanol as the solvents. The physicochemical properties of Pt/TiO2 were investigated by the nitrogen adsorption
and desorption isotherm measurement technique, X-ray di raction analysis and photoluminescence spectra, respectively. Reaction rates
from photocatalytic removal of dichloromethane over Degussa P-25 TiO2 and Pt/TiO2 were evaluated. The average diameter and BET
surface area of the TiO2 catalyst particles were 300 nm and 50 m2/g, respectively. The degradation e ciency was 99.0%, 82.7%, 55.2%,
and 57.9% with TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. And the degradation e ciency was 99.3%,
79.7%, 76.5%, and 73.4% with a 0.005 wt.% Pt/TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. In addition, we
found that the photoluminescence emission peak intensities decreased with increases in the doping amount of Pt, which indicates that
the irradiative recombination was weakened. Furthermore, the results showed that the UV/0.005 wt.% Pt/TiO2 process was capable of
e ciently decomposing gaseous DCM in air. 相似文献
995.
Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by
performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound (F3) and
organic matter/sulfide-bound (F4) forms. For Zn, exchangeable (F1), carbonate-bound (F2), and F3 forms were transformed to F4 and
residual forms (F5). For Ni, F1 and F2 forms were transformed to F1, F2, and F3 forms. Both Cu and Pb were strongly associated with
the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to
F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used
to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28
days. The metal mobilities in the final sludge mixtures were ranked in the following order: Ni > Zn > Cu = Pb. Leaching tests showed
that the mobilities of Zn and Ni in lower pH conditions (pH 4) were higher than those in higher pH conditions (pH 8). 相似文献
996.
Remediation of copper polluted red soils with clay materials 总被引:2,自引:0,他引:2
Attapulgite and montmorillonite were utilized to remediate heavy metal polluted red soils in Guixi City, Jiangxi Province, China.
The e ects of clay minerals on availability, chemical distribution, and biotoxicity of Cu and Zn were evaluated. The results provided
a reference for the rational application of clay materials to remediate heavy metal contaminated soils. From the sorption experiment,
the maximum adsorbed Cu2+ by attapulgite and montmorillonite was 1501 and 3741 mg/kg, respectively. After polluted red soil was
amended with attapulgite or montmorillonite and cultured at 30 and 60 days, soil pH increased significantly compared to the control. An
8% increase in the amount of montmorillonite in soil and 30 days incubation decreased acid exchangeable Cu by 24.7% compared to the
control red soil. Acid exchangeable Cu decreased with increasing amounts of attapulgite and montmorillonite, with best remediation
e ect reached at a dose of 8%. Results also showed that the Cu poisoning e ect on earthworms was reduced with the addition of
attapulgite and montmorillonite. Montmorillonite showed the best e ect, with the addition of a 2% dose the mortality of earthworms
decreased from 60% to zero compared to the control. Our results indicated that the bioavailability of Cu in soils was reduced more
e ectively with the application of montmorillonite than attapulgite. 相似文献
997.
The adsorption behaviors of heavy metals onto novel low-cost adsorbent, red loess, were investigated. Red loess was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectra. The results indicated that red loess mainly consisted of silicate, ferric and aluminum oxides. Solution pH, adsorbent dosage, initial metal concentration, contact time and temperature significantly influenced the efficiency of heavy metals removal. The adsorption reached equilibrium at 4 hr, and the experimental equilibrium data were fitted to Langmuir monolayer adsorption model. The adsorption of Cu(II) and Zn(II) onto red loess was endothermic, while the adsorption of Pb(II) was exothermic. The maximum adsorption capacities of red loess for Pb(II), Cu(II) and Zn(II) were estimated to be 113.6, 34.2 and 17.5 mg/g, respectively at 25°C and pH 6. The maximum removal efficiencies were 100% for Pb(II) at pH 7, 100% for Cu(II) at pH 8, and 80% for Zn(II) at pH 8. The used adsorbents were readily regenerated using dilute HC1 solution, indicating that red loess has a high reusability. All the above results demonstrated that red loess could be used as a possible alternative low-cost adsorbent for the removal of heavy metals from aqueous solution. 相似文献
998.
Cleaning of hollow-fibre polyvinyl chloride (PVC) membrane with di erent chemical reagents after ultrafiltration of algal-rich
water was investigated. Among the tested cleaning reagents (NaOH, HCl, EDTA, and NaClO), 100 mg/L NaClO exhibited the best
performance (88.4% 1.1%) in removing the irreversible fouling resistance. This might be attributed to the fact that NaClO could
eliminate almost all the major foulants such as carbohydrate-like and protein-like materials on the membrane surface, as confirmed by
Fourier transform infrared spectroscopy analysis. However, negligible irreversible resistance (1.5% 1.0%) was obtained when the
membrane was cleaning by 500 mg/L NaOH for 1.0 hr, although the NaOH solution could also desorb a portion of the major foulants
from the fouled PVC membrane. Scanning electronic microscopy and atomic force microscopy analyses demonstrated that 500 mg/L
NaOH could change the structure of the residual foulants on the membrane, making them more tightly attached to the membrane
surface. This phenomenon might be responsible for the negligible membrane permeability restoration after NaOH cleaning. On the
other hand, the microscopic analyses reflected that NaClO could e ectively remove the foulants accumulated on the membrane surface. 相似文献
999.
Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation
for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were
studied. The amount of methanotrophs ranged 61.97 103–632.91 103 cells/g (in dry basis) in aged refuse from Shanghai Laogang
Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I
methanotrophs were detected in the presence of nitrate minimal salt medium (NMS). The clone sequences of the pmoA gene obtained
from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct
with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane
biological oxidation and over 93% conversions were obtained. 相似文献
1000.
气候谈判关乎各国在气候秩序中的权力与义务关系,涉及到各国经济发展的根本利益,已经成为国际政治博弈的新舞台。当前,欧盟与美国正在突破"共同但有区别的责任"原则,争夺气候变化谈判中的领导权;发展中国家阵营逐步分化为"基础四国""小岛屿国家""最贫穷国家"等。从长期来看,在气候变化问题上,各国有一致的利益,各国际阵营若能表现出更合作的态度——发达国家更负责地转变为低碳生产和生活模式,更慷慨和带有诚意地协助发展中国家减排,发展中国家更深刻地认识到碳排放空间的来之不易和低碳生产生活的迫切性,实现自觉减排——就能帮助遭遇"囚徒困境"的世界各国离开个体理性的"纳什均衡",趋向集体理性的"帕累托最优"。 相似文献