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21.
乙醇对硫酸盐还原-甲烷发酵效率影响的研究 总被引:1,自引:0,他引:1
针对硫酸盐还原菌(SRB)、产酸菌(AB)和产甲烷菌(MPB)的生态位特征,采用两级厌氧与循环气提吹脱工艺,以蔗糖和乙醇为有机底物(COD为6 000 mg·L-1),在不同COD/SO2-4时分别研究了底物中乙醇浓度对硫酸盐还原、有机物去除和甲烷发酵效率的影响,以及系统的硫化物吹脱效果和最佳回流率.结果表明,乙醇的添加可以促进SO2-4还原,并使COD/SO2-4降低产生的竞争性抑制作用减弱,SRB、AB和MPB菌群处于良好的协同代谢状态.乙醇/SO2-4从0提升至2后系统的处理效率明显改善,COD/SO2-4为12、 6和4时的SO2-4还原率分别由7.7%、 8.1%、 14.1%提高为84.7%、 87.6%、 82.5%,COD去除率由83.3%、 76.5%、 69.6%提高为92.8%、 93.5%、 89.7%,CH4/COD由225.7、 204.6、 178.6 mL·g-1提高至278.5、 253.7、 236.1 mL·g-1.系统经10倍回流水稀释及气提吹脱30%~55%的硫化物后,硫化物浓度分别低于27.8、 38.4、 52.4 mg·L-1,有效地抑制了H2S的毒性作用.但回流率偏大(20倍)使底物浓度梯度过低,SO2-4还原率下降;回流率偏低(5倍)使污泥床无法充分膨胀,COD去除率降低. 相似文献
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Differential Pulse Anodic Stripping Voltammetry (DPASV) was employed to measure Apparent Copper Complexing Capacity (Lt) and Stability Constants (Ks) of related cupric complexes of cell exudates of the phytoplanktonic alga Dunaliella salina. Three natural seawater samples collected 0.1, 2, 5 miles off the Tyrrhenian coast were used as culture medium. The measurements were carried out 1h and 7 days after the inoculum. Furthermore, on one culture the medium was passed through C18‐SEP‐PAK cartridges in order to separate the cell exudates. The results show that Dunaliella salina influences the value of Lt but does not affect the value of Ks . The C18SEP‐PAK retain only 50% of the ligands produced by the cells and capable of complexing copper. 相似文献
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Some ecotoxic metals such as Cd, Pb, and Cu in Tessaria absinthioides were quantified to study its possible use as a bio‐indicator and/or bio‐monitor of these metals. This plant was chosen for its abundance in the area under study, along Chile and even in southern Latin America. For Cd, Pb, and Cu in all three parts of the plant (leaves, stems and roots) a different concentration pattern in each sampling areas was observed. In sampling areas Coya Sur and La Cascada copper and cadmium concentration decrease in order: leaves > roots > stems. In samples collected in Xalquincha the lowest concentrations of Cd and Pb were observed in stems. A maximum of cadmium concentration (9ug/gd.w. in leaves) was found in samples from La Cascada, a inflow to river Loa in Calama. High concentrations of lead were found in roots and leaves. Collected data demonstrate that the main pathway for cadmium is from ground water via roots into the plant. Some data obtained for lead and copper indicate that the influence of dust particles adsorbed on leaves and stems can be higher than uptake from ground water. 相似文献
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采用中空纤维膜接触器(Hollow Fiber Membrane Contactor, HFMC)回收尿液中的氨氮,系统研究了吸收液类型(H3PO4、H2SO4和HNO3)对氨回收效能、水蒸气的跨膜通量和所获液体肥料的影响.结果表明,使用H2SO4作为吸收液时氨氮回收效能最优,其次是H3PO4和HNO3.当采用H2SO4为吸收液时,氨氮回收率、氨跨膜通量和传质系数分别为84.49%±0.01%、22.92 g·m-2·h-1和2.37×10-6 m·s-1.HNO3的挥发性使其从吸收液侧反向跨膜至料液侧,导致氨跨膜传质驱动力变小;此外,NH3和HNO3会在膜孔中反应并生成NH4NO3气溶胶,增加氨在膜孔中的传质阻力,导致氨氮的回收效能降低.对采用不同吸收液时膜两侧的水的活度差和理论水通量进行了计算,结果表明,随着氨氮的不断跨膜吸收,膜两侧的活度差和水通量逐渐增大,实验结束时水通量分别为7.44×10-2 kg·m-2·h-1(H3PO4)、9.06×10-2 kg·m-2·h-1(H2SO4)和2.00×10-2 kg·m-2·h-1(HNO3).肥料组分分析表明,以H2SO4和HNO3为吸收液可以获得仅含N素的单一液体肥料,以H3PO4作吸收液可获得N-P复合肥,(NH4)2HPO4和NH4H2PO4所占的比例分别为88.33%和11.67%. 相似文献
26.
危险与可操作性分析对于石化装置的工艺安全管理具有重要意义,介绍了HAZOP分析方法在工艺装置上的应用流程,并讨论了HAZOP分析与风险矩阵的结合运用。以克拉玛依石化公司的80吨/小时酸性水汽提装置为例,详细阐述了HAZOP分析的流程及其与半定量分析相结合的方法在实践中的应用,并针对危险源给出了风险削减措施。基于HAZOP分析在实践中的应用情况,总结了一些客观存在的问题,并提出了意见和建议。 相似文献
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Cadmium and lead were determined simultaneously in seawater by differential pulse stripping voltammetry (DPSV) preceded by
adsoptive collection of complexes with 8-hydroxyquinoline (oxine) on to a hanging mercury drop electrode (HMDE). In preliminary
experiments the optimal analytical condition for oxine concentration was found to be 2.10−5 M, at pH 7.7, the accumulation potential was −1.1 V, and the initial scannig potential was −0.8 V. The peak potentials were
found −0.652 V for Cd and −0.463 V for Pb At the 60 s accumalation time. The limit of detection (LOD) and limit of quantitatification
(LOQ) were found to be by voltammetry as 0.588 and 1.959 μg l−1 (RSD, 5.50%) for Cd and 0.931 and 3.104 μg l−1 (RSD, 4.10%) for Pb at 60 s stirred accumulation time respectively. In these conditions the most of the seawater samples
are amenable for direct voltammetric determination of cadmium and lead using a HMDE. An adsorptive stripping mechanism of
the electrode reaction was proposed. For the comparison, seawater samples were also analysed by ICP-atomic emission spectrometry
method (ICP-AES). The applied voltammetric technique was validated and good recoveries were obtained. 相似文献
30.
The determination of trace amount nitrobenzene in wastewater on a hanging mercury drop electrode was studied. The determination
conditions of pH, supporting electrolyte, accumulation potential, accumulation time, and voltammetric response were optimized.
The sharp peak of the nitrobenzene was appeared at 0.05 V. The peak electric current was proportional to the concentration
of nitrobenzene in the range of 1.47 × 10−5 ∼ 1.0 × 10−3 mol/l with relative standard deviations of 3.99 ∼ 8.94%. The detection limit of the nitrobenzene in water was 5 × 10−6 mol/l. The proposed method offered low limit of determination, easy operation, the use of simple instrumentation, high sensitivity
and good reproducibility. It was applied to the determination of nitrobenzene in wastewater with an average recovery of 94.0%
∼ 105%. The proposed method provided fast, sensitive and sometimes real time detection of nitrobenzene. 相似文献