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排序方式: 共有915条查询结果,搜索用时 444 毫秒
1.
2.
本文论述了负硬水只用氯化铵再生时离子交换器的运行过程及离子交换软化除碱的方法,并阐述了控制出水中残留碱的简便方法。经研究证明,此方法可达到除碱度、除硬度、除盐、延长锅炉使用寿命、减少腐蚀、减少排污量、节约燃煤等效果。经济效益十分显著。 相似文献
3.
Characteristics of nitrogen and phosphorus removal in SBR and SBBR with different ammonium loading rates 总被引:2,自引:0,他引:2
Dong-Seog Kim No-Sung Jung Young-Seek Park 《Korean Journal of Chemical Engineering》2008,25(4):793-800
Laboratory scale experiments were conducted to study the deterioration of enhanced biological phosphorus removal (EBPR) due
to influent ammonium concentration, and to compare the performance of two types of sequencing batch reactor (SBR) systems,
a conventional SBR and sequencing batch biofilm reactor (SBBR). Both in SBR and SBBR, the total nitrogen removal efficiency
decreased from 100% to 53% and from 87.5% to 54.4%, respectively, with the increase of influent ammonium concentration from
20 mg/l to 80 mg/l. When the influent ammonium concentration was as low as 20 mg/l (C: N: P=200: 20: 15), denitrifying glycogen-accumulating organisms (DGAOs) were successfully grown and activated by using
glucose as a sole carbon source in a lab-scale anaerobic-oxic-anoxic (A2O) SBR. In the SBR, due to the effect of incomplete denitrification and pH drop, the nitrogen and phosphorus removal efficiency
decreased from 77% to 33.3% when the influent ammonium concentration increased from 20 mg/l to 80 mg/l. However, in the SBBR, simultaneous nitrification/denitrification (SND) occurred, and the nitrification rate in the aerobic
phase did not change remarkably in spite of the increase in influent ammonium concentration. Phosphorus removal was not affected
by the increase of influent ammonium concentration. 相似文献
4.
5.
Large amounts of water containing-ammonium nitrogen(NH4+-N)have attracted increasing attention.Catalytic ozonation technology,involving the generation of hydroxyl radical(OH)with strong oxidation ability,was originally utilized to degrade organic-containing wastewater.In this paper,Ce/MnOx composite metal oxide catalysts prepared with different preparation conditions were used to degrade wastewater containing inorganic pollutant(NH4+-N).The as-prepared catalyst features were characterized using X-ray diffraction(XRD),Brunauer-Emmett-Teller method(BET),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and H2-temperature programmed reduction(H2-TPR)techniques.The results show that the catalyst,prepared by conditions with precipitant Na2CO3 and Ce/Mn molar ratio 1:2 calcined at 400℃for 3 h in pH 11.0,displays the optimal performance,with the removal rate of NH4+-N and selectivity to gaseous nitrogen,88.14 wt%and 53.67 wt%,respectively.The effects of several operating factors including solution pH,initial NH4+-N concentrations and scavengers were evaluated.In addition,XRD patterns of catalyst with the best performance and the comparative study on decontamination of NH4+-N by various processes(O3,catalyst and catalyst/O3)show that the primary metal oxides are CeO2 and MnO2 in Ce/MnOx composite metal oxide catalysts,which have a synergistic effect on the catalytic ozonation of NH4+-N,and the new phase MnO2 plays a great role.After 5 consecutive use cycles,the degradation efficiency is declined slightly,and can still achieve better than 70 wt%over 1 h reaction.Additionally,the application of catalytic ozonation for actual wastewater on the removal rate of NH4+-N was investigated.Possible mechanism and degradation pathway of NH4+-N were also proposed.In a word,the application of CeO2-MnO2 composite metal oxide catalysts in catalytic ozonation can be regarded as an effective,feasible and promising method for the treatment of NH4+-N. 相似文献
6.
针对酸性氯化物中黄铁矿还原浸出锰结核的溶液成分特点,选择黄钠铁矾法进行了沉淀分离铁的研究。结果表明温度和晶种以及溶液pH值是影响铁矾沉淀的重要因素。在pH2.0左右,溶液温度高于90℃,足量晶种加入的情形下,150min后可将溶液中的铁含量降至0.1g/L。沉矾过程的表观活化能为94.66kJ/mol。黄铁矿氧化生成的硫酸根随铁一同沉淀,从而消除了SO2-4在氯化物体系中的积累。 相似文献
7.
Gamal A. M. Hussein 《Powder Technology》1994,80(3):265-270
The thermal decomposition up to 400 °C of ammonium ferric citrate hydrate, of unknown structure and formula weight, was studied by thermogravimetry, differential thermal analysis, infrared (IR) spectroscopy and X-ray diffractometry. The possible identities of the formula weight and the intermediate products of calcination are discussed. The results revealed that the parent material is amorphous and contains two moles of water and two moles of ammonia. Decomposition takes place via six weight-loss processes, three endothermic (90–230 °C) and three exothermic (240–298 °C), leading eventually to the formation of Fe2O3. The intermediate solid products are mainly unstable amorphous oxycarbonates, as indicated by X-ray and IR spectroscopies. The gas-phase decomposition products identified by IR spectroscopy are NH3, CO2, CO, CH3COCH3, CH4 and NH4OH. Surface area measurement and scanning electron microscopy showed that Fe2O3, the final product at 400 °C, hada surface area of 40 m2/g and good crystalline and porous character. 相似文献
8.
探讨了该厂化肥生产中碳铵发青的原因,通过硫化氢含量的测定,分析了系统内外影响因素,提出了解决措施,达到了不停车稳定产品质量的目的。 相似文献
9.
改性硝酸铵的工业制备方法及其性能 总被引:2,自引:0,他引:2
硝酸铵饱和溶液中加入表面活性剂辛基三甲基溴化铵,采用真空膨胀结晶技术工业制备一种新型改性硝酸铵,并介绍其性能特点。 相似文献
10.
还原硅钼酸盐分光光度法测定偏钒酸铵中硅的含量 总被引:1,自引:0,他引:1
李静 《化学工业与工程技术》2002,23(5):47-49
介绍了还原硅钼酸盐分光光度法测定偏钒酸铵中的硅含量 ,讨论了吸收波长、还原剂、酸度及掩蔽剂加入量等因素对测定结果的影响。结果表明 ,还原硅钼酸盐分光光度法测定偏钒酸铵中的硅含量 ,数据准确 相似文献