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采用混凝超滤工艺,选取不同混凝预处理技术(FeCl3、PAC、AS)处理滦河水,并考察后续膜出水水质及TMP变化,3种混凝剂小试最佳投药量分别为8、6、12 mg/L,其中效果最佳的混凝剂为PAC;在小试基础上进行中试试验研究。结果表明,3种混凝剂对超滤膜的跨膜压差贡献依次为PAC相似文献
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混凝/超滤处理微污染原水的试验研究 总被引:12,自引:0,他引:12
采用混凝/超滤组合工艺对微污染原水进行试验。结果表明:混凝作为预处理可以有效地改善膜的过滤性能和提高去除有机物的效果。存在最佳混凝剂投加量,它可使膜过滤通量最大。 相似文献
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pH值对强化混凝去除水中微量有机物的影响 总被引:2,自引:1,他引:1
通过烧杯试验,分别以聚合氯化铝(PAC)和FeCl3为混凝剂研究了pH值对水中有机物去除的影响。研究结果表明:PAC的最佳投加量为8 mg/L,此时有机物和浊度的去除率分别为51.8%和93.6%;FeCl3的最佳投加量为50 mg/L,此时有机物和浊度的去除率分别为57.8%和95.0%。有机物去除的最佳pH值范围为5.5~6.5,浊度去除的最佳pH值范围为7~8;相对于原水而言,调节pH值能够使有机物的去除率提高10%左右,因此调节pH值是一种经济有效的去除水中有机物的强化混凝方法。 相似文献
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《水处理技术》2016,(6)
通过在线投加混凝及粉末活性炭(PAC)处理,研究二者对超滤(UF)进水中有机物相对分子质量分布、亲疏水性的影响,考察在线混凝改善PAC-UF工艺对有机物去除效率和膜污染效能的影响及机理。结果表明,在线混凝和PAC对去除不同相对分子质量的有机物上存在协同互补作用,当PAC投加量仅为20 mg/L时,在线混凝+PACUF工艺的UV_(254)和DOC去除率为93.6%和69.7%。在线混凝和PAC对原水中亲水性有机物的去除效果较差,去除率小于40%,但是亲水性有机物组分的存在对膜污染的影响几乎可以忽略。当PAC投加仅为20 mg/L时,过滤周期末端膜比通量为0.86。在线混凝可以有效的改善PAC-UF工艺的有机物去除效果和膜污染程度,并可以显著的减低投炭量,利于实际工程运行。 相似文献
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《应用化工》2022,(12)
为了经济、高效的提高西北农村地区微污染窖水的水质,实验采用PAC/NPAM/木质粉末活性炭与超滤联用处理微污染窖水,考察了对浊度、氨氮、UV_(254)以及COD_(Mn)的去除效果以及对膜通量的变化研究,并且将其与单独超滤、3种强化混凝(PAC、PAC/NPAM、PAC/NPAM/木质粉末活性炭)进行对比,其结果表明:联用技术的去除效果较单独超滤与PAC/NPAM/木质粉末活性炭的去除效率都高,其中联用技术对氨氮、COD_(Mn)、UV_(254)的去除率分别为50.07%,63.05%和84.7%,而单独超滤的去除率为15.36%,23.50%,16.17%,PAC/NAPM/木质粉末活性炭联合投加的去除率为42.09%,50.47%,64.25%;同时,联用技术下的膜通量衰减速率比单独超滤的缓慢,其中混凝沉淀/超滤的膜通量的衰减速率比单独超滤的平均减缓了36.24%,而在线混凝/超滤的膜通量的衰减速率比单独超滤的平均减缓了42.23%,适用于农村微污染窖水的净化。 相似文献
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以聚合氯化铝(PAC)、聚合硫酸铁(PFS)为混凝剂,采用强化混凝的水处理方法,完成对低浊度微污染水体中多氯联苯(PCBs)的去除,考察了2种混凝剂的投加量、水样初始浊度、水样pH值以及水力条件等因素对PAC、 PFS混凝剂去除低浊度水体中PCBs的效果影响。研究得出,当PAC投加量为7 mL/L,水样初始浊度为62NTU,慢速搅拌时间为15 min, pH值为5.0时, PAC强化混凝效果最佳,其对水样中PCBs的去除率为68.42%~76.02%,剩余浊度为1.01 NTU;当PFS投加量为5.5 mL/L,水样初始浊度为62 NTU,慢速搅拌时间为15 min,p H值为6.5时, PFS强化混凝效果最佳,其对水样中PCBs的去除率为70.30%~77.52%,剩余浊度为4.14 NTU。研究得出, PAC、 PFS均能有效去除微污染水体中的PCBs,且与PAC相比, PFS的去除效果更佳。 相似文献
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在处理以地表水为水源的沉淀池出水时,超滤技术存在产水率较低的问题,反洗水的回收可以有效地提高系统的产水率和降低运行成本。试验设计了两套小试微滤膜系统,将膜反洗水经过预处理后按1∶9比例与滦河水混合作为一套小试膜系统进水,另外一套小试膜系统处理滦河水。试验考察了两种预处理方式对于混配水膜系统的出水水质及膜污染的影响。结果表明,在膜反洗水中投加混凝剂和粉末活性炭(PAC)后,相对仅投加混凝剂的预处理方式,混配水系统的出水水质得到改善,UV254和CODMn的去除率分别提高了9%和6.3%,预处理方式对于混配水系统出水浊度没有影响,比通量衰减速率降低了16.6%。在反洗水经混凝和PAC吸附后,混配水和滦河水系统出水水质与膜污染状况未见显著差异。 相似文献
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ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l/3为氧气,2/3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中:A一混… 相似文献
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P. P. Budnikoff 《Journal of the American Ceramic Society》1924,7(11):817-820
The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO3 and determination of CaO by KMnO4 titration, the SO3 by Andrews method of titration of BaCrO4 has been found to give very reliable results with the least consumption of time. 相似文献
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A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases. 相似文献
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A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
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ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES 总被引:5,自引:0,他引:5
Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log10 viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log10 viscosity as a function of soda content are smooth up to 50% Na2O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO2, 2Na2O) due to Molecular Substitution of CaO, MgO and Al2O3 for Na2O The effect is clearly brought out by plotting (from the results of English) the change of log10η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature Ta. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log10η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A12O3) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al2O3) per 100°. At the aggregation temperature the change of log10η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al2O3. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log10η due to substitution of an oxide for Na2O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na2O-CaO-SiO2. Change of Viscosity of Glass (4SiO2, 2Na2O) due to of Substitution of B2O3 for SiO2 The change of log10η (from the results of English) is plotted as a function of temperature, and also the change of log10η per per cent B2O3. The curves are more complex than for the substitution for Na2O. 相似文献
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面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。 相似文献