Influence of current density on oxygen transfer in an electroflotation cell

The objective of this work is to study the transfer of oxygen from gas to liquid phase in an electroflotation cell. The measurements were performed in a laboratory scale cell using insoluble electrodes, titanium coated with ruthenium oxide as anode and stainless steel as cathode. The volumetric mass transfer coefficient K _L a, was characterized for clean tap water as liquid phase for different values of current density (J). The global coefficient of mass transfer based on the liquid film, K _L , and the specific interfacial area, a, were characterized. A model which relates K _L a to current density was established. Different evaluation criteria of oxygen transfer in electroflotation process were determined and compared with other aeration process.     

天津爱普生有限公司油墨废水处理方案及运行情况

天津爱普生有限公司废水治理工程设计水量5t／d，废水浓度高，水质、水量变化大。采用水解酸化-生物接触氧化处理工艺对天津爱普生有限公司废水进行处理，进水CODCr，平均为2500mg／L左右，CODCr去除率≥90％，排水各项指标均符合国家污水综合排放标准GB8978-1996的二级排放要求。     

Shell煤气化技术

介绍气化效率高、有利于环保、具有一定竞争力的Shell煤气化工艺原理、技术特点及关键设备。建议尽快实现关键技术和设备的国产化。     

Frying Performance of No-<Emphasis Type="Italic">trans</Emphasis>, Low-Linolenic Acid Soybean Oils

Two extruded-expelled physically refined soybean oils with reduced contents of linolenic acid, ultra-low- linolenic acid (ULL, 1.5%) and low-linolenic acid (LL, 2.6%), and a extruded-expelled physically refined control oil (control, 5.3% linolenic acid) were evaluated by frying French fries in a commercial-like setting for 6 h day⁻¹ during 23 days. The oils became darker, increased in yellow color at the beginning, and became redder and less green throughout the process. Free fatty acids levels were not different among the oils until day 14, after which, ULL was different from the control for the remainder of frying. The conjugated dienoic acid values were greatest in the control. Generally, ULL and LL oils had lower percentages of polar compounds than did the control, providing a frying life 2 days longer than the control and ~30% increase in frying time. A trained sensory panel evaluated the French fries on days 2, 5, and 6. Buttery and potato flavors decreased, and rancid and painty flavors increased over frying time for all products. Rancid flavor was highest in the fries from the control oil. Overall, the ULL and LL oils performed better than did the control oil and ULL tended to perform better than the LL.     

Study of the polymerization of 1-octadecene with different rnetallocene catalysts

Summary 1-Octadecene (C18) was polymerized by using different metallocene catalysts. The rac-Et(Ind)₂ZrC1₂/MAO (I) and rac-Me₂Si(Ind)₂ZrC1₂/MAO (III) presented the highest activity as compared with ra-Et(2-Me-Ind)₂ZrCl₂/MAO (II) and Ph₂C(Flu)(Cp)ZrC1₂/MAO (IV) catalysts. Catalyst IV produced polymers with highest molecular weights. The microstructure of the polymers was determined by ¹³C-NMR spectroscopy. Catalyst systems I, II and III produced isotactic polymers while catalyst IV produced polymers with mainly syndiotactic structures but with large amount of stereoregular error. Received: 21 June 2002/Revised version: 4 November 2002/ Accepted: 4 November 2002     

硫酸法钛白粉生产中钛液的分析和铁分离

以硫酸法钛白粉生产工艺中间体浓钛液(硫酸氧钛)和偏钛酸为原料,分析了浓钛液中二氧化钛和铁的含量。总Ti的测试采用Al片还原法和高铁盐氧化还原滴定法,浓钛液中Ti3 直接用高铁盐氧化还原滴定法测定,铁含量用KMnO4氧化还原滴定法进行分析。采用无机陶瓷膜洗涤分离方法考查了水解后偏钛酸中的除铁效率,利用分光光度法和火焰原子吸收法分别测定洗涤液和二氧化钛粉体中的铁含量。试验表明,无机陶瓷膜洗涤分离方法可以将二氧化钛粉体中铁含量降到30×10-3‰以下,煅烧后产品白度大于94。陶瓷膜洗涤工艺可以实现连续操作,是一种值得推广的新工艺。     

PH敏感性水凝胶的分子热力学模型

本工作是在非离子凝胶的分子热力学模型基础，引入Ｄｏｎｎａｎ平衡项和大分子离子链的静电排斥项对凝胶自由能的贡献，建立了一个新的离子凝胶的分子热力学模型。该模型在解释离子凝胶的ＰＨ敏感性及其各种影响因素，以及预测ＰＨ溶胀曲线方面都取得了较好的效果。     

非线性光学偶氮分子的合成和跃迁偶极矩的测定

以对硝基苯胺、苯胺、5 氨基嘧啶和N,N 二羟乙基苯胺为原料通过两步重氮化-偶合反应合成了两种给体-受体型非线性光学偶氮分子,用红外光谱、核磁共振、熔点、紫外光谱进行了表征,测定了分子的跃迁偶极矩,两个化合物的跃迁偶极矩分别为7 12D和8 76D,它们在不同极性溶剂中表现出明显的溶致变色效应,紫外吸收最大位移分别达到20nm和15nm。     

复合溶液膜吸收CO2的性能及其对膜孔润湿的影响

利用自行搭建的CO₂膜吸收实验台，采用聚丙烯（PP）膜组件，以质量分数10%的N-甲基二乙醇胺（MDEA）作为主体胺溶液，添加不同配比的哌嗪（PZ）、乙醇胺（MEA）、甘氨酸钾（PG），考察CO₂脱除效率和传质速率的变化，比较不同复配比的复合溶液表面张力以及对PP膜的浸润性，并以10%MDEA+10%PG混合溶液作为吸收液进行长时间实验。结果表明：添加少量的添加剂对MDEA溶液膜吸收CO₂均有显著的促进作用，当配比小于0.2时，促进作用大小为PZ>MEA>PG；当配比大于0.2时，促进作用大小为PZ>PG>MEA；PZ和MEA均随着添加配比的增加，溶液表面张力减小，而PG相反；表面张力小的溶液对膜浸润性较强，容易造成膜润湿；添加剂质量分数均为10%时，对膜溶胀性和疏水性以及膜孔结构影响大小为PZ>MEA>PG；在20天内，PG/MDEA混合溶液作用下的CO₂脱除效率从89.56%下降为83.09%，对PP的疏水性影响较小，膜组件可以稳定运行。吸收液表面张力对膜吸收法脱除CO₂性能的影响显著。所得结果可为膜吸收CO₂吸收剂复配提供依据，并可为揭示膜吸收CO₂过程中膜润湿导致膜失效的机理以及抑制膜润湿提供实验数据。     

Spinose carbon nanotubes grown on graphitized DLC film by low frequency r.f. plasma-enhanced chemical vapor deposition

Spinose carbon nanotubes (SCNTs) are grown on silicon substrates covered with diamond-like carbon film and iron catalyst film (Fe/DLC/Si structure) by low frequency r.f. plasma-enhanced chemical vapor deposition (LFRF-PECVD). During the pre-treatment of the Fe/DLC/Si substrate, there are three processes happened, namely, iron film spalled to small islands, the DLC film graphitized, and the iron island reacted partially with the graphitized DLC (GDLC), which can be deduced from the Raman spectroscopy and SEM pictures. SCNTs film grew from C₂H₂---H₂ mixture under low plasma density. The good contact of carbon nanotube with GDLC film was acquired by the accumulation of the graphite sheets and the reaction between the iron particles and GDLC film. The homogeneous spines with the length of approximately 15 nm and the thickness of <5 nm burgeoned from the defects at the wall of carbon nanotube and distributed uniformly, which were in fact thin bent or rolled-up graphite sheets.