三聚磷酸钠对硅微粉-水泥浆体zeta电位的影响

采用高浓度zeta电位分析仪,分析不同掺量的三聚磷酸钠对硅微粉-水泥浆体在不同pH值条件下zeta电位的影响。结果发现,不同掺量三聚磷酸钠对不同掺量的硅微粉-水泥浆体初始p H值影响不大。在硅微粉-水泥体系中,相同分散剂条件下,硅微粉掺量越多,浆体分散性越差,而相同硅微粉条件下,分散剂掺量越多,浆体分散性越好。     

阳离子聚丙烯酰胺对克雷伯杆菌絮凝效果的研究

采用有机絮凝剂阳离子型聚丙烯酰胺对克雷伯菌菌悬液进行絮凝处理。探讨了浓度、pH值、温度、助滤剂对絮凝剂絮凝及过滤性能的影响,并采用光学显微镜和扫描电子显微镜对菌悬液、絮凝剂和絮体3个方面进行了絮凝形态观察。结果表明,絮凝剂浓度为0.08 g/L,pH=7,温度为37℃时絮凝效果最佳。添加助滤剂Al2(SO4)3.18H2O、CaCl2.2H2O后过滤效果有明显的提高,且絮凝颗粒增大,沉降速度加快。     

蛋白质zeta电位与离子交换层析容量因子的相关性研究

针对蛋白质离子交换层析分离过程预测的困难,选择zeta电位作为中间参数,建立zeta电位与层析容量因子之间的关联.选择牛血清白蛋白(BSA)作为模型蛋白质,考察了pH、离子浓度、离子种类等对蛋白质zeta电位的影响,证实了zeta电位作为蛋白质表面电荷特性表征参数的可行性.以阴离子交换Sepharose FF DEAE为模型层析介质,测定了BSA在不同pH和盐浓度下的容量因子.综合考虑蛋白质和介质两方面因素,选择两者zeta电位乘积(-ζ1×ζ2)作为中间参数,对于不同pH和盐浓度的流动相,(-ζ1×ζ2)与容量因子的对数呈现良好的线性关系,实现了由简便的zeta电位分析预估宏观离子交换层析分离行为的目的,该关联关系的建立将有助于层析分离过程的优化设计.     

阳离子型聚丙烯酰胺合成与絮凝特性研究

以丙烯酰胺、甲基丙烯酸二甲胺乙酯氯甲烷盐,丙烯酸二甲胺乙酯氯甲烷盐为组份合成阳离子型聚合物,比较了它在污水处理中的絮凝效果.     

一类新型聚丙烯酰胺的合成与絮凝性能研究

以高价铈盐（硝酸铈铵）和多羟基化合物季戊四醇组成的氧化还原引发体系引发丙烯酰胺自由基聚合合成了一类新型多支状非离子型水溶性聚丙烯酰胺。确定了最佳合成工艺条件为：单体质量分数为15％、引发剂用量1mmol·L^-1、反应时间12h、反应温度47℃,此条件下合成得到的新型聚丙烯酰胺相对分子量达400万以上。研究了新型聚丙烯酰胺的絮凝性能,结果表明,当其与无机絮凝剂聚铝复配时絮凝效果较好,模拟污水的透光率由原来的30％提高至90％以上。     

煤泥水溶液化学环境对絮凝效果影响的研究

通过测定pH值、Ca^2＋、Mg^2＋对煤泥颗粒zeta电位的影响,研究了煤泥水溶液化学环境对絮凝效果的影响。     

聚丙烯酰胺絮凝作用的表面形态研究

用扫描电镜观察了非水解型和水解型聚丙烯酰胺及其絮凝物的表面形态，发现随水解度增大，表面形态发生明显变化，这种变化与絮凝效果对比实验的结果一致     

脂质体的粒度及zeta电位表征研究

<正>为成功实现药物传输,理想的途径是将治疗制剂靶向传输至所需位置,实现对受药组织与药物间相互作用的监测。可广泛运用于全身及局部给药的脂质体对这一应用的需求不断上升。由于具备液体、固体、半固体配方携载能力,脂质体已应用于针对真菌感染、甲肝、急性淋巴细胞白血病等疾病的治疗实践中。脂质体的物理表征对配方改良及研发具有十分重要的意义。本文将探讨两项相关辅助技术的成功应用:一是用于检测脂质     

钻井废水的电荷中和絮凝作用研究

研究了钻井废水中悬浮固相颗粒表面电荷被絮凝剂电荷的中和作用,探讨了废水的化学脱稳和絮凝效率．结果表明,当固相颗粒表面 电位分别被2500mg／LAl2(SO4)3和300mg／LCPAM中和为OmV,悬浮液的毛细管抽吸时间CST值被降低到100s以下时,钻井废水达到了化学脱稳。将2300mg／L A12(SO4),与400mg／LCPAM复配使用,对钻井废水中20μm以下细小颗粒的电荷中和絮凝作用能够使其减少到1．2％,分离水的浊度达到30FUN,色度26度,COD95mg／L。     

P(AM-DBC)的制备及其絮凝性能研究

针对难处理的含油污水,以丙烯酰胺(AM)和丙烯酰氧乙基二甲基苄基氯化铵(DBC)为单体,通过反相微乳液聚合方法合成了疏水缔合型阳离子聚合物P(AM-DBC),并进行红外光谱表征。考察了单体质量比、引发剂用量、反应温度、反应时间对P(AM-DBC)分子质量和转化率的影响,并将P(AM-DBC)应用于辽河油田含油污水的絮凝实验,结果表明P(AM-DBC)阳离子度约为9%、相对分子质量为400万左右时絮凝效果最佳,投加量为20 mg/L时除油率达到97%,浊度去除率为95%。     

Oxidation of cod phospholipids in liposomes: Effects of salts,pH and zeta potential

This work examines how different salts and pH influence both the zeta potential and the lipid oxidation rate of liposomes made from cod phospholipids. The rate of Fe²⁺‐induced lipid oxidation was measured by consumption of dissolved oxygen by liposomes in a closed vessel. Cations (Na⁺, K⁺, Ca⁺, Mg⁺) did not influence the rate of oxidation in the tested range [ionic strength (I) 0–0.14 M). Among the tested anions, sulphates and nitrates did not significantly change the oxygen uptake rate, but chlorides (KCl, NaCl, CaCl₂) reduced the oxidation rate down to approximately 45%, and dihydrogen phosphate down to 14%, when I = 0.14 M. The effect of Cl^? and H₂PO4₄^? was additive. Addition of salts increased the zeta potential of the liposomes, divalent cation salts even resulted in a positive zeta potential. When the liposomes contained different concentrations of chlorides, a linear relationship between oxygen uptake rate and zeta potential was observed. When phosphate was added, the oxygen uptake rate was not related to the changes in zeta potential. The decrease in pH was followed by an increase in zeta potential. The oxygen uptake rate did not change significantly at different positive zeta potentials (pH <3). When the zeta potential was negative, the oxygen uptake rate was influenced by the zeta potential and may also be influenced by iron solubility. Absolute values of the zeta potential alone cannot be used to predict oxidation rates.     

Effect of pH and zeta potential of Pickering stabilizing magnetite nanoparticles on the features of magnetized polystyrene microspheres

Styrene as a monomer was emulsified in water using several magnetite nanoparticles concentration and pH values. Emulsified styrene drops were used as templates for polymerization, in presence of water soluble free radical initiator, and formation of composite particles. Styrene template drops stabilization was verified by light as well as scanning electron microscopy imaging, which ensured the participation of the particles in building up a mechanical barrier to stop oil drops coalescence. Furthermore, the produced polystyrene composites were strongly attracted to an external magnet. The difference in particles size as a function of pH was elucidated using zeta potential measurements, which indicated dominance of pH on the hydrophilicity of the particles and consequently the extent of emulsification, which in turn affected the size of the obtained microspheres. Under some circumstances, capsules were formed instead of particles. Thereby, it can be concluded that the magnetic microspheres are optimally formed at pH 2.3 independently of the magnetite content used.     

Yield stress-zeta potential relationship of oxide dispersions with adsorbed polyacrylate — Steric effect and zeta potential at the flocculated-dispersed transition state

The yield stress-DLVO force relationship is obeyed by α-Al₂O₃ and alumina-coated TiO₂ dispersions with adsorbed polyacrylate only if the yield stress and its corresponding zeta potential data were collected in the positively charged region. In this region, the underlying surface positive charge density of the particles exceeds the negative charge density of the polyacrylate. At this state the adsorbed polyelectrolyte lies flat on the particle surface forming a steric layer of fixed thickness at a given polymer concentration. In the negative charge region, the steric layer thickness is not constant and hence yield stress-DLVO relationship is not obeyed. The (critical) zeta potential at the flocculated-dispersed transition state decreases with increasing polymer concentration. This result reflects a decreasing van der Waals force as the steric layer increases in thickness. A steric layer ensured that the surface or zeta potential is sufficiently low in the flocculated regime for the DLVO theory to remain valid. The ratio of the critical zeta potential square between alumina-coated TiO₂ and α-Al₂O₃ is an indication of their Hamaker constants ratio in water. The effect of alumina coating on the value of this ratio is presented and discussed.     

Nanoparticles for convective heat transfer enhancement: heat transfer coefficient and the effects of particle size and zeta potential

This work presents a study of using the Wilson Plot method to determine the convective heat transfer coefficient (CHTC) of the following nanoparticles in water as the base fluid: SiO₂, TiO₂, and Al₂O₃. The experiments were carried out in a double layer concentric glass tube in which the hot fluid and nanofluids exchange heat in a counter current fashion without direct contact. Attention was also given to the volumetric concentration, flow rate, and the size of nanoparticles to investigate their effects on CHTC. From the experiments, it was found that by adding nanoparticles, the CHTC of water can generally be enhanced and a 45% increase has been achieved with a 0.5?vol% concentration of Al₂O₃ nanoparticles at an intermediate Reynolds number around 4100. Moreover, simply reducing nanoparticle size and increasing the nanofluid flow rate do not necessarily lead to the CHTC enhancement, rather, they have adverse effects. It is concluded that the enhancement depends on the stability of the dispersed nanoparticles that can be characterized by their overall mean size and zeta potential as useful measures.     

煤中芳核侧链模型化合物丁基蒽的初次热解

利用Gaussian 03 程序包中的DFT/B3LYP方法, 在6-311G基组上对煤的模型化合物正丁基蒽烷基侧链热解机理进行了研究,计算了不同温度下各反应路径的热力学参数及产物自由基的前线轨道能级差。结果表明:正丁基侧链上最容易发生的反应是β位C—C键的断裂;在正丁基蒽的3个同分异构体中连在γ位的侧链反应活性最高;芳环尺寸对烷基侧链的β位C—C键有一定的影响,但对其他C—C键影响不大。     

酵母细胞连续发酵过程振荡现象的研究进展

振荡现象在连续发酵过程中普遍存在,本文综述了酿酒酵母连续发酵中不同类型振荡现象的研究进展。一类以乙醇连续发酵过程中参数振荡为代表的特殊振荡现象,普遍存在于工业发酵过程,对发酵系统的稳定运行造成不利影响。本文论述了这类振荡现象产生的机理、调控策略的研究进展及其潜在的应用价值。     

酸性离子液体作催化剂的硝基苯加氢合成对氨基苯酚

针对硝基苯催化加氢合成对氨基苯酚(PAP)的过程,提出了Pt/SiO2和新型季铵型Brφnsted酸性离子液体N,N,N-三甲基-N-磺丁基硫酸氢铵(［HSO₃-b-N(CH₃)₃］HSO₄)构成的双功能催化体系。考察了离子液体浓度、Pt/SiO₂用量及操作条件对对氨基苯酚收率和选择性的影响。并与硫酸体系进行了对比。在85℃、4 h、0.4 MPa条件下,硝基苯转化率96.6%,对氨基苯酚的选择性为81.4%,优于Pt/SiO₂和硫酸溶液体系。可能的原因是,离子液体增加了硝基苯溶解度,并且抑制了中间产物苯基羟胺的深度加氢。反应后用减压过滤可分离出Pt/SiO₂催化剂;滤液经由萃取、减压蒸馏和结晶析出PAP。结果证明,该双功能催化体系重复使用3次,PAP收率没有明显的下降。     

新筛选菌种Delftia sp.XYJ5生物降解苯胺的途径

A promising gram-negative bacterial strain for the biodegradation of aniline as the sole carbon, nitrogen and energy sources was successfully isolated and identified as Delftia sp. XYJ6. The optimal temperature and pH for both the growth of Delftia sp. XYJ6 and the biodegradation of aniline were 30°C and 7.0, respectively. Initial aniline of 2000 mg&#8226;L－1 could be completely removed by the strain at 22 h, which showed that Delftia sp. XYJ6 had a strong ability in the biodegradation of aniline. It indicated that aniline was firstly converted to catechol catalyzed by aniline dioxygenase as a first product, which was then further biodegraded to cis,cis-muconic acid catalyzed by the catechol 1,2-dioxygenase of Delftia sp. XYJ6 as a second product. Cis,cis-muconic acid could also be further biodegraded to other small compound again. The pathway for the biodegradation of aniline by Delftia sp. XYJ6 was not previously reported.     

嗜酸氧化亚铁硫杆菌在沥青铀矿石浸出中的作用

为了研究沥青铀矿石的细菌浸出机理,设计了有菌有铁、有菌无铁及无菌无铁3种矿粉浸出试验及有菌无铁、无菌无铁两种试块浸出试验,检测了矿粉浸出体系中细菌的浓度、pH值、Eh、亚铁离子浓度、总铁离子浓度及铀浓度的变化,分析了浸出尾渣中O、Mg、K、P、S、Fe、U等元素的含量,观测了浸出前后试块表面形貌的变化。结果表明,在沥青铀矿石浸出过程中,嗜酸氧化亚铁硫杆菌可以高效氧化浸出体系中的亚铁、还原态硫及元素硫,使得浸出体系中的Eh升高和pH值降低;有菌有铁浸出体系中,高浓度的细菌、高浓度的铁、低pH值和高Eh可加速铀矿石的浸出和提高铀矿石的浸出率;有菌无铁浸出体系中,即使总铁离子浓度很低,但由于有细菌的存在,同样可以加速铀矿石的浸出和提高铀矿石的浸出率。有菌无铁的试块浸出中,试块表面出现了许多溶蚀坑,这表明细菌对铀矿石具有直接氧化作用。