表面活性剂浓度对泡沫体系稳定性的影响

主要探讨了在泡沫体系内,表面活性剂对泡沫稳定性的影响,以表活剂浓度为主要研究点,总结了不同表活剂浓度下气泡的聚并过程,还分析了液膜的排液过程,指出界面流变学因素以及表活剂高浓度情况下的胶束分层现象是影响泡沫稳定的主要因素.表活剂浓度低于CMC时,界面流变学因素起主要决定作用;表活剂浓度高于CMC时,胶团分层起主要决定作用.     

Separation of oil contaminants by surfactant-aided foam fractionation

The separation of oily contaminants out of aqueous/non-aqueous phases using foam fractionation with a surfactant was investigated. In the separation of the light oil (hexadecane), the eluted amount of oil and the o/w (oil/water) ratio increased with the weight percentage of SDS (sodium dodecyl sulfate); and the ratio actually remained the same above the CMC (critical micelle concentration) point (0.23 wt% of SDS). Most of the oil was eluted even at 49:1 initial o/w ratio with the surfactant. For the heavy oil (carbon tetrachloride), the eluted o/w ratio and the oil recovery had maxima at 0.05 and 0.1 wt% of SDS solution, respectively, even though the overall recovery of 20–30 % was much lower than that of 80–100 % in the light oil. It was speculated that emulsion formation might affect oil entrapment in the foams. Higher gas flow rates, in general, increased the oil recovery, but did not increase the o/w ratio in the effluents.     

泡沫分离回收水中低浓度磷酸三丁酯

以吐温系列表面活性剂采用泡沫法回收水中的微量磷酸三丁酯．实验结果表明,在本实验条件下,泡沫法可以回收水中的磷酸三丁酯,磷酸三丁酯的提浓率与残留率与起始磷酸三丁酯浓度、起始表面活性剂浓度和表面活性剂种类有关。     

EFFECT OF SURFACTANT CONCENTRATION ON GAS HOLDUP IN A BUBBLE COLUMN WITH AN ORGANIC LIQUID

This work presents an experimental analysis of the effect of the addition of a surfactant on gas holdup in a bubble column with an organic liquid phase. For the system considered, the addition of surfactant increases the gas holdup by increasing the volume of foam within the column. The surfactant concentration has negligible effect on the intrinsic gas holdup of both the bubbling and foaming regions.     

泡沫分离技术及其发展现状

探讨了泡沫分离技术的原理、泡沫分离设备及泡沫分离技术的研究进展。泡沫分离过程的性能受很多因素的影响 ,例如 ,进料液浓度、气泡尺寸、气体流量、泡沫的排液、进料位置、聚并、温度等。阐述了现有的几种新技术 ,如低重力条件操作、通过压力梯度而提高分离效率。此外 ,还简要介绍了泡沫分离塔中传质单元数和传质单元高度的概念。     

Experimental investigation of foam performance in the presence of crude oil

The foam performance in the presence of oil plays an important role in foam application in enhancing oil recovery. The present study systematically investigated the effect of oil type, oil content, surfactant type, surfactant concentration, alkane chain length, salinity, and polymer concentration on foam performance in both the absence and presence of oil. The results showed that oil viscosity and oil density as well as oil component all contributed to foam performance in the presence of oil. Within a certain oil content, both light oil and heavy oil had a positive effect on foam, but heavy oil had a higher tendency to stabilize the foam. The order of foam performance by different surfactants was changed by the oil. It is noteworthy that heavy oil is detrimental to sodium dibutyl naphthalene sulfonate (BM) foam. Light oil can improve foam performance while heavy oil can harm foam in some specific cases. Lower salinity, longer alkane chain length, higher surfactant concentration and the presence of a polymer all benefited foam in the presence of crude oil.     

Mechanism Study on the Severe Foaming of Rhamnolipid in Fermentation

Although the biosurfactant rhamnolipid has been previously characterized as having low foam ability, its fermentation is largely impeded by severe foaming. Hence, the investigation of this paradox is critically important for improving the mass production of rhamnolipid. Unexpectedly, the hydrophobic cell, instead of rhamnolipid, has been claimed to explain such severe foaming in rhamnolipid fermentation. This study tried to systematically investigate the severe foaming in fermentation, aiming to propose an effective strategy for foam control. The overflowing foam sustained a super high stability in terms of half‐time for over 30 min. The major product of rhamnolipid largely contributed to the severe foaming in the fermentation process whereas other products like cells elicited much more limited effects. Furthermore, the foam stability of the fermentation broth increased with rhamnolipid concentration and noticeably increased with agitation speed. In the classic Bikerman foam test system without stirring, rhamnolipid showed foam stability as low as Tween 20 which is well known for its poor foam stability. However, in a stirring Bikerman system, rhamnolipid exhibited a foam stability almost as high as sodium dodecyl sulfate (SDS) at 10 g/L and even surpassed SDS at a higher concentration of 20 g/L. Hence, the extraordinarily increased foam stability of rhamnolipid with both agitation and concentration could explain the severe foaming at its late‐stage fermentation when rhamnolipid‐rich solution is mechanically agitated.     

化学镀钴液中钴(Ⅲ)的分光光度测定

研究了钴（Ⅲ）－１－（２－吡啶偶氮）－２－萘酚（ＰＡＮ）及溴化十六烷基三甲铵（ＣＴＭＡＢ）体系测定钴。钴与ＰＡＮ二元配合物摩尔吸光系数可达９４～１０３Ｌ·ｍｏｌ－１·ｃｍ－１，加入表面活性剂后，钴与ＰＡＮ生成三元配合物，摩尔吸光系数值提高到２１２～１０４Ｌ·ｍｏｌ－１·ｃｍ－１，钴含量在０～２５μｇ／５０ｍｌ范围内符合比耳定律，方法应用于测定化学镀钴液中钴的测定。     

结构型阻燃聚氨酯软泡塑料的研制

本文介绍了一种含P、Cl元素的结构型阻燃聚氨酯软泡塑料的制造方法及性能。通过磷酸、三羟甲基丙烷和环氧氯丙烷的缩合和聚合反应制得阻燃树脂,然后将它与己二酸、一缩二乙二醇在一定条件下反应制得含P1.5%和含Cl17～18%的聚酯多元醇,再将它与多异氰酸酯、水、催化剂等组分采用一步法发泡工艺制得阻燃聚氨酯软泡塑料。产品性能达到国内外同类产品水平:拉抻强度0.15MPa、伸长率184%、回弹性18.2、氧指数26、火焰传播速度0.4mm/S、密度58kg/m~2。该软泡塑料避免了添加型阻燃软泡塑料存在的耐老化性差、阻燃剂分布不均等弊病,而且发泡工艺简单、设备投资少、易于操作管理。     

Coalescence of air bubbles in aqueous solutions of alcohols and nonionic surfactants

Coalescence of air bubbles in aqueous solutions of two aliphatic alcohols (viz. butanol and hexanol) and four nonionic surfactants (viz. Tween 20, Tween 40, Tween 60 and Tween 80) is reported in this work. Single-component alcohol and surfactant solutions as well as mixed binary surfactant–alcohol solutions were studied. Adsorption of the surface active compounds at air–water interface was studied by measuring the surface tension of the aqueous solutions. The critical micelle concentration and surface tension at this concentration were determined for the single and mixed surfactant–alcohol systems. The effect of concentration of surface active compounds on coalescence of air bubbles at flat air–water interface was studied. The role of electrostatic double layer, hydration and steric forces on coalescence was investigated. It was found that the stability of the thin aqueous films in mixed surfactant–alcohol systems depends on the subtle interplay of the intermolecular and surface forces in the film, which vary with the composition of the monolayer at the air–water interface. Stochastic distributions of coalescence time were observed in all systems. The coalescence time distributions were fitted by the stochastic model. The mean values of the distributions were compared with the predictions of seven film-drainage models.     

Effect of Temperature on Foaming Ability and Foam Stability of Typical Surfactants Used for Foaming Agent

Foam has extensive applications in a wide range of industrial fields. Some surfactants are used as foaming agents in the preparation of foam. The performance of the foaming agent directly affects the application of the foam. In this paper, experiments were designed and conducted to reveal the influence of temperature on foaming performance of 10 typical anionic, cationic, nonionic, and amphiprotic surfactants. They were exposed to different temperature conditions to measure the foaming capacity (FC), foaming expansion (FE), and foam’s half-life. FC and FE represent foaming ability (FA), and half-life represents foam stability (FS). The results show that the FC increased at elevated foaming temperature, while FS decreased with rising temperature. Anionic surfactants are less affected by temperature and have better FA and longer FS. It seems that 20–30 °C is an ideal foaming temperature. This study lays an important foundation for the efficient preparation and utilization of foam in industrial fields.     

Stability of foams containing proteins, fat particles and nonionic surfactants

The foamability of aqueous suspensions of proteins and fat particles containing different nonionic surfactants relevant to ice cream mix, through which air is continuously bubbled in a foam column, is investigated in terms of the growth of the foam until steady state is reached. Less water-soluble but more oil-soluble Spans 20, 80 and 85 (monolaurate, monooleate and trioleate of Sorbitan) reduced significantly the steady-state foam height and hence the foamability by enhancement of bubble coalescence. In contrast, highly water-soluble Tweens 20 and 80 increased only slightly the steady-state height of the foams as compared to that obtained using surfactant-free suspension. However, moderately water- and oil-soluble Tween 85 (polyoxyethylene sorbitan trioleate) decreased the foamability more significantly than the Spans. The bubbles are found to be small and coalesce relatively fast at the bulk air interface. The bridging of the fat particles by the three oleates could weaken the protein and fat network thereby reducing the elasticity of the air-aqueous phase interface. This is corroborated by the lowest interfacial elasticity measured using a biconical disc oscillatory rheometer. The stability of the foams formed is also determined by measuring the decrease in foam height and increase in mean bubble diameter with time after stopping the air flow. The results are found to verify a published theoretical model, which enabled to determine the parameters controlling foam stability. The Spans reduced the foam stability as the bubbles coalesced rapidly with bulk air. In contrast, the Tweens increased the foam stability as the bubbles coalesced very slowly. The increase of foam stability by Tween 85 under quiescent conditions is consistent with the measured high interfacial shear viscosity.     

Synergistic Effect of Mixed Surfactant Systems on Foam Behavior and Surface Tension

Foam and surface tension behaviors of different ionic/nonionic surfactant solutions along with their different combinations have been investigated. Among different surfactants, sodium dodecyl sulfate showed the highest foamability over other surfactants. Mixed surfactant systems were always found to have higher foamability than the individual surfactant. It was also noticeable that nonionic surfactants show good foamability when they combine with anionic and cationic surfactants. In the case of mixed surfactant systems, nonionic/cationic surfactant mixtures showed lower surface tension than nonionic/anionic surfactant mixture due to a synergistic effect.     

含酰胺键的单子表面活性剂性能研究

本文以苯胺、对甲氧基苯胺、氯乙酰氯为原料,通过酰胺化反应在中间体分子结构中引入酰胺键,中间体再分别与N,N-二甲基癸胺、N,N-二甲基十二胺、N,N-二甲基十四胺通过季铵化反应,合成两个系列表面活性剂,即系列Ⅰ和系列Ⅱ,利用1H-NMR和IR对结构进行表征。在25℃条件下,测定系列Ⅰ和系列Ⅱ表面活性剂的临界胶束浓度、起泡性、稳泡性和乳化能力。系列Ⅰ和系列Ⅱ表面活性剂中,Ⅱ14的CMC值最小为0.50 mmol/L,Ⅰ14和Ⅱ14稳泡性最好为100%,Ⅰ12的乳化时间最长为1602 s。相同条件下,传统表面活性剂十二烷基二甲基苄基氯化铵（BAC-12）的CMC值为9.51 mmol/L,稳泡性为44%,乳化时间为366 s。结果表明,系列Ⅰ和系列Ⅱ表面活性剂具有良好的表面活性、起泡性、稳泡性和乳化性。     

混炼工艺对NBR/PVC发泡材料性能的影响

研究了密炼和开炼两种混炼方式及不同的密炼温度对丁腈橡胶(NBR)/聚氯乙烯(PVC)发泡材料性能的影响。结果表明,混炼温度相同时,密炼工艺比开炼工艺的塑化共混效果更好,胶料的门尼黏度更高,发泡材料性能更优;在130～160℃的密炼温度范围内,密炼温度为150℃时得到的发泡材料密度最低、硬度较高。     

泡沫接触式冷却器工艺设计

依据泡沫接触式冷却器结构特性 ,采用数学模型方法 ,结合实例 ,提出了工艺设计方法 ,包括冷却器截面积、泡沫层高度、冷却器外加水量及空气流动的压力损失。可用于指导泡沫接触式冷却器的开发设计和生产运行     

制备凝胶色谱在聚氨酯匀泡剂组成分析中的应用

用制备凝胶渗透色谱分离聚氨酯匀泡剂的混合组分,并对分离的组分进行了凝胶色谱、红外光谱等分析。对两个混合组分的聚氨酯匀泡剂的剖析结果进行了讨论。