pH对酪蛋白/十二烷基硫酸钠体系泡沫性能及泡沫分离酪蛋白的影响

为强化表面活性剂对起泡性差的蛋白质泡沫分离,以酪蛋白/十二烷基硫酸钠(SDS)为研究体系,用吊环法和Ross-Miles法分别研究了pH对酪蛋白/SDS体系表面张力、泡沫性能的影响,在此基础上考察了pH对SDS辅助酪蛋白泡沫分离效果的影响。结果表明,20℃条件下,随着pH下降,酪蛋白/SDS体系的表面张力下降,起泡高度变大,泡沫半衰期增长。在气速为120mL·min-1,SDS浓度为0.03g·L-1,酪蛋白浓度为0.05g·L-1,装液量为850mL条件下,SDS辅助酪蛋白泡沫分离的最佳pH为3.4,偏离了酪蛋白的等电点(pI=4.8),在此条件下酪蛋白泡沫分离的富集比为96.37,回收率为25.12%。     

连续泡沫分离塔回收水溶液中钼(Ⅵ)的研究

以十六烷基三甲基氯化铵为表面活性剂,在连续稳态操作条件下,研究了泡沫塔和填料泡沫塔回收水溶液中微量Mo(Ⅵ)的分离性能。结果表明:随鼓泡区高度的增加,泡沫塔的富集率逐渐增加,回收率逐渐减小;随填料层高度的增加,填料泡沫塔的回收率增加,富集率减小;随泡沫层高度的增加,两种塔的富集率均逐渐增加,回收率均逐渐减小。泡沫塔内的浓度分布基本一致,表明泡沫塔存在较大的液相返混,填料泡沫塔内浓度分布随填料层高度的增加而增大,表明填料泡沫塔的液相返混程度较泡沫塔小。填料的加入有效增大了气液传质面积,提高了气液传质速率。填料泡沫塔的回收率远高于泡沫塔,但富集比略有下降。在实验条件范围内,填料泡沫塔中Mo(Ⅵ)的回收率可达99.8%,富集率可达12.2。     

基于甘草配伍黄芩同时泡沫分离甘草酸和黄芩苷

为了同时分离甘草中有表面活性的甘草酸和黄芩中无表面活性的黄芩苷,开发了甘草配伍黄芩泡沫分离工艺。通过荧光光谱、紫外吸收光谱和红外吸收光谱分析表明,甘草酸与黄芩苷存在相互作用,并且甘草黄芩配伍强化了甘草酸和黄芩苷的提取。以甘草酸和黄芩苷的富集比和回收率为评价指标,当温度为40℃、气体体积流量为100 ml·min^-1、甘草酸初始浓度为0.2 g·L^-1、甘草黄芩质量比为3：1时,获得甘草酸的富集比和回收率分别为11.0和73.5%,黄芩苷的富集比和回收率分别为5.8和38.5%。通过甘草与黄芩配伍,利用泡沫分离获得黄芩中的黄芩苷。同时,与单独泡沫分离甘草中甘草酸相比,甘草酸的富集比提高了194.9%,回收率提高了23.3%。因此,甘草配伍黄芩能有效泡沫分离甘草酸和黄芩苷。     

激光成像技术在气泡生成行为研究中的应用

针对液相中单喷嘴的气泡生成过程,采用激光成像技术结合电荷耦合器件(Charge Coupling Device, CCD)摄像机照相方法研究了甘油水溶液中的气泡生成行为,结果表明该法能够获得清晰的二维气泡放大图像. 考察了溶液浓度、气室体积、喷嘴直径和气体流量对气泡分离体积的影响,发现气泡分离体积分别随着溶液浓度和气室体积的增大而增大;在所研究的喷嘴直径(1, 1.5和2 mm)范围内,气泡分离体积随着喷嘴直径的增大而减小;气体流量对气泡分离体积的影响与喷嘴直径有关,当喷嘴直径为1和1.5 mm时,气泡分离体积随着气体流量的升高而增大,但当喷嘴直径为2 mm时,气泡分离体积随着气体流量的升高先减小后增大.     

牛血清白蛋白和溶菌酶混合溶液的泡沫性能与其浓度的关系

生物表面活性物质的浓度对其溶液的泡沫性能有很大的影响。泡沫性能包括起泡性和泡沫稳定性。本文以初始泡沫高度和泡沫半衰期分别表征了起泡性和泡沫稳定性。首先利用Szyszkowski扩展方程和Rosen的经验模型,导出了低于临界胶束浓度(CMC)时,两种表面活性物质混合溶液的初始泡沫高度与其各自浓度的关系式;然后根据泡沫相中溶液的重力势能和表面能随气泡破裂而减小的规律,建立了低于CMC时两种表面活性物质混合溶液的泡沫半衰期与其各自浓度的关系式;最后用牛血清白蛋白(BSA)和溶菌酶(LZM)作为实验物系考察了这两种关系式的准确性。结果表明这两种关系式能准确预测BSA和LZM混合溶液的泡沫性能。在BSA和LZM混合溶液中,BSA能显著影响溶液的泡沫性能,而LZM对溶液泡沫性能的影响小。     

倾斜泡沫相的角度及长度对泡沫分离十六烷基三甲基溴化铵的影响

为了强化泡沫相排液,采用倾斜泡沫相分离塔,以传统垂直泡沫相分离塔为对照塔,以表面活性剂十六烷基三甲基溴化铵(CTAB)为体系,研究倾斜泡沫相倾斜角度和长度对富集比和回收率的影响。结果表明,倾斜角度和倾斜泡沫相长度对泡沫分离效率有显著影响。富集比随倾斜角度的增大先升高后降低,在倾斜角度为40°时达到最大值,回收率先降低后升高,在40°时达到最小值。随着倾斜泡沫相长度的增加,富集比的增加率和回收率的降低率都趋于平缓,确定倾斜泡沫相长度为650 mm。在最佳倾斜角度和倾斜泡沫相长度,装液量为250 mL、初始浓度为0.07 g·L-1、气体流量为200 mL·min-1时,倾斜泡沫相分离塔的富集比为16.7,是对照垂直泡沫相分离塔的1.8倍。     

泡沫分离除去水溶液中微量金属离子

以十二烷基苯磺酸为表面活性物质,采用泡沫分离技术分别对脱除水溶液中微量的铁、铜、钠离子的分离过程进行了研究.重点考察了溶液的pH、表观气速、表面活性剂浓度及泡沫塔装液量对分离效果的影响.结果表明在各自最佳操作条件下铁离子(Ⅲ)的去除率为95.2%,富集比为13.6;铜离子(Ⅱ)的去除率为94.6%,富集比为16.5;钠离子去除率为73.1%,富集比为32.3.与常规的表面活性剂十二烷基硫酸钠相比,十二烷基苯磺酸在泡沫分离过程结束后不会在体系中引入新的金属离子,这为探索脱盐新方法提供了依据.     

基于甘草配伍黄芩同时泡沫分离甘草酸和黄芩苷

为了同时分离甘草中有表面活性的甘草酸和黄芩中无表面活性的黄芩苷,开发了甘草配伍黄芩泡沫分离工艺。通过荧光光谱、紫外吸收光谱和红外吸收光谱分析表明,甘草酸与黄芩苷存在相互作用,并且甘草黄芩配伍强化了甘草酸和黄芩苷的提取。以甘草酸和黄芩苷的富集比和回收率为评价指标,当温度为40℃、气体体积流量为100 ml·min~(-1)、甘草酸初始浓度为0.2 g·L~(-1)、甘草黄芩质量比为3:1时,获得甘草酸的富集比和回收率分别为11.0和73.5%,黄芩苷的富集比和回收率分别为5.8和38.5%。通过甘草与黄芩配伍,利用泡沫分离获得黄芩中的黄芩苷。同时,与单独泡沫分离甘草中甘草酸相比,甘草酸的富集比提高了194.9%,回收率提高了23.3%。因此,甘草配伍黄芩能有效泡沫分离甘草酸和黄芩苷。     

气体分布器孔径对泡沫分离过程影响的研究

气体分布器孔径是控制气泡大小的重要因素,也是制约泡沫分离效率的重要因素。开发了一种高分子膜材料用于泡沫分离气体分布器,以十二烷基硫酸钠(SDS)为体系,研究了气体分布器孔径对表面过剩,质量流率,消泡液的表观液体流速,泡沫排液速率以及泡沫分离效率的影响。结果表明高分子膜材料适合用于泡沫分离塔的气体分布器。气体分布器孔径对表面过剩影响不明显,而对质量流率有显著影响。当平均孔径从23μm增大到165μm时,消泡液的表观液体流速降低89%,泡沫排液速率降低93%;SDS富集比从1.14增大到2,提高75%,回收率下降80%。由导出的富集比和回收率计算式得出的计算值与实验值吻合很好。     

相间传质对气泡聚并过程影响的实验研究

设计了一套双气泡聚并实验系统,考察了相间传质对气泡聚并过程的影响,气相采用非相变的N2,液相为挥发性的丙酮和乙醇水溶液. 利用该系统测定了25~50℃温度下,不同组分浓度、鼓泡频率和气泡直径时气泡的聚并特性. 结果表明,相间传质诱导的Marangoni效应使聚并时间随温度升高呈先减小后增大的趋势,聚并时间的分散性在较高温度下显著增大,采用聚并效率描述气泡聚并特性更合适;聚并效率在温度升高到一定程度后开始降低并趋于最小值,该值随溶液浓度增加而减小,稳定因子可定量描述Marangoni效应;鼓泡速率和气泡直径增加1倍,最小聚并效率分别减小50%和67%.     

Study on Streptomycin Sulfate Recovery by Batch Foam Separation

The feasibility of foam separation as a technique was assessed for the recovery of streptomycin sulfate from the waste solution by using an anionic surfactant sodium dodecyl sulfate (SDS). The experimental parameters examined were SDS concentration, superficial gas velocity, initial pH, and liquid loading volume. The results showed that sodium dodecyl sulfate as the surfactant for foam separation had good foaming quality and could effectively concentrate streptomycin sulfate of the aqueous solution by technology of foam separation. The enrichment ratio and the recovery rate of streptomycin sulfate were 4.0 and 85%, respectively under the best operating conditions of sodium dodecyl sulfate concentration 0.4 g/L, superficial gas velocity 300 mL/min, liquid loading volume 300 mL and initial pH 6.0 when streptomycin sulfate concentration was 0.5 g/L.     

泡沫分离法回收酶法生产生物柴油中的液体脂肪酶

采用泡沫分离法对酶法生产生物柴油过程中的水相脂肪酶进行回收并富集. 通过正交实验考察了液体脂肪酶溶液中pH值、通气速度、初始酶浓度对富集比、酶蛋白回收率和酶活回收率的影响. 结果表明,气速10 L/(L×h)、进料酶浓度0.2 g/L及pH 7.0时蛋白回收率和酶活回收率接近100%,相应的富集比为3.67;初始酶浓度对富集比和蛋白回收率有显著影响,回收过程中脂肪酶活性无损失. 甲醇的存在能显著提高回收速率,甘油的存在降低了富集比,而生物柴油的存在影响了泡沫的稳定性,要形成稳定的泡沫,生物柴油含量需小于0.01%.     

泡沫分离法提取乙醇水体系中甲基橙

采用泡沫分离法对含甲基橙的乙醇水溶液进行了提取研究. 考察了乙醇体积分数、气体流量、pH、甲基橙浓度和表面活性剂浓度对提取效果的影响,并对泡沫分离乙醇-水体系中提取中药有效成分的可行性进行了探讨. 结果表明,以十六烷基三甲基溴化铵(CTAB)为表面活性剂,在乙醇体积分数25%的乙醇-水体系中,在pH 6.0、气速80 mL/min、甲基橙浓度35 mg/L及CTAB浓度80 mg/L的操作条件下,甲基橙的富集比为14.38,回收率在98.5%以上. 在一定范围内提高表面活性剂浓度或加入稳泡剂以削弱乙醇的消泡作用,从而将泡沫分离技术应用于乙醇-水体系中中药有效成分的提取是可能的.     

Study on Riboflavin Recovery from Wastewater by a Batch Foam Separation Process

Abstract

A batch recovery of riboflavin via foam separation from industrial simulative wastewater was studied using a cationic surfactant, cetyltrimethyl ammonium bromide (CTAB). The experimental parameters examined were the surfactant concentration, air flow rate, pH, and foam height. Under optimal operating conditions obtained through an orthogonal experiment, the maximum enrichment ratio of 48.7 was achieved for riboflavin along with 99.3% removal efficiency. The optimal operating conditions had the concentration of CTAB at 0.3 g/L, air flow rate at 400 ml/min, foam height at 90 cm, and pH at 12. Therefore foam separation proved to be an effective method to recover the riboflavin in terms of the good enrichment and removal efficiency.     

Removal of mercury by foam fractionation using surfactin, a biosurfactant

The separation of mercury ions from artificially contaminated water by the foam fractionation process using a biosurfactant (surfactin) and chemical surfactants (SDS and Tween-80) was investigated in this study. Parameters such as surfactant and mercury concentration, pH, foam volume, and digestion time were varied and their effects on the efficiency of mercury removal were investigated. The recovery efficiency of mercury ions was highly sensitive to the concentration of the surfactant. The highest mercury ion recovery by surfactin was obtained using a surfactin concentration of 10 × CMC, while recovery using SDS required < 10 × CMC and Tween-80 >10 × CMC. However, the enrichment of mercury ions in the foam was superior with surfactin, the mercury enrichment value corresponding to the highest metal recovery (10.4%) by surfactin being 1.53. Dilute solutions (2-mg L(-1) Hg(2+)) resulted in better separation (36.4%), while concentrated solutions (100 mg L(-1)) enabled only a 2.3% recovery using surfactin. An increase in the digestion time of the metal solution with surfactin yielded better separation as compared with a freshly-prepared solution, and an increase in the airflow rate increased bubble production, resulting in higher metal recovery but low enrichment. Basic solutions yielded higher mercury separation as compared with acidic solutions due to the precipitation of surfactin under acidic conditions.     

泡沫分离法分离纯化无患子皂苷的研究

采用泡沫分离法分离纯化无患子皂苷溶液,收集溢出分离柱的泡沫液,采用紫外分光光度计分别测定原液和泡沫液的皂苷含量,通过富集比、回收率以及纯度表征分离效果。结果表明:在进料浓度为 2.0 g/L、进料量为 150 mL、气速为 32 L/h、温度为 30 ℃、pH值为4.3条件下,富集比可达到2.153,收率与纯度分别达到 79.19 % 和 74.68 %。     

泡沫相塔壁对泡沫分离牛血清蛋白分离性能的影响

In order to enhance foam drainage, the column with an inner sleeve in the foam phase was designed for studying effect of the column wall of foam phase on foam separation performances using bovine serum albumin(BSA) as the research system. The effects of the wall on the liquid holdup out of the top column, bubble size, enrichment and recovery percentage were investigated. The results indicated that the experimental column with the inner sleeve decreased the liquid holdup, accelerated the coarsening and coalescence of bubbles and increased enrichment of BSA compared the contrasted column without the inner sleeve. Under the conditions of the initial concentration 0.2 g?L-1 of BSA, air flow rate 400 ml?min-1, the experimental column achieved up to a 2.06 fold increase in enrichment compared to the contrasted column. The enrichment of BSA increased with the increase of inner sleeve length. Channel theoretical analysis showed that the ratio of exterior channels to interior channels increased with the increase of bubble diameter. So the experiment column obtained the better performances at the lower concentration and the lower air flow rate. The better performances obtained by experimental column showed that the drainage rate of plateau borders on wall was greater than that of plateau borders between bubbles. So the inner sleeve provided more plateau borders on wall and improved foam drainage.     

Protein Removal from Whey Waste by Foam Fractionation in a Batch Process

The work investigates the separation of proteins from whey waste collected from a local confectionery by the foam fractionation technique in batch mode. The purpose of this work was to evaluate performance criteria of protein separation. The effects of pH, the concentration of initial feed solution, the nitrogen flow rate, the % gas hold up, the bubble diameter, the breaking time of foam, and the optimization of the protein–surfactant ratio (1.5:1) were investigated in detail. Maximum enrichment ratio (48.189), %Rp (96.378) were observed at a gas flow rate of 330 ml/min and pH 5 that is closest to isoelectric point of observed proteins (Bovine serum albumin, β-Lactoglobulin, α-lactalbumin).     

Study on Technology of Simultaneous Removal of Copper Ion and Crystal Violet in Aqueous Solution by Foam Separation

A system for the removal of Cu²⁺ and crystal violet from aqueous solution by foam separation was used. The goal of this work was to explore a method for simultaneous desalination and decolorization by foam separation. In the aqueous solution of this work, Cu²⁺ was used for studying desalination and crystal violet was used for studying decolorization, respectively, and dodecyl benzene sulfonic acid (DBSA) (C₁₈H₂₉SO₃H) was used as a surfactant. The effect of surfactant concentration, pH, superficial velocity, and foam height on the removal percentage and the enrichment ratio were studied to optimize the conditions. Under the optimum conditions, the removal percentage of Cu²⁺ and crystal violet were 96.5% and 96.3%, respectively, and the enrichment ratio of Cu²⁺ and crystal violet were 3.7 and 3.6, respectively.     

Separation of Tea Saponin by Two-Stage Continuous Foam Fractionation

A technology of two-stage continuous foam fractionation for tea saponin recovery was studied for increasing both the enrichment ratio and the recovery percentage. In the first stage, the effect of air flow rate, the initial pH, the feed flow rate, and the feed position were studied at a temperature of 60°C. The results showed that when the conditions of the first stage were at a temperature of 60°C, air flow rate 150 mL/min, pH 5.3, feed flow rate 1.92 mL/min, and feed position at the interface between the liquid phase and the foam phase, the enrichment ratio, and the recovery percentage of tea saponin were 4.02 and 56.4%, respectively, and the effluent solution was added to the second stage as the initial solution. When the conditions of the second stage were at a temperature of 30°C and an air flow rate of 300 mL/min, the recovery percentage of tea saponin reached 47.6%, and the foamate was added to the first stage as feed solution. The total recovery percentage of tea saponin reached 86.3% by the two-stage continuous foam fractionation.