泡沫分离法除去水溶液中微量铜离子的工艺

以十二烷基苯磺酸为表面活性物质,自制的单金属离子水溶液为研究体系,对泡沫分离法除去水溶液中金属离子的工艺进行了研究,重点考察了溶液的pH、鼓泡气体流量、表面活性剂浓度及泡沫塔装液量的影响. 结果表明,十二烷基苯磺酸具有良好的起泡性能,对水溶液中铜离子的去除效果也比较理想,最佳操作条件下富集比为18.2,去除率为96.1%,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残留金属离子,这为探索脱盐新方法提供了依据.     

泡沫分离除去水溶液中微量硫酸根离子

以十六烷基三甲基氢氧化铵为表面活性物质,采用泡沫分离技术对去除水溶液中微量硫酸根离子进行了研究,重点考察了溶液的pH、鼓泡气体流量、表面活性剂浓度及泡沫塔装液量的影响. 结果表明,十六烷基三甲基氢氧化铵具有良好的起泡性能,对水溶液中硫酸根离子的去除效果比较理想,在溶液pH 10、气体流量0.036 m3/h、装液量900 mL、表面活性剂浓度0.13 g/L的条件下,溶液中的SO42-能很好分离(富集比为22.4,去除率为94.1%). 与其他阳离子表面活性剂相比,十六烷基三甲基氢氧化铵在泡沫分离结束后不会在水溶液中引入新的酸根离子,为进一步探索脱盐新方法提供了依据.     

泡沫分离除去水溶液中微量硫酸铜

为了探索设备和工艺简单、低污染、生产过程费用低的脱盐新方法,以十二烷基苯磺酸和十六烷基三甲基氢氧化铵为表面活性物质,采用泡沫分离技术对脱除水溶液中微量的硫酸铜进行了研究.重点考察了溶液的pH、表观气速、表面活性剂浓度,泡沫塔液面高度及改变分离阴阳离子的先后顺序对分离效果的影响,在最佳操作条件下:CuSO_4的去除率达到97.2%,富集比达到4.2.与其他表面活性剂相比,没有向溶液中引入新的金属离子和酸根离子,从而为脱盐提供了新的方法和依据.     

大豆蛋白废水中乳清蛋白的泡沫分离实验

采用泡沫分离法回收大豆蛋白废水中蛋白,考察了pH值、气体的流速、进料浓度、液柱和泡沫层高度等因素对分离效果的影响.低进气速度、高泡沫层高度、适当的pH值以及低进料浓度有利于较好的分离.结果表明:当进料浓度为0.54 g/L、pH值为5、泡沫层与液池高度比4∶1,通气量为15.0 L/h 时,富集比可以达到3.25;当进料浓度为0.54 g/L、pH值为5、泡沫层与液池高度比3∶1,通气量为15.0 L/h,此时脱除率可以达到48.5%.     

壳聚糖分离富集分光光度法测定微量镍

研究了壳聚糖对Ni(Ⅱ)的富集、洗脱性能及苯并噻唑重氮氨基偶氮苯BTDAB与Ni(Ⅱ)的显色反应,建立了微量镍的分离富集光度测定新方法。实验表明,壳聚糖对Ni(Ⅱ)吸附性能良好,其吸附的最佳pH为8.0,吸附在4h内已基本达到平衡;在非离子表面活性剂Triton X-100的存在下,BTDAB与Ni(Ⅱ)形成3:1的橙红色配合物,最大吸收波长位于550nm处,表观摩尔吸光系数为1.64×105L·mol-1·cm-1,镍含量在0-10μg/25mL范围内符合比尔定律。方法直接应用于废水中微量镍的测定,结果令人满意。     

泡沫分离设备的研究进展

作为一种新型分离技术,泡沫分离技术具有设备简单、能耗低、易于操作、低浓度条件下效率高和无污染等优点,该技术在降低表面活性物质分离成本方面具有极大的潜力,在工业上得到了广泛的应用。本工作分析了近年来文献报道中应用于分离回收蛋白质、有机污染物、天然产物、金属离子、微藻等的各种泡沫分离设备,并结合泡沫分离技术的发展历程将其分为传统泡沫分离设备和改进泡沫分离设备。重点阐述了改进泡沫分离设备的作用机理和分离效果,突显泡沫分离技术的重要性。改进型泡沫分离设备在一定程度上提高了分离效果,但依然存在一些问题,如很多设备在提高富集比的同时也降低了回收率。     

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。     

钛白粉中微量锡的分离与测定

通过选用强碱性的氢氧化钠作为熔剂,使微量的锡与大量的钛分离,而溶液中残余的极少量钛用过氧化氢掩蔽,从而实现了大量钛存在下微量锡的光度测定。本方法用于钛白粉中微量锡的测定,加标回收率在96％－102％,7次测定的RSD≤5．50％。     

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.     

泡沫分离法回收水溶液中微量钼（Ⅵ）的研究

以十六烷基三甲基氯化铵（CTAC）为表面活性剂,采用自制的泡沫分离塔回收水溶液中的微量钼（Ⅵ）,考察了溶液pH、空气流量、表面活性剂质量浓度等对钼（Ⅵ）回收率和富集率的影响,并对该过程进行动力学分析。实验结果表明：随溶液pH增加,钼（Ⅵ）的富集率和回收率均先增加后减少;随CTAC浓度增加,钼（Ⅵ）的回收率增加而富集率减少;随空气流量增加,钼（Ⅵ）的富集率减少而回收率先增加后减少。在溶液pH为9、气体流量为 200 mL/min、表面活性剂质量浓度为0.30 g/L条件下,钼（Ⅵ）的回收率达到90%,富集倍数达到10倍。动力学分析表明,泡沫分离钼（Ⅵ）的过程是零级动力学过程,拟合方程为ρ=-0.288 8t+4.290 4,R2=0.993 8。     

Removal of Trace Metal Impurities from Pretreated Phosphoric Acid by Foam Fractionation

Demands for phosphoric acid are growing rapidly in various industries. This has highlighted the importance of optimizing its production and purification methods. Phosphoric acid can be produced by a wet process. However, due to the presence of many organic and inorganic impurities in the wet product, purification of the resulting product is a major concern in this industry. Removal of trace metal impurities (such as magnesium, cadmium, chromium, zinc, etc.) from produced phosphoric acid in a wet process was investigated by foam fractionation in a semi-batch setup using sodium dodecyl sulfate (SDS) as the surfactant. Effects of inlet air velocity, surfactant concentration, and surfactant selectivity were investigated. The optimum air velocity and surfactant concentration were obtained as 0.020 cm/min and 0.7 g/L, respectively. At the optimum condition, the total removal efficiency and enrichment factor reached were 70.2% and 4.39, respectively, while the acid loss was 8.3%. The total metal removal efficiency was increased to 95.3% in a two-stage experimental run.     

Removal of Trace Levels off Phenols from Aqueous Solution by Foam Flotation

Abstract

Peritachlorophenol (PCP) was removed from water by foam flotation with the cationic surfactant cetyltrimethylammonium bromide (CTAB). With initial PCP concentrations of 20 ppm or less, residual PCP concentrations of less than 0.05 ppm were obtained after 5 min flotation. The CTAB concentration and flotation time are directly related to the amount of PCP removed. PCP removal is most efficient at neutral to basic pH and at low ionic strength. PCP removal is less effective with sodium dodecyl sulfate. As much as 80% of the CTAB can be replaced by dodecylamine without inhibiting PCP removal. Alcohols up to 10% by volume do not affect PCP removal. Other phenols can also be removed equally well by foam flotation if the phenol is in the anionic form during flotation.     

Removal of Trace Levels of Aromatic Amines from Aqueous Solution by Foam Flotation

Abstract

Aromatic amines, including 4-(t-butyl)pyridine, 4-(n-butyl)aniline, benzylamine, 4-aminobiphenyl, 1- and 2-aminonaphthalene, and 2,6-xylidine, were effectively removed from water by foam flotation with the anionic surfactant sodium dodecylsufate (SDS). With initial amine concentrations of 10 mg/L or less, residual amine concentrations of less than 0.1 mg/L were generally obtained after 10–30 min of flotation. The SDS concentration and flotation time are directly related to the amount of amine removed. Amine removal is most efficient at pH values low enough so that the amine is protonated (usually about 3), and at low ionic strength. Alcohols up to 10% by volume do not appreciably affect amine removal. The mechanism of removal is dominated by ion-ion attraction between the surfactant and the protonated amine; there is also apparently some contribution from ion-dipole attraction. Benzidine is not removed effectively; evidently it is insufficiently hydrophobic.     

玉米芯改性前后对水中重金属去除的研究

以玉米芯为吸附剂,经氢氧化钠(NaOH)和硫酸(H_2SO_4)改性得到改性吸附剂,研究改性吸附剂对镉、铬、铅吸附性能的影响。实验研究了吸附时间和吸附初始浓度对吸附效果的影响。结果表明,改性玉米芯吸附剂对Cd~(2+)、Cr~(3+)、Pb~(2+)三种重金属离子的吸附能力都增强,且对Pb~(2+)的吸附效果最好,其吸附顺序为Pb~(2+)Cr~(3+)Cd~(2+);在初始质量浓度为400 mg/L时,酸改性的玉米芯对Cd~(2+)、Cr~(3+)、Pb~(2+)吸附容量为15、26、37 mg/g,而碱改性的玉米芯对Cd~(2+)、Cr~(3+)、Pb~(2+)吸附容量分别为17、29、59 mg/g。相对酸改性,碱改性的吸附剂对Cd~(2+)、Cr~(3+)、Pb~(2+)吸附量提高了14.54%、11.22%、57.86%。     

Simutaneous Removal of Heavy Metal Ions from Wastewater by Foam Separation Techniques

Abstract

The objective of the present work is to extend the application of adsorbing colloid flotation techniques to remove mixtures of metal ions. The systems studied are: 1) Co(II) and Cr(VI); 2) Co(II), Ni(II), and Cr(VI); 3) Cr(VI), Cu(II), and Zn(II); 4) Cr(VI), Cu(II), Zn(II), and Ni(II); 5) Cd(II), Pd(II), and Cu(II). Ferric hydroxide and aluminum hydroxide were used as the coprecipitant, and sodium lauryl sulfate was used as the collector and frother. The ionic strength of the solution was adjusted with NaNO₃ or Na₂SO₄. It was found that all the heavy metals can be removed effectively by a single step foam flotation treatment.     

Removal of Co2+ Ions from Aqueous Solution by Ferrite Process

Abstract

A mathematical model was developed to investigate the characteristics of Co²⁺ removal by the pre-formed ferrite process. In this study, surface adsorption, hydrolysis-precipitation, and ion exchange were considered as Co²⁺ removal mechanisms, and incorporated into the model. In addition, a series of batch experiments was performed to remove Co²⁺ ions from aqueous solution, and the removal characteristics of Co²⁺ were analyzed by considering equilibrium pH, shaking time, ionic strength, and the effect of EDTA and Ca²⁺ as a chelating agent and a competing cation, respectively. Finally, the model proposed in this study was applied to the given experimental system, and it turned out that the pH-edge could be successfully predicted by the model. The experimental results were well-fitted by a Freundlich isotherm, and the standard enthalpy change of the reaction was 25.02 kJ·mol^?1. The removal efficiency was slightly diminished by increasing the ionic strength and the initial concentration of Co²⁺; however, the effect of the competing cation, Ca²⁺, was negligible.     

Separation of Cyanide Ions by Foam Fractionation

Abstract

The technique of adsorption of cyanide ions on foam bubbles was studied as an alternative to chemical oxidation which is practiced in cyanide waste treatment. The technique of foam fractionation was previously applied to the removal of heavy metals and proved to be successful. The free cyanide ions and complex species both responded positively to the formation of a separate foam phase. The results obtained so far show that satisfactory separation of cyanide compounds is possible if certain parameters are properly selected. There are other factors which have not been investigated before, and they seem to have a major role in the performance of this operation.