L35-硫酸铵双水相体系萃取水溶液中Cr(Ⅵ)

以L35-(NH4)2SO4-H2O双水相体系萃取模拟废水中Cr(Ⅵ),考察了初始Cr(Ⅵ)浓度、水相p H值、胶束电荷调节剂1812用量、萃取时间、相分离时间、L35浓度、(NH4)2SO4浓度及萃取温度对Cr(Ⅵ)萃取率的影响.结果表明,溶液p H值对Cr(Ⅵ)萃取率和分配系数影响最大;加入1812后,Cr(Ⅵ)萃取率和分配系数明显提高;随温度升高,两者均逐渐降低;随L35和(NH4)2SO4浓度增加,Cr(Ⅵ)萃取率逐渐提高并趋于恒定;萃取和相分离时间均较短;在最佳萃取条件下,Cr(Ⅵ)单级萃取率达92%(w),分配系数达15以上.四级错流萃取的理论计算和实验结果基本一致,Cr(Ⅵ)浓度由2 g/L降到0.5 mg/L以下,达到国家排放标准.Cr(Ⅵ)依靠其相对疏水性以增溶方式及静电引力方式进入L35胶束内部而被萃取.用Na OH水溶液对萃取相单级反萃取,Cr(Ⅵ)反萃率达99.5%(w)以上,浓缩倍数4.     

醇和小分子有机物二元双水相体系萃取盐酸多西环素

基于小分子醇双水相体系和小分子有机物双水相体系,建立了乙醇与丙酮和(NH4)2SO4形成的二元双水相体系萃取盐酸多西环素的新方法。研究了(NH4)2SO4浓度、pH值、温度、乙醇与丙酮用量和盐酸多西环素浓度对盐酸多西环素分配行为的影响。结果表明,体系的(NH4)2SO4浓度为41%,pH值在4.5～5.0,温度25℃,且盐酸多西环素的质量浓度70 mg/L时,萃取率可达93.61%,分配系数可达83.081。     

聚乙二醇-硫酸铵双水相萃取结晶紫的研究

利用分光光度法研究了结晶紫在聚乙二醇-硫酸铵双水相体系中的萃取行为,探讨了质量配比(mPEG/m(NH4)2SO4)、温度、结晶紫浓度对结晶紫的分配系数(cup/clow)及萃取率的影响。结果表明,在一定的温度和结晶紫浓度下,随着质量配比的减小,结晶紫的分配系数增大,萃取率略有降低;在一定的质量配比和结晶紫浓度下,随着温度的升高,分配系数显著增大,萃取率基本保持不变;在一定的质量配比和温度下,随着结晶紫浓度的增大,分配系数显著减小,萃取率基本保持不变;在mPEG/m(NH4)2SO4为1.25∶1、结晶紫浓度为6.536×10-5 mol.L-1、温度为50℃的条件下,萃取率高达99.81%。     

聚乙二醇一硫酸铵双水相萃取结晶紫的研究

利用分光光度法研究了结晶紫在聚乙二醇一硫酸铵双水相体系中的萃取行为,探讨了质量配比( mPEG/m(NH4)2SO4)、温度、结晶紫浓度对结晶紫的分配系数(cup/Clow)及萃取率的影响.结果表明,在一定的温度和结晶紫浓度下,随着质量配比的减小,结晶紫的分配系数增大,萃取率略有降低；在一定的质量配比和结晶紫浓度下,随...     

PEG-(NH_4)_2SO_4双水相萃取法提取壳聚糖酶的研究

采用PEG-(NH4)2SO4双水相体系直接从Bacillussp.LS发酵液上清液中分离壳聚糖酶。研究了体系中PEG分子量、PEG质量分数、(NH4)2SO4质量分数、NaCl质量分数和pH值对壳聚糖酶分配系数及萃取率的影响。结果表明,室温下双水相萃取最佳条件为:PEG600 20%、(NH4)2SO420%、NaCl 0.1%、pH值6.0,在此条件下壳聚糖酶分配系数达5.91,萃取率达88.7%。     

人血清白蛋白在双水相法体系中的分配规律研究

人血清白蛋白是一种重要的临床药用蛋白质。以PEG/(NH4)2SO4双水相体系萃取分离人血清白蛋白,探索人血清白蛋白在双水相体系中的分配规律。结果表明,人血清白蛋白在双水相体系中的分配系数与萃取率均随着PEG分子量的增大而增大;随PEG和(NH4)2SO4浓度的增加而增加,当PEG为19.53%、(NH4)2SO4为14.07%时达到最大;但若持续增大各相的浓度,其分配系数与萃取率又会下降;随着体系中外加盐NaCl浓度的增加而增加,在NaCl浓度为10%时达到最大。     

海参加工液中有效成分的盐析萃取

考察了不同亲水性有机溶剂-无机盐双水相盐析萃取体系对海参加工液中蛋白和多糖的盐析萃取能力. 结果表明,叔丁醇-(NH4)2SO4和乙醇-Na2CO3体系对海参蛋白和多糖有较好的萃取效果,蛋白和多糖以界面沉淀形式分配在上层有机相和下层水相之间. 叔丁醇-(NH4)2SO4体系的最佳工艺条件为：(NH4)2SO4 300 g/L,海参加工液与叔丁醇体积比为1:1.5,室温下萃取,蛋白和多糖的最高回收率分别为99.6%和96.3%;乙醇-Na2CO3体系的最佳工艺条件为：乙醇16%(w), Na2CO3 12%(w),海参加工液72%(w),37℃下萃取,蛋白和多糖的回收率分别为96.9%和90.6%. 将该体系从30 g规模逐级放大到3 kg,多糖回收率降低1%,蛋白回收率降低0.7%,该体系可同时降低重金属含量.     

双水相萃取直接从枯草芽孢杆菌发酵液中提取β-甘露聚糖酶

研究了聚乙二醇(PEG)平均相对分子质量、PEG浓度、(NH4)2SO4浓度、NaCl浓度对β-甘露聚糖酶和总蛋白分配系数、相体积比和萃取率的影响。实验表明PEG100020%(m/m)和(NH4)2SO415%(m/m),NaCl为2%(m/m)组成的双水相体系,室温下直接对含菌体的枯草芽孢杆菌发酵液抽提β-甘露聚糖酶,可纯化2.76倍,萃取率达98.79%。     

离子液体[BPy]BF_4双水相萃取芦丁的研究

建立了由亲水性离子液体四氟硼酸N-丁基吡啶[BPy]BF4和(NH4)2SO4形成的双水相体系萃取分离芦丁的新方法。研究了(NH4)2SO4浓度、芦丁溶液浓度、离子液体用量和溶液酸度对双水相形成和萃取率的影响。结果表明,当双水相体系组成为:(NH4)2SO41.5 g,2.0 mL离子液体,1.0~1.2 mL芦丁溶液,溶液酸度在pH4~6范围内,该离子液体双水相体系对芦丁有较高的萃取率(E%>90)。     

巯基乙酸萃取工艺的研究

通过对若干种有机溶剂的比较,选定磷酸三丁酯(TBP)作为萃取剂,甲基异丁基甲酮(M IBK)作为稀释剂,对巯基乙酸(TGA)的萃取进行研究。同时考察了TGA浓度、萃取温度、pH等条件对TGA萃取分配系数的影响。实验结果表明,采用V(M IBK)∶V(TBP)=1∶9的混合萃取剂,控制V(有机相)∶V(水相)=1∶2,在室温下萃取TGA合成液两次,TGA萃取率达98.31%。萃取后有机相中含有无机酸杂质H2SO4和有机酸杂质二硫代二乙酸(DTDGA),可采用w(NaOH)=20%的水溶液洗涤去除。洗涤时控制n(NaOH)/n(DTDGA)=7,洗涤后无机酸杂质H2SO4去除率达100%,有机酸杂质DTDGA去除率达80.3%,TGA损失率2.6%,有机相中m(杂质)/m(TGA)=0.007 3。     

Development of Liquid Membrane Pertraction for the Removal and Recovery of Chromium from Aqueous Effluents

Abstract

Liquid membrane pertraction combines the loading and stripping steps of solvent extraction into a single unit operation, allowing the continuous removal and concentration of a given species. In this paper the feasibility of applying liquid membrane pertraction to the recovery of chromium (Cr(VI) from aqueous effluents with the objective of reducing levels to below allowable discharge limits has been examined. A continuous laboratory-scale liquid membrane pertractor was constructed to solve a variety of problems associated with the treatment of Cr(VI)-bearing streams. Various operational factors such as feed velocity, strip velocity, membrane velocity, and composition of the inlet feed were then examined. Satisfactory continuous runs lasting up to 22 days were achieved. Chromium levels in synthetic waste could be reduced from 200–300 mg/L down to 1 mg/L, well within most allowable discharge limits. Experiments showed that the strip phase can be concentrated with inlet Cr(VI) concentrations of 2000 ppm Cr(VI), with indications that it should be possible at even higher concentrations.     

用磷酸三丁酯萃取分离硫酸铵母液中的HCN

研究了磷酸三丁酯(TBP)-磺化煤油体系从重庆某企业甘氨酸生产副产物硫酸铵母液中萃取分离HCN的工艺,考察了萃取体系、TBP体积分数、母液初始pH值、相比(Vorg∶Vaq)对萃取HCN的影响以及氢氧化钠浓度、相比(Vaq∶Vorg)和平衡pH值对HCN反萃的影响。结果表明:选用TBP作为萃取剂能够对硫酸铵母液中的HCN进行快速有效的萃取;TBP体积分数、母液初始pH值及相比对HCN萃取率影响显著;以含体积分数35%TBP的有机相作萃取剂,在相比(Vorg∶Vaq)为2∶1的条件下,pH值为2.92的含氰1.71 g/L的硫酸铵母液经3级错流萃取,萃余液中含氰低于0.5 mg/L,氰的萃取率接近100%;在相比(Vaq∶Vorg)为1∶1条件下,以0.6 mol/L的氢氧化钠为反萃液,控制反萃液平衡pH值大于13.0,氰的单级反萃率大于96%;含氰0.78 g/L的有机相在相比为1∶1条件下,经过2级错流反萃,氰基本上被反萃完全,贫有机相不经过处理可循环使用。     

双水相与超声波耦合法提取香薷黄酮

用丙醇-硫酸铵双水相与超声波耦合法提取香薷中的黄酮,由正交试验确定提取的最优条件。结果表明,在每毫升水加入0.35g硫酸铵、丙醇与水的体积比为0.60、料液比1∶35(g/m L)、超声波提取40min的条件下,香薷黄酮的提取率可达9.39%。     

季铵化壳聚糖及其絮凝六价铬性能的研究

以3-氯-2-羟丙基三甲基氯化铵(CTA)为改性剂接枝改性了壳聚糖,制备得到了2-羟丙基三甲基壳聚糖季铵盐(CTA-CTS),用红外光谱和核磁共振表征了产物的结构;用得到的产品处理含Cr2O72-的模拟电镀废水,研究了接枝时间、废水的pH值、CTA-CTS的质量浓度对Cr(Ⅵ)去除能力的影响。结果表明:接枝反应主要发生在—NH2上,并以反应时间为10.0h的产品对Cr(Ⅵ)的去除能力较强,在pH值为5.0,CTA-CTS的质量浓度为100mg/L左右时,对Cr(Ⅵ)的去除率可达95%。     

Efficient transport and selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process using Aliquat 336 via HFSLM

The selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process by hydrophobic hollow fiber supported liquid membrane (HFSLM) was investigated. The effects of various parameters— types of organic extractants, i.e., metyl trioctylammonium chloride (Aliquat 336), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP) and the mixture of Aliquat 336 and TBP, concentration of the selected extractant, types of stripping solutions (NaCl and NaOH), pH and concentration of the selected stripping solution, and the operating temperature—were studied. The feed and stripping solutions flowed countercurrently. The results showed that the coexisting contamination in spent pickling solution of Fe(II) and Ni(II) ions had no significant effect on Cr(VI) extraction. Among the extractants used in this study, Aliquat 336 was a specific carrier to attain the highest percentage of Cr(VI) extraction. About 70% extraction was achieved by using 0.11 M Aliquat 336 and 0.5 M NaCl at pH 7. The percentage of stripping slightly increased when the concentration of NaCl increased. In addition, it was found that the operating temperature of 20, 30, 40, and 50 °C had almost no influence on the percentages of extraction and stripping of Cr(VI). The calculated diffusion energy of Cr(VI) extraction was 15.14 kJ/mol.     

钢渣颗粒对水中Cr(VI)的吸附与还原作用

以钢渣颗粒为水处理剂,分析了其组成和结构,研究了钢渣颗粒直接吸附去除水中Cr(VI)的工艺过程及机理. 结果表明,钢渣颗粒在适当的粒度与用量下,经10 min搅拌处理,水中Cr(VI)浓度由200 mg/L降低到0.5 mg/L,达到《污水综合排放标准》(GB8978-1996)的要求. 钢渣颗粒对水中Cr(VI)的吸附符合Langmuir等温吸附过程,对Cr(VI)的饱和吸附量达6.878 mg/g. 化学分析和XPS分析均表明,钢渣颗粒对水中Cr(VI)具有吸附与还原的联合作用,吸附后钢渣颗粒中Cr(III)含量由0.0985%提高到0.39%,而FeO含量由9.20%下降到8.35%. 吸附后钢渣颗粒表面形成了Cr(OH)3,说明钢渣颗粒中FeO充当了还原剂,将水中Cr(VI)吸附于钢渣颗粒表面并还原成了低毒的Cr(OH)3随钢渣颗粒沉降直接从水中去除.     

SOLVENT EXTRACTION OF CHROMIUM(Vl) BY 3-(4-PYRIDYL)-l,5-DIPHENYL PENTANE

The distribution equilibrium of Cr(VI) between an aqueous sulfuric acid solution of potassium bichromate and a nitrobenzene solution of 3-(4-pyridyl)-l,5-diphenyl pentane (PDPP or B) has been studied. Hydrogen chromate ion among several ionic species of Cr(VI) in the aqueous solution is extractable in the present system. The chromium concentration in the organic phase is correlated with the concentrations of hydrogen chromate and hydrogen ion in the aqueous phase with PDPP in the organic phase. The interfacial reaction rate is also obtained and it gives the equilibrium relation by equating the extraction rate with the stripping rate. Results of the freezing point depression of the organic solution and the interfacial tension, obtained for the present system, indicate that the Cr(VT)-PDPP complex in the organic phase might be the aggregation of several molecules of chromate acid and PDPP, and that the complex is surface active. A Cr(VI)-PDPP complex adsorbed at the liquid-liquid interface reacts with hydrogen chromate ion in the aqueous phase consecutively.     

Sorption of chromium (VI) by spent grain under batch conditions

Batch experiments were performed to evaluate the ability of spent grain to remove chromium (VI) from aqueous solution. Parameters investigated include pH, contact time, sorbent dosage, agitation rate, and the presence of other anions. Application of the Langmuir isotherm to the Cr(VI)–spent grain system provided a maximum sorption capacity of 18.94 mg/g. This value compares favorably with other reported values for low‐cost materials. Anions such as phosphate, arsenate, nitrate, and sulfate were antagonistic toward the uptake of Cr(VI) by spent grain. It was successful in removing Cr(VI) from a sample of electroplating waste. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2128–2134, 2001     

Removal of Cr(VI) from Aqueous Solution: Electrocoagulation vs Chemical Coagulation

Abstract

Hydrolyzed products of Al(III) have affinity below pH_zpc for oppositely charged mono and bi‐nuclear species of hexavalent chromium. This study investigates the comparative performance of electrocoagulation (EC) and chemical coagulation (CC) for the removal of Cr(VI) from aqueous solution. The highest removal of Cr(VI) achieved with EC was about 42% with 4.36 mA/cm² current density. Cathodic adsorption of chromium boosted up Cr(VI) removal during EC. Simultaneous electro‐ and chemical‐dissolution lead to high current efficiency of about 178%. Both the pH and the coagulant dosage have a significant impact on Cr(VI) removal in the pH ranges from 4.9 to 7.0. CC with alum and aluminum sulfate (AS) removed about 11% and 12% of Cr(VI). Co‐adsorption of divalent SO₄ ^2? ions with Cr(VI) is responsible for the lower removal observed with chemical coagulants. About 0.061 and 0.099 mole of SO₄ ^2? was adsorbed per mole Al in the precipitate in the pH range 4.9 to 7.0 with AS and alum. A higher coagulant dosage increases the removal of Cr(VI) but adversely affects the removal efficiency (Cr(VI) removed per unit of Al dosing). Cell current density (CD) has shown little effect on Cr(VI) removal and the pH elevation at the same charge density. Higher initial Cr(VI) concentration improves the removal efficiency as the species of Cr(VI) is acidic in solution and decreases the pH elevation rate.     

Solvent extraction of hexavalent chromium with tetrabutyl ammonium bromide from aqueous solution

The extraction of hexavalent chromium (Cr) from aqueous solutions by tetrabutyl ammonium bromide (TBAB) salt in dichloromethane was investigated. The results indicated that the maximum extraction efficiency of Cr(VI) was at pH 1±0.1. The strippant 0.1 M sodium hydroxide, completely stripped Cr(VI) from the loaded solvent. The stripped solvent can be reused for extracting Cr(VI). After five extraction cycles, the dichloromethane showed no significant loss in volume and retains the same extracting ability. The solvent extraction method was applied for the removal and recovery of Cr(VI) from real chromeplating wastewater and found to be satisfactory.