微型离心萃取器在萃取工艺实验研究中的应用

微型离心萃取器是一种新型高效液-液萃取实验设备,具有许多显著优点。介绍了微型离心萃取器的基本结构、工作过程及其在一些萃取新工艺实验研究中的应用。     

Measurement of drop size characteristics in annular centrifugal extractors using phase Doppler particle analyzer (PDPA)

Drop size distributions have been measured in a 39 mm annular centrifugal extractor using phase Doppler particle analyzer (PDPA). The power consumption and the interfacial tension have been varied in the range of 10–450 kW/m³ and 13–33 mN/m, respectively. The two liquid phases have been selected with different density and viscosity ratios. The results have been analyzed using Rosin–Rammler distribution function. A correlation has been developed for the drop size distribution. The same has been compared with the correlations in the literature.     

Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

The annular centrifugal extractor (ACE) integrates mixing and separation. It has been widely used in many industrial fields because of its low residence time, compact structure, and high mass transfer efficiency. Most of the literature has focused on flow instabilities, flow visualization, and computational fluid dynamics simulations. More recently, research on hydrodynamic behavior and structural optimization has received widespread attention. With the development of ACE technology, applications have been broadened into several new areas. Hence, this paper reviews research progress regarding ACE in terms of hydrodynamic characteristics and the structural improvements. The latest applications covering hydrometallurgy, nuclear fuel reprocessing, bio-extraction, catalytic reaction, and wastewater treatment are presented. We also evaluate future work in droplet breakup and coalescence mechanisms, structural improvements specific to different process requirements, scaling-up methods, and stability and reliability after scaling-up.     

Hydraulic and Mass-Transfer Performance of a 20-Mm-Diameter Annular Centrifugal Contactor for the Solvent Extraction of Cesium by Bis(2-Propyloxy)Calix[4]-Crown-6 in n-Octanol

A calixcrown extraction process using bis(2-propyloxy)calix[4]-crown-6 (iPr-C[4]C-6) as extractant and n-octanol as diluent for the separation of cesium from Chinese High Level Liquid Waste (HLLW) has been developed at INET. Chinese HLLW is acidic defense waste with high salt content, which is now stored in underground stainless steel tanks. The intention is to use a process to extract cesium from HLLW conducted on multistage 20-mm-diameter annular centrifugal contactors (ACCs), so it is necessary to study the hydraulic and mass-transfer performance of a 20-mm-diameter ACC for the extraction system. In this work, the effects of the parameters such as the rotor speed, the diameter of heavy weir, and the acid concentration on the hydraulic performance were investigated. An operational envelope of the 20-mm-diameter ACC for the n-octanol/aqueous solution system was identified. The mass-transfer efficiency of the single stage 20-mm-diameter ACC for the extraction and stripping of cesium with iPr-C[4]C-6 in n-octanol was studied by varying several parameters, such as the rotor speed, the total flow rate, and the flow ratio. The extraction stage efficiency is greater than 95% at suitable operating conditions for extracting Cs⁺ with 0.025 mol/L of iPr-C[4]C-6 in n-octanol from HNO₃ solution containing Cs⁺. The stripping stage efficiency of Cs⁺ (< 90%) is lower than the extraction stage efficiency of Cs⁺.     

Numerical Investigation of Bubble Motion Behavior in a Centrifugal Vacuum Gas–Liquid–Solid Separator for the Treatment of Contaminated Hydraulic Fluid

Contaminants in hydraulic fluid are the primary causes of premature oil degradation. In this study, we propose a method for removing contaminants from contaminated oil. This method combines centrifugal separation and vacuum negative pressure. Centrifugal separation is utilized to separate solid particulates and free water. Vacuum negative pressure can be used to remove dissolved air. A mathematical model is developed for predicting bubble motion behavior under the complex actions of centrifugal force and vacuum negative pressure. Three performance indices that describe the purification capacity of the separator are proposed to optimise the gas–liquid–solid separator.     

微通道内醇胺/离子液体复配水溶液吸收CO2的传质特性

研究了微通道内醇胺[单乙醇胺(MEA)和甲基二乙醇胺(MDEA)]与离子液体[1-丁基-3-甲基咪唑四氟硼酸([Bmim][BF₄])和1-羟乙基-3-甲基咪唑甘氨酸([C₂OHmim][GLY])]复配水溶液吸收CO₂的传质特性。考察了醇胺/离子液体浓度比(c_AA∶c_IL)对液相体积传质系数(k_La)的影响,发现k_La随反应速率的增大而增大。为进一步阐释复配水溶液吸收CO₂的传质机理,分析了比表面积、扩散速率、增强因子和液弹循环对传质速率的影响。结果表明,四种复配溶液中,反应速率和循环频率(f_cir)分别在低流率和高流率下对传质速率起主导作用。k_La可表示为f_cir的函数,低气相流率下k_La与f_cir呈线性关系,斜率与反应速率成正相关,高气相流率下,液弹循环因膜弹传递困难而对整体传质速率的影响减弱,k_La与f_cir呈指数关系,幂律指数小于1。     

Synthesis and solution properties of a new sulfobetaine/sulfur dioxide copolymer and its use in aqueous two-phase polymer systems

The zwitterionic monomer, 3-(N,N-diallylammonio)propanesulfonate, was copolymerized with sulfur dioxide in dimethyl sulfoxide using azo-bis-isobutyronitrile (AIBN) to afford the polysulfobetaine (PSB) copolymer in excellent yields. The PSB was converted into the corresponding anionic polyelectrolyte (APE) by treatment with 1 equiv. of sodium hydroxide. The solution properties of PSB and APE were investigated by potentiometric and viscometric techniques. The critical (minimum) salt concentrations (CSC) required to promote water solubility for the PSB at 23 °C have been measured. Basicity constant of the amine functionality in APE is found to be ‘apparent’ and as such follow the modified Henderson-Hasselbalch equation. The composition and phase diagram of the aqueous two-phase polymer systems of PSB (treated with 0.60 equiv. sodium hydroxide) and poly(ethyelene glycol) (PEG) in 0.1N KCl has been studied for the first time for this class of PSB copolymer.     

Oxidation of benzothiazole, 2‐mercaptobenzothiazole and 2‐hydroxybenzothiazole in aqueous solution by means of H2O2/UV or photoassisted Fenton systems

Oxidative treatments of benzothiazole and benzothiazole derivatives (2‐mercaptobenzothiazole, 2‐hydroxybenzothiazole) in aqueous solution have been studied by using H₂O₂/UV and iron(III) photoassisted Fenton techniques. Experimental runs have been carried out in the pH range 3.0 –8.0 by means of annular reactors and proper UV lamps. The effect of pH, the initial concentration of hydrogen peroxide, the substrate, and the iron(III) concentrations have been investigated. A suitable model has been developed and used for the best estimation of kinetic constants for HO radical attack on the target molecules with the H₂O₂/UV system. The values obtained with this model are consistent with those reported in the literature for other heterocyclic compounds. © 2001 Society of Chemical Industry     

Preparation and characterization of SnO2 nanoparticles in aqueous solution of [EMIM][EtSO4] as a low cost ionic liquid using ultrasonic irradiation

A facile, template-free, room temperature and environmentally benign green route for the preparation of SnO₂ nanoparticles in aqueous solution of 1-ethyl-3-methylimidazolium ethyl sulfate, [EMIM][EtSO₄], room-temperature ionic liquid (RTIL), via ultrasonic irradiation is proposed. The X-ray diffraction (XRD) studies display that the products are excellently crystallized in the form of tetragonal rutile structure. Energy dispersive X-ray spectroscopy (EDX) investigations reveal the products are pure. The morphology of as-prepared nanoparticles was characterized by scanning electron microscopy (SEM). Diffuse reflectance spectra (DRS) of the products exhibit band gap energy of about 3.98 eV which shows blue shift of 0.38 eV that can be attributed to quantum confinement effect of SnO₂ nanoparticles. A possible formation mechanism of the SnO₂ nanoparticles using ultrasonic irradiation in aqueous solution of the RTIL is presented.