Cloud point extraction of phenol and benzyl alcohol from aqueous stream

Two-aqueous phase extraction of phenol and benzyl alcohol as a solute from their aqueous solutions was investigated using polyethoxylated alcohols (CiEj) as a biodegradable non-ionic surfactant. First, the phase diagrams of the binary systems, water–surfactant (Oxo-C10E3 and Oxo- C13E9), and the pseudo-binary systems, water–surfactant with a constant concentration of solute was determined. The effect of sodium chloride and sodium sulphate on water–surfactant systems were studied. According to the given surfactants concentrations and temperatures, the extraction results were expressed by the following four parameters, percentage of extracted solute, E, which reached 95 and 90% for phenol and benzyl alcohol, respectively, residual concentrations of solute, Xs,w, and the surfactant, Xt,w, in the dilute phase and volume fraction of the coacervate at the equilibrium condition, φc. The values of these parameters were determined by an analyzing central composite designs. After the first extraction process, phenol and benzyl alcohol concentrations in the effluent were reduced about ten times for the first and four times for the second, correspondingly

Extraction of humic acid by coacervate: Investigation of direct and back processes

The two aqueous phases extraction process is widely used in environmental clean up of industrial effluents and fine chemical products for their reuse. This process can be made by cloud point of polyethoxylated alcohols and micellar solubilization phenomenon. It is commonly called “coacervate extraction” and is used, in our case, for humic acid extraction from aqueous solution at 100 mg/L. The surfactants used are alcohol polyethoxylate and alkylphenol polyethoxylate. Phase diagrams of binary water/surfactant and pseudo-binary are plotted. The extraction results are expressed by the following responses: percentage of solute extracted, E (%), residual concentrations of solute and surfactant in dilute phase (Xs,w, and Xt,w respectively) and volume fraction of coacervate at equilibrium (ϕ). For each parameter, the experimental results are fitted to empirical equations in three dimensions. The aim of this study is to find out the best compromise between E and ϕC. The comparison between experimental and calculated values allows models validation. Sodium sulfate, cetyltrimethylammonium bromide (CTAB) addition and pH effect are also studied. Finally, the possibility of recycling the surfactant has been proved

Cloud point extraction of Δ9-tetrahydrocannabinol from cannabis resin

A cloud point extraction coupled with high performance liquid chromatography (HPLC/UV) method was developed for the determination of Δ9-tetrahydrocannabinol (THC) in micellar phase. The nonionic surfactant “Dowfax 20B102” was used to extract and pre-concentrate THC from cannabis resin, prior to its determination with a HPLC–UV system (diode array detector) with isocratic elution. The parameters and variables affecting the extraction were investigated. Under optimum conditions (1 wt.% Dowfax 20B102, 1 wt.% Na2SO4, T=318 K, t=30 min), this method yielded a quite satisfactory recovery rate (~81%). The limit of detection was 0.04 μgmL−1, and the relative standard deviation was less than 2 %. Compared with conventional solid–liquid extraction, this new method avoids the use of volatile organic solvents, therefore is environmentally safer

Phenol and benzenoid alcohols separation from aqueous stream using cloud point extraction: Scaling-up of the process in a mixer-settler

In the present work, the cloud point extraction (CPE) of three organic pollutants (phenol,benzyl alcohol and 1-phenylethanol) with aqueous solutions of biodegradable alkoxylated nonionic surfactants (TERGITOL 15-S-7 and SIMULSOL NW342), is investigated. First, the partial phase diagrams of the water–surfactant binary systems are established. Then, the effects of organic pollutants and sodium chloride on the cloud point (Tc) are determined. Extraction efficiency is evaluated by the following responses: percentage of solute extracted, E (%), residual concentrations of solute and surfactant in dilute phase (Xs,w, and Xt,w, respectively) and volume fraction of coacervate at equilibrium (ϕc). Three-dimensional empirical correlations are used for fitting the experimental results. The comparison between experimental and calculated values allows model parameter identification. Based on these data, CPE was implemented in a continuous mixer-settler device. The feasibility of a multi-stage crossflow process for the purification of samples containing phenol using SIMULSOL NW342 was tested. Six stages were required to reduce the pollutant concentration below the allowed level (0.3 ppm), which proves the efficiency of CPE in the treatment of wastewaters

Easy Removal of Methylparaben and Propylparaben from Aqueous Solution Using Nonionic Micellar System

This study aimed to investigate the simultaneous removal of methylparaben (MePB) and propylparaben (PrPB) from effluents (each one at 16 mg/L) using a nonionic micellar system containing Triton X-114. Response surface methodology (RSM) has been carried out. Extraction results using nonionic surfactant two-phase system were considered as a function of surfactant concentration and temperature variation. Four responses were investigated: MePB and PrPB extraction yield (E), solute (Xs,w) and surfactant (Xsf,w) concentrations in the aqueous phase and the volume fraction of micellar phase (ϕC) at equilibrium. Very high extraction efficiencies (99 % for PrPB and 84 % for MePB) were achieved at optimal conditions. Thereby, the amounts of PrPB and MePB were reduced 80 and 5 times, respectively. The extraction improvement using sodium sulfate was also shown. Finally, the solute stripping from micellar phase by pH change was proved

Cationic Dye Removal from Aqueous Solutions Using Ionic Liquid and Nonionic Surfactant-Ionic Liquid Systems: A Comparative Study Based upon Experimental Design

In order to separate methylene blue from aqueous solution, a novel method based upon liquid-liquid extraction, using a nonionic surfactant-ionic liquid system as extracting phase, was investigated. A comparative study was carried out with the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, known as [C4mim]PF6. By using the nonionic surfactant-ionic liquid system, the extraction efficiency could reach 97.8%, indicating that the addition of nonionic surfactant (Triton X-114) significantly improves the extraction of methylene blue. Under optimal conditions, the dye concentration in the effluent showed an almost 50-fold reduction. However, the extraction extent of methylene blue was found to be low at low pH values, and in the presence of K2CO3, which may be useful for surfactant-ionic liquid system regeneration

Cloud Point Extraction of α-Amino Acids

Cloud point extraction with a polyethoxylated alcohol (Oxo-C10E4) is used to separate five α-amino acids: alanine, valine, leucine, isoleucine, and phenylalanine (0.75 wt.% in water), and their extraction efficiencies are compared. The variables affecting phase separation and extraction (wt.% surfactant and equilibrium temperature) are optimized using experimental design. The four responses are: percentage of solute extracted (E), residual concentrations of solute (amino acid) and surfactant in the dilute phase, and volume fraction of coacervate at equilibrium. E increases with surfactant concentration and amino acid hydrophobicity in the following order: alanin < valin < leucin < isoleucine < phenylalanine, with respective maximum values: 73, 74, 76, 78.5, and 95%, and decreases with a temperature rise. It also makes sense that aspartic and glutamic acids, much more hydrophilic, are poorly extracted (E ˜ 10%). The trend observed is consistent with water/n-octanol partition coefficient (Log P) of amino acids in pure water. A more detailed study is presented for alanine and phenylalanine. Addition of sodium sulphate or cetylammonium bromide greatly raises extraction rates

Prediction of the cloud point of polyethoxylated surfactants and their mixtures by the thermodynamic model of Flory-Huggins-Rupert

The cloud point curves of polyethoxylated surfactants are established experimentally. These experimental data are preliminary to the development of the cloud point extraction process, which appears as an interesting alternative to the usual solvent extraction unit operation. Starting from the thermodynamic model developed by Flory and Huggins for phase separation of polymer aqueous solutions, this paper aims at the prediction of cloud point curves. In this work, Rupert’s approach is extended to commercial nonionic surfactants, mixtures of homologous species, namely a few alkylphenol and alcohol ethoxylates. The limit of such an approach is clearly demonstrated, provided that a fitting parameter is finally required for a successful model application to pilot-plant manufactured surfactants, like C8ΦEn (n = 7.5, 10, 12), C9ΦEn (n = 8, 10, 12), C12E4, C12E6 and commercial Tergitol 15-S-7 (linear C12-C14 secondary alcohol with an average of 7 ethylene oxide units

Purification d'effluents par extraction à deux phases aqueuses

La plupart des composés hydrophobes présents dans une solution aqueuse, peuvent être solubilisés dans les micelles d'un tensioactif non ionique, puis concentrés dans le petit volume du coacervat, après séparation des phases. Dans ce travail, afin d'étudier l'extraction du phénol ou de l'alcool benzylique (soluté) de leurs solutions aqueuses (pollution soluble), nous avons choisi de travailler avec des alcools plyéthoxylés aisément et rapidement biodégradables. Les résultats expérimentaux d'extraction du phénol ou d'alcool benzylique en solution aqueuse à 0.15% massique, sont exprimés par les quatre grandeurs suivantes : pourcentage de phénol soluté, concentrations résiduelles en soluté et en tensio-actif dans la phase diluée, fraction volumique de coacervat à l'équilibre. Le procédé dérivé de l'extraction à deux phases aqueuses, consiste en l'élimination d'une pollution dispersée par désémulsification. Le cas des boues polluées par des huiles de coupe utilisées dans le sciage, le taillage et le pollissage du granit en fournit un excellent exemple.TOULOUSE-ENSIACET (315552325) / SudocSudocFranceF

A qualitative study of mixing a fluid inside a mechanical mixer with the effect of thermal buoyancy

This paper is concerned with the rotational motion of the impeller and the thermal buoyancy within a mechanical mixer. The task was investigated numerically using the ANSYS-CFX simulator. The programmer is based on the finite volume method to solve the differential equations of fluid motion and heat transfer. The impeller has hot surfaces while the vessel has cold walls. The rotational movement of the impeller was controlled by the Reynolds number, while the intensity of the thermal buoyancy effect was controlled by the Richardson number. The equations were solved for a steady flow. After analyzing the results of this research, we were able to conclude that there is no effect of the values of Richardson number on the power number. Also, with the presence of the thermal buoyancy effect, the quality of the fluid mixing becomes more important. The increasing Richardson number increases the value of the Nusselt number of the impeller