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 100mg/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 (X(s,w), and X(t,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.

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 K 2 CO 3, which may be useful for surfactant-ionic liquid system regeneration.

The aim of this work is the extraction of tannic acid (TA) with two commercial nonionic surfactants, separately: Lutensol ON 30 and Triton X‐114 (TX‐114).The experimental cloud point extraction results are expressed by four responses to surfactant concentration and temperature variations: extent of TA extraction (E), remaining solute (Xs,w) and surfactant (Xt,w) concentrations in dilute phase and volume fraction of coacervate (Φc) at equilibrium. An empirical smoothing method was used and the results are represented on three dimensional plots. In optimal conditions, the extraction extent of TA reaches 95 and 87 % using TX‐114 and Lutensol ON 30, respectively. Sodium sulfate, cetyltrimethylammonium bromide (CTAB) addition and pH effect are also studied. Finally, the possibility of recycling of the surfactant is proved.

Cloud point extraction with a polyethoxylated alcohol (Oxo-C 10 E 4 ) 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.

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The purpose of this article is to study the photocatalytic properties of doped titanate nanotubes prepared by hydrothermal treatment using different metals: Ce, Fe, Zn and Zr at 2 wt% content. The textural and morphological properties of the nanopowders were determined by different analysis techniques such as: XRD, RD/UV–Vis, FTIR and TG-DTA. The results of the characterizations showed that nanotubes can be obtained with a hollow structure, and an important thermal stability of whatever element nature. However, the photocatalytic activity ends with the photodegradation under UV-Visible irradiation of the three industrial molecules: Malachite Green, Methyl Orange and Tannic Acid having different molecule charges. It was noted that the degradation rates of the order of 98% were obtained in fairly short times. The final results obtained revealed that the dopant nature and the solution pH play a major role in determining the photocatalytic degradation of pollutants using TiNTs. However the application of TiNTs and doped TiNTs show that these materials have an inhibitory power of fungi and bacteria quite important.