Interaction of cationic surfactant with acid yellow dye in absence/presence of organic and inorganic additives: conductivity and dye solubilization methods

In the present study, the conductometric and dye-solubilization techniques have been utilized to investigate the interaction between an anionic dye (acid yellow 23 [AY]) and a cationic surfactant (cetyltrimethylammonium bromide [CTAB]) in presence of organic (ethanol)/inorganic (NaCl) additives. From the conductometric method, two critical micelle concentrations (cmc) were found for AY + CTAB mixture in an aqueous system and the cmc values were found to undergo a change with the variation of AY concentrations. The cmc values of AY + CTAB systems were observed higher in the alcoholic medium, while the same was found to be lower in the NaCl solutions. The change in cmc of AY + CTAB systems shows an U-like curve with an increase of temperature. The negative free energy of micellization ( Δ G m o ${\Delta}{G}_{m}^{o}$ ) for the AY + CTAB systems has indicated a spontaneous micelle formation in all of the cases studied. The enthalpy ( Δ H m o ${\Delta}{H}_{m}^{o}$ ), as well as the entropy of micellization ( Δ S m o ${\Delta}{S}_{m}^{o}$ ) for the AY + CTAB systems, were assessed and discussed with proper reasoning. Additionally, the enthalpy-entropy compensation parameters were also investigated and illustrated. The solubility of AY and C D was observed to rise linearly with an increase in the concentration of CTAB/NaCl solution. The solubilization capacity (χ) of AY, the molar partition coefficient (K M) amongst the micellar and the aqueous phase, and free energy of solubilization ( Δ G S o ${\Delta}{G}_{S}^{o}$ ) were evaluated and discussed in detail. The former parameters undergo an increase with an increase of NaCl concentrations.

Cloud Point Extraction of Direct Blue 71 Dye using Triton X-100 as Nonionic Surfactant

A surfactant-mediated cloud point extraction (CPE) method using the non-ionic surfactant Triton X-100 (TX-100) has been developed to remove the dye Direct Blue 71 (DB71) from a waste water. Most of the dye molecules are solubilized in the coacervate phase so that the dilute phase remains free of the dye. The effects of surfactant concentration, temperature and salt concentration on the different dye concentrations were studied to determine the optimal conditions for removing DB71. The concentration of DB71 in the dilute phase was measured using UV-Vis spectrophotometer. It was found that the separation of phases was complete and the recovery of DB71 was very effective in the presence of NaCl as an electrolyte. The results showed that up to 25 ppm DB71, i.e. more than 95%, can be quantitatively removed by cloud point extraction procedures in a single extraction at optimal conditions. It was also observed that at a dye concentration of 1 ppm, 100% of the blue dye DB71 can be directly removed with a TX-100 concentration of 12% by weight. At higher dye concentrations of up to 30 ppm, 94.7%-100% dye can be removed. The TX-100 concentration was 12 wt%, the salt concentration (NaCl) 0.005 M and the temperature 75°C. It is concluded that the surfactant mediated cloud point extraction method for dye removal can be an alternative to current dye removal methods.

Binary Cationic Dyes-Counter Ion Extraction by Reverse Micelles

In this study a solvent extraction method is used to investigate the succesive removal of a binary mixture of the cationic dyes Basic Yellow-2 (BY) and Basic Blue-26 (BB) from textile effluents by the anionic surfactant sodium dodecylsulfate (SDS) and isoamyl alcohol as an organic solvent. The dye ions are encapsulated in the core of the reverse micelles which remain in the organic phase and are subsequently separated from the aqueous phase resulting in significant removal of dyes. The effects of different parameters such as the concentration of surfactant, dye concentration, pH, temperature, salt concentration etc. have also been studied in the present work. The removal efficiency of dyes increased with increasing surfactant concentration and decreasing dye concentration. UV-visible absorption spectra were analyzed to evaluate the state of the dyes in bulk water before and after extraction with reverse micelles. In addition, the dyes were recovered successively by backward extraction and then reused. TEM analyses were carried out to determine the size of reverse micelles and shape of the formed clusters.

Solubilization and Thermodynamic Attributes of Nickel Phenanthroline Complex in Micellar Media of Sodium 2-Ethyl Hexyl Sulfate and Sodium Bis(2-ethyl hexyl) Sulfosuccinate

Micellar solubilization and physicochemical behaviour of [Ni(phen)3]F2 EtOH · MeOH · 8 H2O complex in sodium 2-ethylhexyl sulfate and sodium bis(2-ethyl hexyl) sulfosuccinate is addressed in this paper. The interactions of surfactants in the solution of nickel complex were studied by UV-Vis spectroscopy and electrical conductivity. The extent of solubilization in terms of partitioning and binding parameters was determined by UV-Vis spectroscopy, whereas conductivity data were employed to calculate critical micellar concentration and other thermodynamic parameters of micellization. The value of critical micellar concentration increased in both surfactants due to structure breaking effect of nickel complex. The complex showed significant antioxidant radical scavenging and hemolytic activities, without any substantial cytotoxic activity against 3T3 cell line.

Role of Surfactants Cetyl Pyridinium Chloride (CPC) and Cetyltrimethyl Ammonium Bromide (CTAB) in the Reverse Micellar Extraction of Ternary Mixture of Acid Dyes from Textile Effluent

Textile industry produces colored effluent which is the major cause of water pollution. Removal of color from effluent is very important before discharging. Extraction of ternary mixture of anionic dyes, namely, Acid Orange 7 (AO-7), Acid Blue 1(AB-1) and Acid Yellow 17 (AY-17) was carried out from aqueous solutions using reverse micelles of Cetyl Pyridinium Chloride (CPC) and Cetyltrimethyl ammonium bromide (CTAB) in isoamyl alcohol. Extraction efficiency of CPC and CTAB was studied under various experimental conditions, such as pH of feed solution, concentration of surfactant, extraction time, temperature and initial dye concentration. Under the optimized experimental conditions, 93–98 % of dyes were extracted. It was observed that CTAB is more efficient than CPC for extraction of dyes from aqueous medium.

Green and Efficient Reverse Micellar Extraction and Recovery of Mixed Ionic Dyes from Textile Effluent

Colored effluents discharged from textile and other industries pose a major threat to the environment. These effluents must be decolorized before discharging into the main streams. The present study explores a solvent extraction method for selective removal of dye from a cationic and anionic dye mixture by treating the dye mixture with reverse micelles of anionic and cationic surfactants in a stepwise manner. The effect of different parameters such as surfactant and dye concentration was also investigated. It has been found that the percentage extraction of dyes increased with increasing surfactant concentration and decreasing dye concentration. UV-visible absorption spectra were analyzed to evaluate the state of the dyes in bulk water before and after extraction with reverse micelles. The dyes were recovered successively by backward extraction and then reused. Their K/S values were also measured.