Cloud Point Extraction Experiment

Cloud Point Extraction ExperimentBromothy rampart blue(a) (also known as bromothy groin sulfone phthalein, BTB) (Figure 2.1.1) is a pH indicator (yellow at pH 6.0 and blue at pH 7.6). Its chemical name is 4,40-(1,1-dioxido-3H-2,1-benzoxathiole-3,3-diyl)bis(2-bromo-6-isopropyl-3-methylphenol (The Merck Index, 13th edition, 2007)1. pKa of BTB is 7.1. This disgrace is the most appropriate pH indicator stain in physiological tissue and also used in the investigation of the interaction of lipid with protein (Puschett and Rao 1991 Gorbenko 1998 Sotomayor et al. 1998)2,3,4. It is widely applied in biomedical, biological, and chemical engineering applications (Schegg and Baldini 1986 Ibarra and Oliv ars-Perez 2002)5,6. BTB in protonated or deprotonated create is yellow or blue in colour, respective(prenominal)ly, while its theme is bluish green in neutral reply. It is sometimes used to sterilise cell walls or nuclei under the microscope. BTB is mostly used for the evaluation and estimation of the pH of pools and fish tanks and the determination of the presence of carbonic acid in liquid. There are several treatment mathematical functions for dyes from waste materials, including adsorption (Nandi, Goswami, and Purkait 2009)8, curdlingflocculation, oxidationozonation, reverse osmosis, membrane filtproportionn, biological degradation, and electrochemical processes (Shen et al. 2001 Kim et al. 2004 Chatterjee, Lee, and Woo 2010)9,10,11.2.1.2 data-based2.1.2.1 MaterialsAll the issues were prepared with doubling-distilled water.2.1.2.1.1 Triton X 100 (0.1M) Triton X-100 was purchased from Qualigens analytic grade. The TX-100 was cleared of any low-boiling impurities by exposure to vaccum for 3h at 700C following the procedure given by Kumar and Balasubrahmanium19. 31.4 g of TX-100 liquid is change state 500 ml the great unwashedtrical flaskful and make up to the record to obtain 0.1 mol/dm3 upshot. The critical micellar soaking up and Cloud aspi re of TX-100 are 2.8104 20 65-C 21 respectively.2.1.2.1.2 Bromothymol Blue (BTB) 1.0 g of BTB dye Merck India was turn in 5.0 ml of ethanol (99.8%) for dissolution then dilution are make with double distilled water into a 1000 ml batchtric flask up to the mark to obtain an assimilation of 1000 mg/dm3(Babak Samiey, Kamal Alizadeh et.al 2004)22. In enunciate to avoid fading stock solution was wrapped black color paper. The working solutions of BTB were prepared by appropriate dilutions of the stock solution at once prior to their use.2.1.2.1.3 Acetic acid (0.5M). 28.5 ml glacial acetic acid (A.R.grade) Qualigens was demoralized with distilled water in a 1000 ml hoi polloitric flask to give 0.5M Acetic acid solution. The solution obtained was debauchd to needed closeness and standardized as per the procedure (Vogel et. al. 1989)23 with standard NaOH solution.2.1.2.1.4 Sodium acetate (0.5M) 13.6 g sodiumacetate.trihydrate, (CH3COONa.3H2O) of Analytical grade Qualigens is dis solved in 100 ml volumetric flask and made up to the mark (Vogel et. al. 1978)24.2.1.2.1.5 NaCl (0.1M) 2.922 g sublimate dry table salt of sodiumchloride of analytical grade Qualigens is weighing out and dissolved in 500 ml volumetric flask to give 0.1M NaCl solution(Vogel et. al. 1989)25.2.1.2.1.6 Na2SO4 (0.5M) 16.1 g of sodiumsulphate decahydrate,(Na2SO4.10H2O) A.R.grade from Merck (India), is dissolved in 100 ml volumetric flask and made up to the mark to give 0.5M Na2SO4 solution(Vogel et. al. 1989)26.2.1.2.1.7 KH2PO4(1.0M) 34.02 g of KH2PO4 of Analytical grade Qualigens is dissolved in 250 ml volumetric flask and made up to the mark (Vogel et. al. 1978)27.2.1.2.1.8 Na2HPO4 (1.0M) A.R. grade disodium hydrogen phosphate, Na2HPO4.2H2O, is taken in porcelain crucible and heated until no more than water is liberated. Then 17.8 g of this cold residue is taken in 100 ml volumetric flask and made up to the make to give 1.0 M of Na2HPO4 solution (Vogel et. al. 1978)28. The reagent i s prepared freshly to each one time.2.1.2.1.9 devotee solution of pH4.0(0.05) 5 ml of 4M sodium acetate (A.R. grade) Qualigens and 20 ml of 4M acetic acid (A.R. grade) Qualigens are sundry(a) in an 100ml volumetric flask and made up to the mark which has terminus pH of 4.0(0.05) (Vogel et. al. 1989)29 .2.1.2.1.10 Buffer solution of pH5.0(0.05) 17.5 ml of 4M sodium acetate (A.R. grade) Qualigens and 10 ml of 4M acetic acid (A.R. grade) Qualigens are mixed in an 100ml volumetric flask and made up to the mark which has terminus pH of 5.0(0.05) (Vogel et. al. 1989)30 .2.1.2.1.11 Buffer solution of pH6.0(0.05) 13.2 ml of1M KH2PO4 (A.R.grade) Qualigens and 86.8 ml of 1M Na2HPO4 (A.R.grade) Qualigens are mixed in 100ml volumetric flask which has resultant pH of 6.0(0.05) (Vogel et. al. 1989)31.2.1.2.1.12 Buffer solution of pH7.0(0.05) 61.5 ml of 1M KH2PO4 (A.R.grade) Qualigens and 38.5 ml of 1M Na2HPO4 (A.R.grade) Qualigens are mixed in 100ml volumetric flask which has resultant pH of 7 .0(0.05) (Vogel et. al. 1989)31.2.1.2.1.13 Buffer solution of pH8.0(0.05) 94.0 ml of 1M KH2PO4 (A.R.grade) Qualigens and 6.0 ml of 1M Na2HPO4 (A.R.grade) Qualigens are mixed in 100ml volumetric flask which has resultant pH of 8.0(0.05) (Vogel et. al. 1989)31.2.1.2.1.14 Buffer solution of pH9.2(0.05) 1.905g of Na2B4O7.10.H2O of (A.R.grade) Qualigens is dissolved in 100ml volumetric flask and made up to the mark to obtain 0.05 M of borax solution.The resultant pH of the solution is 9.2(0.05) (Vogel et. al. 1989)32.2.1.2.2 Methodology for demoralise heyday blood2.1.2.2.1 mathematical operationThe cloud point temperature was set by literature method account by Carvalho et al. 33. This is based on the visual observation of the separation of variants in the micellar solution. The solution was heated in stages in the water bath until turbidness appeared. To verify the results, the opposite process was carried out by cooling gradually with constant stirring and the cloud point was co nsidered as the temperature at which the solution became clear. The report determine was the average of these twain determinations in most cases, these two temperatures were identical, within + 0.5oC.Cloud point filiation experiment was conducted by exploitation a 10 ml separator tube with a fucking cap containing divergent concentrations of Triton X-100 and BTB and sonicated for 2 proceeding for proper mixing. The solution is heated up to 80C in a thermostatic temperature bath for 20 min. The turbid solution was then centrifuged at 3500 revolutions per minute for 5 min and cooled in an ice bath for 2 minutes in order to separate the courses. Both the arranges are separated and the volumes of wetting agent rich bod (coacervate phase) and dilute phases were measured. Average of three determinations is reported in all cases. The concentration of dye in both the phases has been measured by using PerkinElmer lamda-25 UV-Visible spectrophotometer. In order to determine the i nfluence of the reagents added to the surface-active agent phase, cloud point determinations were performed with the additions of buffer, dye and inorganic salts. The procedure for the determination of critical temperature was the analogous as to a higher place, nevertheless using only a firm surfactant concentration. The phase diagram for Triton X-100 was obtained by measuring the cloud point temperature of aqueous surfactant solutions at different concentrations.2.1.2.2.2 Spectra and calibrated graphThe concentration of the dye was determined by U.V-visible spectrophotometer (PerkinElmer lamda-25). Pure BTB was initially calibrated each for different concentrations in terms of absorbance units, which were recorded at ripplelength 430 nm, at which upper limit absorption takes place (Figure 2.1.2, 2.1.3). No hearty change in the absorbance has been find even in the presence of TX-100. Therefore all the absorbance gists were performed at this wave length.Figure 2.1.2 Spect ra of BTB dyeFigure 2.1.3 Calibration curve of BTB dye2.1.2.2.3 tendency of Phase volume Ratio, Fractional coacervate phase volume and pre-concentration m all overThe volumes of the respective surfactant-rich and aqueous phases obtained by and by the separation of phases were determined using calibrated centrifuge tubes for calculating the pre concentration instrument. Surfactant solutions containing typical amounts of the BTB were extracted using the CPE procedure, followed by the measurement of the respective phase volumes. The results reported are the average of three determinations.The phase volume ratio is define as the ratio of the volume of the surfactant-rich phase to that of the aqueous phase. It is calculated using the following formula. (2.1.1)Where RV is the phase volume ratio, VS and VW are volumes of surfactant-rich phase and aqueous phase respectively.The pre-concentration gene, (fC) is defined as the ratio of the volume of bulk solution before phase separatio n (Vt) to that of the surfactant-rich phase after phase separation (Vs). (2.1.2)Where Vt and VS are the volumes of the bulk solution before phase separation and the surfactant-rich phase respectively.The fragmentary coacervate phase volume with the throw surfactant concentration is calculated by using the relationship (2.1.3)Where FC is the fragmental coacervate volume and Cs is the molar concentration of the run for surfactant solution, for fixed feed dye concentration, the parameters a and b vary linearly with temperature. The value of Fc lies in between 0.04-0.23 for various operating conditions.Surfactant partition coefficient (m) is defined as the ratio of concentration of surfactant in coacervate and dilute phase. - (2.1.4)The power of extraction is defined as - (2.1.5)2.1.4 DiscussionThis section is divided into quaternity parts. In first part, factors influencing the extraction cleverness (e.g., concentrations of non-ionic surfactants, dye and salt, temperature and p H of the solution), fractional coacervate phase volume have been discussed. The nature of solubilization isotherm at different temperature has been applyed in the second part. In the third and fourth parts, thermodynamic parameters and a advisement procedure for the determination of surfactant requirement for the dye removal to a desired level is briefly discussed.2.1.4.1 Factors influencing efficiencyFor ionizable solutes, the charge of the solute clear greatly influence its extent of binding to a micellar assembly 34. The ionic form of a molecule normally does not interact with and bind the micellar essence as strongly as does its neutral form. Thus adjustment of the solution pH for maximum extractability is of special importance when controlling experimental variables in CPE.With increasing pH, the efficiency of extraction increases up to pH 8.0 and then decreases. This is in accordance with the decrease in cloud point till pH 8.0 and a sudden increase at pH 9.2. Further, the pK value of BTB is 7.1. In the absence of any buffer solution, pH of the dye solution is 7.0 and in that location is no change in pH event after the extraction process is completed. Hence, all the parameters were optimized at this fixed pH of the medium. No signifi freightert increase in efficiency is observed with increasing Dye since the cloud point is not altered much with increasing the concentration of dye.The extraction efficiency of dye increases with the increase of surfactant concentration. The concentration of the micelle increases with the surfactant concentration, resulting in more solubilisation of dye in micelles. The surfactant concentration in the dilute phase remains constant (and equal to around CMC) the surfactant concentration along with the solubilised dye in the coacervate phase (micellar phase) increases to maintain the material balance42-46. The extraction of dye with TX-100 solution is due to hydrophobic interaction between BTB and hydrophobic micelles in the solution. However, with the increase of TX-100 concentration, the analytical signal becomes weak due to the increase in the final volume of the surfactant rich phase that causes pre concentration factor (phase volume ratio) to decrease 35. In view of these observations, a 0.04 mol/dm3 newt X- 100 is used throughout.It has been shown that the presence of electrolyte whoremaster change the CP in different ways36. Salting out electrolyte such as NaCl, decreases the cloud point temperature. They potful promote the dehydration of ethoxy groups on the outer surface of the micelles, enhancing the miceller concentration wind to solubilisation of more dye and resulting in a more efficient extraction 37 and reduce the time demand for phase separation. A lower salt concentration gives a smaller pre concentration factor, due to the vaingloriousr volume in the surfactant-rich phase at lower salt concentrations 38. As shown in the fig the ability of salts to enhance extraction efficiency of the dye was in the order of Na2SO4NaCl.Temperature has pronounced effect on the extraction of solute. (i) At full(prenominal) temperature, CMC of non-ionic surfactant decreases. (ii) the non-ionic surfactant becomes more hydrophobic due to dehydration of ethoxyethane oxygen 39 and increase in micellar concentration and solubilization.A general preconcentration factor of 20-60 was obtained with this CPE method and similar pre concentration has been reported for other analytes (40). Typical preconcentration factors reported in the literature41 vared fiom 10 to 100. The CPE method gives a better preconcentration factor compared to conventional solvent extraction methods. In general, high pre concentration factors in CPE can be achieved using small amounts of surfactants which have large capacity to accommodate dye molecules. The hydrated nature and relative sign of the zodiac of micelles, on the other hand, limit the extraction of dye into the surfactant-rich phase.From the vie wpoint of concentrating the analytes present in aqueous solutions, the larger pre concentration factor, e.g., the smaller phase volume in the surfactant-rich phase is desired. A lower surfactant concentration gives a higher pre concentration factor. However, it becomes very difficult for sampling and accurate summary with a very small volume of the surfactant-rich phase. On the contrary, excessive amount of added salt of salting-out effect can give the higher pre concentration factor, but it is likely forming the very viscous liquid crystalline phase, instead of the fluidic fluidness phase, in the system, making it difficult to separate the surfactant-rich phase. Therefore, optimization of the pre concentration factor is very critical in a feasible CPE technique. Hence, surfactant concentration of 0.04 mol/dm3 was chosen to conduct CPE experiments in this research.2.1.4.2 Solubilization isothermThe adsorption isotherm relating moles of solute solubilized per mole of surfactant50 a re presented in Figure2.1.8.The isotherm can be expressed according to Langmuir type construction (2.1.6)Where, both m and n are functions of temperature.Figure 2.1.8 Solubilisation curve of BTB dyeAssuming a homogeneous monolayer adsorption, the linearized Langmuir sorption model of comparison (2.1.6) can be written as (2.1.7)Plot of 1/qe vs. 1/Ce over the entire dye concentrations was linear with a correlation coefficient of 0.983 as shown in Figure 2.1.9. Thus, the solubilization of dye obeys the Langmuir adsorption model. The calculated values of Langmuir parameters m and n from the slope and intercept of the linear plot of 1/qe vs. 1/Ce were found equal to 4.29X 10-3 (mol/mol) and 2.04X104 dm3 /mol, respectively.Figure 2.1.9 Langmuir isotherm of BTB dye2.1.4.3 Thermodynamic parameters The overall thermodynamic parameters G0, S0 and H0 were calculated using equations (2.1.8, 2.1.9) 48,49as follows. (2.1.8) - (2.1.9)Where T is the temperature in (K), qe/Ce is called the solub ilization affinity.S0 and H0 are obtained from a linear plot of log (qe/Ce) versus (1/T), from Eq. (2.1.8) and. Once these two parameters are obtained, G0 is determined from Eq. (2.1.9) and presented in tabular array 2.1.6. Plot of log (qe/Ce) versus (1/T) is shown in Figure 2.1.10.Table 2.1.6 Thermodynamic parametersTemp = 800.1c BTBinitial =12.8010-5 mol/dm3 TX-100 =4.010-2 mol/dm3pH ( 0.05)-G ( KJ/mole )S ( KJ/mole/K )H ( KJ/mole )3533433336.019.5716.9314.280.2773.927.022.1118.7515.380.3496.768.021.1018.6316.160.2566.06Figure 2.1.10 log (qe/Ce) versus (1/T)2.1.4.4 Design of experiment The amount of surfactant undeniable can be evaluated from the residual dye present in the dilute phase of the solution after conducting cloud point extraction can be determined 45.qe is the mole of dye solubilized per mole of non-ionic surfactant. (2.1.10)Moles of dye solubilized can be obtained from mass balance equation, (2.1.11) (2.1.12)Where, A is the moles of dye solubilized in the micel les, V0 and Vd are the volume of the feed solution and that of the dilute phase after CPE, C0 and Ce are concentration of the BTB dye after CPE respectively Cs is the concentration of surfactant in feed.From the equation 2.1.10, 2.1.11 and 2.1.12 we can write, (2.1.13)Moles of dye solubilized can be obtained from mass balance equation,Where, qe is the mole of dye solubilized per mole of non-ionic surfactant, x is moles TX-100 used, A is the moles of dye solubilized in the micelles, V0 and Vd are the volume of the feed solution and that of the dilute phase after CPE, C0 and respectively Cs is the concentration of surfactant in feed. (2.1.14)Now, by involving the definition of fractional coavervate volume in the above equation we get, (2.1.15) - (2.1.16)Where a,b are the parameters a and b which are functions of temperature. replace the above equation in equation (8) we get, - (2.1.17)Substituting the above equation in equation (1) and rearranging we get, (2.1.18)From the above eq uation the desired surfactant required (Cs) can be obtained knowing the value of m and n the Langmuir constants, a and b the operating temperature constants, Ce the amount of dye in dilute phase after cloud point extraction.By using the above equation experiments which are conducted were compared for surfactant used and required are shown in Table 2.1.8.Table 2.1.8 Comparison data of required and used TX-100 at 80C105 BTBinitial mol/dm3105 BTBdilute mol/dm3102 TX-100 used mol/dm3102 TX-100 Required mol/dm33.201.114.002.646.401.874.003.828.002.224.004.329.603.194.003.7912.804.094.004.4616.006.724.003.748.003.603.002.428.001.734.504.328.001.185.005.60