دراسة إزالة صبغتي السافارانين و الكونغو الأحمر من محاليلها المائية بالامتزاز على صدفة الحلزون ذو الناب المدبب وشكلها المحور

Study Removal Safranin and Congo Red dye from aqueous solution by adsorption on Snail Shell (Rostellaria) and Modified Form

Were studied This thesis included a study of the adsorption of Safranin and Congo Red dyes on the surface of Snail shell powder and its axis shape. Snail Shell powder was treated with melamine to prepare the Snail Shell-melamine complex, then the polymerization process of the complex with formaldehyde was carried out to prepare the Snail Shell-melamine-formaldehyde- polymer. The axis was formed using infrared techniques (FT-IR), X-ray diffraction (XRD), and the external appearance was determined using scanning electron microscopy (SEM), in addition to the diagnosis by atomic force microscopy (AFM) of the surface. A series of experiments were conducted and several experimental variables were studied, including: equilibrium time, adsorbing surface weight, PH, the effect of ionic intensity, and the effect of temperature (isotherms). The results showed that equilibrium was obtained for Congo Red dye at an equilibrium time of 20 min. The adsorbing surface weight was 0.0200 g and the acid function PH = 5 for Snail shell, while the equilibrium time was 10 min and the adsorbing surface weight was 0.0100g at PH = 5 for the axial shape of Snail shell as for Safranin dye, the results showed that equilibrium occurs at a time of 20 minutes. The weight of the adsorbing surface was 0.0200 g and the acid function PH=8 for Snail shell ,while the equilibrium time was 10 min, and the adsorbing surface weight was 0.0100g at PH = 8 for the axial shape of Snail shell as for the ionic strength, the results of the study of the effect of ionic strength on the adsorption of Safranin and Congo Red dyes on Snail Shell and modified Snail Shell indicate a decrease in the adsorption capacity with an increase in ionic strength. The greater the charge and the larger the volume interferes more in the adsorption with Safranin dye in the following order:
Ca+2 > Mg+2 > K+1 > Na+1
Where the percentage of removal of Congo Red dye with sodium chloride salt is higher than the percentage with calcium chloride salt, while the effect of these salts with Congo Red dye is completely opposite to that of Safranin dye, and the order of effect of ions is as follows:
Na+1 >K+1 >Mg+2 >Ca+2
The effect of the concentration of these salts on the dyes Safranin and Congo Red, whereby the increase in the salt concentration corresponds to a decrease in the percentage of removal.
The values of thermodynamic functions (ΔG, ΔH, ΔS) were calculated it was found that the adsorption process of Congo Red and Safranin dyes on the surface of Snail Shell powder and its axis shape is spontaneous, emitting heat and a decrease in randomness through negative values of compression energy and negative values of change In enthalpy and entropy. The removal of two dyes, Congo Red, Safranin, on the surface of Snail shell powder, and their axis shape as adsorbent surfaces at different temperatures (298-338k) was studied to determine the adsorption isotherms and thermodynamic functions.
The models of Langmuir and Freundlich isotherms were used and were to describe the empirical isotherms and the isotherms constants. The equilibrium data of the two dyes Congo Red and Safranin showed that they agree with the hypothesis of Freundlich and Langmuir isotherms well on the surface of Snail shell powder and its axis shape. The isotherm form of a dye takes the shape of the letter S, according to Giles’ classification. A comparison was made between the use of both surfaces for the adsorption of Safranin and Congo Red dyes, and it was found that the adsorption of Safranin and Congo Red dyes on the Modified surface of Snail Shell (SSMFP) was better than using the surface of Snail sell.