دراسة حركية امتزاز بعض صبغات الملونات الغذائية باستخدام الكاربون المنشط كمادة مازة

الملخص EN

The research included the application of some kinetic models on the experimental results for adsorption of some food coloring dyes on activated carbon, Such as pseudo first order model (Lagergreen), pseudo second order model, Elovich kinetics model and intra particle diffusion model.

The food coloring dyes used in the industries food like juices, soft drinks, jams pastries and in drugs which bear codes (E110, 122, 102, 133, 123, 124,127) .

This coloring dyes constitute a very wide sector of industries that are important to humans everywhere in the world, and with the large number of factories producing them and the increase in their consumption, as these coloring dyes are thrown from factories, homes, stores and juice shops, as well as, throwing these products when they expire in to the environment as these coloring dyes are complex organic chemical compounds prepared and not found in nature , it is biodegradation, and therefore the highest values of biochemical oxygen demand have been recorded in this sector.

The kinetic study is used to obtain important information to describe the adsorption process, as well as, to help design simple and economical adsorption systems to remove those coloring dyes as one of the pollutants to the environment .

When application the adsorption kinetic models on the experimental results , we found this results applicable on pseudo second-order model by obtaining a good relationship for this model through a high correlation coefficient ,as well as, the experimental adsorption capacity (qe exp)(in poise state) is close to or equal to calculated adsorption capacity (qe cal.) which calculated from the slope of straight line from this model relationship, and obtain the value of adsorption(h) for each dye, while found this experimental results not applicable on the pseudo-first-order model , because the admission requirements for application of this model not achieved .

When checking the results obtained from the application of the Elovich kinetics model ,we noticed a great applicability of the experimental results of the adsorption process with this model through the liner relationship resultant for this model and a high correlation coefficient, where the values of initial rate constant of adsorption (α) for food coloring dyes is very high ,while the values of desorption constant (β) is very low , which represents the value for the leaving of coloring dyes molecules the surface of the activated carbon to aqueous solution , by means the adsorption process of coloring dyes molecules on the activated carbon surface is stronger compare with molecules returns to solution .

The intra particle diffusion model gave good information through the straight relationship of this model, which provide us a clear picture of the forces affecting and the nature of mechanism for adsorption process of food coloring dyes, the relationship gave straight lines with a high correlation coefficient with intercept (C) which represents the thickness of the outer layer to the limit of the solution , the increase of intercept value (C) refers to the greater effect of this layer on the adsorption process , and the effect of this layer was less for( E124) dye, while it did not affect the adsorption of each of the (E123, 127) dyes .

All this refer to that the intra particle diffusion mechanism , it is not only mechanism influencing the adsorption process because the straight line dose not pass through the origin point , which is assumed by this model, but has intercept .

Which indicates the presence of other effective mechanisms , that is, the adsorption process in one of its steps is controlled by pseudo second-order forces, which has a mechanism different from the intra particle diffusion mechanism , and even the pseudo first-order mechanism is effective in one of its steps, because the values correlation coefficient were obtained are high , but it is not applicable between the values of ( qe exp) and (qe cal ) for adsorption process.