Résumé:
The aim of this work is to test the effectiveness of some pollution control methods, applied to the methyl green in an aqueous environment. The first method is destructive and has two distinct techniques that are photolysis (homogeneous environment) and photocatalysis (heterogeneous environment). The second method is not destructive and involves the adsorption of the substrate on a solid support that is activated carbon powder.
The photolysis at 254 nm and 365 nm resulted in discoloration of solution and, therefore, elimination of the polluting molecules, however, irradiation at 245 nm gave the best results. The results have also showed that the increase of light intensity promotes photodegradation, contrary to the effect noted when increasing initial concentrations of substrate solutions.
Among all photochemical processes, photocatalysis has given the best discoloration results. The influence of hydrogen peroxide was the acceleration of the degradation process, while the effect of salts: sodium sulphate and sodium chloride was detrimental to it. All photochemical processes have adopted first-order kinetics.
The treatment of methyl green solutions, by adsorption on activated carbon, has partially removing pollutant molecules. The increase of: initial solution concentrations, the adsorbate weight and agitation rate, accelerated this phenomenon. The process of methyl green absorption on activated carbon powder has followed FREUNDLICH model.
