engleski

Influence of the process parameters for the application of persulfate salts in photochemical wastewater treatment

Colored wastewaters present a serious problem for environment. Discharge of dyes is undesirable not only for aesthetic reasons ; color is visible even in a low dye concentration. Many dyes and their breakdown products are toxic to aquatic life and carcinogenic and mutagenic to humans. Concerning to these reasons, bleaching and degradation of colored wastewater is still a significant environmental issue. Advanced Oxidation Technologies (AOTs) could be successful method for the wastewater degradation, without any further secondary waste generation. The most important oxidative agent produced in different AOTs is hydroxyl radical that can be used for removing or degradation of organic compounds in water solutions. In the present study UV/S2O82- processes have been applied to decolorize and mineralize organic dye C.I. Acid Orange 7 (AO7).in water solution. The rate of color removal was studied by measuring the absorbance at the characteristic wavelength while mineralization rates were obtained on the basis of total organic carbon (TOC). The influence of different cation type in oxidant was studied , K2S2O8, Na2S2O8, (NH4)2S2O8. The statistical study of the process was performed using an experimental design method, particularly a response surface methodology (RSM) hexagonal design. Optimal operating conditions for each process were established in terms of initial pH and concentration of used oxidant salt. A complete color removal was achieved in all studied combinations of process parameters, while only partial mineralization extents were achieved. According to the developed statistical model of the process and performed kinetic study, experimental data were fitted into a model of homogeneous system.

organic dye; kinetic model; statistical analyses; process optimization

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