Degradation Of Congo Red With Advanced Oxidation Technology Based On Activated Persulfate

The technology based on activated persulfate produces a powerful oxidant known as the sulfate free radical, which can potentially destroy organic pollutants, is applied to the envioronmental pollution control field. Among them, the metal ions catalyzing decomposition of persulfate produces the sulfate free radical is a very promising technique because of the simple methods, mild reaction conditions and low cost.The paper adopts the sulfate radical introduced by five kinds of transition metals catalyzing two oxidants (potassium peroxodisulfate and peroxdisulfate) to degrade the nonbiodegradable organic pollutants. In this study, Congo red was chose for model compouds. The effects of pH, the intial concentrations of metal ions and persulfate on the degradation efficiencies of Congo red were studied. It can further improve the treatment efficiency, reduce the running cost, eliminate various unfavorable factors of factors and understand the optimum technology advantages and disadvantages. The results of transition metal catalyzed potassium peroxodisulfate shows that the sequence of the five kinds of metal ions catalytic activity is Fe2+>Cu2+>Co2+>Mn2+ >Ni2+. Obviously, Fe2+ showed the best effect toward activating persulfate. When used Fe2+ for catalyzing degradation Congo red,40 minutes later, the efficiency of decolorization of Congo red reached 95.9% and removing rate of TOC reached 47.4%.The great effect of the efficiency of decolorization of Congo red is pH, and follows the order:pH 3.0> pH 2.0>pH1.5. The sequence of the five kinds of metal ions catalyzing peroxdisulfate is Co2+>Fe2+>Cu2+>Mn2+>Ni2+. And Co2+ was the most efficient transition metal for the activation of sulfate radical, and it can form a complete cycle in the reaction. When used Co2+ for catalyzing degradation Congo red in acidic condation, the great effect of the efficiency of decolorization of Congo red is the intial concentrations of Co2+. The advantage of the process is the efficiency of decolorization of Congo red reached 98% after 1 hour. And the disadvantage of the process is the low removing rate of TOC.