Study On Degradation Of Organic Pollutants In Electroplating Waste Water By Fenton-like Reaction Catalyzed By Copper Ions

Copper plating waste water contains high concentration of organic pollutants and large number of copper ions. Copper ion as a kind of 3d orbital transition metal ion has the similar properties of iron ion, it also can catalyze hydrogen peroxide to produce active substances with high oxidability. In this paper, Copper plating waste water which representing about 20% of all electroplating water was taken as object of study. The copper ions in electroplating wastewater were used as catalyst, Adding hydrogen peroxide which is green, efficient, cheap and easily to get as oxidant. Take advantage of these active substances which were produced in reaction process to degrade organic pollutants in electroplating wastewater, not only saving the cost, but also eliminating the influence of organic matters for the reuse of mental ions.In this paper, the influence of transition metal ions, inorganic anions, organic complexing agents on the degradation of organic matters was studied on the basis of simple Fenton-like reaction catalyzed by copper ions. at the same time, the preliminary research of reaction mechanisms about simple and complex Fenton-like reaction catalyzed by copper ions was also studied. the results indicated that: In pure Cu2+- H2O2 system, under the condition of normal temperature, when the value of pH was 5.5, the concentration of Cu2+ and H2O2 was 0.8mM and 0.08 M respectively, after 180 min, the removal rate of nitrobenzene could reach 94.67%, the degradation rate of organic substances reached the maximum value. The nature of the reactive oxidants originated from copper-catalyzed Fenton-like reaction has a strong dependence on the value of pH.Under acidic conditions, hydroxyl radicals are the main active species, while under slightly acidic, neutral and alkaline condition, hydroxyl radicals and high-valence copper species are both participate in the reaction and compatible. In addition, the higher value of pH, the more content of high-valence copper species in the system. in Fenton-like reaction catalyzed by copper ions, phenol, 4-nitrocatechol,nitrohydroquinone, and benzoquinone intermediates will be generated during the degradation of nitrobenzene. These intermediates will promote the translation of cuprous ions to cupric ions, increasing the generation of active substances with high oxidative properties, consequently, the removal rate of nitrobenzene in Fenton-like reaction catalyzed by copper ions was improved markedly. the degradation of nitrobenzene in Fenton-like reaction catalyzed by copper ions has autocatalytic effect.Ni2+can inhibit the degradation of nitrobenzene in Cu2+-H2O2 system, While Mn2+canpromote the degradation of nitrobenzene obviously. The inorganic anions ClO4-, Cl-,NO3-, H2PO42- all have significant inhibitory effects on the oxidative degradation of nitrobenzene. Organic complexing agents edetic acid(EDTA) has a significant inhibitory effect for Fenton-like reaction catalyzed by copper ions, nitrilotriacetic acid(NTA) has a relatively strong promotion. However, tartaric acid(TA) has a obvious promoting effect to the oxidative degradation of nitrobenzene in Cu2+-H2O2 system.