Nickel Promoted Degradation Of Organic Chloride Pollutants With Fe@Fe₂O₃Nanowires

Water, a precious resource, is an essential condition for existence and economic development. In recent years, problem of the shortage of water resources is more and more serious. On one hand, the water of the earth is limited, the growth of global population decreases per capita availability of water resources; On the other hand, the rapid development of social economy and the frequent human activities lead to serious water pollution. Nowadays, water pollution has become a global concern. Water pollution is a serious threat to human survival and development, a huge challenge the environmental workers faced is that how to prevent and control the water pollution effectively.In recent decades, environmental workers have dedicated to prevention and control of water environment, and developed a lot of methods. Zero-valent iron has advantages of high reactivity, environment friendly, cheap. It has been widely applied in wastewater treatment. Zero-valent iron could activate molecular oxygen and produce reactive oxygen species which induce the degradation of pollutants. On the basis of the research of degradation of pollutants with nanoscale zero-valent iron, we launched the study of nickel promoted aerobic degradation of organic chloride pollutants with nanoscale zero-valent iron.First, we prepared the Fe@Fe2O3core-shell nanowires and iron-nickel bimetallic (nZVIN), which are used for the aerobic degradation of4-CP. The degradation efficiency of nZVIN/Air system towards4-CP is much larger than Fe@Fe2O3/Air system. We added scavengers of reactive oxygen species in two systems, the degradation result showed that, aerobic degradation of4-CP with Fe@Fe2O3was induced by the oxidative degradation of hydroxyl radicals, while superoxide radicals played a major role on the aerobic degradation of4-CP with nZVIN. Compared intermediate products of two systems, we found that major intermediate products in Fe@Fe2O3/Air system were hydroquinone and quinine, in nZVI/Air system phenol was generated. We explored the mechanism, the enhancement of degradation efficiency appeared to be attributable to more superoxide radicals which induced the reduction of4-CP, H didn’t play a major role.Second, we studied the degradation of atrazine by Fe@Fe2O3/Ni(Ⅱ)/Air and Fe@Fe2O3/Ni(Ⅱ)/Air systems. The result showed that Ni (Ⅱ) could greatly enhance the degradation efficiency of atrazine by Fe@Fe2O3under air atmosphere. By measuring intermediate products, we found that a lot of dechlorination products generated in Fe@Fe2O3/Ni(Ⅱ)/Air system, while major intermediate products was dealkylation products in Fe@Fe2O3/Air system. Degradation of atrazine by Fe@Fe2O3/Air system was attributed to the oxidation of hydroxyl free radical; Ni(Ⅱ) enhanced the ability of Fe@Fe2O3to activate molecular oxygen, but reactive oxygen species didn’t play a major role and there is another kind of active species which induced the reduction degradation of atrazine. The XPS characterization of Fe@Fe2O3in the process of degradation of Atrazine confirmed that Ni (Ⅱ) can generate Ni on the surface of zero-valent iron and Ni can promote the generation of H which can catalyze the reductive degradation of atrazine. In order to verify the possibility of further degradation of C3N3H5, we compared the degradation efficiency of C3N3HS by two systems. The result showed that Fe@Fe2O3/Ni(Ⅱ)/Air system could degrade C3N3H5, NO2-and HCOOH was generated, mineralization of triazine ring was achieved.