Influence Of Inorganic Anions P₄O₁₃^6- And SO₄^2- On The Activity Of Pollutants Degradation With Iron

Water is the source of lives, and the material basis for the survival of life on Earth. With the continuous improvement of the level of industrialization, many kinds of waste water drained off into the environment, causing great water pollution. Drinking water safety is facing great threat. According to statistics,31.1%of the surface water resources in our country is under the class IV, which cannot be drank directly.Because of its complicated composition, industrial wastewater is a great threat to the environment. Common wastewater treatment technologies are difficult for all the pollutants treatment in a short time. Zerovalent iron (ZVI) processing technology scope widely attention with its environmentally friendly, low cost, no secondary pollution, wide applicable feature.In this paper, we adopt ZVI processing technology for treating two typical organic pollutants,4-CP and MO, and we studied the two kinds of typical inorganic anions’ impact on the whole process of pollutant degradation. First of all, we improved the classical zerovalent iron\EDTA system, the tetrapolyphosphate with zerovalent iron system can active the O2and produce hydrogen peroxide, and finally hydroxyl radicals degrade chlorine phenol. By adopting pyridine inhibition experiment, we found that the generation of hydrogen peroxide was mainly from oxygen single electron reduction process. Further study showed that tetrapolyphosphate can accelerate the ZVI dissolution process to promote the degradation. In addition, we found ZVI has s bigger superiority than nZVI in terms of degradation of high concentration of pollutants. Secondly we studied the mechanism of the degradation of methyl orange with nZVI, and found that the degradation process is redox reaction, iron nanowire give electrons to methyl orange, and methyl orange fade. Due to the using of sodium sulfate as additive in the printing and dyeing industry, methyl orange in the industrial wastewater contains a high concentration of sulfate. Our experimental results show that sulfate can greatly restrain methyl orange reduction. By adopting situ infrared characterization of nZVI, we finally found that with the sulfate, nZVI surface can form FeSO4protective layer, the protective layer can prevent nZVI from reacting with methyl orange, causing the activity decline.Based on the present work, we deeply studied the different effects between tetra- polyphosphate and sulfate on the ZVI processing technology, and explain the reaction mechanism of different anions affecting the effect of the ZVI processing procedure. This mechanism may provide theoretical support on the ZVI processing technology.