The Experimental Study Of Removing Ni²⁺and DMP In Waste Water By The Way Of Fenton And Flocculation Together

With the persistent development of the city,some industries are promoting the national economy,such as metal plating and plastic products.At the same time,they can also discharge wastewater containing both heavy metal and organic matter,expecially Ni²⁺and dimethyl phthalate?DMP?.Serious environmental pollution problems arise and need to be solved.The aim of this topic is to deal with simulated wastewater with DMP and Ni²⁺by the way of Fenton reaction and flocculation together.The simulated wastewater comes from industrial park which contains the industries of plastic products and metal plating.The optimal solution to deal with this wastewater is sure by the study of different influencing factors and orthogonal test.The study on the Fenton reaction's synergy of flocculation process is explored on the condition of the optimal solution.The study on the varying pattern of?OH and Fe in Fenton reaction by the way of electron paramagnetic resonance?EPR?is considered.And we can study the possible intermediate products in Fenton reaction by using mass spectrometry?MS?and speculate the Fenton degradation pathway of DMP.We can draw the conclusion by different influencing factors test and orthogonal test.High initial concentration of H₂O₂ and excessive H₂O₂/Fe²⁺mole ratio are not conducive to Fenton reaction and flocculation together.Excessive dosage of Ca?OH?₂ has a stimulative effect on the reaction slightly,while high PAM dosing quantity has an inhibitory effect on it.When the mole ratio of H₂O₂/Fe²⁺is 4:1,the initial concentration of H₂O₂ is 200 mg/L,the dosages of Ca?OH?₂and PAM are respective 475mg/L and 1.0 mg/L,the treatment effect of the wastewater with DMP and Ni²⁺by the way of Fenton reaction and flocculation together is the best.On the condition of the optimal solution,the removal rates of DMP and Ni²⁺reach 100%and 14.31%respectively after Fenton reaction.The removal rates of DMP?COD and Ni²⁺reach 100%?65.80%and 99.08%respectively,and the concentrations of COD and Ni²⁺with the outlet are145.2mg/L and 0.10mg/L after Fenton reaction and flocculation together.The study on the Fenton reaction's synergy of flocculation process is considered by using indirect measurement.The removal rates of COD?Ni²⁺?Fe²⁺and Fe³⁺are respective 26.87%?80.32%?50.85%and92.53%in the flocculation process.The varying pattern of?OH and Fe in Fenton reaction of distilled water system and DMP system is studied.We can draw the conclusion that?OH in two kinds of system change rapidly and the concentrations of?OH go down greatly in the initial reaction stage,and then the variation trend is relative stable.The concentration of?OH in DMP system is much smaller than that in distilled water system.The concentration of Fe²⁺in Fenton reaction system has an big effect on?OH.The variation trends of Fe²⁺and?OH are similar.The concentrations of Fe²⁺decline greatly and remain stable relatively.And the concentrations of Fe³⁺increase greatly and remain stable relatively.We study part of the possible intermediate products in Fenton reaction within 60min and speculate the Fenton degradation pathway of DMP by the way of ESI-MS and APCI-MS.We can know that the intermediate products include hydrolysates?hydroxylation products?benzene ring substituting products?homologue products andopening loop small molecular products generally,such as phthalic acid?1,8-dihydroxy methoxy benzene?the hydroxy methyl phthalate?DEP?succinic acid and so on.The?OH in the Fenton reaction can attack carbon atoms both in the benzene ring and side chain connected to the benzene ring.And then some organic intermediate products with benzene ring generate.These intermediate products'benzene rings break down and they come to be opening loop small molecular products under the attack of?OH.Finally,these products mineralize to be H₂O and CO₂.