Study Of The Aeration Degradation Mechanism And The Content Determination Of Polyacrylamide In The Sewage Containing Polymer

At present, the existence of oil and suspended solids is the main factor restricting the oily sewage treatment. We need to establish the content determination of polyacrylamide, explore the optimal aeration condition to deal with oily wastewater effectively and the aeration degradation mechanism of polyacrylamide to deal with oily wastewater effectively.Firstly, we studied comprehensively the three content determination of polyacrylamide in the sewage containing polymer:Starch-cadmium, Turbidity method, UV spectrophotometry, and took methodological evaluation for each method. Starch-cadmium has good linearity in the range of 0-60 mg/L provided correlation coefficients (R2=0.9926); the average recovery rate between 97.36%and 103.68%, RSD of precision was from 2.37%to 3.38%; RSD of Repeatability test was 4.48%. Turbidity method has good linearity in the range of 0-200mg/L provided correlation coefficients (R2=0.988); the average recovery rate between 95.60%and 103.68%, RSD of precision was from 2.26% to 4.50%; RSD of Repeatability test was 4.64%. UV spectrophotometry has good linearity in the range of 0-300mg/L provided correlation coefficients (R2=0.9953); the average recovery rate between 95.25% and 104.72%, RSD of precision was from 2.40%to 4.22%; RSD of Repeatability test was 2.47%. The experimental results demonstrate that these three methods have been successfully applied to determine the content of polyacrylamide in the sewage containing polymer.Secondly, experimental study shows that even limited aeration can make the effect of oily sewage treatment after aeration best. Therefore, we need to fully explore different aeration conditions, such as the optimal dehydrating agent and static placing time after adding dehydrating agent, aeration gas, experiment device, temperature, the aeration volume and time. The results show that the optimal aeration conditions:static placing time after adding dehydrating agent for 40 min, aeration time for 40-50min, aeration air volume for 4-5L/min, experimental apparatus for diameter/height ratio of 1/4, aeration temperature for 40-50℃ and conditions are suitable for the vast majority of oil-bearing sewage.Finally, GC-MS and High Performance Liquid Chromatography (HPLC) analyze the extract and aqueous solution of polyacrylamide after aeration:the results show that parts of polyacrylamide degrade small molecule monomer acrylamide (AM) in the process of aeration. Solution viscosity has a tendency to reduce after aeration, provide further evidence for the degradation of polyacrylamide after aeration. So it proves oxidative degradation mechanisms exist in aeration process.Contrast the analysis before and after polyacrylamide aeration by transmission electron microscopy (TEM), parts of polyacrylamide change after aeration, Reunited polyacrylamide becomes small and adheres to some of the suspended solids. The results showed that polyacrylamide occur partial oxidation degradation after-aeration, long-strand rupture lead to that polyacrylamide aggregates become smaller; meanwhile, polyacrylamide will adhere to some suspended solids and oil and floate in the stripping effect. Experimental results show that the polyacrylamide were significantly reduced after aeration, and there is more consistent correspondence with the decrease of oil content and suspended solids content after aeration, indicating the polyacrylamide in polymer-containing wastewater have important synergies with aeration oil and suspended solids.