Study On Fenton Reaction Sludge Reduction And Comprehensive Treatment Of Solid Waste Containing Manganese

Fenton reaction is one of the most successful Advanced Oxidation Technologies?AOPs?.Because of the advantage of high efficiency,simple process,low cost and reagent toxicity,Fenton reaction has been widely used to degrade various refractory substances in wastewater.Currently,the main problem is the large sludge produced in the Fenton process,and reducing sludge reduction can be achieved by increasing its efficiency.The wastewater produced by the co-operative enterprise contains refractory substances such as benzimidazole,which can be degraded by the Fenton reaction.In this paper,the 2-?a-Hydroxyethyl?benzimidazole?HEBZ?was used as substrate and the Fenton sludge reduction was achieved by using the uniform deceleration feeding method for the first time according to the reaction mechanism.The effects of uniform deceleration feeding?ferrous and hydrogen peroxide?on the Fenton reaction efficiency were investigated via measuring the yield of hydroxyl radical?·OH?and the chemical oxygen demand?COD?removal rate.Compared with one-time feeding and uniform feeding,the total concentration of·OH was the highest under the same conditions,reaching 247.77?M?the other two modes was 188.52?M and 221.52?M,respectively?,and the COD removal rate was 79.3%during the uniform deceleration feeding?the other two modes was 60.7%and 72.1%,respectively?.The degrading pathway of HEBZ was detected by UV-vis absorption spectra?UV-vis?,photoluminescence spectra?PL?,Fourier transform infrared spectroscopy?FTIR?,high performance liquid phase?HPLC?and gas chromatography mass spectrometry?GC-MS?.As a result,the HEBZ was ultimately decomposed into three small molecules?2-Hydroxypropylamine,Oxalic acid,2-Hydroxypropamide?,and this process conformed to the first order kinetics.This research is of great significance for the application of Fenton reaction in wastewater treatment.In order to deal with a large amount of manganese dioxide?MnO₂?/potassium salt/organic matter mixed solid waste,the acid-water comprehensive treatment process was designed to recover MnO₂ products according to the electrode potential of manganese salt.Orthogonal experiments were conducted to optimize the technological conditions such as water quantity,acid amount,sulfate content,temperature and time.In the optimum process conditions,when one ton of manganese dioxide mixed solid waste was handled,0.334 tons of excellent grade pure manganese dioxide products with content of 87.3%,0.009 tons of trimanganese tetraoxide?Mn₃O₄?product with content of 97.01%and 1.37 tons potassium sulfate?K₂SO₄?product with content of 92.4%can be obtained.The estimated cost of industrialization indicates that this process provides a net profit of 7,934 yuan/ton of manganese dioxide mixed solid waste for the company,which not only realizes the utilization of solid waste resources,but also increases the economic benefits.The above process has completed the pilot test.