| With the increase of the national demand for fuel,the refinery product greatly used in the alkylation processes to produce alkylated oils to meet the demand.The 98%sulfuric acid was used as a catalyst when use the alkylation unit to produce a high-octane alkylated gasoline,and the alkylated waste sulfuric acid was produced during the process,containing a large amount of organics,bring great harm to the ecological environment.In order to make the alkylated waste sulfuric acid to be treated of resource and harmless,the organics in the alkylated waste sulfuric acid were oxidative degradation by the natural manganese ore,and a combined treatment of Mn02/activated carbon(AC)was developed to further oxidative-degradation and adsorption the organics in the manganese sulfate filtrate.And then the industrial grade MnS04 H20 were obtained after removal the impurities and high temperature crystallization.The slag produced during the reduction leaching stage were used as raw material to produce composite materials of lag/carbon through calcination-thermal reduction,and studied the lag/carbon as a catalyst to catalyze the hydrogen peroxide to oxide the organic dye.The main results are as follows:(1)The effect of reaction time and reaction temperature on the oxidative degradation of organics in alkylated waste sulfuric acid by pyrolusite was investigated and the TOC removal was used as the index,and the FT-TR,XRD,SEM and XPS was used to analyze the mechanism of oxidative degradation process.The experimental results shows,the TOC removal and manganese leaching efficiency were 46%and 16.44%,respectively.When the reaction temperature was 95? and the reaction time was 1 h.It can be seen from the FT-IR spectra of the solutions and slags at different reaction times that the pyrolusite can effectively mineralize organics in waste sulfuric acid into H20 and CO2.According to the results of the SEM analysis,the oxidative degradation of organics in alkylated waste sulfuric acid by pyrolusite was from the surface to the core.The results of the XPS,XRD and RM analysis shows,the MnO2 phase disappears during the reaction of pyrolusite with organics and an intermediate Mn2O3 is formed and the following sequence was suggested as the oxidative degradation of the organics by manganese oxide:Mn(?)?Mn(?)?Mn(?).In addition,pyrites was applied to extract Mn from the pyrolusite,and an Mn leaching efficiency of 98.31%was obtained under the optimized conditions of 4/1 liquid/solid ratio,350 rpm stirring speed,1.5 mol/L H2SO4 concentration,and 95? for 1 h in the first oxidative degradation stage and a molar ratio of FeS2/MnO2 of 0.55/1 for 4 h in the reduction leaching stage.The TOC removal was 58.53%,which is 12.35%higher than the previous stage.And the removal of the organics at this stage is oxidative degradation from the FT-IR spectra.(2)The MnO2 was used to deep oxidative degradation the solutions obtained from the reduction leaching stage,and a TOC removal of 66%was obtained under the optimized conditions of room temperature,pH of 2.3 and a mass ratio of Mn02/H2SO4 of 0.4 for 1.5 h.The reaction of Mn02 with the organics is oxidation degradation.The AC was used to further adsorption the organics in the solutions,and a TOC removal of 84.11%was obtained under the optimized conditions of room temperature and a mass ratio of AC/H2SO4 of 0.11 for 1 h.The organics removed by the AC is mainly through adsorption.(3)The MnS04-H20 product was obtained after removed the irons and heavy metals and crystallization at high temperature.The XRF,XRD and FTIR was used to analyse the the composition,crystalline phase,and chemical structure respectively.The results show that the percentage of MnS04-H20 in the product was>99.4%,containing less than 0.1%of iron and<0.4%of other impurities,which met the requirements of industrial manganese sulfate.The XRD results showed that the crystal structure of the product was the same as that of analytical grade MnS04 H20.and the FTIR spectra shows that the functional groups of the product and analytical grade MnS04-H20 were approximately the same,implying that no organics left in the product.(4)The slag generated during the reduction leaching stage was used as a raw material,and calcined by a muffle furnace to obtained a slag,and then the slag is mixed with soluble starch to calcined in a tube furnace to prepare a Fe3O4/C composite material.Different treatment methods were used to treat cationic dyes represented by Congo red and anionic dyes represented by saffron red T.The role of Fe3O4/C composites in the removal of dyes from H2O2 was analyzed.The results show that the removal effect of dyes is as follows:Fe3O4/C composite + H2O2>slag + H2O2>Fe3O4/C composite>slag>H2O2.Moreover,the Fenton-like system composed of Fe304/C composite + H2O2 has a dye removal rate of 95%under relatively neutral conditions. |
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