The Preparation Of The Modificated Palygorskite Load With Fe-Mn Catalyst And Its Application For Dyeing Wastewater Treatment Combined With Ozone

The annual dyeing wastewater emissions in Zhejiang Province account for one of third of the total dyeing wastewater amount of our country,and is the largest dyeing wastewater discharge area in China.The Chemical Oxygen Demand(COD)emissions of dyeing waster is the first place in Zhejiang of the industry.New environmental laws make the emission standard of COD more strict in the dyeing and printing industry,the traditional wastewater treatment technology has been difficult to meet the new national wastewater discharge standard as the low removal rate of COD and the high price.Therefore,to seek and develop efficient and economical treatment technology of dyeing wastewater has an important significance.The raw palygorskite resources are abundant in our country and the price is cheaper than the traditional vector like activated carbon and rare-earth-containing.Therefore,the raw palygorskite was used as a raw material for catalyst carrier in the paper.The palygorskite was loaded on the active components of Fe3+ and Mn2+ by sol-gel method after purification and modification.So the new catalyst was be development,and treatment of methyl orange as the simulated wastewater was studied by the catalyst combined with ozone.The research contents are mainly divided into the preparation and characterization of the catalyst,the treatment of printing and dyeing wastewater,ozone treatment,catalyst / ozone and the mechanism of the treatment of printing and dyeing wastewater.The effects of the kind of acid,the time,acid concentration,the temperature and other factors on the influence of acid modified of palygorskite were investigated;The effects of ozone oxidation time,p H and the dosage of ozone on treatment of methyl orange wastewater by ozonation was investigated;Ozone oxidation time,p H,the dosage of ozone,the dosage of catalyst,the reuse times of catalyst and other factors on the load effect of palygorskite ozone treatment of methyl orange wastewater were investigated;Effects of ozone,palygorskite / ozone and purified palygorskite / ozone and acid modified palygorskite / ozone,ozone / palygorskite load synergistic effect of five kinds of system of treatment of dyeing wastewater by ozone,ozone / catalysis were investigated;Kinetics of methyl orange wastewater and radical masking experiments were investigated,to verify the main way of the load of palygorskite and ozone synergistic treatment of methyl orange wastewater.After characterization by BET,XRD,SEM and other means,it was found that the specific surface area of the palygorskite was increased by 92.3 m2/g,the characteristic peak of impurity was disappeared in XRD map,and the crystal was loose and the pores were opened.It was showed that the best modification conditions: nitric acid with the concentration of 2 mol/L,modification time of 2 h,and the modification temperature of 40°C.Choose the modified palygorskite as the vector of the load.The surface area and pore volume of the modified palygorskite continue to increase.The XRD figure showed some peak which was behalf of Fe2O3 and Mn O2 appeared after loaded,and the crystal is compact,which indicated that the active components were well loaded.The effects of the ozonation time,p H,and the ozone dosage on the single ozone treatment of the methyl orange were studied.The study found that under the reaction conditions of the p H value of 3,ozone dosage of 2 g/h,the removal rates of color and COD reached 99.9% and 60.4% after 30 min,respectively.The combined treatment with loaded palygorskite and ozone were studied on the effect of the ozonation time,p H,the ozone dosage and the catalyst dosage.The treatment using methyl orange as simulated wastewater showed that under the reaction conditions of the p H of 3,ozone dosage of 2 g/h,and the catalyst dosage of 0.6 g/L,the removal percentages of color and COD reached 100.0% and 92.5% after 30 min,respectively.Comparison of treatment in dyeing wastewater by synergistic action of the different stages of palygorskite and ozone.Like ozone,palygorskite/ozone,purified palygorskite/ozone,modified palygorskite/ozone and loaded palygorskite/ozone,the final COD removal of methyl orange are: ozone < modified palygorskite/ozone < palygorskite / ozone < purified palygorskite/ ozone < loaded palygorskite/ozone.The experiment confirmed that the introduction of palygorskite could significantly increase the treatment effect of ozone on methyl orange.Through the research on the mechanism of ozone,loaded palygorskite / ozone oxidation of methyl orange simulated wastewater,and confirmed the degradation of methyl orange wastewater both in line with the first-order kinetics model,and the process of ozone and ozone catalytic oxidation of methyl orange wastewater following radical oxidation mechanism.After the methyl orange simulated wastewater treat by ozone and a self-made modified palygorskite supported Fe-Mn catalyst,the utilization rate of ozone was improved,mineralization rate and COD removal rate of wastewater is also greatly improved,the system has a certain guiding significance for the application of advanced ozone oxidation technology in wastewater,and has broad application prospects.