Evaluation And Optimization Of Heterogeneous Fenton-like Reaction Catalyzed By Natural Mineral Materials

In recent years,more and more scholars turn attention to the heterogeneous Fenton method,because of its enhancement effect on the degradation of organic wastewaters.In this study,the natural mineral materials,Maifan stone and schorl were used as raw materials.In-situ growth of the magnetic nanoparticles Fe₃O₄ on the surface of Maifan stone was conducted using the liquid deposition method,which is named as MFM.The porous schorl ceramic?PSC?was successfully obtained based on the method of low temperature sintering.The obtained MFM and PSC sample was used as heterogeneous Fenton catalysts in the following studies.Many testing approaches were adopted for the characterization of the MFM and PSC samples,such as X ray diffraction?XRD?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,Fourier transform infrared spectroscopy?FT-IR?,Zeta potential and Vibration magnetometer?VSM?.The organic dyes,methyl orange?MO?and methylene blue?MB?were selected as the target pollutant to evaluate the heterogeneous Fenton reaction efficiency of MFM and PSC samples.The response surface method?RSM?was implemented for the optimization of the process parameters.For MFM heterogeneous catalyst,the results show that the Fe₃O₄ particles are uniformly distributed on the surface of Maifan stone and closely linked by chemical bonds with Maifan stone,and the Fe₃O₄ has strong magnetic properties,which can be rapidly separated in the solution by magnet.The MFM composite with 85 % Fe₃O₄ content synthesized at 95 oC for 3 h displays the optimum degradability for MO,and the decoloration ratio can reach to 84.76 % when the Fenton dosage is 1 g/L.The performance evaluation results show that the MO decolorization rate first increases and then decreases with the increase of initial pH value of solution or the concentration of H₂O₂,the decolorization of MFM gradually improves with the increase of catalyst dosage or reaction temperature,and the decolorization rate forMO gradually declines with the rise of initial dye concentration.RSM optimization analysis illustrates that the optimal degradation parameters for MFM is 3.1 of pH value,14.98 mM of H₂O₂ concentration,2.13 g/L of dosage catalyst and 120 min of reaction time.The actual and predictive MO decolorization rate are 81% and81.75 %,respectively,which the relative error is 0.75 %,indicating that the model has high reliability.For PSC heterogeneous catalyst,the results show that the porous schorl ceramic presentes the porous surface.The performance evaluation results displays that the MB decolorization rate first increases and then decreases with the increase of initial pH value of solution or the concentration of H₂O₂,the decolorization of PSC gradually improves with the increase of catalyst dosage or reaction temperature,and the decolorization rate for MB gradually declines with the rise of initial dye concentration.RSM optimization analysis show that the optimal degradation parameters for for PSC is 2.41 of pH value,9.85 mM of H₂O₂ concentration,6.98g/L of catalyst and 99 min of reaction time.The actual MB decolorization ratio was99.65 %,and the relative error is only 0.4 % compared with the predictive value of100.05 %,indicating that the model holds the high accuracy and reliability.