Preparation Of CoMoO₄ Multifunctional Separation Membrane And Its Synergistic Persulfate Activation For Dye Wastewater Treatmen

AOPs based on SO₄^·-have attracted extensive research because of their strong oxidation ability and good selectivity.Cobalt based compounds are recognized as the best catalysts for PMS activation,but their catalytic efficiency is still limited by the kinetic rate of Co（Ⅲ）/Co（Ⅱ）cycle.In addition,heterogeneous catalytic PMS system also faces some problems,such as difficult recovery of catalyst and slow mass transfer rate of pollutants in liquid-solid phase.In this thesis,CoMoO₄nanorods were designed and synthesized.The synergistic effect between Mo and co bimetallic elements was used to promote the Co（Ⅲ）/Co（Ⅱ）cycle,so as to improve the activation efficiency of PMS.CoMoO₄/rGO complex was loaded on the surface of organic filter membrane as a functional layer to form a multifunctional separation membrane with the ability of activating PMS and filtering at the same time.The membrane is used as the carrier to solve the problem of catalyst recovery.The filtration process strengthens the mass transfer of pollutants and PMS between liquid phase and solid catalyst,so as to show good water treatment performance.The specific research contents and results are as follows:（1）CoMoO₄nanorods were synthesized by one-step hydrothermal method.The performance of CoMoO₄nanorods in activating PMS was investigated with MB as the target pollutant.The experimental results show that when the dosage of CoMoO₄nanorods is 0.1g/L,the concentration of PMS is 0.8mmol/L and in the neutral environment（p H=7）,the CoMoO₄/PMS system can completely degrade 50mg/L MB in 20 minutes.After five cycle experiments,the degradation rate of MB can still be maintained above 85%,which proves that CoMoO₄has excellent stability.The free radical capture experiment shows that the surface free radical is the main ROS of the system,and Mo（Ⅴ）plays a key role in promoting Co（Ⅲ）/Co（Ⅱ）cycle in the catalytic process.（2）It was synthesized by one-step hydrothermal method CoMoO₄@rGO multifunctional separation membrane.The performance of the CoMoO₄@rGO multifunctional separation membrane was investigated by filtration of organic solution containing PMS.The experimental results show when the doping amount of rGO is 1wt%,PMS=0.3mmol/L,the functional layer load is 0.1g,the multifunctional separation membrane achieves the best performance.The catalytic membrane can maintain good performance in the drive pressure P≤2.5×10^-2MPa and wide p H range（3～11）.After continuous filtration of 8 cycles MB/PMS solution,the removal rate of MB can still reach 90%,which proves that the CoMoO₄@rGO catalytic membrane has good stability.Taking HA as the target,the anti pollution performance of the membrane was evaluated.The results showed that the introduction of PMS into the system could alleviate the decline of water flux caused by membrane pollution to a great extent.It is proved that the multifunctional separation membrane has good anti membrane fouling ability.The free radical capture experiment proved that the degradation of MB was completed by the surface free radical path dominated by CoMoO₄and the non free radical path dominated by rGO.