Co3S4/PES Catalytic Membrane Reactor for Oxidative Degradation of Rhodamine B in Water
Peroxymonosulfate(PMS)-based heterogeneous advanced oxidation processes are restricted in practice by the low activation efficiency of PMS and the utilization rate of reactive oxygen species(ROS).A Co3S4/PES catalytic membrane reactor(CMR)is constructed using a flowing synthesis approach,employing a metal-organic frameworks(MOFs)template exchange strategy with ZIF-67 as the precursor and a polyethersulf-one(PES)porous membrane as the substrate.The catalytic membrane is characterized by field-emission scanning electron microscopy(FESEM)and X-ray diffraction(XRD).The results indicated that Co3S4 nanoparticles with an average particle size of 23 nm are synthetically immobilized in situ within the pores of the PES membrane and are uniformly distributed along the membrane thickness,achieving an immobilization amount of 15.9％.The catalytic performance and reaction mechanism of the catalytic membrane are investigated by activating PMS to degrade a typical aro-matic organic compound,Rhodamine B(RhB),as a model pollutant.Experimental results demonstrate that the Co3S4/PES catalytic membrane ex-hibits a RhB degradation rate exceeding 90％under conditions of a RhB solution concentration of 20 mg·L-1,an initial solution pH of 7,a temper-ature of 25 ℃,and a membrane flux of 0.80 mL·min-1·cm-2(corresponding to a residence time of 0.68 s).The apparent reaction rate constant is 97.83 min-1,and the turnover frequency(TOF)reaches 489.15 L·min-1·g-1,both of which are 2 orders of magnitude higher than those achieved using the conventional suspension batch treatment mode with Co3S4 powder.The Co3S4/PES catalytic membrane also maintains good stability.The dispersion of membrane pores effectively prevents the aggregation of Co3S4 nanoparticles while confining the reaction within the micro-nano-scale membrane pores under flow-through conditions.This enhances mass transfer and contact between reactants and catalysts,accelerates PMS activation,and facilitates the efficient generation of singlet oxygen(1O2),which plays a dominant role in the rapid degradation of RhB.
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