Research On The Application Of Coagulation-conductive Membrane Filtration In The Treatment Of Slightly Polluted Surface Wate

Membrane separation technology has been widely used in the treatment of micro-polluted surface water.Among them,the microfiltration and ultrafiltration membrane technologies commonly used in water plants have shortcomings such as low removal efficiency of dissolved pollutants,and membrane fouling has a significant impact on the efficiency of use.In this study,conductive membranes based on ultrafiltration hollow fiber membranes were prepared,and the Coagulation-Electric Ultrafiltration membrane Filtration（C-EUF）process was proposed to be used in the treatment of micro-polluted surface water to improve the removal efficiency of dissolved organic pollutants and alleviate the Membrane fouling improves operating efficiency.The C-EUF process and the Coagulation Ultrafiltration membrane Filtration（C-UF）process were compared and studied,the differences in the pollutant removal effects of the C-EUF process and the C-UF process were analyzed,and the effect of coagulation membrane filtration and electrochemical oxidation on pollution in the electric field was explored.The influence of the removal effect of the material was optimized,and the process parameters suitable for C-EUF operation were optimized.The optimal operating process conditions of C-EUF were determined in the experiment:Fe²⁺(10mg L^-1)+Fe³⁺(20mg L^-1),voltage 2V,conductive membrane flux25 L m^-2h^-1.Studies have shown that all pollutant indicators in the effluent of the C-EUF process are lower than those of the C-UF process.The C-EUF process generates hydrogen peroxide through the reaction of dissolved oxygen,hydrogen ions and electrons in the solution;obtains electrons from ferric iron and reduces to ferrous iron;ferrous iron and hydrogen peroxide undergo Fenton reaction to generate hydroxyl radicals.Hydroxyl radicals and oxidizing substances such as hydrogen peroxide degrade and mineralize organic pollutants to achieve the purpose of electrochemical reaction removal.At the same time,the hydrogen peroxide and hydroxyl radicals generated by the electrochemical reaction can improve the utilization rate of coagulation hydrolysis products,and the electric field can enhance the collision efficiency of charged particles.The resulting flocs have a larger specific surface area and more active sites,reducing the floc particle size and increasing the floc fractal dimension;the coagulation efficiency of pollutant removal is improved.In the continuous operation of the C-EUF process,the floc formation,crushing and regeneration stages are more conducive to the removal of pollutants than the C-UF floc.The membrane fouling status of C-EUF process and C-UF process in continuous operation was compared and studied,the types of membrane fouling in C-EUF and C-UF process were judged,and the ways of alleviating membrane fouling in C-EUF process were analyzed.The results show that the dominant mechanism of membrane fouling in the C-EUF process is filter cake clogging in the first 5 h;blocked.The C-EUF process can alleviate the pollution of the filter cake layer through the polarization of the coagulation solution flocs and the filter cake layer and the electrochemical oxidation of the electric field;through the electrochemical oxidation reaction and the electric field repulsion,the membrane pore pollution can be alleviated;by reducing the concentration difference The method of polarizing pollution and raising the Zeta potential of the coagulation solution can alleviate the pollution of the coagulation solution.The acquisition of the effect and mechanism of membrane fouling mitigation in C-EUF provides a reference for further mitigation of membrane fouling.